Broadcast Band DXing
Battery & Antenna Adapters - http://www.prc68.com
Seperate Computer web page - PDA
Electronic Construction Techniques - point to point wiring with vacuum tubes to multilayer boards with ASICs
Frequency Assignments - ULF to SHF
General Electronics - LEDs -
Ham Radio - ICOM 706
HF Propagation - RCS-5A Chirp Sounder - G3PLX Chirp method using the EVM5600DSP -
Military Electronics Information - Outdoor Intrusion Detectors - Squad Radios
Military Field & Technical Manuals - How to Get On Line - SEPERATE WEB PAGE
PC Based O-scope -
Satellite Navigation -Sputnik - Transit -
Global Positioning System (GPS)Differential GPS Post Processing
Stanford Telecom 5001A Navstar Test Transmitter page -Motorola GPS Rcvrs -
Surplus Electronic Equipment
Telephone (Military, Cell, Satellite)
Rack and Stack SystemsNews Groups: sci.electronics.basics & sci.electronics.cad & sci.electronics.components & sci.electronics.equipment & sci.electronics.misc & sci.electronics.repair
My main interest is in propagation and in particular chip sounders. See the September '93 issue of Popular Communications article "Monitoring the World's ionosounds" by Andrew W. Clegg. This is about the BR Communications (now part of TCI/BR in Sunnyvale, CA) chirp sounders. Another aspect of High Frequency listening is called utility stations, these are all stations other than commercial broadcasters. A huge list of radio related web links. Spy numbers stations have been around for many decades with all kinds of speculation about what they are doing. The Spooks Newsletter has some remarks on the numbers stations as well as military related utility stations. Note that on one of the audio recordings of a numbers station you can hear tones in the background. This may indicate that the voice is a cover to allow tuning to the frequency, but the real communication is taking place using a modulation scheme that can not be heard on a conventional radio (like with a GRA-71 code burst transmission). I currently have an old McKay Dymec DR33 (Photo) (review). 541-751-0108 This is a mid nineteen seventies vintage digital tuning receiver that is built with standard components, no ASIC or custom circuits. It has a knob for tuning each of the frequency digits and is therefore good for following the chip sounders. My dream receiver was the WJ HF-1000 or one of the military versions in theWJ 8712 series. These Watkins Johnson receivers use Digital Signal Processing (DSP) to do the IF filtering and signal demodulation. They are capable of hearing signals that are very weak and undetectable with conventional analog type receivers and can be controlled by a remote computer. Japan Radio Corporation is introducing it's NRD-545. This receiver uses DSP for IF filtering like the HF-1000 but has an 18 bit A/D converter instead of a 16 bit converter adding some dynamic range. It also has a DSP IF filter with variable bandwidth. There is an optional CHE-199 card that increases the frequency coverage to 2 GHz.
It is interesting that Robert B Fenwick was involved with the BR Communications chirp sounder equipment and his brother Richard C. Fenwick working at Electrospace Systems in TX developed the time delay antenna system mentioned below.
The Sounds of the Various Digital Radio-Communications Protocols - includes Over The Horizon (OTH) Radar
Digital Modes Samples
RSED Over-The-Horizon Radar - some information on OTH-B
News Group: rec.radio.shortwave
Digital Modes includes RTTY - North American Data Communications Museum -
Ten-Tec - RX-320 DSP PC Receiver - N2JEU's Web Controlled Shortwave Radios - SWBC DX & Listening Pages - Skytronicscontrol box for 320 (and maybe Racal RA-6790) - RX-320 Handheld Controller - 68HC11 based, RX 320 Page by Gerry,
Titanex - High-Tech HF Antennas - V160S vertical - with custom tuner would be good for chirp sounder receiver
Mediumwave Associates - AM and Shortwave Tube Radio Kits
Passport to World Band Radio -
International Radio Club of America (IRCA) -
National Radio Club -
FineWare - control software and SWBC lists
Bonito - RadioCom 5.0 - Software to decode digital modes, about US$200
HF-Fax by Marius
International Listening Guide (ILG) - (free password) database of station information, Antenna Corner,
Clandestine Radio Watch - QSL Information, Clandestine Radio Watch, Pirate Radio Address List
Clandestine radio Intel Web -
MVSWLC Clandestine Page -
Clandestine and Opposition Shortwave Radio Stations -
Workbench Shortwave publications -
Interference-Reducing Antennas from VOA - interesting Al foil, a second whipand some plywood for portable receiver
AOR (UK) Ltd - AORUSA -
Development of Over-the-Horizon Radar in Australia -
Shortwave Radio web Ring -
Build Your Own High Performance Radio Receiver by Gary Pershin
The Number of the Beast - the beginnings of Carnivore and Echelon
KWCOLOR THE REAL STORY OF WARRENTON By "Jaywalker" PART I - October 18, 2000,
Raytheon Systems Canada Ltd., a subsidiary of Raytheon Company HF SWR-503 - shore-based, long-range HF Surface Wave Radar "Buzzer"
Alfa Lima International - pirate info
WJ8888 - home brew interface
Audio Squelch (Voice Operated Squelch)Ten-Tec 1064 Smart Squelch can be added to receivers that don't have built in squelch, works on audio signal so you don't need to get into the agc circuit.
A Voice Squelch for HF and Other SSB Applications -
Numbers Stations898 Verbindingsbataljon RadioCie - sound clips
A visit to Jupiter/Tequesta – Intrigue Revisited! - Jan 2001 - new site & Netscape viewable -
Conet Project - samples of numbers stations & 4 CD set of data (on line for personal use) - ENIGMA Newsletter -European Numbers Information Gathering and Monitoring Association. - info sheet - Enigma web page
CNVI - Index of /radio/skeds/output -
Covert Comms - collection of monthly mag articles
Espionage Is in the Air - "Secret Signals, The Euronumbers Mystery" by Simon Mason
http://www.spynumbers.com by Chris Smolinski
Intrigue Revisited! by Eric Wilson
Mysterious Sites around the world - numbers stations or similar
New Star Broadcasting Station - China or Taiwan numbers station
NPR program on numbers stations: Atencion: Seis Siete Tres Siete Cero:The Shortwave Numbers Mystery -
Numbers & Oddities -
Radio Station U V B 7 6 "The Buzzer" by Jan Michalski
Ryan Grabow's Numbers Station Page -
Simon Collings: Articles -
Simon Mason - Shortwave Espionage - "Secret Signals, The Euronumbers Mystery" 1991 out of print
Tequesta almost gives up her secrets by Havana Moon
Tomonori Izumi - Babble Fish Translator (set for Japanese to English)
Radio Intrigue with Don Schimmel - someof what you hear is training
USA Today - Spies hide in strange shortwave signals -
WUN - Recent Numbers Stations - I find the "utilities" stations more interesting than conventional voice stations
XPH - Babble Fish Translator (set for Spanish to English)
Low Power Broadcasting
Brooke's NRD-545 pageNews Group: rec.radio.shortwave
British Military Communications
DXing.com - receiver reports -
Sherwood Engineering Inc. - Reveiver Test Data -
The R390A/URR - DSP ``Smart" Audio Detection -
Kneisner + Doering Elektronik GmbH - KWZ30 -
Utility World - article in Monitoring Times - Spook Radio -
Worldwide Utility News (WUN) -
Shortwave Radio Stations of the World - with links to the station
Palstar Inc. - R30 SW receiver
MFJ - many ham radio & SW boxes
shoc - high end dealer in Switzerland & Wavecom decoder dealer
Broadcast Band DXingNow that I have the NRD-545 I am finding a lot of AM and FM stations that just were not heard prior to this.
Broadcast Station Location Page - AM, FM, TV & more search engine, nice resource
Early Review - with a color brochure as a pdf document
Universal Radio NRD-545 page -
Lowe Technical Review of the NRD-545 - Lowe also carries the HF-1000 and in this review "...very best HF receiver I've ever had the pleasure of using..."
Monitoring Times - a Grove publication
International Radio Club of America (IRCA) -
Amateur AM page - BC610 transmitter mods -
Beginner's Guide to Low Power Broadcasting -
AM Antennas by Bruce Carter - EE Links -
News group - rec.radio.broadcasting
BE Radio magazine - Shielded AM loop -
Medium Wave Circle -
AM Stereo -
Radio Homepage of Martin Schöch / SRS Germany - Clandestine Radio Watch, Pirate Radio
The "Beam and null switch step steerable antenna system" U.S. patent 4063250 by Richard C. Fenwick is a great explanation of time delay beam steering. The "phased array" antenna is a special case of the time delay steered antenna. Note that in the time delay steered array the direction of the maximum lobe is frequency independent whereas in the phased array it is a direct function of frequency.
Fenwick also patented a "Three band monopole antenna" 4145693 that was sold with the beam steering network by "Omega-T".
I have seen references that say a loop antenna will work as well in a forest as on open ground. Since I am in a forest this needs more research.Ian Cummings -Wullenweber/CDDA Antenna Homepage - nice coverage of the CDDA
Servo RDF errors page - Aircraft band (VHF) 16 element Quasi-Doppler system low errors in the presence of reflections
Ferrite Rods & Use as antennas - Amidon
Omnidirectional Loop Antenna System - US 269509
antenneX - magazine
TCI International - has combined with BR Communications -
News Group: rec.amateur.antenna
A Wide-Aperture HF Direction-Finder With Sleeve Antennas - NRL Memorandum Report 843 -Unclassified (was Confidential) 20 Aug. 1958. Describes a 434 foot diameter array of 40 equally spaced sleeve antennas on a wire mesh ground 600 feet in diameter and 580 ground radials over 1,000 feet long. The array was complete just in time to track Sputnik on 20.005 Mc. This showed the need for a grounded screen inside the active antennas. It was added 16.5 feet back or on a 200 foot radius. Once the ground screen is added the name changes from Wullenweber to Elephant cage (maybe both are correct?). This system was used with a Goinonmeter that used a printed circuit to capactivitly couple the signal. It was motor driven. They also used delay lines (see the above patent) to form 40 separate beams that were fixed.
TowerTalk Reflector FAQ - Tower related rather than antennas
Publications on Antenna Simulations -
University of Surrey - Dr Jefferies - antenna theory -
Max-Gain Systems - fibergalss products for antenna construction, surplus stuff-
Antennas Service and Education by L. B. Cebik, W4RNL
Computer Controlled Phased Array by Jim Lux W6RMK
KMA Antennas - LPA
Amateur VerticalBencher - Butternut HF9V -US5016021: 12 and 17 meter adapter assembliesCushcraft - R7000 -
US4833483: Vertical antenna - automatic 10 band
US4785308: Antenna - 10, 15 & 20 meters
US4630060: Vertical antenna with decoupling sections for multiband operation - 8 band
US4593289: Multi-band dipole antenna with matching stubs - 20, 15 & 10 meters
US4259672: Multi-band vertical antenna - 20, 15 & 10 meters
US4222053: Multi-band vertical antenna - 20, 15 & 10 meters
US4209790: Vertical antenna with stub cancellation means - VHF
USD0288564: Antenna - design (for HF9V?) USD0277483: Antenna - DesignUS5600334: Mobile antenna mount -Hygain - vertical - DX88 -US4604628: Parasitic array with driven sleeve element - 10, 15 & 20 metersUni-Hat Corporation -Capactance Terminated Short Vertical Radiator (CTSVR) -
US4293955: Diversity reception system -US5835067 Short vertical 160 meter band antenna - Photo -Other DesignsUS4442436: Vertical antenna - 6 bands 80 to 10 meters
US4642650: Portable HF antenna -
US4829311: High impedance, base loaded, whip antenna -
TRW - US5652598: Charge collector equipped, open-sleeve antennas - maybe VHF or UHF many references
Motorola - US5231412: Sleeved monopole antenna -
The Aerospace Corporation - US4860020: Compact, wideband antenna system - 3:1 bandwidth
Mosley Electronics Inc.- US3653053: Multiband Monopole Antenna With Adjustable Tuning -
US4496952: Trap vertical antenna with parallel L-C circuits for broadbanding -
US5625367: Variable capacitance antenna for multiband reception and transmission -
US5048641: Van-mounted ladder assembly with concealed radio antennas -
US4535336: Antenna luggage rack
Arinc - US5767812: High efficiency, broadband, trapped antenna system - traps
Secretary of the Navy - US5600335: High-power broadband antenna -
Astron - US5111213: Broadband antenna - continuous coverage over the VLF, HF, VHF, and UHF - Interesting
L. Barker & Williamson, Inc. - US4423423: Broad bandwidth folded dipole antenna - balun & termination
Timetco Corporation - US4511898: Terminated inverted V antenna with matching transformer - 1/2 of B&W with center raised
Quadrifilar Helix.pdf - by W2DU
Chris Guenthner (DK9SQ)-Telescoping 10 meter mast & associated ham antennas -
Channel Master - home antennas -
KB7QHC - Discone & MUF information
Pennants & Flags - K6SE design
Tennamast - Antenna Masts -
US3564551 02/16/1971 Dipole Antenna with Electrically Tuned Ferrite Sleeve = CCD see Oct. 78, "73"
Superantennas.com - small size can be used for backpacking
Tennadyne - HF Log Periodic with a very good reputation
Kaeferlein (AMA) - Magnetic Transmitting Loop, High Q, uses motorized tuning cap
Gap Antenna Products - Vertical antennas with the feed point raised so that ground losses are minimized, no radials required
US3984834 Diagonally fed electric microstrip dipole ant - U.S. Navy, used by Trimble for AN/PSN-10 GPS ant.
DDRR Dr. J.M. Boyer
3151328 Open Ring Antenna 343/742; 343/744; 343/748; 343/752 DDRRHelical Antenna for circular polarization, H.A. Wheeler 2495399 Antenna System 343/749; 343/742; 343/828; 343/843; 343/848; 343/865; 343/895; 343/899
RE026196 Open Ring Antenna 343/742 Includes multiple caps for wider bandwidth
3247515 Low Profile Antenna 343/742; 343/743; 343/744 DDRR
3680135 Tunable Radio Antenna 343/742; 343/748; 343/750; 343/867
2955286 Plural Loop Antenna Having Ferrite Cores 343/742; 343/788
3447159 Diode Bandswitch Loop Antenna 343/742; 342/435; 343/788; 343/855; 455/188.1; 455/193.1; 455/275; D14/233
3564421 Ariel Arrays 455/274; 343/701; 343/728; 343/742; 343/867 amplified receiving loop
3619655 Noise Paralled Signal Seriesed Multistaged Amplifier 330/124D; 327/482; 343/742 used with LF, VLF loops
3671970 Switched Rhombic Automatic Direction Finding Antenna System and Apparatus 342/435; 343/739; 343/742; 343/744; 343/788; 343/895 Aircraft ADF
6538616 Cubic antenna March 25, 2003 343/788 ; 175/45; 342/459; 343/742; 343/867 - VLF loop construction
Direction FindingTaio-Musen Co. - direction finding antennas
MicroFinder Doppler -
Amateur Radio Direction Finding Web Ring -
How to Build a RDF-Unit -
Radio Direction Finding - Radio direction finding equipment for 144 MHz -
Adcock HF RDF by George (Russ) Andrews, K6BMG
CommercialKreco - VHF low and high, UHF, Diskcone
In part 15 of the FCC rules there is a provision for unlicensed operation in a number of frequency bands. One of these is 160 - 190 kHz. You are allowed a total feed plus antenna length of 15 meters (about 50 feet) and an input power of 1 Watt. I used a Palomar® Engineers longwave transmitter kit that used an adjustable powered iron core in a Lotz wire coil and AFAICR an IRF-510.
Since a high-Q antenna circuit is required the bandwidth limits the mode to very narrow band modes such as CW or narrow band digital modes. The Longwave Club of America is for "Lowfers". In order to get good results you need a high-Q coil. In order to learn about the subject of high-Q coils I spent a couple of years finding and reading out of print books about inductors and got a Boonton Model 160 Q-meter and did a great many experiments.
An interesting idea is to use a frequency converter like the Palomar to translate the lower frequencies up to 3.5 or 4.0 MHz (for zero frequency) and then use the NRD-545 receiver to take advantage of it's 10 Hz DSP based IF filter. This should allow the reception of signals that would otherwise be buried in the noise present in the much wider IF bandwidths of conventional receivers. Need to try this.
List Server - send mail to: email@example.com , leave the subject field blank, in the text enter: subscribe lofer<>Aerth Group - communications through the ground - Cave Communication Equipment -
Amidon - Ferrite Rods, Bars, Plates and Tubes and Iron Power, pot cores - and app notes
AMRAD Low Frequency - Modifying the RX320 Receiver for LF/VLF Operation - Active LF antenna covers 10 kHz - 30 MHz
BPSK Adventures Bill Cantrell, “TEXAS” & WD5CVG
Bryce's Lowfer Equipment -
Canadian Lowfer (Low Frequency Radio) Page -
Constructing a LowFER Antenna by Robert Bicking, W9RB
Cooner Wire - has Litz Wire but web site is just starting (213) 882-8311 when I bought from them
Dan's Small Parts and Kits -
Digital Signal Processing (DSP) - by Bill VE2IQ- Scientology -
Eric Vogel\Noumenon, Inc. - Whistler receiver, SID receiver, Rotating VLF Loop (by Bill Farmer) - good set of Links -
Exploring ULF-ELF and VLF radio band (below 22 kHz) - Reception of Submarine Communications Systems by IK1QFK
GW4ALG's 136 kHz Pages -
GWEN - These sites are going to be converted to GPS differential correction sites to serve the land mass of the CONUS.
High-Performance Low Frequency Converter by Tim Brannon, KF5CQ
IK1QFK Home Page: Exploring ULF-ELF and VLF radio band -
K3PGP ULF/VLF/MF Beacons -
Kiwa - Earth Monitor - 10 Hz to 15 kHz.
LF Engineering - active whips & other LW hardware (new site, nothing there 12/30/99)
Light Weight Beacon Part Number 123402 - seperate web page
Literature about 136kHz and related topics by ON7YD
Lyle Koehler, KØLR - This page is dedicated to LF experimenting and home brewing
MWS Wire Industries - Litz wire -
Navaid Information -
New England Electric Wire Corp - Litz wire manufacturer
New Zealand LF Scene -
Part 15 Operation and Beacon-Related Files - a number of LWCA articles
Receiver Sensitivity at LF - comparison test of premium receivers
Sample VLF Radio Signals - NASA site with spectrograms and sound files
Schedule for NDGPS Site Construction CY2000 - conversion from GWEN
Scientific American - Detecting the Earth's Electricity -
Secretary of the Air Force - US3984839: Low height VLF antenna system -
SM6LKM's home page - Ant imp circuit, Spectrogram radio version - 74HC4053 Longwave upconverter - PIC controlled longwave transmitter - 74HC4053 Longwave upconverter -
Southern Avionics Company - makes beacon transmitter systems
Spectrogram - PC sound card based audio spectogram
Submarine Communications Shore Infrastructure - also see SOSUS & the Glomar Explorer -
Thinking about Ideal Loops - 10 Hz to 1 MHz design
U.S. LF Beacon Database - Non-Directional-Beacons (NDB) at airports - LF Utility Stations - Longwave Online Resources -
Tour of NSS -
VK2ZTO Low Frequency and Below Experimentation Pages - ULF, ELF and VLF -
Weak Signals - a number of freeware waterfall programs for the PC
ZEVS, The Russian 82 Hz ELF Transmitter -
In the process of studding antennas and low frequency techniques I came across Nikola Tesla. He was a brilliant inventor. When he went to the U.S. patent office and applied for a single patent on an A.C. power generating and distribution system it was rejected and he was told to break it down into over a hundred separate patents.
In "The Colorado Springs Notebook" it can be seen that he shows photographs of all of what he was doing PRIOR to getting the antenna into a high-Q resonance mode of operation. He did this by top loading the antenna and using a small coil to tune the antenna. AFTER this he did not show photographs of the complete system. He had discovered high-Q resonance but did not understand it. Note that most "high school Tesla Coils" do not have enough capactive loading to get the Q up and are therefore just high voltage transformers operating at a Q near 1. A coil operating at self resonance has a Q of 1. To get high Q values the loading capacitance must be much larger than the self capacitance of the coil. Today there is much pseudo science associated with Tesla's name, but what Tesla did is amazing.
23 May 2005 - After Googling to see why 60 Hz was used I came up with multiple answers:
It also appears that Westinghouse had an A.C. power system consisting of a generator, transformers and street lights prior to Tesla. His system was more efficient than the Edison G.E. system of D.C. powered lights, but was lacking an A.C. motor.
- The one I remembered had to do with minimizing the cost of the copper and iron used in generators and motors. As the frequency goes higher less magnetic material is needed in a motor, generator or transformer. Note that aircraft A.C. systems are typically 400 cycles per second. This allows the dynomotors and transformers to use less iron and be lighter in weight. But as the frequency gets higher skin depth limits the effective current carrying capacity of a copper wire. Tesla used Litz wire in his coils at Colorado springs to get around this problem with operating frequencies in the hundreds of kc range.
- One said the frequency needed to be high enough to avoid flicker in electric lights. Note that movies run at 18 and 24 frames per second and don't flicker. A TV set uses 60 interlaced fields per second instead of a simple 30 frames per second to avoid flicker. So this seems like a consideration.
- One said that large generators of the time could only turn in the hundreds of revolutions per second so there was some limit, but I think the frequency can be higher than the RPM of the generator. But as the frequency gets higher there are phase delays associated with the inductance of the distribution grid. This may relate to two points on the grid being connected together even though they are different distances from the generator.
- It occurs to me that in applications where there are large amounts of power being transferred, like in electric trains, that the frequency is moved down to around 16 Hz. This allows copper wires to carry larger currents. The iron core weight penalty is much easier to take than the expense of Litz wire. If the skin depth is 8.57 mm for copper wire at 60 Hz then a wire twice this diameter or 0.675" dia is the largest single conductor that can efficiently carry 60 Hz power, if it's larger you're wasting copper. The common tables only go to OOOO gauge wire (0.46" dia) which makes sense since you don't want to be using a single conductor at 60 Hz much larger than that.
Nikola Tesla Colorado Springs Notes 1899 - 1900 by Nikola Tesla Museum, Beograd, Nolit, 1978, ISBN: 0913022268 see the Tesla Book Store
Nikola Tesla Page - This page seems to have all the Tesla links you could want.
Here are just a few of his patents I found when looking into electric motors:
------- Patents to Nicola Tesla May 1, 1888 -------
381968 Electromagnetic Motor, 310/102R
381969 " " 318/705 ; 318/700
381970 System of Electrical Distribution, 307/17
382279 Electromagnetic Motor,
382280 Electrical Transmission of Power, 318/750
382281 Electrical Transmission of Power, 318/700
382282 Method of Distributing and Converting Electrical Currents, 307/17
------- Patents to Nicola Tesla Dec 3, 1889 -------
416191 Electromagnetic Motor, Dec 3, 1889, 318/734
416192 Method of Operating Electromagnetic Motors, Dec 3, 1889
416193 Electromagnetic Motor, Dec 3, 1889 310/172 ; 318/781
416194 Electric Motor, Dec 3, 1889, 310/166
416195 Electromagnetic Motor, Dec 3, 1889
555190 Alternating Motor, N. Tesla, Feb 26, 1896,
645576 (Google)System of Transmission of Electrical Energy, N. Tesla, Mar 20 1900, filed Sep 2 1879, 375/259
This is THE patent for wireless communiction although most of it is framed for energy transmission.
You can learn a lot about what is going on in your community by listening to a scanner radio. It also can by used as a lab instrument if it has remote programming capability as does the ICOMR7000 (Photo). I have added an AGC DC output that I can read with my HP 34401 DMM by means of a LabVIEW and convert into input power in dBm. The program also controls the frequency and mode of the R7000.
Office of Spectrum Management - Freq Allocation Chart.pdf (can magnify and read), SPECTRUM USE SUMMARY 137 MHz - 10 GHz
News Group: rec.radio.scanner - alt.radio.scanner -
Strong Signals - scanner reviews and news + a scanner web ring
Scanners Unlimited - San Carlos, CA
Scanner Outlet - San Mateo, CA
Optoelectronics - Patent US5471402: Frequency counter - shown in ad for counter that sets freq of scanner.
AOR - hand held and desk top scanners
Alinco - wide band handheld and desk top scanners
Popular Communications - magazine
Grove Ent - many radios, accessories and publishes MT Times magazine
Nil-Jon - highest gain Omni 25-1300 MHz antenna is the HD-SCAN-WB-OMNI-F
Eavesdroppers - Decoding Software -
Probability of Intercept - a paper about the concept
When I was a boy a number of relatives gave me "Crystal Set Kits". A few years ago after learning about coils I made my own crystal set that could pick up about two dozen stations and the powerful ones could drive an antique horn speaker to room volume.
I spent a couple of years winding coils and testing them on a Boonton 160.
QQ is the Quality of an inductor and is the ratio of the inductave reactance to the resistance (XL / R). There are a number of components to the resistance.
- DC resistance of the wire depends on the gauge and length.
- AC resistance is effected by skin effect, as the frequency gets highter the resistance goes up in a linear manner.
Importance of minimizing Coil Self CapacitanceWhen winding a milti-turn coil (1) that's a single layer, like on a Quaker Oats box spacing the turns about 1 wire diameter works very well where there's an air gap between turns. But if you wind a coil where the conductor diameter is the same as the above coil but achieve the spacing by using the insulation the coil will have a much higher self capacitance.
In the above case if you wind two layers (coil 2) , the first left to right and the second right to left the self capacitance is very high. This is because the effective capacitance depends of both the voltage difference between any two turns and the mechanical capacitance between those same two turns. In the case of coil 1 the voltage between all adjacent turns is just V/(n-1) where n is the number of turns. But in the case of coil 2 the voltage between the left top turn and the left bottom turn is all of V so it's self capacitance is very high.
You can get around this by bank winding the coil. For example winding two turns on layer one, then one turn on top then one turn on the bottom etc. This keeps the voltage across adjacent turns down.
All of the above is very important since a coil operating at it's self resonant frequency has a Q of 1, no matter how it was made. (This is something that 99.99% of the Tesla coil builders don't get.) So in order to get high Q you need to load the coil with a capacitance that's substantially larger than the self capacitance. You can see the it's very important to not only wind the coil in such a way that the HF resistance is minimized but also in such a way that the self resonant frequency is as high as possible. PVC is not a good coil form because of this. The best forms come as close to looking like air as possible.
In order to determine where the coil losses are coming from you can plot the Q vs. frequency and look at the slope. This way you can see the difference between DC resistance (zero slope), skin effect (linear slope), dielectric loss (f^2 slope).
If I remember correctly when you differentiate Wheeleres equation it comes out that when D is about 2.54 times the length you get the most inductance for a given wire length on a lingle layer coil like (1) above. But most coil plans and the ones that came with crystal raios kits (I built many of these) got it backwards and the coils were about 2.5 times longer than the diameter (i.e. more like a toilet paper roll).
There is a Xtal Set Society that publishes a newsletter and some books on crystal sets.
Amateur Electronics Supply has Crystal Radio Kits.
Ben Tongue - Crystal Radio Set System Design, Measurement and Improvement -
Wenzel - Techlib - Crystal Radio Circuits -
Home Made Crystal Radio circa 1800? - very simple circuit diagram and "Foote Phila." crystal holder.
Crystal Radio Connections ...blending art and science
Crystal Radios - nice collection of links
Scott's Crystal Radios -
I have an old technician class license that only allows CW operation in the HF bands, not digital modes. In my opinion the morse code requirement is way out of date. The maritime CW distress frequency of 500 kHz has now been decommissioned as being obsolete, but the rules for a amateur radio license still require morse code to use the HF frequencies. I occasionally use 2 meter radios for voice and digital modes. The ARRL and the FCC propose to restructure the amateur radio licenses so that more people can use HF voice WITHOUT passing a code test.
Amateur Restructuring is Here: Three License Classes, One Code Speed - all code is now 5 wpm!
FCC Amateur Radio web page with restructruig news -
Software Systems Consulting - Weather from Satellites, HF fax & email - hardware & software
KB9JJA Heathkit HW-9 - my current HF rig in storage - KK4KF's Heathkit HW-7/8/9 - HW-9 Nearly Complete Guide to Mods by Gary L Surrency
News Groups: rec.radio.amateur.antenna & rec.radio.amateur.equipment & rec.radio.amateur.homebrew & rec.radio.amateur.space
Bob Bruninga - APRS - combines GPS & ham radio
Kenwood - amateur radio - TH-D7A 144/430 + TNC, VC-H1TV camera
..--.. - APRS information
Harry's Homebrew Homepage -
Amateur Electronic Supply (AES) -
Ham Radio Outlet (HRO) -
AC6V - lots of well organized links
No-Code Technician Ham Tests -
BAT, CAT & RAT - SF bay area clubs
SG Club - for SGC World 2020 tranceiver (no computer control at this time)
The R.F. Connection - wire, cable & connectors for RF and audio
HAL communications - RTTY & digital modes
HF Fax page -
Special Communications Systems (SCS) - HF digital mode hardware
HariFax IV - SSTV transmissions decoded with different modems and programs & has a ziped *.wav file for testing others
EasyDSP - DSP based image interface
DSPCOM - with 16x2 LCD display
My ICOM 706 MkII G web page -
Slinky Toys - used for some antenna designes
DK9SQ 46" to 33' Fiberglass mast made in Germany
Tokyo Hy-Power -
Radio Mods -
- Radio Direction Finding
I have had an interest in computers since grade school when only mainframe machines existed. My MSEE courses included all the computer classes that San Jose State had to offer. Also see my Rack and Stack Systemspage for HP Rocky Mountain Basic Workstations.
See my separate page for Personal Digital Assistants, hand size computers. I have not yet got one of these, but they are interesting. My interest would be connecting the PDA to other equipment like GPS, camera, radio, sensors, etc.
SWTP 6800 ComputerStarting with a SWTP Motorola 6800 microprocessor based system that came with no software and a wallet programming card I learned how to write directly in hex and later in assembly code. This computer always had the cover off because I was connecting some new I/O card or other hardware to it. In the end I had the luxury of two double sided 8" floppy disks and a TI 132 column character printer and a Lear Sigler "glass TTY" terminal. The Motorola 6800, 6809, 68000 series of chips was way ahead of the Intel chips in their elegant instruction set and in their capability. The story I heard is that Motorola when asked by IBM to supply chips for their "PC" said that they were already too busy building chips for all the GM cars so IBM ended up with Intel chips. At the "Home Brew Computer Club" that met at the SLAC auditorium I got the TTY paper tapes with the Motorola assembler and editor. Later Tom Ptiman used these to write a version of "Tiny Basic" based on an article in Dr. Dobbs Journal. In exchange for the use of my equipment, I got a copy of Tiny basic.
Later Tom worked with AMD to make a microcontroller with Tiny Basic as it's operating language.
One of the key things about the Motorola 6800 (& newer chips) is that you can write relocatable code. That means that a code module will run if placed in a memory location other than that where it was written. Reusable, Recursive, Relocatable are all very desirable features of software. I soon replaced the Motorola BIOS ROM chip with one from Microware that contained a Real Time Operation system. This was possible with Motorola chips but not with Intel chips because of the RRR power of the Motorola chips. This is the reason that the Apple and HP workstations computers were more capable than the Intel based machines.
Radio Shack - Color Computer (CoCo)This was based on the Motoroa 6809. There was an application note that had the circuit diagram. It used a standard NTCS monitor or TV as the display device. I have the 4 slot expansion accessory and a number third party boards. The operation system that is stored in ROM is copied into RAM and run from the RAM. This allows other operating systems to be used. I used OS-9 by Microware.
Home Office - HP Pavilion 8380I got this at my local Staples office supply store. Since I am in the Wine country there is not a local Fry's store and I like the ability of being able to get local support. The good thing about this computer is that the case is very easy to open to insert cards. The bad thing is the lack of any technical documentation.
Feb 2004 - Main computer was built to order. Large tower case. 2.4 GHz Pentium CPU. Removable hard drives. Motherboard supports serial hard drives, but have not yet installed them. Sony DRU-540 DVD/CD-ROM burner.
Sony VAIO Z505SXI choose this model because it has an IEEE-1394 "Firewire" interface that has the potintial to control a Hard Disk Drive Head test system.
Sony - VIAO- Z505SX -
Firewire Stuff - Cameras -
USB Stuff -
Laptop on Commercial AircraftNone of these companies have an adapter for the Sony VAIO Z505SX, which is the one I have.
Primex - EMPOWER™ - makes the special connector
Absolute Battery Network - EmPower In-Flight Power Adapters -
Mobility Electronics - EasiPower - both auto & aircraft
Universal Sources, Inc. (USI) - Power Charger - # AP-8520 for Sony 505 about $100
Xtend Micro Products, Inc. - PowerXtender -
PIC MicrocontrolersNow my interest is in the Microchip PIC series of Microcontrolers. These are very capable chips at low cost. I prefer to use their native assembly language although a friend likes the pseudo Intel commands that the Paralax compiler supports. There are two kinds of user programmable micro controllers: (1) the classical EPROM type that has a quartz window so that it can be erased by using a UV lamp, and, (2) then newer EEPROM "flash" type that is in a conventional epoxy or ceramic package, these are electrically erased and are much easier to use. This is the reason for the popularity of the 16F84 series. I have a project on the back burner to use a PIC to control an oscillator based on the timing signals from the Motorola VP+ GPS receiver. This is similar to the project by Brooks Shera W5OJM that appeared in the July '98 issue of QST Amateur Radio magazine.
Hardware to read Motorola binary data and display date, day of week and time on LCD.
Main Components: 16F84-10/P, LCD with 44780 controller, 10.0 MHz oscillator, MAX 232N, 78M05
The LCD was surplus, maybe because the 14 pin header was installed on the wrong side of the PCB, easy to fix.
Nov 2002 - Have started to work with PICs after a few years away. There are some very interesting new developments. The 16F84 is in an 18 pin package and has 13 I/O pins the newer 16F628 is also in an 18 pin package but has 16 I/O lines. See the Table of package pins and I/O pins for just some of the PICs available as of Nov 2002. Note that the 16F876 has more memory than the 16F873 than the 16F870 but otherwise they are very similar.Programming Methods:PICList home page - the digest no longer shows all the messages, too bad. More information on LISTSERV commands can be found in the LISTSERV reference card, which you can retrieve by sending an "INFO REFCARD" command to LISTSERV@MITVMA.MIT.EDU (or LISTSERV@MITVMA.BITNET).
- Conventional by plugging chip into a programmer
- In Circuit HV programming (uses +13 to burn the Flash)
- In Circuit LV programming (the chip makes its own programming voltage)
- Some chips have bootstrap self loading capability where they can be updated via an RS-232 connection
This makes use of the LV programming mode and has restrictions on one of the I/O pins. It also requires
hardware handshaking on the RS-232 port so that needs 4 pins (TxD, RxD, RTS, CTS).
- In In Circuit Debugger 2 has the ability to HV program the chip (uses 5 wires on a 6P6C modular telephone type jack) This looks very similar to conventional In Circuit HV programming except now there is a standardized modular connector rather than no standard. Of course for those chips that have the internal debug hardware this also works for In Circuit Debugging. The version 2 ICD rquires the use of MPLAB 6.x and a USB port for the fastest transfers.
SP 5-GFX1 128x64 LCD Graphic display with on board controller reasonable price
Almost All Digital Electronics - Has a picture catalog of Radios, and good Link page, Other Rdaios & Specifications pages,
David Tait - the PIC archives -
Embeded Web Ring -
Embed Inc - PIC Development Resources - macros
Fast Forward Engineering - Andrew Warren's PIC business - he is a very helpful supporter of the PIC list server
FTP site for Electronics Now - older PIC source code
Glitch Busters - disty for hobbyists building PIC projects
How to control a HD44780-based Character-LCD -
Jeff Frohwein - source code for a number of apps
Kits R Us - many PIC projects
Maplin - English source for kits & supplies
Marktech Optoelectronics - Four Digit Displays -App Notes -TB62709F - uses clock, load, and data (3 wires) from uC
Maxim Integrated Products - MAX7219/MAX7221 Serially Interfaced, 8 Digit, LED Display Drivers - +5 Volt RS-232 -
Microchip- Links -
microEngineering Labs - PICmicro microcontroller development tools - PICProto18.dwf - prototyping board
muRata - find a ceramic reasonator for a given PIC model number - this is the lowest cost solution for high volumes
Myke Predko's Reference Page - using 2 I/O pins to drive Hitatchi 44780 based LCDs -
Myke Predko - Programming and Customizing the PIC Microcontroller -
Oricom Technologies - prototyping supplies
Patent 5,847,450 - Microcontroller having an n-bit data bus width with less than n I/O pins
Peter Anderson's PIC Page - a whole lot of projects
The PICmicro ring -
PIC Development Tools - PIC web Ring -
Square 1 Electronics - Easy Pic'n, Pic'n up the pace, books
Starting with PICmicro controllers by Wouter van Ooijen
SubTech - Electronics & Hardware For R/C Model Boats & Submarines
TV Screen Display project board -
Ubicom - SX18/20/28 family - SX Web Ring
Velleman - many of their Mini Kits (MKnnn) use PIC uC, so by adding a socket could be used for development of a similar product
Virtual Micro Design -
Wouter van Ooijen's PIC (and other electronics) pages - JAL high level language for PICs and fast Ubicom (formerly Scenix) PIC clones.
ZL1HIT Hellschreiber / PIC Beacon - HF radio digital mode
Basic LanguageSimilar to the AMD Tiny Basic chip (see 6800 above), Parallax offers PIC (and other uC chips) with basic language capability called Basic Stamps. These are aimed at educational applications (and hobbyist) and have a lot of support in terms or documentation and related products. Based on the success of the Basic Stamp there are a number of related basic language products. The Picaxe (NZ PicAxe web page) may be one of the lowest cost Basic language uC chips. As of Jan 2004 Peter H. Anderson - Embedded Processor Control - is carrying the PicAxe for the US and Canada
On one hand the Basic Language chips are easier to program for simple tasks for someone who's a new programmer, hence their acceptance in schools. But on the other hand they run much slower than the chip's machine code speed since they are interpreted languages and cost 10 to 50 times more than the raw uC chip. The manual for the Parallax Basic language is much much bigger than the few pages it takes to list the 35 assembly commands the mid range Microchip uCs support.
Motorola Microcontrollers68HC908G20 - in circuit FLASH, interesting looking
SputnikOn October 4, 1957 when the Russian Sputnik satellite was launched (they played the "beep -beep" sound over our high school PA system) some scientists found that it's orbit could be determined by knowing the location of the receiver on the Earth and using the doppler shift information. It became clear to John Hopkins University that if the orbit parameters were known then the position of the receiver on the Earth could be determined.
Early Days of Sputnik - "...WWV 20-MHz standard broadcast was at nearly the Sputnik frequency, the output from the receiver could be made to be the audible difference between the WWV standard and the Sputnik signal. Superimposed was the WWV timing signal..."
TransitThis idea was bought by the U.S. military and the Transit navigation satellites were the result. Transit-1B launched 13 April 1960 (1A 17 Sep. 1959 failed to reach orbit). The Transit birds transmitted their orbit parameters on 150 MHz and 400 MHz. By using two frequencies the atmospheric effects on the signals can be removed. This system was used by submarines to reset their inertial navigation systems. The problem with the system was that the receivers needed an extremely accurate local clock and were therefore very expensive. FOr example the Magnavox MX 4102 has a 5 MHz OCO that's lab quality.
Now the system is used for research and is called " Navy Ionospheric Monitoring System (NIMS)".
An Overview of the Navy Navigation Satellite System
The Legacy of Transit -
Transit Satellite System at Univ of Texas with Two Line Elements for a couple of operational birds
FAS - Satellite Navigation - Transit -
Celebrating Our Past: Sputnik and American navigation satellites -
Jonathan's Space Report No. 302 - historical information
Timation and GPS Satellite History from NRL
Global Positioning System (GPS)When the Global Positioning System was being designed it was done to allow a low cost (simple crystal oscillator) clock to be used. In order for this to work GPS has four unknowns 3 position coordinates and time. A GPS receiver can have the capability of not only telling it's user where he is but also the precise time. I can set the my local clock to within about 30 nanoseconds by means of GPS.
The early days of the GPS system showed that it was much more accurate than expected. After the KAL-007 airliner was shot down (it was using inertial navigation that was incorectly set) the Coarse Acquisition (CA) code was put into the public domain and Selective Availability (SA) was turned on. SA has the effect of degrading the accuracy of the CA signal. In 2000 SA was turned off.
I have taught myself quite a lot about GPS by buying and learning from development systems.
- The first was the TrimbleSV6 -
- then a couple of the MotorolaVP+ in the form of an evaluation kit. -
- I found an EDO brand Canadian military surplus GPS set called R-5133/URN-502. EDO no longer appears to be in the GPS business. I have done some reverse engineering on it.
- Stanford Telecom 5001A Navstar Test Transmitter which I need to reverse engineer because so far I have not been able to get any data from STEL since they have gone out of the GPS business.
- 9 May 99 a Garmin - IIIPlus - Averaging mode after 5023720 1 second readings 39.19018 N 123.16405W101.336 feet/arc sec N-S, 78.541 feet/arc sec E-W or the last digit on above Garmin display is 2.8' E-W & 3.6' N-S
the Garmin readings are within about 10 counts( about 36 feet) of what I think is the correct answer.
- Motorola announces model "M-12" a 12 channel reveiver - Motorola GPS Receivers -June 2004 - Carrier phase professional survey. House GPS antenna is at:In addition I have an extensive library of GPS books most I got from NavTech. My interest is both in the timing aspects and in surveying applications where carrier phase postprocessing can be used to get very good relative accuracy. Synergy (Tech Notes) is an official Motorola GPS reseller. TAPR has a PIC based board that takes in the Motorola Binary differential data and sends it out as an RTCM SC-104 Type 1 message. This can be used for differential corrections to improve the position accuracy of all GPS receivers that accept the RTCM SC-104 format signals.
The standard for ship instrument to instrument communication is NMEA 0183. Most all GPS receivers output data in NMEA-0183 format as well as allowing the selection on a proprietarily format instead.News Group: sci.geo.satellite-nav -
4-Way GPS Splitter Plans -
Agilent - ESG Signal Generator GPS personality allows simulating one SV
Aquapac - waterproof bag for GPS, camera, etc.
Axiom Navigation Incorporated - uses SiRF chip set
Canadian Space Geodesy Forum -
CMC Electronics - makes a line of GPS receivers. - Superstar has carrier phase @ about $120/board - @Navtech -
Casio - Timepieces - Introduces World's First Watch With Built-In GPS reveiver - small photo photo2- large photo1photo2 - "Protrek" is name in the photos
David L. Wilson's GPS Accuracy Web Page -
Electro Mavin - $20 GPS kit -
Garmin - handheld GPS receivers
Garmin & Kodak DC260, 265 & 290 - imprint Lon, Lat on photo - Kodak Field Imaging System (FIS) 265 - combined with a map w/ dots that you can click
Garmap CE - freeware
Garmin Hacking Project -
Garmin 12-Series Receiver Accuracy Report - Post SA by John Bonde
GIS data for northern California - many useful links
Global Positioning System Logging -
GPS Accuracy Monitor by Dennis Milbert
GPSLIB An SDK to add GPS support to your Windows applications -
GPS Receiver Manufacturers, System Integrators, Equipment Suppliers, and Service Providers -
GPS Nuts -
GPS Patents - some GPS and Satellite Navigation patents
Global Positioning Systems (GPS) Resources - has freeware program to convert Trimabe ssf files into RINEX format
GPS Time by CNS Systems - Low Cost High Accuracy GPS Time paper from ION
GPS Thing - moving map program
GSP World - is THE magazine for GPS information
IGS Data & Products from JPL - 2 wks, 2 days & real time GPS corrections archived by GPS week #
Intuitave Circuits - Video Overlay to add GPS data to NTSC or PAL video
Fastrax - iTRAX02 - Eval kit.pdf (500 nS claimed time accuracy,
Joe Mehaffey and Jack Yeazel's GPS Information Website - Cables for Garmin GPS receivers -
KEK GPS Clock System - TACGPS backup module -
L3 Communications (Interstate Electronics Corporation) - Shot from guns - 30,000 G spec
Larry's Garmin Connector - to make your own cables
Magellan - handheld GPS receivers
Main Course Technologies - GPS based position reporting using web browser - RIM950 2-way pager among other devices
MASTERCOM GPS antennas - concealed mounting automotive
Modeling of GPS Positon Errors and GPS Position Error from Averaging by David L. Wilson -
Motorola - Global Positioning Systems (GPS) Products - including Oncore User’s Guide - but VP guide is needed for advanced work
Navtech - a very good set of links - they sell a lot of technical GPS books - OEM Boards & Kits - Canadian Marconi ALLSTAR - interesting
NMEA-0183 De-Mystified -
NMEA data repeater - no name or contact info on web site, PIC16C54 based with 2x16 LCD display
No-Frills Technical Links Page by Andrew Dart
Observations of the Garmin-Garmin Protocol by william soley
Obtaining raw data from some Garmin units - GPS12 used, but others may also work
OutlookGPSPlus - Free beta software as of 9/23/99 - I have not tried it - the Outlook version supports the Motorola Oncore -
Peter Bennett's pages - NMEA 0183 & GPS - NMEA 0183 is a specification for both a physical interface (similar to RS-232) and for the content of data packets from a GPS receiver and other equipment on ships.
Philips Semiconductors - SAF1576 news release - replaces the SAA1575 -
Totally Accurate Z3801A 1PPS timing pulse and "heartbeat" LED modification -
Quantics Q5200SM Timing GPS Receiver -
Richard Bollar & Leesa Stephens - Garmin GPSIII Plus map setings - some ideas on how to get the III+ display to look like you want it to.
RINEX Format: Current Status, Future Developments by Werner Gurtner, U of Berne & Gerald M. Mader, NGS
Royaltek - GPS Engine Board REB-12R 12 channel
Sam's Storm van Leeuwen GPS Raw Data Pages - Step by Step math & information on boards - antennas - He found me @ 39:11:24.692 N, 123:09:50.548 W, 249.7 meters (WGS-84). - Obtaining raw data from your Garmin GPS12 (or XL) -
Sam Wormley's GPS site - excellent GPS page
Satellite Positioning Specialists- Windows CE software
Septentrio Satellite Navigation -
SiRF provides innovative, cost-effective, silicon-and-software
Stanford Telecom - was into the GPS Simulation market, but GPS doesn't appear on the web page now - see my 5001A Navstar Test Transmitter- page
Stelios Web Cellar - GPS to Kodak DC camera link & other small projects
Synergy Systems - distributes Motorola ONCORE™ GPS receivers and carries a complete line of value added accessories including antennas, cables, and receivers in ruggedized housings. highly recommended by Brooke
Tom's Garmin GPS Pages -
TopoGrafix - Waypoint management program for Garmin GPS receivers or no receiver
Trimble - photos of a military Trimpack -
UNAVCO - high accuracy geosciences research
University of New Brunswick - GPS for Geodesy School -
µ-blox AG - GPS-MS1 is a fully self contained receiver module for GPS, fitting into the form factor of a PLCC84 package
Waypoint - GrafNav Lite - carrier phase post processing software
Zeli carrier boards for GPS receivers
HP Z3801A - Z3816A - 58503A - 58540A - 55300A GPS ReceiversPractical hints and suggestions for the HP Z3801A and Z3816A GPS receivers - many pulled form telco service
GPScon - plots of users results - there is a great variation in the results
Leapsecond.com - plots -
Converting 19.6608 MHz outputs to 10.0 MHz outputs on the Z3816A -
Official GPS Information
China Lake - USCG Navigation Information Service FTP Site - a source for Ephemerides data -
- Holloman Air Force Base 746th TEST SQUADRON (CIGTF) -[sungps.46tg.af.mil:/pub/] - Comment -
CORS ftp site - GPS Continuously Operating Reference Station archives code & carrier phase data used for post processing part of NGS
GPS For Air and Space Power - #178 has article on jamming
GPS: Our Strongest Asset or Weakest Link? -
GPS Satellite Performance by JPL using their quick look process
IGS Products - the Ephemerides data to 5 cm available 2 weeks after the orbit - use for post processing pseudorange data
Interactive GPS Satellite Prediction Utility -
Joint Program Office - User Equipment Pgm Office - Lm and Lc: How the Military and Civilian Users of GPS Can Reuse Our Existing Spectrum -
MIT Linclon Labs Glonass (Russian equivalent to GPS)
National Geodetic Survey - NGS - advanced mapping to go with GPS
NGS Data Sheet By Area - Data Sheets can be retrieved within a two mile radius of a given latitude and longitude.
Peter Dana's GPS System Overview - Univ. of Texas
Recent Disclosures Underscore GPS Vulnerability to Jamming -
Satellite Geodesy - Precise orbit data for post processing
Stanford -Dept of Aeronautics and Astronautics - Global Positioning System (GPS) Lab - Projects - Links -
US CG Navigation Information Service FTP Site - a source for Ephemerides data
US Coast Guard Navigation Center - the official government web page for GPS and other radio navigation systems - The GPS Week1024 rollover - Mirror Site -
US Air Force NAVSTAR Global Positioning System - official A.F. web page
US CG Navigation Information Service FTP Site - a source for Ephemerides data
Wide Area Augmentation System (WAAS) on line as of 15 Oct. 2000 - an enhancement of GPS for use by aircraft
*** some of the above have changed their URLs from *.mil to *.gov, so if one is broke you might they that change.
Differential GPSDGPS is a way to correct for a number of error sources by using a reference station and a rover. Most commonly done using a radio to send the DGPS correction data to the rover in real time such as for ship navigation in coastal waters (283.5 - 325 kHz). This requires recording information about the range and range rate for each satellite in view. The RTCM 104 specification covers the data format to transmit DGPS corrections. This is used by the U.S. Coast Guard DGPS stations. The great majority of DGPS is done in real time using only the C/A code signal. The accuracy after DGPS is around 5 meters. There are ways to do C/A code DGPS as a post processing operation.
The WAAS system is a geosynchronous satellite system of providing differential corrections.
In order to do postprocessing you need to convert the receiver output into RINEX2 format. Then OMNI software can be used.
The origional work on DGPS receivers was done by The Analytic Sciences Corp. (TASC) in 1994 under contract to the U.S. Coast Guard by way of Volpe National Transportion Systems Center. Titles:The receiver uses 2 DSP chips and looks almost exactly like the origional Trimble DGPS receiver, but they don't seem to offer it anymore.
- Marine Differential GPS MSK receiver System - Operator's Manual, June 1992
- Marine Differential GPS MSK receiver System - Final Report (Revised), June 1993
- Marine Differential GPS MSK receiver System - Maintenance Manual, Feb 1994
- M16577.1 Differential Golbal Positioning System Broadcast Standard Apr 21, 1993
US Patent 6397147 Relative GPS positioning using a single GPS receiver with internally generated differential correction terms May 28, 2002 by CSI Wireless - uses this patent only in one of their WAAS receivers - note that any given satellite will only be visible for tens of minutes to a few hours. As satellites that were overhead when the differential corrections were generated start setting the corrections will degrade and when only 3 satellites are left will cease to have much value.
US Patent 5828336 Robust real-time wide-area differential GPS navigation May 28, 2002 assigned to U.S.A. has details on the errors in the GPS system
Build Your Own DGPS Receiver by Rich Heineck - Printed circuit board is available & H & E filed antennas
Communication Systems International (CSI) - Beacon Receivers & OEM board - antennas - ABX-3 sensitivity of 2.5 uV/m for 10dB SNR, SBA-1 sensitivity of 10uV/m for 6dB SNR
DGPS - Coverage map including GWEN (See Longwave Above) proposed stations - Site Number 859 -
Garmin - GBR-21
Jim Bixby's Home Page - DGPS Receiver Project -
Magellan - DBR-IV sensitivity of 10uV/m for 6dB SNR
Omnistar - wide area differential correction service using satellite downlinks for data
Starlink - DGPS receiver -
TAPR - Differential GPS Reference Station Interface Board - Use the Motorola Binary Differential output as input to a PIC that outputs RTCM104 data
Trimble - World Wide Beacon Station List -
DeLorme - GPS PostPro $100 for the Earthmate Receiver $100 - uses the CORS data available free on the www - 3D Topo Maps on CD - D Wilson Review of PostPro -
DCI - DGPS service
DGPS over InternetWolfgang Rupprecht - DGPS over Internet -
host: dgps.wsrcc.com dgps.wsrcc.com dgps.wsrcc.com port: 2101 2103 2104 location: Pt. Blunt, Ca USA 37.19 -122.39 Texas A&M, TX, USA 30.60 -96.36 Youngstown NY
Stanford Telecom 5001A GPS Test TransmitterThis was built to test GPS equipment before the satellites were launched. My 5001A web page.
Motorola GPS ReceiversA web page about the various Motorola GPS receivers.
Post ProcessingPost Processing refers to the idea of recording data from a roving GPS receiver and then at a later time processing that data to improve it's accuracy. There are a number of techniques of doing this. Land surveyors use carrier phase in addition to the C/A code and also use the L2 frequency without knowing the crypto key and can get centimeter accuracy relative to their base station. If the base station happens to be a USGS "monument" (or a base station that is known relative to a monument) then the accuracy is in the centimeter range.
Alfred Leick - author of GPS SATELLITE SURVEYING
GPSPACE is a PC-compatible GPS point positioning program that provides DGPS accuracies without requiring access to base station data. You need to wait a few days after the survey. Cost CND$200 + CND$70/day.
Moore Associates Inc. - not postprocessing but rather data viewing
Obtaining raw data from some Garmin units - G12
PC Software from the National Geodetic Survey - utilities
"Precision GPS Measurements" by Dr Thomas A Clark (W3IWI) - antenna properties & concerns for mm measurements
Spectra Precision Terrasat - free RINEX based post processing software
TEQC: The Toolkit - Translators for common survey grade rcvrs & the Rockwell Zodiac binary (records 1000, 1002, and 1102 w/o checksum)
Agilent (HP) Small Quantity on line orders - in association with Newark Electronics ($25 min or $5 service charge)
EAGLE Layout Editor - free software to make small 2 sided printed circuit boards
Everyday Practical Electronics - English publicatioon
Jan Axelson's Lakeview Research - computer port info
Oatley Electronics Pty. Ltd. - nice LED & LCD projects
Private Companies in the Silicon Valley -
Zen News- A Monthly Review of the Semiconductor Industry
Analog Devices - auto zero op amp -
Statpower - Sine wave DC to AC converters
Trace Engineering - Sine wave DC to AC converters - Backup Power -
Sun Frost very low energy use refrigerators
Pocket Tools -
LEDs - seperate web page
X-10 Automation Knowledge Base - modifications and a lot of other info - Webring -
Control of Stepping Motors, a tutorial by Douglas W. Jones
Brooke's StuffBrooke's Military Information - Top Index page to Mil Stuff
Used military and commercial electronics equipment sometimes is a very good deal. I have some of it.
Surplus Rack 1 -
Surplus Rack 2 -
Equipment in my office - test equipment connected via HP-IB to my computer
PRD-1 Direction Finding HF Receiver - Tube type receiver, loop and whip, 28 VDC + jeep mount, in wood crates
Watson-Watt (Goniometer) - for use on a ship-the label:
AntennaIt is made to go on top of a mast with a 2" O.D.
NUS-883 Serial 54-8
Manufacturing, Co. Ltd.
It has 4 each vertical dipoles 50" end to end that are in a square pattern 14" on a side.
A Type-N connector and a male 10-pin military connector.
There is a lamp at the top that I think is a 110 Volt unit.
I am looking for more information about this Goniometer email Brooke
Stoddart Field Strength Receiver -
PRC-6 & BC-611 -
Radio Receiving Set AN/TRQ-23- seperate web page
Light Weight Beacon Part No. 123402 - seperate web pageI am looking for more information about the TRQ-23 & OE-4/GR email Brooke
PRC-47is a 2 - 12 MHz Special Forces Radio Set, in a metal shipping case with all accessoriesSo Now you have a PRC-47 - some history & tips by Dennis Starks
Steve Hill's Military Rdio Page - PRC-47 -
See my Outdoor Intrusion Detection page for info on the PSR-1, PEWS (TRS-2), and TRC-3 Intrusion Sensors, and much more
See the Military Telephone Equipment page for phones and related items
Military Surplus Personal Home PagesMilitary & Surplus Dealers
Armed Forces Communications & Electronics Association (AFCEA) - members build military radios - Siganl is their magazine -
Army Signal Corps Museum - FT GORDON, GA
Combat Survivor / Evader Locator (CSEL) - Photo of PRC-112 (PRC-112A w/COMSEC used for black ops)
Defense Reutilization and Marketing Service (DRMS) - See the LLC Electronics page (or my list below) for FSC codes
FSC Search page at DRMS - NSN=FSC+NIIN, 5820-012482852 is AN/PRC68B(V)2
Government Electronic Research Programs - Army , Navy, Air Force
Levy/Latham Global LLC - Official Surplus Seller for DRMS starting Oct. 98 - As of 17 Oct. they don't have anything in FSC 5820.
Hard / Hard Hard Core Item Information - Government Systems on back Order
If you have questions about this email BrookeBack to Brooke's Products for Sale, Military Electronics Inforamation, Home web page
This is the time this page has been accessed since 21 Jan. 2000.