JRC NRD-545 Receiver

© Brooke Clarke, N6GCE 1999 - 2023


Modulation Modes
Computer Cable
JRC NRD 545 Controlling Software
NRDWIN Spectrum Plots
    Decoders & Computer control
    Multicoupler (Rx)
    Antenna Coupler (Tx)
    Other Receivers


This page is devoted to data from the Japan Radio Corporation model NRD-545 receiver.  At first the JRC remote control program called NRDWIN is being used to gather data.    Then I will be writing a LabVIEW program to do more interesting things.

100 kHz to just under 2 GHz coverage.

There is a report in the Passport to World Band Radio that says that the DSP chip in the 545 has digital noise crosstalk that causes the ultimate rejection to be tens of dB lower that it should be.  This may be the case, but the reason that I got this receiver is that it has the narrowest IF filter bandwidth available at 10 Hz.  This allows listening for the carrier of an AM station or the carrier of a TV station.  It also allows decoding WWV's 100Hz digital data by reading the s-meter with a computer.

Review in German -

Spectrum Plots

Low Frequencies
AM Broadcast Band
FM Broadcast Band
Wide Band Scans
44 Meter Aero & Fixed
34 Meter Maritime Coastal
22 Meter SW BCB
19 Meter SW BCB

The Setup

McKay - Dymec DA-100 (now called a Stoner-  ) active antenna located very near my GPS base antenna so the location of the antenna is:

Latitude:       39:11:24.692 N   Longitude:    123:09:50.548 W   Altitude:    249.7 meters  819' 3" (WGS-84)

This is the antenna used up to 30 MHz.  Above 30 MHz I now am using a Radio Shack Scanner antenna (20-176) until I can put up better antennas.  This antenna is connected using about 50 feet of 75 Ohm coax and no amplifier.
The computer is an HP 8380 Pavilion with the HP M70 Monitor both of which are very RF quiet.

Also the B&W 1.8-30 terminated Folded Dipole is used with much better results.

Modulation Modes


This is one of the earliest modes and consists of turning the Continuous Wave carrier on and off using Morse Code.  The bandwidth needed is the narrowest of the commonly used modes and most receivers have a 500 Hz wide IF filter for CW that also works for narrow shift RTTY.

A disadvantage of CW is that when the key is up no power is being transmitted.  FSK has an advantage in that power is always being transmitted so it's easier to define the two conditions (zero or one).

Coherent CW

The idea was to make the on/off and off/on transitions at times known to the receiver allowing better demodulation that when they occur at random times.  But it did not have any control of the phase of the transmitted signal, which would improve the s/n even more.  Far better in terms of s/n are the Pseudo-random codes and spread spectrum for getting the most signal for the power used, although at the expense of modulation low bandwidth.


Amplitude Modulation is used by medium wave and short wave broadcast stations as well as aircraft.  It changes the carrier amplitude with the loudness of the modulation signal.  This is probably the oldest method of broadcasting voice and when viewed on a spectrum analyzer there is a lower sideband with voice modulation, a fixed carrier and a upper sideband with voice modulation.  It can be detected by a simple crystal radio or by using the LSB or USB mode on a modern receiver.  Doing that has an advantage if there's interference on either the upper or lower sideband.  It's an easy listening mode in that when the speaker's voice stops and there's silence the radio goes silent.  This is because the carrier remains when there is no voice or music to modulate the sidebands.

AM has another advantage in that if there are two stations on the same frequency and they are at the same power level a receiver will hear both stations.  This is not the case with FM modulation where the stronger station completely suppresses the lower power station.  That's an unacceptable safety consideration for aircraft.


In Frequency Modulation the frequency of the carrier is changed with the loudness of the modulation signal.  Since the carrier is always on at full power the audio output will be quiet when there is no modulation signal.  This is the mode used on the VHF broadcast band.  The modulated signal has a bandwidth that on the order of 100 kHz, much wider than the bandwidth of a music modulation hence there is some process gain that works in a similar way to antenna gain. 

Narrow band FM that's used for utility communications has a signal that's 5 kHz wide and a voice signal is about 3 kHz wide so it doesn't have much process gain, but you can get a lot of channels into a given slice of the spectrum.  In this application the FM capture effect that pervents hearing two stations at the same time is a benefit because the other station is most likley one you don't want to hear.


In Single Side Band modulation either the lower sideband or the upper sideband that's in an AM transmission is sent to the antenna and the carrier is supressed completly.  This makes SSB verry efficient in terms of getting the highest radiated signal for the power used.  But it requires much higher frequency stability in the transmitter and the receiver.

If you were listening to a SSB radio and music went soft the noise level would come up, not at all an entertainment type of mode.


Frequency Shift Keying is a way of sending digital data.  The transmitter is at one frequency for Mark and another frequency for Space.  It's much easier to make the binary decision with FSK than with CW where one of the conditions is the transmitter is turned off.  This mode was used to send Radio Teletype messages.


Minimum Shift Keying is a version of FSK where the shift is as narrow as possible.  It's used on LF, VLF and ELF stations to keep the transmitter frequency within the bandwidth of the high-Q antenna matching network.


Phase Shift Keying is similar to FSK except it's the phase of the transmitter that's being modulated. 

Spread Spectrum

By making the transmitter signal much wider than the modulation signal bandwidth there is a process gain that has the same effect as using more RF power or an antenna with gain.  This is used in satellite TV systems where the RF bandwidth is on the order of 36 MHz compared to a signal bandwidth of 5 MHz.  In the GPS system the signal level at the Earth's surface is below the ktb noise level, it's only after demodulation of the pseudo-random code that the s/n comes up.  Note that since all the GPS satellites transmit on the same frequency they differ in what pseudo-random code each satellite uses so the codes are chosen to have very low cross correlation.  This also means that the s/n radio will never be very high because there's always going to be interfering signals from other satellites.

Modern Digital Modes

Early telephone computer modems used simple FSK and could only achieve limited data speeds on the plain old telephone system (POTS).  The next generation modems used a modulation that sounded like noise and could support much higher baud rates.  The latest Digital Subscriber Line (DSL) modulation uses frequencies above hearing (allowing the POTS telephone to still work on the same line) and is adaptive in that it changes what frequencies are used depending on line condition.  It's not uncommon when there's trouble on the line for the POTS phone to quit working while the DSL signal still gets through (although at a slower speed).

Modulation Test Equipment


Displays the amplitudeof a signal vs time.  For example: Rigol DS1052E  The scope is the oldest of the three dynamic display instruments.  It was used to observe AM modulated RF signals.  If the modulation was too strong it would cause the RT to clip on the negative peaks causing a lot of distortion.

Spectrum Analyzer

Displays the amplitude of a signal vs frequency.  For example the HP 4395A.   This is a much more complex instrument in that it consists of a receiver that has a sweeping local oscillator and various band pass filters.

Modulation Domain Analyzer

Displays frequency vs time.  If you think of the signal inside a cube where the three axis are Amplitude, Time and Frequency you can get three views of the signal depending on which face you look at.  It takes modern digital signal processing techniques to make a modulation domain analyzer so it's a fairly new type of instrument.

Specalized Analyzers

There are phase-amplitude and I-Q displays that are specific to certain modulation schemes.


The RS-232 cable that is sold by Universal radio to go with this receiver has DB-25(m) connectors on both ends and is a null modem cable:
1    -    1
2    -    3
3    -    2
4    -    5
5    -    4
6    -    20
7    -    7
17    -    24
20    -    6
24    -    17
It turns out that my computer only has DB-9(m) com ports (which have a reversed pin numbers from the 25 pin cables) so I made up my own cable (545toPC.pdf drawing):
2 Tx
2 Rx
3 Rx
3 Tx
7 Gnd
5 Gnd
1, 4, 9*
* on the computer connector pins 1, 4 and 9 are tied toghther.  This fools the computer into seeing hardware flow control, it may or may not be needed here, but I do this to be safe.

JRC NRD 545 Controlling Software N545PRO.EXE

The English version is new as of March 2003.
Date: Sun, 16 Mar 2003 11:58:32 +0100
From: Martin-Fischer-von-Frieling@t-online.de
Subject: Re: N545Pro Software now Freeware

Registration is easy. Enter the program, click


NRD545EN as ID

2B353B84344E508A as Password

Thats all

Cheers nŽ beers, Martin
http://www.thiecom.de/mlb.htm  Receiving longwire matching transformer for 100 kHz to 40 Mhz German page but "RF Systems" in title.

NRDWIN Spectrum Plots

There is a spectrum plotting function in the NRDWIN software.  The radio is set up for mode, IF bandwidth, etc. then the "Setup" function in the PanoranaRecv program is set for Start, Stop and Step, and single/continous sweep, when OK is clicked, the scan starts.  When the plot appears, if the cursor is clicked once a marker is seen and with a double click the radio is tuned to the marker frequency.  It is hard to get the cursor exactly on the peak so I typically need to go back to the receiver and tune up or down a little.  The plot does NOT show the mode and IF BW, adding these would be a good thing.
Radio Locator -  Extensive data including station web pages
AM FM Station -

Low Frequencies

When listening to NDBs (Non Directional Beacons) with a narrow IF BW the LSB carrier and USB can be separately tuned.
10 kHz    - 100 kHz, CW-narrow
100 kHz  - 200 kHz, CW-narrow
200 kHz  - 300 kHz, CW-narrow
300 kHz - 500 kHz, CW-narrow

AM Broadcast Band

One thing that became clear is that this receiver is picking up more than one station on many frequencies!  Sometimes it is possible to separate them using either LSB, USB or ECSS (pressing this button causes LSB then USB then OFF, sequentially).  Note that plain old LSB and USB depend on the accuracy of the station carrier relative to the NRD-545 (I have the high stability option) and may work better than ECSS in this case of 2 stations.  A long term solution is a stearable antenna system.  I will be working on that in the future.

500 kHz - 1800 kHz, step 0.25 kHz, CW-narrow mode, all the following AM BCB plots were done with 0.25 kHz steps

500 kHz - 700 kHz,    CW-narrow mode
700 kHz - 900 kHz,    AM-narrow mode
900 kHz - 1100 kHz,  AM-narrow mode
1100 kHz - 1300 kHz, AM-narrow mode
1300 kHz - 1500 kHz, AM-narrow mode - my local AM station is easy to see
1500 kHz - 1700 kHz, AM-narrow mode - a number of stations are in the new 1600 to 1700 band

The 545 will receive stero AM and FM when headphones or an external amplifier are used.

www.AMStereoRadio.com - has station listings

FM Broadcast Band

88 MHz - 108 MHz, FMW mode - There is a HUGE birdie at 106 MHz!  The manual mentions that there will be some.

Wide Band Scans

Birdie Search - 30 - 1230 MHz - there appears to be a limit of 1,000 MHz in the NRDWIN panaromama software.
5.0 - 10.0 MHz, AMw  23:00 UTC
10.0 - 15.0 MHz AMw
15.0 - 20.0 MHz AMw
108.0 - 136.0 AMw

44 Meter Aero & Fixed

6,525 kHz - 7,000 kHz CWn

34 Meter Maritime Coastal

8,195 - 8,815 kHz CWn

22 Meter SW BCB

13,600 - 13,700 kHz CWn
13,700 - 13,800 kHz CWn
13,800 - 13,900 kHz CWn

19 Meter SW BCB

15,100 - 15,200 kHz CWn
15,200 - 15,300 kHz CWn
15,300 - 15,400 kHz CWn
15,400 - 15,500 kHz CWn
15,500 - 15,600 kHz CWn


I have started to write some LabVIEW code for the NRD-545.
Since the IF bandwidth can be made very narrow and in addition there is a notch filter that will take out a continuous tone it is possible to "hear" the 100 Hz digital sub carrier on the WWV HF time signal stations.  I have the start of a program that outputs the digital time code.


There's a rumor that if you put a zero Ohm resistor (short) in the R13 position inside the converter it will unblock the receiver, but I have not yet confirmed this.



Japan Radio Corporation - NRD-545 - DSP - CHE-199 converter - Remote Control - Abridged Operation Manual - Nrdwin software is downloadable
Universal Radio - NRD-545 -
Lowe Electronics Ltd - Review - compared to WJ HF-1000
Dave's Radio Receiver page - NRD-545 -
Premium-RX Home Page - Table Premium Rcvrs - High End Commercial -
Battle of the Shortwave Super Sets! The NRD-545 DSP Receiver Versus the 535-D by David Sharp -
JRC mailing list - @ www.QTH.net
NRD-545 Comments/News - review by davez
JRC NRD545 with VHF/UHF Converter by Bob Grove
LEM132 - DXpedition to Lemmenjoki - used 545's
Orchid City Software - DX & SWL - Freeware control software
FCC ID = CKENRD-545 - wideband converter block diagram, internal photos (huge file B&W), test report, there appears to be a CR2032 battery on the Display Board see manual pg 32, on line Manual -
Everything You Ever Wanted To Know About the JRC NRD 545 (But Were Afraid To Ask) - plots of AF response
SWL IR Remote - SWL IR Remote for JRC NRD-535 and NRD-545 Aug 2004 to be available Sep 2004 - Use a standard TV Universal IR remote to control the 545 radio.

Decoders & Computer control

Worldwide Utility News (WUN) - THE main source for utility information
HF-FAX - THE main source for visual radio modes fax, sstv, weather sats, etc.
shoc - dealer in high end radios, antennas, decoders, etc
Wavecom - nice DSP base decoder manf - the W40PC and W41PC-MkII are ISA cards, the other decoders are stand alone boxes (2008 - the 40 & 41 manuals & docs still on line)
Klingenfuss Publications - utility data base & dealer for wavecom decoders, also has CD-ROM with many digital sounds that can be fed into the decoder
Computer International - ARMAP, Radio Com, Visual Radio & Wavecom dealer
Bonito Communication Technologies - Radio Com - does DSP using the PC CPU
VisualRadio Automated Monitoring (Liedtke GmbH) -
RadioRaft - has free demo version, needs interface circuit or modem -  the "RR modes user's guide" (at the bottom) there is a frequency list by mode. sole proprietor
DXtreme - logging software
Icom CI-V Interface by Ekki, DF4OR
Hoka - the code 30 is an A/D card for a PC (probably a modem with filters) plus DSP software running in the PC, the code 3 is an dongle interface system like Radio Raft
Robert S. Parnass - Control Software for the 545 and other radios
SkySweep Technologies - Windows based decoders done in software, 3 price grades, many many HF and VHF type modes

Multicoupler (Rx)

SkyWaves by Al Klase - N3FRQ - passive multicoupler and 4:1 ant balun plans
Stridsberg Engineering - Multicouplers - I have the MCA104.  It's abut the size of handheld calculator and will run off of a 12V battery.  Rated for 100 kHz to 50 Mhz.  Works GREAT! I tried just using a "T" connector to connect two radios, but that degraded the signal over 10 dB!.  With the MCA104 (2 ports termintated now) both receivers are hearing as well as if they had the antenna all to themselves.  By the way they also make rack mount versions with a lot more outputs.
Boatanchor Dreams - Collins CU-168/FRR Antenna Multicoupler - Boatanchor Webring -
Collins  CU5069 32 port multicoupler

Antenna Coupler (Tx)

Note that an antenna coupler typically has a ceramic insulator holding a connection for a wire that goes to the antenna.
The coupler is placed very near the antenna.
An antenna tuner (aka line flattener) typically has coax inputs and coax outputs and is used near the transmitter.
Harris - RF-2601 Antenna Coupler -
Butternut remote antenna tuner  - motor driven cap across the 80m coil, works on 80 & 40, little or no effect on higher bands.
Murphy Surplus has the C-3698/URA-38 control box & CU-938/URA-38 ant. couplers

Other Receivers

R390 -
R390A/URR - WA4HHG Chuck Rippel Restoration, Service, Parts
R-1051B - R-1051 -
SRR-13A -
Yahoo Groups: armyradios - NRD545 -
Ten-Tec - 340 w/o front panel = 331 - RX-320 PC Radio - 340 review at Radio Netherlands, 1254 Kit Review -
Collins - HF-2050 - the first radio to use DSP
Collins - AN/VRC-100 - URG-III -
Racal RA-6790GM - RA1792, RS2290, RA1784, RA1772 - RA3791 - 1792@WJ Ford
KNEISNER+DOERINGKWZ-30 -[ KWZ50 as of 24 Apr 2008 not shown as available]
Harris - RF-590 - $2,250@TS&S - Preselector @Mike Murphy
Sunair Electronics - tranceivers, amplifiers, CU-2430 antenna coupler, R9200 receiver
Palstar R30 - gets very good reviews, in the same class as the Collins 2050!
WJ HF1000 discontinued, replaced by the WJ8711 now sold by BAE Systems, note the WJ8711 includes IEEE-488 interface (not on HF1000).
Toronto Surplus & Scientific - Radios


Motorola Mobile Radios - MICOM-2E - ALE, 1.6 - 30 MHz, 125W - Mobile Workstation 520 computer with seperate LCD, KB, CPU box
Ten-Tec - Pegasus - Ten-Tec has announced a Front Panel (FP) version of the Pegasus that hopfully will retain the computer control capability.
Harris - RF-350 -
ICOM - 706MKIIG - this is a very capable rig in a small package. Brooke's 706 Page -
Elecraft -
Totally QRP by K4MSW

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Page created 19 Jan. 2000.