Service Monitor as a Receiver

[spongella]

Does anyone use a service monitor for receiving? I have used an IFR-500A occasionally for HF/VHF/UHF listening. It isn't designed for that use and lacks the options a communications receiver has but once in a while I fire it up just for fun.

 

[mmckenna]

I've got a 100KHz - 7GHz spectrum analyzer that I've used on occasion. Audio is a bit weak, but it's fun to play with. I've had it up at some high sites and scanned the bands to see what I can find.

 

[prcguy]

I've used various service monitors for monitoring and they can work ok. Some are really deaf and others like the IFR 1200S have about 2uV sensitivity. I find the selectivity just fine and not much different than a scanner since they seem to use similar ceramic IF filters. The only problem a service monitor will have is no front end filtering, so they will suffer in a high RF environment.

I used an Anritsu 20GHz portable spectrum analyzer for years and it had AM/FM/SSB demodulation built in and was fun to receive some of the microwave amateur bands.

 

[RFI-EMI-GUY]

My HP8920B is programmed to wake up on the local NOAA WX channel with audio and spectrum analyser enabled. More as a self check so I know it has booted up. But I would not listen 24/7 as I like to give it a break.

I used to have a Motorola S1327B and would listen to the local T Band police repeater with it.

 

[majoco]

HP3586A selective level meter HF only and USB only too. Noise floor about -120dBm and no AGC, only manual control so not the ideal tool but works well for winkling out those small signals. Very annoying for aero monitoring as you can't get rid of the background noise and hear the weaker signals.
Singer Ailtech NM37/57A field intensity meter 25MHz to 1GHz - also very sensitive but not digital so hard to tune to an intermittant signal. Great AFC and can be used as a spectrum analyser if you couple it up to a 'scope. The big spikes are signals on the VHF FM band.

 

[RFI-EMI-GUY]

HP3586A selective level meter HF only and USB only too. Noise floor about -120dBm and no AGC, only manual control so not the ideal tool but works well for winkling out those small signals. Very annoying for aero monitoring as you can't get rid of the background noise and hear the weaker signals.

I had one of those for a while, even added a spinner knob. Same experience. It does have a crude autoranging system, but that is not smooth like AGC. You could probably breadboard an audio AGC using a few parts. Or use a Timewave DSP599ZX to enhance the audio plus AGC. But then, you could find a nice ICOM R-71 for the price. I finally sold it off for a good price.

 

[majoco]

Already got a JRC NRD515, a Kenwood R2000, a FRG7 and a Debeg/Skanti R5002 for HF and an Icom R7000 for VHF so I don't really need any more gear!

Really? Nah - you can't have too many radios - I had 23 at the last count.....

 

[krokus]

As a kid, I used my dad's IFR AM/FM 1000S. It worked decently, even though I was using his VHF-hi whip antenna. (This was part of his work bench, for the radio shop he ran out of the house.)