Anyone Hear Anything above 1GHz?

[KG9NZ]

I have an Icom PCR-1500 that can receive up to 3GHz. I've tried scanning between 1 and 3GHz, but have not found anything too interesting. I do hear some pulsed noise just above 2.4GHz, which I assume is some type of spread-spectrum digital (maybe bluetooth?). I can also hear a buzz from my microwave oven about 30 feet away from about 2450 to 2460 MHz (in fact, I can hear the frequency vary as the food rotates). Interesting, but as far as anything to actually listen to I have not found it.

I think part of the problem is that sensitivity is drastically reduced in general coverage receivers at frequencies above 1GHz. For example, my PCR-1500 is specified to have a NFM sensitivity of 0.63uV at 1GHz, but only 5.6uV at 2GHz and 18uV at 3GHz. This is close to a 30dB loss in sensitivity at 3GHz vs. at 1GHz. I've seen similar specs for other wide-coverage receivers, so I don't think the reduced sensitivity at higher frequencies is unique to my particular radio.

Assuming one went to the trouble of making a good antenna - say a yagi or dish good at these frequencies - is there anything worth receiving for a scanner and utility listener? That can be received without resorting to modifications such as IF taps and the like?

Thanks,
Frank

 

[zz0468]

I've done quite a bit of listening at frequencies as high as 24 GHz. It's been quite a number of years since I've bothered to listen outside the amateur bands, however. In the past, there were many analog microwave signals that could easily be demodulated, although NOT with the type of wideband receivers out there today. I worked for a local government agency, and could listen to our microwave system from home, which was a wonderful troubleshooting tool in the middle of the night.

I also found the MDS TV channels with movies, and "Marilyn Chambers Television", which was QUITE a surprise. Most of that was in the 1.8 to 2.3 GHz range. Obviously a large chunk of that is gone to PCS, and more is going soon. There's still some video distribution taking place further up the 2 GHz band, I believe.

It would really be helpful to look at the frequency allocations and try to understand what's there now. There's still a few analog microwave systems out there, but those are fading fast. Outside the amateur bands, there really isn't anything that's listenable, or even worth trying for. I do wonder what the purpose of those ultra wideband receivers are, especially with such horrible performance. To have even a glimmer of a chance to hear anything on the amateur bands, you'll need to add a low noise preamp, and a decent antenna system. And even then, you're only likely to hear things on contest weekends.

Outside the amateur bands, there is nothing (no, really... there's NOTHING) to listen to that won't require considerable technical skill to even detect, let alone demodulate. Unless that PCR-1500 has either a 70 MHz IF output port and/or AM and FM video demod capability, you'll find it to be completely useless above 960 MHz or so, with the possible exception of the ham bands.

edit: look for USB around 1296.1 and 2304.1 on weekends and evenings. Those are the "weak signal" frequencies used by hams. In populated areas, you'll hear repeaters across the band from 1240-1300, but those are far and few between, really. Get a hold of a repeater directory and see what may be out there.

 

[SAR923]

From 1240 to 1300, you may be able to hear occasional voice by hams assuming any in your area are using this band. Above that, it's almost all telemetry, satellites, aids to navigation, and microwave. I guess that's one of the reasons senistivity drops off so fast above 1 GHz - there's just not much to listen to without specialized equipment.

 

[jon_k]

Much of the items within this part of the spectrum will be data like other posters have said.

802.11, Bluetooth, Satelites.

I can think of only two things worth finding. I believe some cordless phones run on 2.4ghz and I know that some (or most here) drive-thru systems run on those frequencies.

However, hearing "Can I take your order?" and "Ma fell down in the bathtub again today" can only be interesting for so long.

 

[KG9NZ]

Recommend a preamp?

Can anyone recommend a preamp to get the sensitivity of the Icom PCR-1500 up to something reasonable for frequencies above 1GHz? I don't seem to be able to find broadband preamps that work past 1GHz.

Thanks,
Frank

 

[zz0468]

Try looking at what Mini-Circuits has to offer.

Try RF Bay, too: http://www.rfbayinc.com/LNA.html