Frequency Hopping on SW

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SCPD

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Pretty cool SDR shot around 1am EST on a remote SDR located in PA.

The little dots sounded like raindrops across the spectrum. Twas pretty cool.

 

Token

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This spread spectrum technique has been around for a long time, but I have noticed a real increase in activity over the past month or so. Not sure if that means it is really more active or if it means the region it is being used in is having better propagation to my location.

Your spread spectrum signal here is about 170 kHz wide, I have seen it be anything from 40 kHz to 300 kHz wide, but 150 to 250 kHz does seem to be the more common range of the examples I have received.

T!
 

Token

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I have received it on the west coast, here at the house, pretty often when I go looking for it. But, the signal levels are not often what I would think of as from this region. I have always had the impression, just an opinion, that this is something more used in Europe or maybe Mid East. I have occasionally seen it strong on the west coast, so it may be used more localy at times, but that seems to be an exception, not a rule.

T!
 

AlaskaMike

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Any ideas about the nature or source of these, even if just based on the frequencies used?
 

SCPD

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Any ideas about the nature or source of these, even if just based on the frequencies used?
Mike, I would guess US military but it could be just about anyone with the cash to afford the equipment.

I found this PDF on the QMAC and if you look at Page 5... the computer monitor shows a similar pattern on it:

http://www.aerospace-index.com/images/qmac/HF-90M Transceiver_Mar03_web.pdf

Here's another unit by Thales:

http://pdf.textfiles.com/manuals/SCANNERS-S-Z/Thales_TRC3600 HF Combat Radio_Datasheet.pdf
 
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Token

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Mike, I would guess US military but it could be just about anyone with the cash to afford the equipment.
nick, my guess would be most likely military, but not US military. As far as I know the most common frequency hopping capable radio systems that the US mil uses are HAVE QUICK and SINGARS. And these are VHF and UHF, but not HF.

Also, good finds on the pdfs you have there. Notice the HF-90M is 5 hops / sec and the TRC3600 is 10 hops / sec in voice mode and 20 hops / sec in data mode. Should make it possible to ID either system when found on the air.

I did a quick search, and cannot find that US mil forces have adopted either the HF-90M or the TRC3600. I freely admit my search was not exhaustive, but most companies that sell hardware to the US mil do tout that on a product description.

T!
 

Token

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I was under the impression that radios like the PRC-138 and PRC-150 (and similar radios) had hop for two primary reasons, to maintain interoperability with friendly forces with such capability and to maintain interoperability with SINCGARS radios that operate in the overlapping bands, primarily 30 to 87.875 MHz. Also, these radios use different hop techniques in the HF and VHF ranges.

In other words, a lot of US equipment has capabilities that might not be regularly used by US forces.

Not proof by any means, but one of the things I have always taken as an indicator is that if frequency hopping sideband modes on HF were commonly used by US forces I would think I would be getting them quite a bit here, about 50 air miles from Ft Irwin. The VHF/UHF FM hop modes are all over the bands here pretty often (VHF Lo can be interesting), but I very seldom see HF hop modes with regional strength qualities. There is also a lot of Air Force and Navy activity around here, Edwards AFB, China Lake NAWS (both less than 50 air miles, China Lake a LOT less), Pt Mugu and operations off the coast there. But again, HF hop with what appears to be regional characteristics just are not that common here.

Now, every JTRS radio (like the PRC-155) down to the Rifleman Radio level will have hop, no doubt, but will that be a technique used in the HF range? So far I have not seen an indication that it will.

Not really my areas of expertise, so I admit most of my thoughts on this are opinion / supposition / assumption.

T!

PS Hey, is that avatar image concerning the AAC Honey Badger? Or is it the web thing?
 
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mancow

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It's the honey badger from the funny voice over on the web.

Some specs from the PRC-150 data sheet:

Frequency Hopping Serial Tone ECCM
Vocoder
HF: LPC-10-52E (600/2400) MELP (600/2400),
VHF: CVSD
Data Link Layer
Protocol (ARQ)
STANAG 4538 (3G), pFED-STD-1052
VHF Features
Data Wideband FSK (16 kbps)
Voice Digitization CVSD (16 kbps)
AN/PRC-150(C)
COMSEC
Interoperability
ANDVT/ ANDVT/HF/BD, KKG-84 (R+NR), VINSON
(VHF), CITADEL (coalition
 

prcguy

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I have a couple of Harris PRC-138s and RF-5020/RF-5022 series radios. Frequency hopping on HF is a standard feature and they will hop narrow band keeping the center frequency within about 2.5KHz for narrow band antennas or the full HF spectrum with a wide band antenna.

You can specify discreet hop frequencies or a band of frequencies withor without a list of excluded frequencies.

I've tested them (into loads of course) and its very cool to watch on a spectrum analyzer while hearing the really good recovered audio from the second radio programmed to the same parameters.

The US military has a very large inventory of Harris HF radios that hop and I would guess they get used quite often.
prcguy
 

Token

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nick, just caught an FH on the the first freqs you reported, the 9870 to 10040 kHz, here localy. 0045 UTC, Jan 19, 2012. Ended aobut 0049 UTC. Was very fady and not near the strength of the one in your image.

T!
 

mancow

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The 10 meter hopping is back and it's around 28.305-450 this time.
 
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Token

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The 10 meter hopping is back and it's around 28.305-450 this time.
I see a lot of things happening in that range, including a repeating non-linear sweeper, but no hopper seen on the West coast.

mancow, you have any pictures of this so that we can compare what is seen in different locations?

T!
 
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