Feds on close call??

bottk · Feb 26, 2015

Hello everyone,
I have noticed lately that I am getting a lot of hits on my 996T, on the close call setting,

The frequency is 388.9500,it sometimes gets annoying, I looked that frequency up on a generalized listing
and found it to be in the range for federal land mobile, I am sure its not actually a government frequency,
Just wondered if any one knew what it was,

I live in Wamego ,Kansas
This happens mostly at night , and I never hear any actual traffic , Iam mostly just curious

Thanks for any help.

ecps92 · Feb 26, 2015

Could be Cable TV leakage.

TV 51 is right there.
North American television frequencies - Wikipedia, the free encyclopedia

bottk said:
Hello everyone,
I have noticed lately that I am getting a lot of hits on my 996T, on the close call setting,

The frequency is 388.9500,it sometimes gets annoying, I looked that frequency up on a generalized listing
and found it to be in the range for federal land mobile, I am sure its not actually a government frequency,
Just wondered if any one knew what it was,

I live in Wamego ,Kansas
This happens mostly at night , and I never hear any actual traffic , Iam mostly just curious

Thanks for any help.

wtp · Feb 26, 2015

i did not see it

385.25 384.0192 385.25 387.00 389.75
close but not close enough.
try turning stuff off to see if it disappears, like the cable box, tv, wifi, modem, computer.
i had a computer that put out signals on 150, 250 and 350 mhz
now a cable box sends out stuff on 144 and a bunch in the 200 range.
ok get hunting.

rbm · Feb 26, 2015

You're probably picking up an 'Orderwire' signal.

I get CC hits on more than 40 scanners at the same time when they fly over my area.

Rich

Orderwire on 338.950 MHz:

http://forums.radioreference.com/military-monitoring-forum/286162-338-950-uniden-15x.html

And on a different frequency discussed in these threads:

http://forums.radioreference.com/mi...rderwire-over-ny-today-sdr-virtual-radar.html

http://forums.radioreference.com/mi...47-new-england-area-milcom-5.html#post2202484

rbm · Feb 26, 2015

And, since you have a Uniden scanner, here's a programming file that contains most of the Orderwire frequencies.
You may be surprised how often they're in the area.

You can import it into FreeSCAN or use it directly with Uniden UASD software.

The System Quick Key is the same as the first two digits in the file name. (61)

Rich

Also, if you go to this link, you should be able to track many of those flights.
Search for:
Callsign GOTO FMS

GOTO FMS live flight tracking - Plane Finder

wtp · Feb 26, 2015

338=/=388

388 not 338
but could it be the same anyway?

DaveNF2G · Feb 27, 2015

rbm - do you have that list in any other format - Butel ARC or Uniden Sentinel perhaps?

rbm · Feb 27, 2015

DaveNF2G said:
rbm - do you have that list in any other format - Butel ARC or Uniden Sentinel perhaps?

Hi Dave, I no longer have the Butel software installed and I don't have Uniden Sentinel but ....

I created several other formats that may help. Even if you just have to copy/paste one of those.

The attached zipfile contains the file in .txt, Excel .csv, .html, FreeSCAN .996, and .usd formats.

Maybe one of them will help.

Rich

rbm · Feb 27, 2015

There's an E6B orbiting around the midwest right now.
Almost certainly there's an ORDERWIRE frequency active that could be heard more than 100 miles away.

Rich

GOTO FMS 164388-Feb27-2015

Edit: Still going. (17:34)

And now another one heading east from OK.

And 164388 is still in the air heading toward the west coast:

pro106import · Mar 3, 2015

May not be relevant, but I was getting hits also on 388 Mhz. and change (I forget the exact freq) in P25 mode on my 396XT (essentially the same as the 996XT). Turns out it was an image of my towns PD transmissions on 460.400 Mhz.
Do you have anything transmitting in the 460 mhz. range very close to you?
Just a possibility.
Bob

DaveNF2G · Mar 4, 2015

Thanks to rbm for the zipfile. I'll see what I can do with it here.

rbm · Mar 5, 2015

CC hit on close to 30 scanners.

A late night Navy GOTO FMS flight over New York, out of Tinker AFB, OK.

With ORDERWIRE on 338.950 MHz.

Rich

mancow · Mar 5, 2015

Tap the wideband fm audio chip and feed that to sdr sharp and you can decide the embedded audio.

pro106import · Mar 5, 2015

I got that "transmission" also on my recordings ( I was in la-la land) starting at 01:33. All I got was what sounded like an open carrier with no audio. Continuous up to 02:04. What am I missing? Guess I need a lesson on what these transmissions are susposed to be. I tried searching and doing some reading on Orderwire, but still don't fully understand. I put in the nice bank of freqs in my 396XT that "rbm" posted on this forum and let her rip last night. I actually may have picked up these transmissions on 2 other freqs. earlier but just locked them out thinking it was a birdie or something (same open carrier characteristics).
Bob

mancow · Mar 5, 2015

It's a system that dates back to the beginning of the cold war. Basically it's a doomsday comms system. They are thousand watt transmitters that use frequency defined multiplexed signals that carry a dozen voice channels. Ground receivers referred to as GEPs route the comms back to silos or command centers or wherever. The signals often carry data as well. The system works like a phone system. It's full duplex and traffic on it sounds like a phone call rather than the two way stuff we are used to.

mancow · Mar 5, 2015

mancow said:
Tap the wideband fm audio chip and feed that to sdr sharp and you can decide the embedded audio.

I meant demodulate not decide.

pro106import · Mar 5, 2015

mancow said:
It's a system that dates back to the beginning of the cold war. Basically it's a doomsday comms system. They are thousand watt transmitters that use frequency defined multiplexed signals that carry a dozen voice channels. Ground receivers referred to as GEPs route the comms back to silos or command centers or wherever. The signals often carry data as well. The system works like a phone system. It's full duplex and traffic on it sounds like a phone call rather than the two way stuff we are used to.

Oh OK, that is a good explanation, thanks. So I wonder if the FM mode is what the radio should be set for. Or should it be WFM? Maybe next time I hear one I'll do a little experimenting with the scanner receive mode.

mancow · Mar 5, 2015

You can dig signals out if you use a single side band rig but it's tedious since there is no way to know what sub channel you are on and what side band unless you do it quite a bit and it's not great audio.

To do it right you need to set a radio to wide fm then tap the wide fm chip. You then demodulate that using a single side band rig. The easiest way is to feed that to a pc with an sdr program like sdr sharp and the sound card as the receiver.

I have never heard a regular fm modulated transmission. They have all been ssb sub carriers.

The bct15 works well for this.

pro106import · Mar 5, 2015

mancow said:
You can dig signals out if you use a single side band rig but it's tedious since there is no way to know what sub channel you are on and what side band unless you do it quite a bit and it's not great audio.

To do it right you need to set a radio to wide fm then tap the wide fm chip. You then demodulate that using a single side band rig. The easiest way is to feed that to a pc with an sdr program like sdr sharp and the sound card as the receiver.

I have never heard a regular fm modulated transmission. They have all been ssb sub carriers.

The bct15 works well for this.

Yes sounds like a plan. Stuck in the house again with this snow here, ugh. So maybe there is another reason to take my SDR dongle back out of the drawer.

Thanks for the info.

mancow · Mar 5, 2015

Ah but you don't need or particularly want a dongle. Basically this:

Uhf receiver tuned to an active signal in wide FM mode

Tap the wide FM discriminator chip (not the discriminators you see for decoders) the WIDE FM chip

Route that tapped unfiltered wide FM discriminator into the microphone port of the PC

Set the sound card to to at least 120 kHz bandwidth (up to 190 is fine) but 120 is perfect

Use SDR# or similar with the sound card set as the receiver

The signal will appear as a series of vertical thin stripes. Those are the 2600 Hz off hook tones

Voice signals will appear every 8 kHz alternating LSB USB etc...

To get real fancy edit the SDR# config file and add in 8 kHz tuning step below the 8.33 step.

Add in one of the frequency manger plugins and create voice channels at every 8 kHz

That's it.

Crystal clear audio every time.

I suppose virtual audio or VB cable would work to route wbfm audio from a dongle into another instance of SDR# but I haven't tried that yet. I will have to experiment with that.

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