Over the last few weeks I've gotten a hit on close call with this frequency a handful of times. Always around the same time. I've googled but couldn't find anything. Also checked the ads-b sites but nothing shows up. Anyone know anything about it? There's no traffic just open air. It eventually fades out after a few minutes. Some sort of military wire?
338.9625
- Thread starter StephenVa
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That sounds like some terrestrial birdie, or intermod.
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probably a birdie. mil-air does not have 12.5 steps
E4 or E6 orderwire. 1000 watts at 25000 feet will trip close call easily. Tap a wide fm radio and feed the audio to a soundcard while running sdr and demod it with ssb.
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It is the high power Northstar wideband FM on 338.95 from aircraft that includes Air Force 1, NAOC (National Airborne Operations Center E-4B aircraft), and the USN TACAMO E-6B aircraft (that transmit VLF from a long trailing wire antenna to submarines). Most of the time it is TACAMO. Single sideband subcarriers carry the actual traffic and a 1.6 kHz tone when no traffic that you can sometimes here without properly decoding the subcarriers (an ordinary scanner cannot do that). On a scanner, you will sometimes here voice, data, or a 1.6 kHz tone leaking through from the subcarriers. Traffic is very light as this is basically a backup for satellite. The ground stations are spread out the country at some select military bases and select AT&T sites. The ground side (GEP or ground entry point) for 338.95 is 356.15. The TACAMO and NAOC sometimes run Mode-S (so you will not get position) so look for E-6B and E-4B in Mode-S at the time.
See the post by Zguy1243 in 2011 at
https://forums.radioreference.com/military-monitoring-forum/218431-mystery-mode.html
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Please do not call it "order-wire". "Order-wire" is the name of only the sub-channel that coordinates with the network. That is the definition of order-wire. But many hobbiest have wrongly thought it is the name of the network when they heard "This is ... on order-wire." when the aircraft radio operator is on that sub-channel (usually one of the 8 kHz single sideband subcarriers) coordinating traffic.
spacellamaman
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This past winter, with a bc125 hooked to a RS800 suction-cupped to the inside rear passenger side window i got a close call hit on 338.95, more than once over the next 15 mins and since nothing else was going on monitored it till it was no longer Rx-able. it was over an hour of listening to that racket. that thing is a Masta-Blasta.
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It is typical to hear them for longer periods. If one does not want a scanner to stop on them, 338.95 should be in the skip list as should be 247.75, 301.65, 325.4, 337.3, 341.0, 362.25, 365.0, and 366.6.
An order wire is a teletype circuit between communications centers. They were using PC-based teletype emulators when I left the military comms world, so I assume things have progressed beyond that.
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Order wires can be voice or teletype, not necessarily teletype. In the case of the system being discussed, it is a voice single-sideband subcarrier channel, one of 15 subcarrier channels in a wideband FM transmission where the system is called "Northstar" (though sometimes mistakenly called "order wire" by some hobbyists). It coordinates trouble shooting and coordination with the network of ground stations. The traffic subcarrier channels can carry either data or voice.
I have seen order wires on HF where the order wire was voice on one sideband and the traffic channels were on the other sideband.
pdgls
Newbie
I use a 2 step process to listen to WBFM. First I record the RF signal in FM mode with a bandwidth of at least 120 KHz. I then play that audio file back to tune the sub channels. The audio signal from the E-6 is about 60 Khz wide and the sub channels are spaced 8 Khz appart both USB and LSB. The first video shows the second step. Here we have the E-6 Absentee making the initial contact with the Network coordinator (Gass House). This is done on the sub channel orderwire bravo at 8 KHz LSB. Orderwire alpha is at 0 KHz and orderewire Charlie is at 8 KHz USB. Absentee passes the "flight plan" that lets the Network coordinator know what GEP stations Absentee is going to be using. In this case it's stations Ant House and possibly Affluence. Absentee also passes a mission #. This is the only routine traffic that I hear out on the West coast other than terminating the link at the end of a flight. I do catch a phone call ocassionaly and one is made here on 56 KHz USB. It is a DSN call where Absentee informs someone the are executing exercise GSRV.
https://drive.google.com/file/d/0B52Hdc3cbOpxdGFoVlhmdGFVOWc/view
I rarely get a good signal from the Beale GEP. Here are the better catches.
https://drive.google.com/file/d/0B52Hdc3cbOpxR0lOX1YxV3RQSEE/view
https://drive.google.com/file/d/0B52Hdc3cbOpxSmgweHVWQUFCSGM/view
STRATCOM GOC can be heard a few times switching to secure comms in this one
https://drive.google.com/file/d/0B52Hdc3cbOpxRGVxbEdEci1tdm8/view
Here is another where I do my best to show the steps I use including a necessary change in the SDR# config file to get the necessary bandwidth in NFM mode. WFM mode will not work. It filters the audio whether the Filter audio box is checked or not.
https://drive.google.com/file/d/0B52Hdc3cbOpxWHBNaXVSZm9uZkE/view
Paul
https://drive.google.com/file/d/0B52Hdc3cbOpxdGFoVlhmdGFVOWc/view
I rarely get a good signal from the Beale GEP. Here are the better catches.
https://drive.google.com/file/d/0B52Hdc3cbOpxR0lOX1YxV3RQSEE/view
https://drive.google.com/file/d/0B52Hdc3cbOpxSmgweHVWQUFCSGM/view
STRATCOM GOC can be heard a few times switching to secure comms in this one
https://drive.google.com/file/d/0B52Hdc3cbOpxRGVxbEdEci1tdm8/view
Here is another where I do my best to show the steps I use including a necessary change in the SDR# config file to get the necessary bandwidth in NFM mode. WFM mode will not work. It filters the audio whether the Filter audio box is checked or not.
https://drive.google.com/file/d/0B52Hdc3cbOpxWHBNaXVSZm9uZkE/view
Paul
When they fade in, out, and then after some time back in, this is due the fact they find a clear spot to fly in and then fly circles, all in an effort to make that vlf long wire as vertical as possible. I suspect they're typically higher than 25000, making their uhf tx coverage greater, but must admit I've no provenance.
Great information! Didn't know this was possible. Always wanted to explore this.
E6's can be routinely monitored on ADS-B receivers fyi. I see them fly in these tight circle patterns, don't recall at what altitude, but I don't think it was as high as FL250
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They used to do that over the east coast but now are *usually* Mode-S rather than ADS-B. That means all one gets with an ADS-B is the altitude (no position).
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Another way to do this is to use HDSDR to tune the dongle or SDR# (using the SDR# plugin) in WFM. Then set the up VBCable (free and better than VAC which is pay). Set it up for 192 kHz. Set the output for HDSDR to VBCable. Then use SDR# using VBCable as the input and tune there. Set SDR# for LSB or USB. When a signal is seen on the bottom window of HDSDR, identify the frequency and pull in the filters from the sides to that subcarrier channel and then tune that subcarrier with SDR#. Works extremely well. (This is done with not audio wiring and no recording necessary.)
It's pretty boring but neat to try.
Likely the best method.
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Note you can pull in the filters from the right and left in the bottom of the HDSDR display. This will improve the S/N particularly on 40 kHz subcarriers. You can test your setup by tuning an FM broadcast station and tuning the L-R stereo subcarrier as either LSB or USB at 38 kHz. And of course listening to SCA narrow FM subcarriers on FM broadcast stations (mostly reading services now for the blind in the 88-92 kHz range) comes under ECPA act.
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