Callsign "Uncle Sam" being used most of this morning on the GHFS freqs; saying "Standing by for traffic".
4724 KHz; I listen a lot; just was funny hearing that callsign.The call signs used are "Tactical Call Signs" and change every 24 hours.
Also the message "Standing by for Traffic" can be heard quite often if you watch one of the GHFS frequencies for a longer time.
"Standing by for traffic" only means that the station is now ready for incoming messages.
On which frequency could you receive the message ?
Propagation for me is best on 4724 most of the time as I'm not too far away from Andrews. During the day the 8992 - 11175 - 13200 - 15016 freqs can be received most of the daytime hours. I have a vertical Comet CHA-250B HF antenna on the deck for rx on my Yaesu FT897; 2 end fed long wires (75' each) for Radio Shack DX394 receivers.Here in Germany, several frequencies are often used simultaneously for transmission.
Transmissions from 4724 kHz are also very often received on 8992 kHz and on 11175 kHz.
Is it the same by you ?
Propagation for me is best on 4724 most of the time as I'm not too far away from Andrews. During the day the 8992 - 11175 - 13200 - 15016 freqs can be received most of the daytime hours. I have a vertical Comet CHA-250B HF antenna on the deck for rx on my Yaesu FT897; 2 end fed long wires (75' each) for Radio Shack DX394 receivers.
thanks for this input.13200 is no longer used.
T!
13200 is no longer used.
thanks for this input.
since WWIII began I have had all HF-GCS frequencies on scan so i will lock this out. i compare signals using http://websdr.ewi.utwente.nl to what i can hear at my location.
A day or two ago I noticed a distinct echo in the audio at 11175, but I also picked up the messages on 8992 and 15016, where the echo was not present at all. The callsign at that time was Magnolia. It was kind of funny, actually, because during skip conditions I often hear CBers identifying themselves as Magnolia, meaning they're in Mississippi, the "Magnolia State".
The 'echo' you're describing sounds like you were picking up their signal by both 'short path' and 'long path'. Basically the propagation conditions were at a point where you could receive the transmitter's signal directly (short path) and at the same time it was bouncing all the way around the world and back into your receiver at almost the same time (long path) therefore you hear an echo.
And on the other frequencies you didn't have the propagation to hear both short and long path together.
Probably not in this case. Or at least, long path (or short path) RF propagation delay is not the only reason the echo is heard on HF-GCS.
Yes, long path delay and echo are a thing, no argument there. However, with the HF-GCS the echo is often deeper than would be possible with long / short path delays. I.e. the circumference of the Earth is ~24,900 miles, this means that the longest possible long path propagation delay would be on the order of 0.134 seconds, possibly very slightly more (allowing for multi hop path stretching), but certainly under 0.175 seconds. And that is the longest possible delay, most long path propagation delays are less than that, as the paper you point out says, measured in 10's of milliseconds.
However, I have measured HF-GCS echo depth of over 0.5 seconds (the longest I have actually measured is about 0.8 sec, but I think I have heard deeper echo's). Far, far, longer than would be possible with short / long path RF propagation delay alone.
The HF-GCS uses multiple transmitter locations around the world transmitting the same traffic on the same frequencies at the "same" time. I.e. a person at Joint Base Andrews (Maryland, USA) talks into a microphone and the audio is sent to multiple different transmitter locations around the world, the Azores, Diego Garcia, Yokota, Guam, etc, to be broadcast all at once. However, it appears the backbone carrying the audio is something like VOIP, and there is network latency involved. That means the audio is not actually simultaneously transmitted, but instead there is different delay in getting the audio to each transmit location, so each location actually transmits at a very slightly different time. This transport time delay does not appear to be strictly related to physical distance of the transmitter sites from the audio source.
So the "echo" on HF-GCS would be present even if there was no post transmitter RF propagation delay and there is no long path delay. Hearing just short path delay you will also hear the echo, even if you are exactly half way between two transmitter sites, and the RF propagation time from each is identical.
T!
When in California, I was sometimes able to receive both WWV and WWVH at the same time, and there was frequently a pretty good delay in time, much more than could be accounted for by strictly the distance.
Thats great research... You're clearly way into it.Are you familiar with BPM and how it interacts with WWV / WWVH timing? For those not familiar, BPM is the Chinese equivalent to US WWV / WWVH. BPM is on the same frequencies as WWV / WWVH, and on the US west coast BPM is often heard at the same time as WWV or WWVH. And during certain (multiple) minutes of each hour it sends one second time ticks based on UT1 time, instead of UTC time. When it sends UT1 time it can sound like an off time echo of WWV or WWVH.
I don't want to assume, but from your description BPM and its UT1 pulses would be my first guess as to what you were hearing.
I am in California, and I, pretty regularly, measure the actual time of arrival delta between WWV and WWVH signals. For I while I was doing this (and recording the specific delays) measured against GPS based 1 PPS timing as part of a TDOA geolocation experiment. Also to estimate / measure specific propagation modes and layers and to specifically measure and look for long path timing. I also measure BPM looking for the same kinds of things. I have almost never seen any delay that was not explained by distance, propagation, and hardware factors. And the deltas from anticipated timing that I have observed are not large and could not be discerned by ear from normal anticipated delays, both long and short path.
That is not saying that long delay echoes or strange delay happenings are not a thing. But they are the exception, not the rule. Gross deviations from calculable propagation delays are generally rare and not regularly repeatable.
In most cases, pretty much every one I can really think of, any odd or super deep echo that I have heard I have been able to resolve a reason for, if I dig deep enough.
Also, was this with a single receiver tuned to a single frequency, receiving both signals at the same time on the same frequency? Or was it multiple receivers (or VFO's), on different frequencies (something like WWV on 5000 kHz while monitoring WWVH on 10000 kHz)? If multiple receivers and frequencies, what kind of receivers and what were the measured delays through the receivers? I have encountered receiver designs and processor settings with delays up to over 200 milliseconds, while other receivers or processor settings might be measured in microseconds. Using one receiver (or receiver setting) with a long delay and one without, combined with normal distance and propagation delays, and you can end up with echoes that are longer than would be possible via long path.
T!
Thats great research... You're clearly way into it.
My high technology set was (in about 1991),
a Sony 2001 with its built in antenna and sometimes a short wire around my room. It was definitely WWVH and WWV though, mostly (if not everything) was the same (GPS constellation status etc...). I couldn't receive them all of the time. There was a definite delay, not a "long echo" maybe a 1/2 second or so would be typical. (WWVH tics being halfway between WWVs tics.) Signal strengths between the female WWVH voice and the tics were about the same, so I assume same station.
It was a few years ago, but there was something different about the tics and tones I heard vs. the recording.