We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissable in your locale.

Author Topic: new frequency for HM01?  (Read 2447 times)

Offline glimmer twin

  • DX Legend
  • ******
  • Posts: 1089
  • "I found my way to heaven , I did my time in hell"
    • View Profile
new frequency for HM01?
« on: October 14, 2013, 1317 UTC »
I saw this in GH's daily logs.

** CUBA [and non]. 7320, Oct 9 at 0516, big open carrier, and then just-barely-modulated spy numbers alternating with digital bursts. Also barely audible underneath is R. Rossii, which normally has no such QRM. At 0531, still JBM only with longer 5-digit number strings. New frequency for this? RHC itself never uses the 7 MHz band as an international law-abiding station (Glenn Hauser, OK, DX LISTENING DIGEST)

I'm not sure how they ended up on 7320 & I have checked for them since seeing this but haven't heard them there. I've tried to figure out what combination of frequencies work out to put HM01 on 7320 as a third order type of deal but ....?? It always turns out to be a simple computation that I just overlooked so if anybody can figure it out....
KCMO  Icom R 75 , SDR-IQ, Grundig Satellit 750 ,Tecsun PL 880, Tecsun PL660 , Tecsun PL380 & PL360  10 meter random wire  w/ RF systems MLB    Alpha Delta SWL DX sloper  
qsl   keithglimmer810@gmail.com

gentlemen,you can not fight in here, this is the war room

Offline Token

  • Global Moderator
  • DX Legend
  • *****
  • Posts: 2107
    • View Profile
Re: new frequency for HM01?
« Reply #1 on: October 14, 2013, 1403 UTC »
With any numbers station, and particularly with the Cubans, one (or even a couple) transmission does not make it a new frequency of use.  Many numbers stations operators have errors in settings, accidental uses of frequencies and modes, and the Cubans seem to do this more than others.  He is called Pedro for a reason.

The Cubans apparently use the same transmitters for Radio Habanna Cuba, their numbers transmissions, and some of their jammers.  It is not all that uncommon for them to forget to change the freq, and for numbers to come up on a scheduled R. Habanna or jammer freq, or the other way around.  Or other times their numbers (or R. Habanna, or a jammer) may appear one time on an oddball, unexplained, frequency and never be seen there again.

These days HM01 is pretty much AM only, but in the past the Cubans made many errors in transmission mode.  M08a, V02a, and SK01 were all normally sent in AM, with M08a using MCW, a modulated 1 kHz tone instead of keying the transmitter off and on.  To receive this M08a the listener had a few options, either tune to the correct frequency in AM mode, the correct frequency in either USB or LSB mode, or plus or minus 1 kHz in CW mode, it all worked.  But sometimes, on a regular schedule, M08a had no AM carrier present.  It was not keying the carrier on and off, as one does with true CW, but rather it was still using the 1 kHz modulation, but the transmitter was typically in LSB mode.  In these cases the listener could tune to the same frequency as the AM transmission, but in LSB mode, or they could tune 1 kHz low and in CW mode.  This led to some M08a schedules having more than one frequency listed, often 1 kHz apart.

What does the above have to do with errors in mode?  Sometimes after an M08a (no carrier) transmission they would forget to switch out of LSB mode.  Resulting in V02a and SK01 transmissions in LSB instead of AM.  Sometimes they would catch these errors mid transmission, and you would see the signal go from LSB to AM without pause.

The Chinese have the same bad habit with V26.  V26 transmissions are almost always preceded by 2 other transmissions, a Chinese 4+4 digital modem in LSB, and then M97 in CW.  Sometimes the transmitter is left in LSB when switching form the 4+4 to M97, so the M97 ends up being 1 kHz low.  M97/V26 transmits on 3 frequencies at once normally, all in the same modes, but one time I caught each freq in a different mode, one LSB, one AM, and one USB.

The point of all that rambling is that errors happen.  Watch 7320 kHz and see if HM01 returns, but donít be surprised if it never does.  There do appear to be some frequency changes happening for HM01, but that might be normal as winter sets in, or possibly just as time goes on.  Most numbers stations do change freqs over time, sometimes to keep up with seasonal propagation changes and other times for reason only they know.

Mojave Desert, California USA


  • Guest
Re: new frequency for HM01?
« Reply #2 on: October 14, 2013, 2310 UTC »
I can confirm HM01 on this Frequency and also there has been one other report of HM01 on 7 Megs (7980 kHz).



As Token says Pedro is most interesting. I'm not sure yet if there is a schedule change, but knowing Pedro it is most likely not. I also intercepted a HM01 Message starting with Multiple #1's the other day (More than a 5 number group). I don't know for sure what the count was, but I would say at least 10 (1111111111). Possibly a stuck key(?) or a computer glitch. (I'm not sure but I think I heard that in some old number stations this means a test message? I'm pretty sure it means Pedro again though.)

Offline ssfahrer

  • Jr. Member
  • **
  • Posts: 21
    • View Profile
    • Email
Re: new frequency for HM01?
« Reply #3 on: December 06, 2013, 2306 UTC »
Could this frequency be an odd mixing product of 5855 and 9330-- the early UTC frequencies for 05 and 07 (the sum divided by two)? I now that this would mathematically yield 15185 / 2 or 7592.5 (which is close to 7320, but not quite).  If so, would this difference (~ 270 KHz) imply that the transmitter for 5855 is NOT the same as the one for 9330 (since the mixing is a bit off) or not?  (Note that I am NOT an audio engineer, so I am grasping at the potentially obvious straw here....)


Item image   Johnson Viking 4740 CB Radio Service Installation Manual