[Lowfer] TACAMO on 27.2 kHz

[Graham]

I missed that one on 27.2, my VLF grabber has been having some Win7 issues.

However, I did capture the start of an earlier transmissions on 22.6 at 
2014-10-04 21:29:55.

My grabber stopped working at 21:35 so I missed the rest.

https://www.dropbox.com/sh/zqf8k8kbohz8v3o/AACShZl_zKY4INDSDHZdcMqRa#lh:null-ve3gtcVLFgrab20141004_213500.jpg

Kurt, the most common frequency (in my experience) for TACAMO 
transmissions is 17.9 KHz, followed by 27.2, and then by 22.6. There are 
other frequencies they can and do use but from my location in Eastern 
Ontario these are the ones I see most frequently. I have seen 
transmissions on 31.6 but that is very rare. The document to which Garry 
posted a link is a good reference.

It is (in my experience) that you will find only one TACAMO transmission 
occurring at a time. However, two on different frequencies at the same 
time is not uncommon but not a daily event. Three however is very rare 
but I did capture one such event not too long ago with 17.9, 27.2 and 
31.6 all visible at the same time:

https://www.dropbox.com/sh/zqf8k8kbohz8v3o/AACShZl_zKY4INDSDHZdcMqRa#lh:null-ve3gtcVLFgrab20140917_195500.jpg

My VLF grabber can be accessed here:

https://www.dropbox.com/sh/ahvgr4sekcgg99s/AACd6pWv1hMNk6xvLGxGydKpa#/

It is updated every 5 minutes and keeps a running 48 hours of grabs

cheers, Graham ve3gtc FN25

On 2014-10-05 08:29, Garry Hess wrote:
> Laurence, nice grabber capture of two TACAMO bursts. I saw the earlier 
> one too but only the very end of it so didn't report it.
>
> Kurt, these signals come on randomly at various VLF frequencies. 
> That's why a grabber is the only way to catch them all. Depending on 
> where the source is the signal can be very loud or weak. The format is 
> usually a short period of 50 baud RTTY followed by one or more periods 
> of wide/wider/very wide encrypted MSK that just sound like noise. 
> http://w5jgv.com/downloads/Worldwide%20ELF%20VLF%20Guide.pdf is a nice 
> compilation of VLF sources with the various TACAMO frequencies noted.