[MilCom] 254.2 Activity

Fri Feb 2 09:02:16 EST 2007

After thinking a bit more about Jody's reception, I am leaning more towards 
one of the classified DoD molniya orbit high fliers. There are several 
different mission types launched by DoD into this orbital profile (including 
the new SBIRS mission satellite, see my milcom blog link 
http://mt-milcom.blogspot.com/2006/11/on-orbit-checkout-of-sbirs-payload.html).

In order for this to be a high flyer serving CONUS and using 254.200 MHz, it 
would have to be positioned over the NW loop instead of the NE loop (which 
would interfere with the Skynet 4D/F birds which use the 254.200 MHz 
downlink). This NW loop theory would correspond well with Jody's reception 
of the Calgary AB approach controllers being picked up by this transponders 
uplink and relayed back via the d/l.. The fact that this d/l is not being 
heard 24/7 and appears to come up at about the same time everyday lends 
credit to this high flyer theory.

So now we can add Jody's 254.200 MHz milsat d/l to my 252.950 MHz d/l from 
last June 
(http://mt-milcom.blogspot.com/2006/06/possible-new-milsat-downlink-freq.html). 
Both are transmitting from unknown milsats, probably both high flyers. Both 
of the new downlink frequencies above are not on any of the published DoD 
milsat bandplans. I will be posting a special message to the blog soon about 
some more probable frequency downlinks for radio monitors to monitor for 
possible satellite activity on.

73 de Chief

Larry Van Horn, N5FPW
ATC (AW)      USN (Ret)
MT Milcom/Help Desk Columnist
Assistant Editor Monitoring Times
Blog Address: http://mt-milcom.blogspot.com/
Founding Father Milcom/Fedcom/Trunkcom

----- Original Message ----- 
From: "Larry Van Horn, N5FPW" <n5fpw at brmemc.net>
To: "Bryan Herbert" <bryan at bryanherbert.com>
Cc: "MILCOM" <milcom at mailman.qth.net>
Sent: Friday, February 02, 2007 8:00 AM
Subject: Re: [MilCom] 254.2 Activity

>> Skynet 4F stationed over the Atlantic does operate on 254.200, the same 
>> satellite also sends out data on 257.325.
>> Based on what folks are posting on the RadioMonitors list id have to say 
>> it is probably that bird.
>
> As I told Jody in a private email offlist, I have looked at both the 
> Skynet 4D and 4F milsats which has downlinks on 254.200 MHz. And they have 
> to be ruled out since both of their orbital slots are way to far east for 
> their uplinks to pickup any transmissions from Calgary, Alberta, Canada. 
> According to the latest information I have from the SSC# catalog, Skynet 
> 4d is at 34 west and 4f is at 6 deg east. This puts Calgary way out of 
> both birds footprint. There are three other scenarios that make sense.
>
> 1) A previously retired milsat satellite operating in this range has come 
> back to life and is relaying transmissions (I have ruled out all the UK 
> Skynet milsat birds, see above). This is the least likely as DoD normally 
> boost these birds into a higher orbit out of geo and they turn them off.
> 2) We have a unknown geo milsat using the 254.200 MHz downlink that has 
> not been cataloged to date.
> 3) Jody may have uncovered a previously unknown milsat high flier in 
> Molniya orbit.
>
> Here is a complete list of Skynet milsats (none look like a likely 
> candidate for Jody's transmissions from Calgary):
>
> Bird            Intl Desig       SSC#
> Skynet-1A 1969-101A / 4250 (retired)
> Skynet-2B 1974-094A / 7547 (retired)
> Skynet-4B 1988-109A / 19687 (reorbited above geo ring in June 1998)
> Skynet-4A 1990-001A / 20401 (34 deg west)
> Skynet-4C 1990-79A / 20776 (1 deg west)
> Skynet-4D 1998-002A / 25134 (34 deg west)
> Skynet-4E 1999-009B / 25639 (53 deg east)
> Skynet-4F 2001-005B / 26695 (6 deg east)
> Source: UK Registry of Space Objects with the UN 
> (http://www.bnsc.gov.uk/assets/channels/about/ukregistry.pdf)
>
> More to follow...
>
> 73 de Chief
>
> Larry Van Horn, N5FPW
> ATC (AW)      USN (Ret)
> MT Milcom/Help Desk Columnist
> Assistant Editor Monitoring Times
> Blog Address: http://mt-milcom.blogspot.com/
> Founding Father Milcom/Fedcom/Trunkcom
>
> ----- Original Message ----- 
> From: "Bryan Herbert" <bryan at bryanherbert.com>
> To: <vampire11 at comcast.net>
> Cc: <milcom at mailman.qth.net>
> Sent: Thursday, February 01, 2007 6:08 PM
> Subject: Re: [MilCom] 254.2 Activity
>
>
>> Skynet 4F stationed over the Atlantic does operate on 254.200, the same 
>> satellite also sends out data on 257.325.
>> Based on what folks are posting on the RadioMonitors list id have to say 
>> it is probably that bird.
>>
>>
>>
>> vampire11 at comcast.net wrote:
>>
>>>Currently here in North Georgia I am hearing the following on 254.2 all 
>>>at the same time!
>>>SNAKE flights very weak in ACM comms -AM mode
>>>Calgary Alberta Approach control weak-AM mode
>>>Secure comms in FM mode-
>>>Clear comms in FM mode , can hear speed dialing DTMF and some random mike 
>>>keys
>>>
>>>Anyone else copy any of this? kinda wild..
>>>
>>>Jody
>>>North Georgia
>>>
>>
>> -- 
>> Bryan Herbert - KE6ZGP - Ridgecrest, Ca.
>> http://bryanherbert.com
>> http://radio.scannerbuff.net:8010/eastkern.m3u
>>
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>
>
>
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