[amsat-bb] Fwd: Re: Terrestrial QRM to FM satellites

Nate Duehr nate at natetech.com
Fri Sep 21 00:25:35 PDT 2007


Oops, I replied to Luc and not the list.   Meant to send follow-up to  
the list.  LOL!

Begin forwarded message:

> From: Nate Duehr <nate at natetech.com>
> Date: September 21, 2007 12:42:19 AM MDT
> To: Luc Leblanc <lucleblanc6 at videotron.ca>
> Subject: Re: [amsat-bb] Re: Terrestrial QRM to FM satellites
>
>
> On Sep 20, 2007, at 3:25 PM, Luc Leblanc wrote:
>
>>> There are apparently several stations.  I heard a part of a call
>>> "?A9??" on voice and at another time "/R" on CW on the 20:00Z
>>> pass of AO-27 over the US.  Someone else was complaining of
>>> a strong unmodulated carrier for awhile.  I guess I'll have to
>>> set the computer up to start recording.  I doubt it's malicious.
>>> Hopefully it's just "I didn't know".  But, as time passes, they
>>> will perceive ownership of the frequency, of course.
>>>
>>> Bob
>> On the 2000Z AO-27 pass i was on this pass and i hear 2 folks  
>> discussing about
>> a hamfest and they seems to be on a trunking system as we can copy  
>> clearly the
>> "trunking tone" at the beginning of their transmission. AO-27 was  
>> over the
>> eastern side of NA. If someone is aware of an amateur trunking  
>> like repeater
>> this can give a clue even if the path of AO-27 was covering near  
>> all North
>> America...
>>
>> P.S. with 50W on a 14 elem cross yagi their signal capture mine!!!  
>> at a time!!!
>
> My previous note notwithstanding, this description sounds like it  
> might be a link transmitter for a voted receiver link on a large  
> repeater system.
>
> How high was the tone you heard Luc?  1950 Hz or 2175 Hz?  Those  
> are the two most common voter "pilot" tones for receiver links, one  
> GE the other Motorola, typically.
>
> Hams don't use much trunking but in certain areas of the country,  
> voted receiver sites are heavily used, and they might be on VHF now  
> that Auxiliary Stations are allowed in VHF, meaning that repeater  
> links can also be allowed in VHF which wasn't allowable prior to  
> this year -- or the thing might be throwing a wicked spur or  
> something.
>
> Generally, but not always... voted systems tend to be in high- 
> population density areas, and the coasts and the eastern mid-west  
> are the most common places to see them used.  As you get into the  
> Mountain West, the repeaters are high enough that voting receivers  
> may or may not be useful for anything other than small "blackout"  
> area fill-in coverage...
>
> But that's not saying a whole lot -- it could literally be anywhere.
>
> --
> Nate Duehr, WY0X
> nate at natetech.com
>
>
>

--
Nate Duehr
nate at natetech.com





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