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Signal issues (was ISS repeater...)



I just worked the 1645 UTC pass over the Caribbean and of the 5 stations I
heard, only 1 had trouble getting through clearly. Maybe it is a combination
of issues with one of them being all the extra signal noise generated over
densely populated areas of the world. I heard no activation without an
operator talking until the pass started up the East coast of the US.

Thanks TI2MAB and CO8TW for the contacts.

Kenneth - N5VHO

-----Original Message-----
From: owner-SAREX@AMSAT.Org [mailto:owner-SAREX@AMSAT.Org] On Behalf Of Dave
Taylor
Sent: Saturday, September 25, 2004 2:36 PM
To: sarex@AMSAT.Org
Subject: Re: [sarex] ISS repeater mode to be active


The D700 is using the same antenna for VHF and UHF: it's WA1, located 
on the bottom (earth-facing) side of the ISS.

It's more likely that your difficulties are because (1) UHF is more 
sensitive to Doppler than VHF and (2) the duration of the transmission 
makes a meaningful signal harder for voice than digital.

-- Dave, W8AAS

On Sep 25, 2004, at 3:13 PM, Patrick Green wrote:

> I've noticed something different which to me tells me the UHF receive 
> antenna is in an unfavorable location on the spacecraft.  I've made it 
> in on 50mw so I know it's not receiver sensitivity but I find it 
> really hard to get in even sweeping the whole band for doppler 
> thinking that my KEPS were off enough to make a difference.  My 5 
> watts with the Arrow beam antenna aren't enough to get in a lot of the 
> time.  When ISS is APRS, I can digi on it from 3 degrees of elevation, 
> go figure.
>
> Also take not that 145.8 x 3 = 437.4.  Sounds far fetched seeing as 
> the antenna are seperated but another thing to look at.
>
>
> On Sat, 25 Sep 2004 13:48:56 -0500, Charlie Schlieper <n5td@vvm.com>
> wrote:
>> Hello Francisco and All,
>>
>>           I have noticed the same effect on the ISS crossband 
>> repeater, but have not commented as I am NOT sure what is happening.  
>> Just as CT1EAT mentioned, there have been times that the ISS repeater
>> will completely cut OFF, then later come back ON.
>>
>>           It simulates a possible DESENSE of some kind,
>> and it may even be from another ISS system.  I do not completely rule 
>> out an earth-bound cause, or a system anomaly or timeout-- of some 
>> kind?
>>
>>           Does anyone else have any thoughts?
>>
>> Thanks,
>> Charlie Schlieper, N5TD
>> Temple, Tx
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "Francisco Costa" <fcosta@mail.telepac.pt>
>> To: <sarex@AMSAT.Org>
>> Sent: Friday, September 24, 2004 5:29 PM
>> Subject: Re: [sarex] ISS repeater mode to be active
>>
>>> Hi all
>>>
>>> ISS repeater was on at 2011z pass over Europe.
>>> It was back at 2146z, but very few QSO's were
>>> made, not because the lack of stations, but due
>>> the repater not operating as expected. It was working
>>> fine, and then goes QRT for a couple minutes,
>>> and then is back for 30 secs, and after is off for
>>> a minute or two... and so on. Any comments?
>>>
>>> 73 F.Costa, CT1EAT
>>> www.qsl.net/ct1eat
>>>
>>> ----- Original Message -----
>>> From: "RANSOM, KENNETH G. (JSC-OC) (BAR)"
>>> <kenneth.g.ransom1@jsc.nasa.gov>
>>> To: <sarex@AMSAT.Org>
>>> Sent: Friday, September 24, 2004 9:53 PM
>>> Subject: [sarex] ISS repeater mode to be active
>>>
>>>
>>>> The repeater mode on board the International Space Station will be
>>> activated
>>>> soon (if not already) by ISS Science Officer, Mike Fincke. The ISS
>> amateur
>>>> radio station should remain in this configuration until just prior
>>>> to
>> the
>>>> next school contact. The Primary School of Montaud in France is
>> currently
>>>> scheduled for Oct 30 at 1158 UTC. After that contact, the radio
>>>> will be
>>>> returned  to packet operations.
>>>>
>>>> Kenneth - N5VHO
>>> ----
>>> Via the sarex mailing list at AMSAT.ORG courtesy of AMSAT-NA. To 
>>> unsubscribe, send "unsubscribe sarex" to Majordomo@amsat.org
>>
>>
>> ----
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