[amsat-bb] Re: Dual Hop

[Sil - ZL2CIA]

Bob,

Thanks for your reply. I had the chance to make 
another attempt at a dual hop this afternoon. 
While I could copy both satellite beacons, I was 
not successful in making a dual hop. I used the 
path "via ARISS ARISS SGATE". It was fun to see 
the interleaved beacons and digipeated messages 
appearing on my screen (copied traffic was s-gated).

Tellingly, only ANDE repeated my packets. Until 
now, almost all the passes I have worked have been 
in the evening and I have had no problems getting 
traffic through RAFT..

I haven't had the opportunity to work NO60 and 
NO61 in the past few days, family taking precedence.

However, I will make some careful observations 
over the next few days and provide an assessment 
for you.

Unfortunately, I don't have a great QTH for 
horizon satellite work. I live in a small valley 
on the side of one of this cities many hills and 
these raise my effective horizon.

Sil - ZL2CIA


Robert Bruninga wrote:
>>The ANDE & RAFT satellites maybe be a little 
>>difficult with simple omnidirectional antennas, 
>>but both are a breeze with just a little more antenna.
> 
> 
> Sil,  Thanks for the report.
> Do not worry about ANDE usage.  It is well below anticipated, so
> we are not woried about life.  But this week both are entering
> night time prime-time in the northern hemisphere and so usage
> will increase.
> 
> Also, I do want your assessment of their links.  My rig is 22
> elements cross polarized on AZ/EL mount with 100W amp/preamp at
> base fed from 150' of coax.  I have not changed it in years,
> since I get the same performance to a VHF DX beacon about 30
> miles away...
> 
> BUT... 1) The preamp is not really a low noise one, just one of
> those in a 100W remote PA to overcome some coax loss.  2) I
> suspect my deviation setting could be tweaked...
> 
> My results are:
> 1) I cannot access RAFT below 20 degrees and never in the day
> (due to overvoltage)
> 2) I can decode RAFT above about 10 deg, and some times all the
> way to 1 deg if lucky 
> 3) ANDE is also about 10 deg but sometimes lower.
> 
> If you get better performance, let me know, since I want to know
> how my performance is relative to other setups..  I measure
> performance relative to elevation angle, because that is a
> direct correlation to range.
> 
> Thanks
> Bob
> 
> 
> 
>>-----Original Message-----
>>From: Sil - ZL2CIA [mailto:zl2cia at amsat.org] 
>>Sent: Friday, March 30, 2007 12:16 AM
>>To: bruninga at usna.edu; AMSAT
>>Subject: Re: [amsat-bb] Dual Hop
>>
>>
>>>
>>>Actually, they are intentinoally on the same frequency and
> 
> they
> 
>>>are intended to be dual or even triple hop possible (when
>>>PCSAT-1 is working)..  Notice that both satelites respond to
> 
> the
> 
>>>same path VIA ARISS.  SO you could use the path VIA
> 
> ARISS,ARISS
> 
>>>and get a dual hop.  This ia also why we invite any other
>>>university or amateur satellite builder to add more
> 
> spacecraft
> 
>>>on this 1200 baud relay channel (with IARU coordination of
>>>course).
>>>
>>
>>Bob,
>>
>>Thanks for your reply.
>>
>>I have already tried "via APRSAT,APRSAT,SGATE a 
>>number of times, but so far without successs. I 
>>wasn't sure if this was an acceptable practice, so 
>>I had been discrete about it.
>>
>>I have been previously successful once getting a 
>>dual hop between PCSAT-1 and the ISS (when it was 
>>operating on 145.825 MHz)
>>
>>The ANDE & RAFT satellites maybe be a little 
>>difficult with simple omnidirectional antennas, 
>>but both are a breeze with just a little more antenna.
>>
>>I use nothing more than a horizontally polarised 6 
>>element beam. It's home built and that without any 
>>fancy tools. It's horizontally mounted and 
>>steerable in azimuth with a simple rotator. I 
>>mention this just to make the point that both are 
>>really pretty easy satellites to work with just a 
>>little more antenna.
>>
>>Both satellites are very quiet down here and I 
>>very seldom see any other users. I end up gating 
>>my own packets. This does allow me to experiment 
>>since I'm not obstructing anyone else.
>>
>>I'll persevere with further dual hop tests in the 
>>future now that I understand it's okay to do so.
>>
>>I am of course aware of ANDE-1's rather finite 
>>power reserve and do keep that in mind.
>>
>>Sil
>>
>>
> 
> 
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