[TheList] ISS Comms

Thu Mar 21 05:20:26 AEDT 2013

Ummm,

The profile of most passes is an arc at something well below 90 degrees 
above the horizon, so a vertical is actually a good bet. At the 
beginning and end of the pass they'll be in the lobes of best gain and 
when a pass is almost directly above the line-of sight distance is 
shorter so the lower gain directly above is less an issue.  A pair of 
crossed dipoles horizontal are going to be cloud warmers for most of the 
workable window of a low low elevation pass I'd have thought.

For the ISS, given it's not running flea-power like the amsats a 
vertical is easiest and best bang for buck non-steerable antenna option 
I reckon.  For most of the other amsats though you need something you 
can point at it, either by hand or az/el rotator setup.

My experience with the digipeater is that I can consistently hit it with 
10w on the vertical for elevations above about 10 degrees above horizon, 
and 5w with a HT and hand held 5el short yagi on visible passes so I can 
aim the thing!  :-)

I did try to hit the U/V repeater quite a few times recently before 
reading they'd taken it offline to use one of the radios for the ARISS 
programme.  Makes it hard to trigger when it's not listening!

I've not tried any of the amsats yet...   Need to build me a hand held 
U/V yagi, there's lots of designs around for them...

Cheers, Chris H

On 20/03/2013 11:42 p.m., Denis Dawson wrote:
>
> A vertical antenna is not really the ideal configuration as it's 
> radiation pattern is mostly towards the horizon.
>
> If someone was interested in making contact either through the on 
> board repeater or with the astronauts on the rare occasions they do 
> speak to hams, then a dipole or pair of crossed dipoles facing upwards 
> would be more suited.
>
> Denis
>
> *From:*TheList [mailto:thelist-bounces at radiowiki.org.nz] *On Behalf Of 
> *Chris Hellyar
> *Sent:* Tuesday, 19 March 2013 10:47 p.m.
> *To:* thelist at radiowiki.org.nz
> *Subject:* Re: [TheList] ISS Comms
>
> 'Urro,
>
> I've managed to get a packet back off the APRS repeater onboard a 
> couple of times, and heard voice on 145.8 in June last year.  Someone 
> in VK7 (Tasmania) working the ISS on a fairly low elevation pass for 
> us.  I tried both the VHF uplink frequencies and didn't get a reply 
> though.
>
> If you can decode the APRS you'll quite often see packets coming back 
> from ZL3REW down in Ashburton, he quite often works it, and I've heard 
> him using the VHF uplink frequencies as well but not heard him talking 
> to anyone yet.
>
> I'm just using a 3m dual-band colinear above roof height, and given 
> it's line of site just about any antenna/RX should do the job.  Some 
> folks report working the ISS with just a handheld and decent quality 
> whip antenna.
>
> I have a cunning plan to put up a steerable U/V pair of yagi's to give 
> the ISS and amsats a proper go but that requires quite a few more 
> round-toit's than I seem to be able to find right now...  Where did I 
> put them I wonder?
>
> Cheers, Chris H.
>
> On 18/03/2013 9:22 p.m., Tim Devaney wrote:
>
>     Hello All
>
>     Has anyone on the list listened to comms from the International
>     space station and if so is it easy to do , can I do it with a
>     scanner and are they any certain freqs I could listen into .
>
>     Cheers
>
>     -- 
>
>
>     *Tim *
>
>
>
>
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