[OZAPRS] SatGate around VK7?

Sat Dec 9 11:18:57 AEDT 2017

Construction was based on this design:
http://umarca.blogspot.com.au/2013/05/project-8-turnstile-antenna-for-weather.html
but dimensions scaled for 145MHz.

I used 75 ohm coax for the delay line as per
https://www.digitalham.co.uk/turnstile-antenna/ - again scaled for 145MHz.

SWR is about 1.15:1 at 145.825 which was an absolute fluke and had me
convinced for a while that my SWR meter was broken.

Its fed with about 10m of RG58 and was initially connected to an RTL-SDR
via an $8 ebay LNA running off 5v to limit the gain.

Then I switched to a Kenwood TR-2400 1.5w HT that's almost as old as me,
via a Digitor D-2510 amplifier. That combination produces about 7w which
is ample for getting into ISS and NO-84 with this antenna - but the HT's
1.5w was not enough by itself.

Using the SDR it also works great as a Wx antenna, with good reception
down to just a few degrees above the horizon.

- Josh VK2HFF

On 9/12/2017 10:34 AM, vk4tec at tech-software.net wrote:
> Thanks Josh
> 
> Can you describe how you fed it 
> 
> Andrew 
> 
> -----Original Message-----
> From: OZAPRS [mailto:ozaprs-bounces at aprs.net.au] On Behalf Of Josh
> Sent: Saturday, 9 December 2017 9:32 AM
> To: ozaprs at aprs.net.au
> Subject: Re: [OZAPRS] SatGate around VK7?
> 
> I use a turnstile antenna as well, no issues with low elevation passes.
> I made mine out of 20mm PVC conduit and 2.4mm wire (tig filler rods).
> Initially I built a 6el beam for the job and the turnstile was a stop gap while I made a rotator for the beam, but the turnstile turned out to be all I needed so I stuck with that.
> I was surprised how rubbish it is for terrestrial APRS use, but it picks up ISS and PSAT every pass, and PCSAT too when its awake.
> (well it did until my CHIP SBC's power regulator failed a couple of weeks ago, I haven't got around to replacing it yet)
> 
> - Josh VK2HFF
> 
> On 9/12/2017 9:56 AM, Mark Jessop wrote:
>> Unless you apply some serious weatherproofing, an arrow antenna is 
>> probably not a good idea for a long-term outdoor install. Keep the 
>> arrow antenna for portable ops and either build or buy something else 
>> to go on the rotator.
>>
>> I've been using a turnstile for my 2m SatNOGS ground station (also a
>> SatGate) for a while, and that works just fine for APRS from the ISS. 
>> It doesn't perform amazingly well below 20 degrees elevation, but it's 
>> definitely usable.
>> The turnstile I'm using is from
>> eBay: 
>> https://www.ebay.com.au/itm/Set-of-2-antennas-turnstile-crossed-dipole
>> -RHCP-2m-and-70cm-N-connector/292347719120?hash=item4411482dd0:g:Ry0AA
>> OSw8gVYBd1P
>>
>> My only gripe with it is the spacing of the elements could have been a 
>> bit larger, for a more hemispherical pattern. As it is, it has a bit 
>> of an upwards lobe, hence the degraded performance at low elevation angles.
>>
>> I thought you built a turnstile - why not use that for the SatGate, 
>> i'm sure it would perform just fine. Maybe put a filtered preamp on it 
>> to eke out a bit more performance.
>>
>> 73
>> Mark VK5QI
>>
>>
>>
>> On Sat, Dec 9, 2017 at 6:03 AM, Andrew Rich <vk4tec at tech-software.net 
>> <mailto:vk4tec at tech-software.net>> wrote:
>>
>>     Josh
>>
>>     Try this
>>
>>     Telnet rotate.aprs.net <http://rotate.aprs.net> 14580
>>     User password
>>     #filter p/RS0ISS
>>
>>     Than watch
>>
>>     I just sold my vertical
>>
>>     Arrow will go up on a rotator
>>
>>     I have beaten my head against a brick wall trying to get vk4 going
>>
>>     Andrew
>>
>>     Sent from my iPhone
>>
>>     > On 8 Dec 2017, at 9:28 pm, Josh <vk2hff at vk2hff.ampr.org
>>     <mailto:vk2hff at vk2hff.ampr.org>> wrote:
>>     >
>>     > From Sydney I often get picked up by satgates in VK3/4/5 and ZL - the
>>     > ISS's footprint is pretty large.
>>     > ISS is probably the only bird you'll have much luck with using just a
>>     > HT, but you might get into NO-84 on a good pass.
>>     >
>>     > - Josh VK2HFF
>>     >
>>     >> On 8/12/2017 10:11 PM, Marcus B wrote:
>>     >> I'm about to go on a hike through Tassie (Overland Track) in a few
>>     >> weeks, and I've been thinking about taking my VX8 with me and
>>     attempting
>>     >> a few posits along the way, is there anyone in earshot of the ISS
>>     >> SatGating around there? Any other aprs sats worth giving a go?
>>     >>
>>     >> 73,
>>     >> Marcus
>>     >>
>>     >>
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