[amsat-bb] EsHail Microwave transponder satellite
bruninga at usna.edu
Wed Jun 1 20:33:43 UTC 2016
> I asked a manufacturer of feeds (...) and they said
> a dual feed was not possible. Uplink is circular and
> downlink is linear using a normal LNB.
But linear is a subset of "circular", so, couldn’t we use a dish that is 40%
larger (to make up the 3 dB loss of going linear) and use a linear feed on
the uplink so it can be cross polarized with the downlink and thus get maybe
20 dB of isolation? Maybe that 20 dB of isolation is still not enough?
However many Europeans may have one dish for TV anyway. It is relatively
easy to mount two LNBs on one dish for 2 different satellite positions, so
one dish for household TV with a second LNB for Eshail sat, The LNB that is
offset from prime focus will see a smaller gain than prime focus so a
slightly larger dish may be needed and a separate dedicated dish for
circular uplink. That is not to say it could not be done, but to have both
at the same focal point is not a good idea.
A rotator is not needed for EsHail as it is proper geostationary.
So do you currently have satellite TV, how big, and what satellite is it
Also what is your location?
On 01/06/2016, Robert Bruninga <bruninga at usna.edu> wrote:
> Im not following this closely, but if the bands were cross polarized,
> it should be possible...?
> Bob, WB4APR
> -----Original Message-----
> From: AMSAT-BB [mailto:amsat-bb-bounces at amsat.org] On Behalf Of John
> Sent: Wednesday, June 01, 2016 1:23 PM
> To: Žilvinas Atkočiūnas
> Cc: amsat-bb at amsat.org
> Subject: Re: [amsat-bb] EsHail Microwave transponder satellite
> I don't think it is possible to create a dual-band dish feed that
> 2.4 and 10.5 GHz. AMSAT folks are working hard on a 5G/10G dual-band
> feed, and that is difficult. Even more complicated is your desire to
> use a commercial 10G satellite TV LNB as one of the two feeds. I think
> you are going to have to use two antennas for those 2 bands. The 10G
> dish with satellite TV LNB for one of them, and either a separate dish
> or a loop yagi or something else for the uplink. A Yaesu Az/El rotor
> can handle a pair of antennas, in fact it is almost a re
> On Wed, Jun 1, 2016 at 6:19 AM, Žilvinas Atkočiūnas <
> zilvinas.atkociunas at gmail.com> wrote:
>> Hi all,
>> Any ideas how to use two antennas with single dish ? (one of them SAT
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