[amsat-bb] Help needed please

Aayush Yadav aayushyadav825 at gmail.com
Wed Dec 16 11:25:37 UTC 2015


Hello all,

Currently we are planning to transmit 1 Watt signal from the satellite but
due to vswr losses, the transmitted power is around 100 mW. This is due to
the antenna's S11 loss being around -1 rather than -10. This is for the VHF
band for which we are using an antenna 17 cm long, thus such high loss. The
length can not be increased much and so is the case with the
electronics(power amplifier) as we are restricted by other constraints.
We would love to hear some of your suggestions so as to how can we still
increase the transmission power meeting all these requirements. And if not,
what can be done on the Ground-Station to improve the reception. Are there
satellites available which transmit such low power and still can be
received?
Any Help would be appreciated.

Thanking you,
Aayush Yadav
Team Pratham.

On Mon, Dec 7, 2015 at 9:01 AM, Nitin Muttin <vu3tyg at yahoo.co.in> wrote:

> Hi Aayush,
>
> As discussed please consider the below points.
>
> 1. Fine tune your antennas in the satellite sub band on VHF and UHF. VHF -
> 145.800Mhz - 146.000 Mhz. UHF 435-438 Mhz.
>
> 2. Replace the RG -58 Cable with Heliax or LMR 400 Cable.
>
> 3. Move the pre amp (LNA) to the mast closer to the antenna.
>
> 4. Refer http://www.dk3wn.info/satellites.shtml for the list of
> satellites , modes and frequencies.
>
> 5. For some satellites you can use sound card based software TNC like
> http://uz7.ho.ua/packetradio.htm for AX25.
>
> 73
> Nitin [VU3TYG]
>
> ------------------------------
> *From:* Aayush Yadav <aayushyadav825 at gmail.com>
> *To:* Nitin Muttin <vu3tyg at yahoo.co.in>
> *Cc:* Mani VU2 WMY <wmy at isac.gov.in>; Somashekar S. <vu3jba at gmail.com>
> *Sent:* Saturday, 5 December 2015 2:27 PM
> *Subject:* Re: Help needed please
>
> Hello sir,
> As discussed over the phone, could you please provide me with the various
> satellites to track, information regarding softwares and the cables.
> Thank you sir,
>
> Yours sincerely,
> Aayush
> Team pratham
>
>
>
> On Tue, Dec 1, 2015 at 6:28 PM, Nitin Muttin <vu3tyg at yahoo.co.in> wrote:
>
> Hi Aayush,
>
> Sure, we can discuss on Saturday after 11AM. I can be reached on
> 9880018675.
>
> 73
> Nitin [VU3TYG]
>
> ------------------------------
> *From:* Aayush Yadav <aayushyadav825 at gmail.com>
> *To:* Nitin Muttin <vu3tyg at yahoo.co.in>
> *Cc:* Mani VU2 WMY <wmy at isac.gov.in>; Somashekar S. <vu3jba at gmail.com>
> *Sent:* Tuesday, 1 December 2015 3:40 PM
>
> *Subject:* Re: [amsat-bb] Help needed please
>
> Hi Nitin,
> I was wondering if you were free this week, we would really appreciate the
> help.
>
> Thanking you,
>
> Regards,
> Aayush Yadav
> Team Pratham.
>
>
>
> On Tue, Nov 24, 2015 at 9:10 PM, Nitin Muttin <vu3tyg at yahoo.co.in> wrote:
>
> Sure Aayush we can discuss this next week over a phone call. This week we
> have a tight schedule to the HAMFEST 2015 in Rajkot.
>
> 73
> Nitin [VU3TYG]
> Secretary, AMSAT INDIA
> www.amsatindia.org
>
> ------------------------------
> *From:* Aayush Yadav <aayushyadav825 at gmail.com>
> *To:* Nitin Muttin <vu3tyg at yahoo.co.in>
> *Sent:* Tuesday, 24 November 2015 7:37 PM
>
> *Subject:* Re: [amsat-bb] Help needed please
>
> Hello Nitin,
>
> We would love to have your help on the same. If you have any advice on how
> we should continue our work we really welcome the suggestions. Thanks a lot
> for your reply.
> If you could help us in improving our sensitivity, as currently we get
> around -110 dbm noise at the antenna but as per our calculations the power
> of the signal we need to recieve would be of an order of -150 dbm.
>
> 73
> Aayush Yadav.
> Team Pratham.
>
>
>
> On Tue, Nov 24, 2015 at 11:40 AM, Nitin Muttin <vu3tyg at yahoo.co.in> wrote:
>
> Thanks Burns for the pointers.
>
> @Aayush, I can help you with information so that you are able to
> successfully receive and decode telemetry.
>
> 73
> Nitin [VU3TYG]
>
> ------------------------------
> *From:* Burns Fisher <burns at fisher.cc>
> *To:* Aayush Yadav <aayushyadav825 at gmail.com>
> *Cc:* "amsat-bb at amsat.org" <AMSAT-BB at amsat.org>
> *Sent:* Tuesday, 24 November 2015 1:28 AM
> *Subject:* Re: [amsat-bb] Help needed please
>
> Hello Aayush,
>
> Starting out with very strong signals is probably a good idea even though
> you can probably get any satellite
> that you wish with a good ground station.  Start out with AO-85 for FM
> reception and AO-73 for SSB
> reception.  AO-73 is especially strong during local day time during
> Mon-Friday (UTC).  There is not
> transponder turned on then, so all the power goes into the telemetry.
>
> Both of these can be received with an HT (handheld with a simple antenna)
> so you are very likely to receive
> them on any station you have and optimize from there.
>
> I would also suggest that you might find local colleagues in AMSAT-India
> who would be able to tell you
> things of local interest (what parts are available where, for example).
>
> 73,
>
> Burns  W2BFJ
>
> On Mon, Nov 23, 2015 at 2:16 PM, Aayush Yadav <aayushyadav825 at gmail.com>
> wrote:
>
> > Hello all,
> >
> > As a part of a student satellite project from India, I have a few
> questions
> > regarding how can i improve my reception of data on the ground station.
> We
> > have a TS2000 and have designed a few yagi antennas for uhf and vhf
> band. I
> > would like to know some satellites on which we can practice receiving any
> > signal. We are totally new to this system and have practiced some failed
> > attempts of the same. Further, we would really appreciate If anyone could
> > help on how we can increase our reception power. Any other help or advice
> > would also be appreciated. Thank you.
> >
> > Aayush Yadav,
> > Team Pratham,
> > IIT Bombay.
> > _______________________________________________
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> > expressed
> > are solely those of the author, and do not reflect the official views of
> > AMSAT-NA.
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>
>
> >
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
>
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