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https://www.satsig.net/cgi-bin/yabb/YaBB.pl Anything else >> General and other topics >> Low Ku-band transmission https://www.satsig.net/cgi-bin/yabb/YaBB.pl?num=1299072192 Message started by Agor on Mar 2^nd, 2011 at 1:23pm

Title: Low Ku-band transmission
Post by Agor on Mar 2^nd, 2011 at 1:23pm

A question to the forum:
Is a special feed/antenna required for low Ku-band (12.75 to 13.5 GHz) transmission?

I am asking, as I assume there are some filters in standard feeds that suppress out of band frequencies.

Thanks,

AGOR

Title: Re: Low Ku-band transmission
Post by Eric Johnston on Mar 2^nd, 2011 at 2:28pm

If you are going to transmit in the band 12.75 to 13.5 GHz and receive simultaneously, presumably around 10 or 11 GHz, you will need special filter arrangements.

Specify both your receive and transmit frequency bands.

Most Ku band systems receive in part of the range 10.7 - 12.75 GHz, and transmit in part of the range 13.75 - 14.5 GHz. � Note the gap between the top of the receive band and the bottom of the transmit band. �The narrower this gap, the more difficult it becomes to make a suitable filter. �Many filters are designed for operation only in parts of the above bands, e.g. 10.95-12.75 GHz and 14-14.5 GHz.

Best regards, Eric.

Title: Re: Low Ku-band transmission
Post by Agor on Mar 2^nd, 2011 at 3:02pm

Thanks Eric.
The uplink frequency range is 12.75 to 13.5 GHz.
The downlink frequency range is 11.7 to 12.2 GHz.
Very close...

I believe this frequency range arrangement is meant mainly for one way services (such as, TV). The question is if it is possible to operate two way service without having to use non standard feeds, etc.

Regards,

Agor

Title: Re: Low Ku-band transmission
Post by Eric Johnston on Mar 2^nd, 2011 at 3:13pm

For two way service you will need a non-standard feed/ filter arrangement.

Feasibility for end users customers will depend on the price for the part. �

Can you find any source with an acceptable price ?

Can anyone suggest a source for suitable filters ?

Best regards, Eric.

See https://www.bscfilters.com/?page=SATCOMKUR&tmpl=prodgen part number SATCOM395

Title: Re: Low Ku-band transmission
Post by Agor on Mar 2^nd, 2011 at 3:53pm

Thanks Eric.
I will approach BSC Filters soon.

Regards,

Agor

Title: Re: Low Ku-band transmission
Post by Eric Johnston on Mar 2^nd, 2011 at 7:13pm

Ask their advice regarding a complete feed system design. �You need an OMT as well and flanges must be suitable. �The distance of the TRF filter reflection point back to the OMT may matter. I've seen strange transmit cross pol problems when that distance is wrong - no idea why.

I would keep searching for a complete unit or someone who can make use of such a filter above to make up a complete feed that does what you want.

Best regards, Eric.