Hi Michael, HB9WDF
I think we have another problem too: Since the Dutch transponder is very sensitive someone will attempt to use it in FM using an HT and arrow antenna.
73" de
i8CVS Domenico
----- Original Message ----- From: "Michael Lipp, HB9WDF" hb9wdf@bluewin.ch To: "i8cvs" domenico.i8cvs@tin.it Cc: "Ib Christoffersen" oz1my@privat.dk; pe0sat@vgnet.nl; pe1rah@yahoo.com; "Amsat - BBs" amsat-bb@amsat.org Sent: Friday, March 16, 2012 2:47 PM Subject: Re: [amsat-bb] Re: Dutch transponder versus the Indian transponder.
Hi Domenico
I think we have also another problem: In the last few years, the OP's growing up without fullduplex TRX (Ic-706 and similar) and use the ssb sat. They can't hear her own downlink signal from the bird.
73's de Michael
HB9WDF, Michael Lipp, JN47AE
Am 16.03.2012 um 12:14 schrieb "i8cvs" domenico.i8cvs@tin.it:
Hi Ib, OZ1MY and William, PE1RAH
Thank you for the information about the diode limiter into the William's transponder.
I got the link of PE1RAH describing the block diagram of indian and Duch transponders but without information about AGC or diode limiter.
http://www.qsl.net/pe1rah/HAMSAT-info.htm
I hope that William will informe us on this matter.
73" de
i8CVS Domenico
----- Original Message ----- From: "Ib Christoffersen" oz1my@privat.dk To: pe0sat@vgnet.nl Cc: amsat-bb@amsat.org Sent: Friday, March 16, 2012 11:36 AM Subject: [amsat-bb] Dutch transponder versus the Indian transponder.
Hi all, The two transponders are not built exactly the same way.
The Indian transponder has an AGC - but according to my memory Williams transponder has a diode limiter.
I think that can be the difference.
In theory the AGC will regulate the gain down so that the "stronger" station "drowns" the ones with a lower uplink signal.
The diode limiter will of course limit the signal for the strong
stations -
but also create distortion in a broad frequency range for all stations. That is if there is a very strong signal - or many stations at the same time.
Whatever the reason KEEP THE POWER DOWN
73 OZ1MY/Ib
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Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb