[amsat-bb] Re: SSB Preamp

[wouter weggelaar]

Hi Peter,

Does it show PAMP on the display or does it come on for only very shortly?
I have this setup working at the Delfi-C3 groundstation without
problems with a lightning arrestor in the circuit (gas discharge type)
If you have a short somewhere in the cable the PAMP sign will only
light very shortly and will be off again due to the protection inside
the IC-910.
You could also carefully check the setup with a bias tee if you have
one available.
Should you have access to the preamp right now (ie, its not already
outside and hard to reach) you could try with a short cable and listen
if the relay comes up (no voltage on the coax means pre-amp bypassed =
relay off)
If I understand correctly you have enabled the pre-amp in the menu?
(Press MENU long, go to 435 PRE with up and down keys and make sure it
says ON)
If you have a TX PA, then most probably it has an input capacitor as
Alan already pointed out. Try without the PA in the loop.

Good luck and 73's

Wouter Weggelaar
PA3WEG


On Tue, Aug 12, 2008 at 1:29 PM, Alan P. Biddle <APBIDDLE at united.net> wrote:
> Also, most TX amplifiers have a series capacitor on the input, which will
> also block the DC power.  With the TX amp switched off/out, there is usually
> a DC path, but check the schematic.
>
> Alan
> WA4SCA
>
>
>
> Not sure what you mean by "recognized a preamp" (I don't have a 910), but if
> you have a lightning arrestor in between the rig and the preamp, they
> usually block DC from passing.  Mine does, so I had to power it with an
> external cable (which, now that I think of it, kind of defeats the purpose
> of the lightning arrestor...!).
>
> Greg  KO6TH
>
>
> ----------------------------------------
>> Date: Mon, 11 Aug 2008 16:39:56 -0400
>> From: roi at optonline.net
>> To: AMSAT-BB at amsat.org
>> Subject: [amsat-bb]  SSB Preamp
>>
>> Hi,
>>
>> Is anyone using a SSB SP-7000 preamp and an Icom 910H powered via direct
>> feed from the coax.  I am not able to turn the preamp on with this method,
> I
>> set the menu for the preamp and the front panel; it recognizes a preamp
> but
>> it's not working, any ideas?
>>
>> 73 Peter
>> WB2OQQ
>>
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