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Re: LF: TRANSVERTERS

from [Stefan Schäfer] [Permanent Link][Original]
To: [email protected]
Subject: Re: LF: TRANSVERTERS
From: Stefan Schäfer <[email protected]>
Date: Tue, 06 Nov 2012 18:06:38 +0100
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Mal,

If you're generating 500 kHz with a HF TRX then this can happen. I guess the output transformer of the PA appears almost like a short cut for the output FETs, so the losses will be relatively high.
A 3 dB attenuator on the output will not help of course.
One method may be to contact the driver directly, as you say. Or, find the pot to allow to set the output power to even lower levels. I have an IC-275H for 2m which has a pot to adjust the RF power from 10...100W. But inside there is a seconds pot. With this pot it is possible to increase the range to 1...100W !

Or you may try to run the TRX on 11V instead of 13.8V! Just insert 2 or 3 diodes in series...

73, Stefan/DK7FC

Am 06.11.2012 17:45, schrieb mal hamilton:
   RIG/TRANSVERTER HEAT
I have noticed when running a Transceiver at low power for Transverter or other use the Transceiver PA gets very HOT so it would appear that this is an inefficient approach except the Transceiver has a dedicated low power output.
I was wondering what system was used to reduce this power. It would be better to disable the PA and take the output from the driver stage.
It is vy noticeable on an IC-706
 
de G3KEV
 
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