[Moon-net] TS-950SDX and transverter problem

[Darrell]

Hi Folks;
I have the the TS -950SDX. TS-870,TS-2000 as IF receivers.......as 
much as we all like to believe.....the  output MUST be terminated... 
personally I use 100 Ohms....the drive. or pre-driver is NOT 50Ohm output/

To determine the Impedance  for your situation hang a 100 Ohm 
Resistor across the output , assuming the input to your Transverter 
is 50 Ohm's......still plenty of drive unless U need more than a few 
10 to 20 mW's .....specifically the TS 950 and 870 where a 28Mhz is 
assumed.........TS2000.....NOT a problem.

This Power drift will go the way of the of the Canadian Goose and 
disappear after going South for the COLD Winter.

Regards & Have Fun, Darrell

At 05:49 AM 2/17/2007, David Anderson GM4JJJ wrote:
>On 17 Feb 2007, at 09:00, Carsten Esch wrote:
> > a friend of mine is using his TS-950SDX with a DB6NT TR144H
> > transverter.
> > When going to TX (CW or SSB) the transverter will put out 20W and
> > within
> > seconds (3 to 4) the power will drop to 14W or so.
> > When you release PTT power will start at 20W again and will drop
> > again ...
> > It seems to me that IF output of the 950SDX is changing? Is someone
> > on this
> > list also using an TS950?
>
>
>Yes Carsten, I use the same transceiver as IF here and suffered from
>the same problem, it seems to be thermal drift in gain of the
>transmit driver stages when no ALC. I ended up building an external
>detector/amplifier to feed back ALC voltage to the TS950.
>
>I also made some modifications to the 950 to stop the bias on the PA
>transistors when transverting.
>
>The TS-950SDX transverter system is very poorly thought out IMO.
>
>
>73
>________________________________________________________________________
>___
>David Anderson, GM4JJJ         E-mail: david at gm4jjj.co.uk
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