[1000mp] MK 5 Driving Amp - a twist?

[Rob Atkinson]

hi,

is there some reason why the input swamping resistor can't be swapped 
out for one that's around 60 ohms?

rob / k5uj

On Tuesday, October 24, 2006, at 08:58 AM, Rob Murray wrote:

> I have been following the exciter/amp interface thread with great 
> interest,
> and have learned a lot from it, thank you all. I have a Mk 5 driving 
> an old
> Dentron MLA-2500 full power amp, and on reading much earlier in this 
> forum
> that the Mk5 internal tuner did not add much to the process, 
> discontinued
> using that tuner.
>
> This leaves me with pretty much a permanent SWR at the Mk 5 of about 
> 1.8,
> independent of band choice; I haven't worried about it much, but have
> thought it would be nice to get it lower. While the thought of the 
> 20.5 ft
> coax matching section is most interesting, I had been thinking of 
> simply
> winding a toroidal impedance matching transformer (say N1/N2 = 1.4:1) 
> and
> placing it somewhere in the input line of the amp (on the amp input 
> side
> after the bypass relay). This thinking based on the thought (guess?) 
> that
> the amp input impedance is pretty well set by the 100 ohm input 
> swamping
> resistor, slightly reduced by the tube input, ie., about 90 ohms 
> resistive
> (generally), consistent with the Dentron specs in the manual.
>
> Since none of the discussion has considered such a solution, I must be
> missing an important point (or two or more...)
>
> What am I missing?
>
> 73
>
> Robert Murray    VA7RMM
> RR1 S5 C16
> Edgewood, BC    V0G 1J0
> Phone/Fax (250) 269-7698
>
>
>
> ______________________________________________________________
> 1000mp mailing list
> Home: http://mailman.qth.net/mailman/listinfo/1000mp
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:1000mp at mailman.qth.net
>