[Drake] Filter for R4C - what's this for a filter

[Lars E. Pettersson]

On Saturday 01 March 2003 18:03, Rolf G. Schroeder wrote:
> Hi,
> I have recently bought a Drake 4C line which came with an addtional
> Filter from Network Sciences inc. With numbers like SL 4006 (last three
> digits unsure) 7904 and 5.645-4.0/8 on it. It was produced on May 15
> 1979 (that at least is the stamp on the bottom. Should I replace the
> original filter in the first IF by this one?

I think it is the SL-4000 filter. A 4 kHz wide filter for the Drake R7 and 
TR7.

It will not work in the first IF of the R4C due to different impedances, 
the filter is 50 ohm, the R4C first filter is supposed to be 1000 ohm and 
15 pF. The second IF should have 50 ohm filters and the IF frequency for 
AM is 5.645 kHz (5.695 kHz for SSB/CW) so you might use it there. If you 
do so you must remove the three resistors (R37, R134, and R135) to get the 
impedances right.

73 de Lars, sm6rpz

-- 
Lars E. Pettersson, SM6RPZ
Gothenburg, SWEDEN
sm6rpz@home.se
http://www.gbg.bonet.se/cassegrain/