[Amps] Amps Digest, Vol 159, Issue 6

[Patrick EGLOFF]

Hi Jim,

As i wrote, the components are all OK. I measured them with my LCR meter.

Anyway, the problem is solved... i use the 24 MHz input circuit and it
works perfectly on 21 MHz as well. Not an elegant solution, but the easiest
! 2 wires unsoldered and 2 small pieces making a short circuit between 21
and 24 Mhz rotary switch positions.

Perfect match on both bands and full output power.

73, Patrick



> ##  Did you actually check the tuned input coil, and the 150 pf fixed cap
> and the
> adjustable cap with a digital LCR Meter ??
> My drake L4B also uses a pair of 3-500Zs, and the caps are  both  fixed.
> The coil is adjustable....slug tuned.  Input swr is  1:1  across the 15m
> band.
>
> ##  The L4B  uses  paralleled  100 pf caps  ( total = 200 pf)  on the
>  xcvr  side......
> and paralleled 65 pf caps  ( total = 130 pf) on the cathode side.
>
> ##  I suspect that either your fixed 150 pf cap is out of spec, or your
> fixed .34uh
> coil is out of spec.   Two paralleled  75 pf caps  ( total = 150 pf)  will
> handle  more RF
> current vs a single  150 pf cap.  Your 150 pf cap may well have been out
> of spec since day
> 1.
>
> Jim   VE7RF
>
>
-- 
Patrick Egloff - TK5EP
email : pegloff at gmail.com
Web page : http://www.egloff.eu