Probably the capacitor. Try 2 or 3 smaller values in parallel to make your
2200pf. Then see if the drift is the same.
Or the coil wire size is too small.
73
Gary K4FMX
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
> Steve London
> Sent: Sunday, March 12, 2017 10:42 PM
> To: Topband; towertalk@contesting.com
> Subject: [TowerTalk] What's heating up ?
>
> I am experimenting with the N4KG reverse feed method for 160 meters on a
> tower with a lot of stuff already on it. I like the possibility that
> elevated radials will be an improvement over my terrible, dry,
> mountaintop ground characteristics.
>
> As I transmit, the SWR creeps up, pretty significantly. Something is
> clearly getting warm.
>
> Possibilities:
>
> - I am matching the 160 feedline with an L-network (series L, shunt C).
> TLW says 7 amps through the capacitor, with 3 watts of dissipation. The
> capacitor measures 2200 pf, the usual transmitting capacitor,
> cylindrical, about 3/4" in diameter.
>
> - The M2 balun feeding the 40 meter beam on the same tower. I monitored
> the SWR on the 40 meter beam while transmitting on 160. No change in 40
> meter SWR.
>
> - The M2 balun feeding the KT-36XA on the same tower. I monitored the
> SWR on the KT-36XA while transmitting on 160. No change in KT-36XA meter
> SWR.
>
> - Gamma match on homebrew 15 meter beam. Gamma match is just a piece of
> RG-8 dielectric/center conductor inside aluminum tubing.
>
> Suggestions on how to troubleshoot this ? Start by disconnecting the
> feedlines to the baluns ? And once I determine which component is
> heating, what then ?
>
> 73,
> Steve, N2IC
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