I agree about the padding caps, good addition. I know of instances of both,
fixed caps with insufficient current rating, and the balun insufficient for
160m blocking.
If the caps were starting cold, there would be some period where the SWR
was normal and then start climbing.
The 160m stressed
Had the same issue as you Lloyd here - in a prior antenna matching net.
On 160 it would start to drift after calling CQ a few times. I did not
flip to vac caps. But instead ended up using lower valued, paralleled
doorknobs, so that the current was shared among multiple paralleled caps
and
Hello Dale,
I had this same problem.
In my case I discovered that it was the "Doorknob" capacitors heating up and
changing value.
I had installed some fixed value doorknobs to "pad" the variable cap in the
matching circuit.
Changed to Vacuum Caps, no more problems.
73
Lloyd - N9LB
While air variables certainly do flash over, the effect is sudden, and has
no "ramping up" effect.
From Dale's original post: "The problem I having is that when transmitting
the SWR goes up with power
and if I key-down for very long the SWR rises rapidly and takes off."
He can observe the SWR
I experienced wide spaced air variables flash over at moderate to high power in
my shunt feed omega match. I changed to vac variables. That solved the problem
with the additional benefit of easier tuning via the vac cap's verniers.
GL - Steve WB6RSE
> On Aug 27, 2020, at 10:58 AM, John Harden,
I am wondering if the air variable is flashing over. I am willing to bet that a
vacuum variable would correct the problem. I use two (2) Vacuum variables in an
Omega match.
73,
John, W4NU
Sent from my iPhone
> On Aug 27, 2020, at 1:38 PM, Guy Olinger K2AV wrote:
>
> Hi Dale,
>
> The
Hi Dale,
The RF voltage is always looking at the far end (stuff on the end away from
the tower base) to jump onto.
*** Provide a deliberate, designed, long-term weather survivable metallic
path to the boom of the highest yagi and provide a low R path from the
boom to BOTH sides of at least one
Hi Steve and all...
Tks for the first QSO this summer Steve!
There was not much activity from NA or from EU. Static was high here as was
W1AW (S8-9)
See you all on 160
73
Len SM7BIC
-Ursprungligt meddelande-
Från: Topband
För VE6WZ Steve
Skickat: den 27 augusti 2020 17:40
Till:
The balun heating hypothesis could be tested by disconnecting the balun.
Dave, KH6AQ
On Thu, Aug 27, 2020 at 7:06 AM Dale Drake wrote:
> Here's my problem. I'm experiencing SWR problems
> with 160M shunt feed on my tower. Using a gamma
> match with HV air variable caps I am able adjust
>
Here's my problem. I'm experiencing SWR problems
with 160M shunt feed on my tower. Using a gamma
match with HV air variable caps I am able adjust
the tap point to get a very nice SWR curve using
my AA-35 Zoom analyzer. The problem I having is
that when transmitting the SWR goes up with power
and
Last night before watching the news with my xyl, I decided to check 160. I
didn’t expect much with the solar wind above 400km/s and a pretty hot looking
AU.
In spite of the high QRN I saw a trace on the waterfall from Andy DL8LAS
calling CQ. As the amp was warming up, I also could see Len
Hello Andy
I will try to get on in the morning. I have been very busy repairing my
VHF ham shack and have little time for anything else. I have done
almost no trout fishing this summer, but spend my time replacing rotten
wood in walls and floors! Two days ago, I drove back up the hill and
12 matches
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