I had something similar happen, and it was the capacitor in the EFHW
heating up on 12 and 10 meters. It didn't heat up on any other bands.
On 7/17/22 11:38, Andy Durbin wrote:
Don't need to have ferrite in the antenna system to see this sort of SWR
"runaway". I have the same problem with
Hello Andy
The main reason I abandoned small transmitting loops was their susceptibility
to temperature variation, one cause being power input, the other due to
instantaneous change when the sun comes out.
Apologies for sliding off topic.
David G3UNA
> On 17/07/2022 16:38 Andy Durbin
Don't need to have ferrite in the antenna system to see this sort of SWR
"runaway". I have the same problem with my home brew small transmitting loop
if I run over 100 W.
Spent some time trying to figure out what was heating and causing the loop's
resonant frequency to shift. My preliminary
From what has been stated, this not a true end fed Half wave using a 9-1 balun.
That is the issue. The balun needs to be a 49-1 ratio to properly feed an
EFHW antenna. The method you are using requires a different counterpoise than
an EFHW. EFHW are efficient at one frequency and direct
No. Over time the current does not "back up".
Something in your system is heating up. My bet would be that your
toroids used as common mode chokes are heating up due to the very high
voltages that exist at the end of an end fed half wave antenna. It's
not likely to be a current problem
On 7/15/2022 10:35 PM, Peder Kittelson wrote:
That is a good question. I was thinking of adding to the answer above.
I called Palstar about a year ago and asked if there was any problem
linking a coax cable through a short length of balanced line. He said
he did not see any problem with
On 7/15/2022 10:21 PM, Peder Kittelson wrote:
The antenna is homemade, in a sense. I bought a 9-1 Balun from Balun
Designs with the capacity for a tie into a counterpoise which I use. I
have a 30 DB inline RF attenuator attached to the Balun Designs piece.
I have run RG213 to my radio room.
Something in the antenna system is heating up. Ferrite
baluns/transformers are likely culprits.
73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/
On 16-Jul-2022 05:53, Peder Kittelson wrote:
When on 80 meters, the longer I hold the tune button down the
On 7/15/2022 9:53 PM, Peder Kittelson wrote:
When on 80 meters, the longer I hold the tune button down the higher the
SWR goes to the point the KPA500 folds back with warnings. I don't usually
hold down the tune button longer than about 5-6 seconds.
I use a Manual Palstar BT1500A tuner which
Hi,
A bit more information please...
1. How much power are you putting out?
2. How long in seconds before the SWR starts to increase?
3. What is the native antenna SWR, not what the tuner is showing, but
the real SWR?
4. Are you running with a balun of any kind?
5. What type of
When on 80 meters, the longer I hold the tune button down the higher the
SWR goes to the point the KPA500 folds back with warnings. I don't usually
hold down the tune button longer than about 5-6 seconds.
I use a Manual Palstar BT1500A tuner which does a good job of tuning my
EFHW wire antenna.
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