Re: [Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-18 Thread Tom N4LSJ
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

Re: [Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-17 Thread CUTTER DAVID via Elecraft
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 wr

[Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-17 Thread 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 a

Re: [Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-16 Thread Bill Johnson
22 10:42 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500 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 heatin

Re: [Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-15 Thread David Gilbert
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 sin

Re: [Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-15 Thread Dave Erickson
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 that

Re: [Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-15 Thread Dave Erickson
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. 

Re: [Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-15 Thread Victor Rosenthal 4X6GP
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 highe

Re: [Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-15 Thread Dave Erickson
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 do

Re: [Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-15 Thread Dave (NK7Z)
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 antenna

[Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

2022-07-15 Thread Peder Kittelson
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.