[Elecraft] RF feedback

[AJSOENKE at aol.com]

In a message dated 12/5/2008 9:05:02 A.M.  Pacific Standard Time, 
rlindzen at MIT.EDU writes:
I'm running the K3 with an  Ameritron AL800 and a Steppir 3 element 
with 40m dipole add-on.  I have  a severe though intermittent feedback 
problem on 40m that I did not have  with an Icom 751a.  The feedback 
only occurs when I'm using the amp  (even with very low drive).  I've 
common core choked virtually every  lead with ultimately no luck.  I'm 
using the Elecraft hand mike.   Is there a known problem 
here?  Otherwise, I'll just keep  searching.

Dick

Dick Lindzen, KA1SA
301 Lake Avenue
Newton,  MA 02461 USA

1-617-332-4342  

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++++++++++++++++++++++++++++++++++++++++++++++++++
Have you tried other bands?  What Version Firmware are you  using?
 
I have a problem that may also be RF feedback related. I occurs only on 40M  
and only when I exceed 80 W to my Dipole antenna. No problem full power up to  
120 watts into Vertical or any other band. Problem started immediately after  
upgrading FW to V 2.46. I have a couple upgrades to do on the rig including 
the  AGC upgrade, which I have held off making until my Sub Receiver upgrade. 
Since  that arrived a few days ago I will be doing all upgrades and the 
subreceiver  install this weekend. I don't plan on any changes in FW other than 
activating  the KRX3.  I will then test the 40M issue. I do not have a good earth  
ground on the K3 nor am I running any form of Amp. But, the rig has worked  
perfectly since it was installed a year ago and the ATUs have always provided a  
good match in the 1.X:1 range on both Vert and Dipole including 160M, 30M, 
12M,  17M in addition to the usual 5 bands the Ants are designed for.
 
Al WA6VNN
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