[Kenwood] RE: 950sdx rf problem

Thu Jul 1 04:05:18 EDT 2004

Vince,
I would suspect the RF is getting in through the mains. (The 850 and MP 
were
being run off separate power supplies I would assume.)
Also, if any of the radios you mention have a history of RF problems it 
would be the 850.
I have read many reports (and fixes) for rf problems with 850s.
In my case I took an 850 (which I always had RF problems with) and 
replaced it with a 950sdx and cured my rf
feed back dilemma.
Best wishes,
Berry W6EZ
>Hi all,
>>For those that remember a couple of weeks ago I asked for readers views on
>the merits of a 950SDX as against a new 870 or a used 756 PRO2.
>>Well, my experiences with the 850 and the views expressed on here was enough
>and I had the 950 which was delivered a couple of days ago, and I had the
>good fortune yesterday to have a day free from work where I could get used
>to it.
>>I concur wholeheartedly with the views expressed on here in respect of the
>receiver which is all I expected it to be. I really need a while to get the
>best out of it but the noise floor is very low and very easy to isolate weak
>CW signals from the crud with the used of the filtering and the AF/IF VBT.
>>On transmission I had an immediate problem - RF in both the audio and the CW
>on all bands (raspy auroral note to the CW and audio, erratic behaviour of
>the ALC, erratic power levels etc...). The antenna I used was a Carolina
>Windom (at 35 feet), used successfully with the 850 and a 1000MP on all
>bands. After removal of all "inputs" to the 950 (external speaker leads,
>key, headphones, RS232 lead etc.,) was done but the problem persisted.
>>Some work on the antenna, changing feeders back from Aircell 50 back to
>RG58, insertion of a RF choke into the feed line and repositioning the
>TS950SDX inside the shack, a thorough check (and changing a few) of the
>patch leads and antenna switch in the shack has reduced the problem to 24
>MHz and (occasionally) 28 MHz.
>>I've taken the antenna down and I can't see any problem around the balun or
>the choke on the vertical radiator and as night was falling that's where I
>left it. This morning, having slept on the problem, I check it before going
>to work and initially there was no problem on 24mHz but it returned after a
>couple of minutes. There was plenty of RF around in the shack too, the PC
>objected strongly to it and the ELCB blew out sraightaway - and that was at
>20 watts !
>>Both the 850 and the 1000MP don't seem to have a problem with it although
>when I crank up the power to 200 on the 1000MP there is a little RF in the
>shack.
>>Repositioning the antenna is impossible (I have a long narrow garden) - does
>the 950 have a known issue with being susceptible to RF and can anyone
>suggest anything else I could to alleviate it. I would like to stick with
>the Carolina Windom as its been very successful for me and due to the joke
>that is the "planning consent" regulations in the UK I can't get a tower or
>mast up. Or rather I can have a mast, but I can't put any antennas on it
>!!
>>Vince G0ORC
>