Kenwood TS 850/DSP-100 Problem

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tbd
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Joined: Fri Jun 01, 2012 10:31 am

Kenwood TS 850/DSP-100 Problem

Post by tbd » Wed Sep 19, 2012 10:15 am

Hi, I have RFI problem and I believe that it comes from the DSP-100 and not from the TS-850. When
I turn on the amplifier which is a Kenwood TL 922A there is where my problem starts getting a high
Distortion due to high RFI, if I keep my amp on but I reduce the power on the transceiver to let’s say 40 watts then there is no problem, this problem is in 40 meters, but not on other bands, I’ve checked the
SWR on the antenna and it’s at 1.2 so there is no problem with the antenna I’ve used ferrite clamps
On the Cables, I have a good ground to the Radio and Amp.

Any tips ?

Thanks

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Post by Voodoo Guru » Wed Sep 19, 2012 4:05 pm

Howdy,
You didn't say, but were assuming that all your rack and mic equipment is hooked up while this is happening. We have had similar problems on 40 meters with the TS850/DSP100 combo. The end result was that the antenna was just too close to the studio and had a lobe cutting right through the shack. The Mic and mic cable was where the RF Ingress was happening. You could touch the mic or the cable and the sound of the RFI would change.

We were able to reduce the RFI to a tolerable level by shortening the Mic cable while adding bypass caps to the XLR, along with mix #31 ferrite added to the cable at both ends and the middle. We also repositioned the mic. Ultimately the antenna had to be repositioned to cure it completely.

The key is to find out where the RF Ingress is happening at. So the first step is to start removing units and see when/if the RF goes away. It is a trial and error systematic approach.

RFI hunting is an art in itself as no two studios are the same.
Good Hunting!
Voodoo Guru
From Deep in the IDD of the Sub-Harmonix Realm

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