[CQ-Contest] FT-1000D HUM in RX audio

Bob AD5VJ ad5vj at ad5vj.com
Tue Apr 17 10:28:16 PDT 2012

I am a little upset after buying the RASCAL 90.00 after shipping. Then
finding out it will only do soundcard modes and not key my rig for CW nor
use the 4 pin connector RTTY interface. Oh well live and learn I guess.

I redid the entire station grounding scheme after taking all equipment off
of the bench, got behind the table and installed a grounding buss made from
an unused shelf support bracket. I installed a ground from each piece of
gear to this home brew grounding bar and took the bar to ground about 8 feet
from the shack to a grounding rod.

The hum still persisted. I then realized I had not included the computer in
the grounding scheme. After connecting the computer to the grounding bar the
hum immediately went away.

Now my issue is my DX software, DXLABS will not key the rig with my present
setup. The guy I bought the radio from was using different software and had
the CW keying done through the same port as the CAT was connected to. DXLABS
does not allow for this although I have logger32 and N1MM working with it

So now I build a separate keying setup to use on a different port other than
port1 and I will be able to use my computer for keying CW as well.

73, AD5VJ

-----Original Message-----
From: cq-contest-bounces at contesting.com
[mailto:cq-contest-bounces at contesting.com] On Behalf Of Bob AD5VJ
Sent: Sunday, April 15, 2012 7:41 PM
To: CQ-CONTEST at contesting.com
Subject: [CQ-Contest] FT-1000D HUM in RX audio

I have a FT-1000D which, with the RF and AF gain CCW (off) and everything
disconnected from the radio except a Heil PRO headset or my Yeasu SP-8
filtered speaker, has a very noticeable 60 Hz hum on both channels (ie.,
main and sub in "stereo"). After searching in Google with various phrases,
all they can talk about is ground loops.

I am about to start throwing filter caps at the headset and the external
speaker, but would rather solve the problem (if there is a known problem)
rather than just the symptom. The hum level doesn't vary with the AF gain
control, the AF output is clean and the hum disappears into the "normal"
volume level.

I just bought a RASCAL GLX last week and hooked it up a couple days ago. The
hum also appears in this setup but the hum doesn't appear in the digital
decode window. I can hear it in the head set for a second as I send, then it
disappears into the sounds of the monitor signal as my signal is sent back
to the headset. It doesn't appear in the transmitted signal in the decode
window however.

I've been living with the hum for a couple of weeks now, I went to the shack
of the ham who I purchased the radio from and he had it all hooked up when I
got there, while listening to very low signals on his headset off the
beverages I noticed no hum at all, until after I drove it home and hooked it
up here.

He uses a Heil headset which is the PRO with the phase switching in it and
also an external speaker. I use the standard Heil PRO without a phasing
switch and the SP8 external speaker. It was fine with all the other rigs I
used it on including an FT-775DSP and an FT-1000MPMKV and Icom 756PROII that
I had before.

Has anyone fixed this in the 1000D?

Thanks for listening and looking forward to your responses,

73, Bob AD5VJ

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