[Kenwood] Difficulty keying linear in CW with TS-850

[Carl Smidt]

Hi Vince,

If I remember correctly, the switching time is too slow and the relay is too
noisy, "clacking".

Most build an external reed relay circuit to key the amp with most Kenwoods.

Use the control voltage from the 850's 'REMOTE' socket (Pin 7).

A Radio Shack reed relay (275-233), with coil rated at 12V at 11 ma is what
I used, but a similar relay will do.

The 850 can supply only 10 ma at 12V via pin 7 of its 'REMOTE' socket.

So hook at 100 ohm resistor from pin 7 in series with the relay coil and
connect the other side of the relay coil to common on the 'REMOTE' socket
(via shielded audio cable terminated to fit the 850's 'Remote' socket.

Put the whole thing in a 35 mm film canister and use a shielded, properly
terminated cable in and out. Takes only about 15 minutes or so to finish the
job.

Works like a charm and is noise-less. I used it with the 850 and now use it
with an 870 and an Alpha 91B.

Circuit was published in QST many years ago and can also be found in ARRL's
Hints and Kinks, 14th Edition, page 1-18.

Good luck.

73,  Carl   VE9OV






----- Original Message ----- 
From: Vince Shirley
To: kenwood at mailman.qth.net
Sent: Friday, June 04, 2004 4:48 AM
Subject: [Kenwood] Difficulty keying linear in CW with TS-850


Hi all,

I've just acquired a TS-850 for a very good price and am pleased with it in
all respects with the exception of one item.

When attempting semi break in on CW, the rig keys the linear OK (ground to
transmit) but there is no RF output and the rig emits a fast "chattering
relay" type of sound.

If I manually ground the linear, or use the rec/send switch all is OK on CW
as it is in SSB.

I've experimented with SW1 (external/internal keying) which doesn't make any
difference (neither did I expect it would) and the VOX hang time doesn't
seem to make any difference to the problem either.

Am I right in thinking that the fact that that there is no RF would indicate
that its either seeing an open circuit or the switching time is too slow.

Anyone any ideas ?

Vince G0ORC


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