[Elecraft] OT: manual & automatic tuners

John McClain [email protected]
Sat Jan 11 15:04:01 2003


When I was in the Air Force in the early 60's, they trained me on
aircraft radios, one of which was the ARC-65.  I don't recall much
about it other than it was round and looked something like a garbage
can. It was used in the B-52 and it had its own built in automatic
antenna tuner.

John
K7SVV
[email protected]
K1 #1378, K2 #2569, SST 20, Rock Mite 20, Rock Mite 40, Nor'Easter

----- Original Message -----
From: "lhlousek" <[email protected]>
To: <[email protected]>
Sent: Saturday, January 11, 2003 9:29 AM
Subject: [Elecraft] OT: manual & automatic tuners


> Julian wrote:
>
> >> As I recall, in the early 80s. (when automatic ATUs were first
introduced)<<
>
> I don't know when they were first introduced but I've seen automatic
tuners that look to date from the 40's or 50's, maybe even
earlier...they look to be some type of commercial, military, or
maritime gear.
>
> >>2. Manual tuners usually seem to be able to match a wider range of
loads<<
>
> Whether tuner is manual or automatic is irrelevant as far as its
tuning range goes.  That depends on the network and components used.
Some automatic tuners use motors to drive variable capacitors and
coils, some use relays to switch in binary weighted components (KAT1
and 2, LDG, SGC...), and some use a combination of both.
>
> >>The disadvantage is that it seems to take most people a couple of
minutes to tune them up<<
>
> Maybe for the initial tune up, but once you find it, is generally
possible record the settings and simply return to them and operate.
Depending on the tuner and the SWR bandwidth of the antenna (and
sometimes weather condx), it may be necessary to touch up the tuning
but that shouldn't take more than a few seconds..
>
> >>apparently it's necessary to do it at full power<<
>
> I tune up at a couple of watts and then go immediately to 1.5KW with
no problems.  The power should not affect the tuning.  If it does,
something is probably wrong.  Tuning the output tank of a tube amp
must be done at operating power but again, if the settings are
recorded, you can usually just return to those settings and operate.
>
> Lou W7DZN
>
>
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