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Old September 29th 09, 08:28 PM posted to rec.radio.amateur.antenna
Michael Coslo Michael Coslo is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 828
Default Open wire feedline

Tim Shoppa wrote:
On Sep 29, 1:59 pm, Michael Coslo wrote:
TimShoppawrote:
On Sep 29, 10:07 am, Cecil Moore wrote:
However, 50 feet of ladder-line is ~1/4WL. The low 80m feedpoint
impedance tends to be transformed to ~4k ohms. Most built-in
autotuners will not handle such impedances.
I personally think it's unlikely that even if someone is trapped by
the fancy-pants autotuner they bought, that they probably don't need
an extra fifty feet of line to deal with it. In my experience even ten
extra feet of line at 80M can noticeably change the matching taps I
use on my tuner if you're working in the 1/4 WL 65 foot feedline
range. Of course that extra ten feet might make their fancy pants
autotuner crap out on 20M, etc. and I can see how someone might start
feeling like the old lady that swallowed the fly. I would rewrite the
song to "swallowed the autotuner".

Wow, you do not like autotuners, eh?


The autotuners that the neighboring hams have do not have knobs. They
just have a little button you push and then relays chatter and it
either succeeded or failed. There's a little LED idiot light to tell
you that it succeeded or failed.


Those are simple indeed. My autotuner has channel memories, an analog
meter and a cool little lcd meter that tells me how much inductance and
capacitance are inserted in the circuit. plus I can manually adjust
both. It's pretty cool in fact.


I myself do not understand how a piece of radio equipment does not
have knobs. Or how it has little blinky LED's but no meters.


Majik? (grinning)

My homebrew tuner has alligator tips for selecting the turns on the
output link, as well as plug-in link-coupled coil sets for each band
and of course knobs on the variable caps. IMHO if a tuner has plug in
coil sets and alligator clips then you know you're cooking with gas. I
was looking a a picture of a station in the 1972 ARRL handbook last
night and realized that my tuner looks almost identical to the one in
the picture (which itself was probably 20 years old in 1972).


I certainly don't have anything against old school radios and tuners.
Dunno if you have yours this way, but I would be inclined to mount that
alligator clipped tuner coil on a nicely finished wood base, and go
really old school pretty with it. Maybe make the coil supports out of
the same type wood turned to a dowel or maybe even polished glass or
plastic. If yer going old school, flaunt it!

Anyhow, it's all good, old or new. Gives me a lot more to mess with
since I like both.


- 73 de Mike N3LI -