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KAT100 tuning ability for bad antenna match

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barry-5

KAT100 tuning ability for bad antenna match

I live in an upstairs flat (apartment in us!), and have a small loft
space about 23ft long at the ridge and about the same across.

Would a KAT100 tuner be able to tune a random length dipole strung along
the ridge?

If not can you suggest an alternative antenna that would, I am seriously
limited in my options for aerials as you can see.

Any advice most welcome ... Barry G0MPA

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n6wg

Re: KAT100 tuning ability for bad antenna match

Hello Barry
Since your dipole will be indoors, I would suggest making
it a bit longer, closer to 33 ft.

Run the first 23 feet as you plan, with the feedpoint in the
center. At the ends, let the extra wire extend down 1 foot.
The bring the remainder back toward the center, keeping
the 1 foot spacing. Use something like wooden dowels or
plastic rods to keep the folded back sections parallel to the
main part of the dipole.

This will give you a 20m dipole, a 15m 3/4 wave dipole,
and 2 halfwaves in phase on 10m.

If you use 450 ohm window line, or 300 ohm TV twinlead
of good quality, you should be able to tune this on all bands
40m through 10m, including the WARC bands.

You will need the Elecraft BL-2 switchable balun (4:1 or 1:1
ratios) to allow your rig to get the best match. On some bands,
the 4:1 ratio will allow the KAT100 to match most easily. On
others, the 1:1 ratio will work better. Experiment until you
know which settings go with which bands in your setup.
If you have trouble matching on any particular band, adding
a little extra feedline will change the impedance enough
that the KAT100 will handle it.

I use a set of dual banana plugs, not sure what you call them
on your side of the pond. This lets me quickly add in a short
extension feedline. Actually, if this extra length still allows
the KAT100 to match ok on the other bands, just splice it in
and leave it as a permanent part of the feedline.

Good luck and 73
Bob N6WG

----- Original Message -----
From: "barry" <[hidden email]>
To: <[hidden email]>
Sent: Wednesday, April 18, 2007 7:54 AM
Subject: [Elecraft] KAT100 tuning ability for bad antenna match

> I live in an upstairs flat (apartment in us!), and have a small loft
> space about 23ft long at the ridge and about the same across.
>
> Would a KAT100 tuner be able to tune a random length dipole strung along
> the ridge?
>
> If not can you suggest an alternative antenna that would, I am seriously
> limited in my options for aerials as you can see.
>
> Any advice most welcome ... Barry G0MPA
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

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crmabbott

Re: KAT100 tuning ability for bad antenna match

In reply to this post by barry-5

I like challenges of attics;

Just for fun, place centeral point of antenna at center of ridge in the attic [assume ridge runs north & south for this discussion] on north side of center point to to ne corner on right; come back up along roof line to center point; from there go along roof line to nw corner; now bring with back to center connector.

Now facing south got to SW corner; run antenna long roof line to center ridge; down roof line to SE corner; from there back to center feed point.

If you have a 45 degree roof line you should be in the neighborhood of 80' dipole so you, your antenna, and tuner should have a great time.

I have worked a lot in a 39' roof line attic.

73 Chuck AA8VS

--
______
_______/ Chuck \_________
| |
| www.aa8vs.org/aa8vs |
================================
The pessimist complains about the
wind; the optimist expects it to
change; the realist adjusts the
sails."
-- William Arthur Ward

-------------- Original message --------------
From: barry <[hidden email]>