In article t3ali.3392$Y_3.570@trnddc04, "Woody"
wrote:

Well.. a million thanks for that. Quite a cool history lesson as well. So
now I'm looking for an SEA tuner... LOL...

Listen, that all makes perfect sense but just to clarify, a.) now I know why
that triton did so poorly when tested. We calc'd 1/2 wavelength for the
longwire, and b.) Again, for continuity and clarity of this thread for
future surfers...... what then, considering our discussed auto-tuners, would
be the optimal length for a longwire that would be used for amateur/MARS,
3-30MHz?
Pick 1/2wavelength on say 2.8Mhz and just cut it? Or calc 1/2wavelength on
the lowest and add 5% or some arbitrary odd number??
Which plan will offer the least chance of dropping a 1/2wl further up the
band on a desired frequency?
thanks,
Woody


What we did, is to try and have a Longwire with a 1/4 Wave Point near
the lowest Operating Frequency like for the 2006Khz Alaska Private
Fixed Frequency, then calculate the Natural 1/2 Wave Point for that
Wire, then adjust the 1/4 Wave Length, SHORTER, until the 1/2 Wave Point
DeadBand (2.5% or so) was in a part of the speectrum the Station wasn't
Licensed for, Marine and Alaska Private Fixed have specific Channels,
and Bands in the MF/HF Spectrum, and it isn't to hard to move the
DeadBand to a nonused portion of the Spectrum. For the HAMS, that want
a "Do everything, cover the whole Dc to Light Spectrum, with one
Longwire Tunter", the answer is "Design and Build your own Dam Tuner
with an integrate Longwire Switch and put up Multiple lengths of wire",
because there isn't a product out there, that I am aware, of that does
this, YET....

Bruce in alaska
--
add a 2 before @

On Jul 9, 2:16 am, Richard Clark wrote:

Anything more convoluted is unlikely to
give you more performance.

73's
Richard Clark, KB7QHC

Hi, Richard:

Should you check with your legal counsel before you make that
statement?

Bill

Hey, I'm just learning and absorbing so anything new is a place for me to
start. Thanks again!
woody

"Owen Duffy" wrote in message
...
"Woody" wrote in news:hYdli.29709$BT3.8034@trnddc06:

Hi Owen. 5% was just a number picked out at random by me for
clarification of my question.
So you wouldn't want to share your 'sweet' findings, would you??
thanks!

I had a dig around through a few thousand spreadsheets... and found it.

9.05m, 12.6m, 18.3m, 26.4m, 33.3m, 44.9m.

If you want to cover 60m, leave the 26.4 out of the list.

Did someone mention 60' (18.3m), it is in the list, but it is more
critical than 26.4 or 12.6.

As noted in my earlier post, if you want to be 10% or more away from n
half waves on all bands, there is no solution.

These calcs don't consider proximity of objects that may shift the
tuning.

My advice still stands that the higher order parallel resonances aren't
such an issue, so this method unnecessarily constrains the solution..

Owen

Yep, amen to that! LOL...
woody

"Denny" wrote in message
ups.com...
Yes, the history of the autotuners is fascinating...
The discussion of integral half waves, parallel resonance impedences,
ground impedences, etc., is meat and potatos for antenna freaks like
me...

BTW, in the older ARRL handbooks is a table of guy wire lengths (for
towers) that avoid resonances in the ham bands... Those lengths would
make an excellent guide for the length of a random wire antenna... It
might also be in the new editions, but I haven't looked at one in
recent years.. Anyway, that table will give you a good starting
point...

B U T , what I want you to do is to simply either cobble up an L
match, or pick up a tuner (any tuner, automatic or not), run some wire
any length through those trees, and get on the air!
If the tuner has problems with any particular band, change the length
of the wire by 4 to 12 feet until it tunes OK...
Once you have a working antenna you can spend time and energy gilding
the lily with just the 'perfect' length and configuration...

Don't waste time over analyzing - pick a tuner, throw up some wire
and ground radials, and operate...
A local ham who lives in a trailor park is closing in on 300 countries
confirmed and his only antenna for all this is a single multiband
vertical, 21 feet tall, disguised as a flag pole...

Just do it...

cheers ... denny

LOL, and then there's that....

also a great idea!
thanks much!
Woody

"Bruce in Alaska" wrote in message
...
In article t3ali.3392$Y_3.570@trnddc04, "Woody"
wrote:

Well.. a million thanks for that. Quite a cool history lesson as well. So
now I'm looking for an SEA tuner... LOL...

Listen, that all makes perfect sense but just to clarify, a.) now I know
why
that triton did so poorly when tested. We calc'd 1/2 wavelength for the
longwire, and b.) Again, for continuity and clarity of this thread for
future surfers...... what then, considering our discussed auto-tuners,
would
be the optimal length for a longwire that would be used for amateur/MARS,
3-30MHz?
Pick 1/2wavelength on say 2.8Mhz and just cut it? Or calc 1/2wavelength
on
the lowest and add 5% or some arbitrary odd number??
Which plan will offer the least chance of dropping a 1/2wl further up the
band on a desired frequency?
thanks,
Woody


What we did, is to try and have a Longwire with a 1/4 Wave Point near
the lowest Operating Frequency like for the 2006Khz Alaska Private
Fixed Frequency, then calculate the Natural 1/2 Wave Point for that
Wire, then adjust the 1/4 Wave Length, SHORTER, until the 1/2 Wave Point
DeadBand (2.5% or so) was in a part of the speectrum the Station wasn't
Licensed for, Marine and Alaska Private Fixed have specific Channels,
and Bands in the MF/HF Spectrum, and it isn't to hard to move the
DeadBand to a nonused portion of the Spectrum. For the HAMS, that want
a "Do everything, cover the whole Dc to Light Spectrum, with one
Longwire Tunter", the answer is "Design and Build your own Dam Tuner
with an integrate Longwire Switch and put up Multiple lengths of wire",
because there isn't a product out there, that I am aware, of that does
this, YET....

Bruce in alaska
--
add a 2 before @

On Fri, 13 Jul 2007 16:56:57 -0700, Bill wrote:

On Jul 9, 2:16 am, Richard Clark wrote:
Anything more convoluted is unlikely to
give you more performance.

Should you check with your legal counsel before you make that
statement?

Talk about convolution. Plug your legal counsel in and see if DX pegs
the S-Meter.

73's
Richard Clark, KB7QHC

In article ,
Richard Clark wrote:

Talk about convolution. Plug your legal counsel in and see if DX pegs
the S-Meter.

73's
Richard Clark, KB7QHC

No, Legal Counsel type folks are just one step Up the ladder from
Politicos, and they are only good for starting Diesel Engines in
very cold weather. Lots of HOT AIR, coming out of those guys.....
but how to get them to Blow it down the Intake Manifold.....

Bruce in alaska
--
add a 2 before @

"Denny" wrote in message
ups.com...


snip

Don't waste time over analyzing - pick a tuner, throw up some wire
and ground radials, and operate...
A local ham who lives in a trailor park is closing in on 300 countries
confirmed and his only antenna for all this is a single multiband
vertical, 21 feet tall, disguised as a flag pole...

Just do it...

Yup. I'm on HF with a $50.00 used transceiver, a $5.00 pi-network tuner,
some coax, a balun and two pieces of copper pipe laying on my roof. It
ain't purty but I'm talking to people and they're talking back.

"Sal"

You guys crack me up. The poor guy wanted a simple longwire solution.

I want one too, and that's how I found this thread.

I read in W1FB's Antenna Notebook that you can take a 1 wavelength
piece of wire, feed it with 75 Ohm coax 1/4 wavelength in from one
end, with the hot side going to the 3/4 wavelength piece and the
shield going to the 1/4 wavelength piece. It looks like you don't
need any type of tuner.

Has anybody tried that? I'm looking for a simple antenna for PSK-31
QRP that the homeowners association won't even see, and this looks
like the deal, but I can't find any corroboration for the concept.

Dave Morris
N5UP
www.eQSL.cc

In article om,
wrote:

I read in W1FB's Antenna Notebook that you can take a 1 wavelength
piece of wire, feed it with 75 Ohm coax 1/4 wavelength in from one
end, with the hot side going to the 3/4 wavelength piece and the
shield going to the 1/4 wavelength piece. It looks like you don't
need any type of tuner.

Has anybody tried that? I'm looking for a simple antenna for PSK-31
QRP that the homeowners association won't even see, and this looks
like the deal, but I can't find any corroboration for the concept.

That sounds like a form of off-center-fed resonant doublet. Since the
radiator is 1 wavelength long, it will have current maxima 1/4 away
from each end (which is where you're feeding it).

I'd guess that it will provide a reasonable (although imperfect) match
to a 75-ohm coax... you might see an SWR of 2:1 or so on the coax.
The impedance seen by the rig will depend on the length of the
feedline, and a rig designed to drive a 50-ohm load might see a fairly
low SWR, or perhaps one as high as 3:1 or 4:1 (at a guess). If your
rig has a built-in ATU, it's probably adequate to flatten this sort of
SWR down to the point where the rig's finals are happy with it.

There's likely to be some amount of RF current present on the outside
of the coaxial feedline, due both to conduction at the feedpoint and
to induction from the wire (since the feedline is not located
symmetrically in the center of the radiating element). If this causes
sufficient "RF in the shack" to be a problem, you might want to add an
isolating choke where the feedline enters the building... and if there
isn't enough RF in the shack to cause problems, then don't worry about
it. In either case, it's probably going to be less RF-in-the-shack
than you'd get with an end-fed longwire, fed against the station
ground or a counterpoise.

Seems like a reasonable candidate for a "stealth" antenna, if you can
conceal the coax running up to the feedpoint, and use a thin-gauge
wire as a radiator (e.g. thin-gauge enamel-insulated magnet wire).

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
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