Hello all. I'm thinking about a wire antenna ... even thinking about
buying a pre-made 40-10m (short) antenna ... I have about 40' to play
with on the 11th floor balcony facing due west (USAF member stationed
in Ankara, Turkey). I also have a tuner that I've never used. I
think I'm primarily interested in primarily 10, 20 and 40 ... and
perhaps 12, 15, 17 and 30? I'd love to work Europe and possibly back
to the states if possible (barefoot).

I happened across an ad for Van Gorden Engineering baluns &
insulators, Hi-Q 1:1 or Hi-Q 4:1 Baluns. I have no clue as to how to
choose one beyond knowing they connect coax to a dipole. Is coax
length important?

Can anyone explain how I'd choose and install a balun given my desire?
1:1 or 4:1 impedance ratio?

Finally, can anyone suggest an off-the-shelf antenna based on their
experiences with it?

Thanks!
Rich
(Please don't reply via e-mail ... deed address)

On 22 May 2004 01:52:11 -0700, (Rich) wrote:

Hello all. I'm thinking about a wire antenna ... even thinking about
buying a pre-made 40-10m (short) antenna ... I have about 40' to play
with on the 11th floor balcony facing due west (USAF member stationed
in Ankara, Turkey). I also have a tuner that I've never used. I
think I'm primarily interested in primarily 10, 20 and 40 ... and
perhaps 12, 15, 17 and 30? I'd love to work Europe and possibly back
to the states if possible (barefoot).

I'm not sure 40' is long enough to get on 40 meters. I tried a 44'
dipole (3/8 wave on 40 meters), and it would only tune 30m through
10m. I extended it to 51', and now it tunes 40m, too. It's fed with
ladder line to an antenna tuner, an mfj unit.

You might just put up the longest dipole you can, 40' or so, feed it
with ladder line, and then tune it with the tuner you already have. If
it has balanced line connnections, you're all set. If not, a simple
coax choke will transition the balanced line to your tuner.

bob
k5qwg


I happened across an ad for Van Gorden Engineering baluns &
insulators, Hi-Q 1:1 or Hi-Q 4:1 Baluns. I have no clue as to how to
choose one beyond knowing they connect coax to a dipole. Is coax
length important?

Can anyone explain how I'd choose and install a balun given my desire?
1:1 or 4:1 impedance ratio?

Finally, can anyone suggest an off-the-shelf antenna based on their
experiences with it?

Thanks!
Rich
(Please don't reply via e-mail ... deed address)

Rich wrote:
Finally, can anyone suggest an off-the-shelf antenna based on their
experiences with it?

Not off the shelf, but a 40 ft dipole will work well on 40m
if you can get the RF into the dipole. A quick session with
EZNEC says if you create a G5RV-like dipole, 40 ft. long, fed
with 20 ft. of 450 ohm ladder-line, and install a 1000 pf cap
at the ladder-line/coax junction, it will be close to 50 ohms
on 7.2 MHz. Of course, it will have to be "cut and tried".

Other lengths of ladder-line should allow it to work well on
the higher HF bands without a tuner.
--
73, Cecil http://www.qsl.net/w5dxp



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I should have been more precise in my estimating (I know ... doesn't
make sense). I actually have 59' to play with. Dohhht!

Cecil, any chance you can take one more look-see for me with EZNEC?
How well do you think it will radiate on all the bands?

Bob, you make a good observation regarding proximity to theater and
Turkish reaction. When I arrived, I filed with the Turkish
Telekomuncations Office (their version of the FCC) and got a Turkish
Call sign, TA2ZAD. I figured it was appropriate whether I was going
to go on the air or not, especially given that I brought a couple of
radios into the country. ;-)

I have a separate post going regarding using my SGC-230 coupler ... I
was thinking about loading up the hot water pipes as a counterpoise
and dropping a 100' of wire out the window. I saw a few folks'
replies so far ... and they got me thinking otherwise now.

Thanks!
Rich
(Please don't reply via e-mail ... dead address)

Rich wrote:

I should have been more precise in my estimating (I know ... doesn't
make sense). I actually have 59' to play with. Dohhht!

Cecil, any chance you can take one more look-see for me with EZNEC?
How well do you think it will radiate on all the bands?

Since an analysis of a 51 ft. G5RV-shorty would be interesting
to the group, I will do that, hopefully today.
--
73, Cecil http://www.qsl.net/w5dxp



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Rich wrote:
Cecil, any chance you can take one more look-see for me with EZNEC?
How well do you think it will radiate on all the bands?

Rich, the easiest way for me to present a G5RV shorty version
is by listing the 50 ohm SWR at the ladder-line/coax junction.
The antenna is a 51 ft. center-fed dipole at 40 feet. The
series-section transmission line is Z0 = 400 ohms with a VF
of 0.9. I use Z0 = 400 because "450" ohm ladder-line is
usually closer to 400 ohms.

Freq. 50 ohm SWR for n' Length of "450" ohm line
6' 9' 12' 15' 16' 19' 40'
7.2 31 16 5.8 *2.2* 2.7 8.3 100
10.125 16 23 29 33 34 34 *1.9*
14.2 70 53 32 13 8 *1.2* 55
18.14 51 18 *1.5* 13 23 57 19
21.3 22 *1.5* 19 61 74 98 61
24.95 *1.7* 30 76 94 88 48 6
28.4 26 30 17 3.3 *2.0* 12 31

The lowest SWRs are highlighted like *n.m*. It appears
that a fixed length of about 17 ft. will be a good
performer on the harmonically related bands, 40m, 20m,
& 10m. Varying the series section length from 6' to
19' would allow covering all HF bands except 30m. A
51 ft. dipole is not a good length for 30m and requires
40' of "450" ohm line to resonate it close to 50 ohms.

IMO, any 50 ohm coax SWR above about 10:1 is unacceptable
for ordinary coax (depending on frequency).
--
73, Cecil http://www.qsl.net/w5dxp



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Rich, coax can be a consideration when loking at multi-band tuning. There
are a number of books out threre with the formulae.

As to baluns, you might not even need one. Many hams mistakenly include
baluns automatically in ther antennas, and introduce problems. I would
suggest you try a dipole with no baluns, and only add one if you discover
TVI or RFI problems.

- KI6PR
El Rancho R.F., CA

"Rich" wrote
Hello all. I'm thinking about a wire antenna ... even thinking about
buying a pre-made 40-10m (short) antenna ... I have about 40' to play
with on the 11th floor balcony facing due west (USAF member stationed
in Ankara, Turkey). I also have a tuner that I've never used. I
think I'm primarily interested in primarily 10, 20 and 40 ... and
perhaps 12, 15, 17 and 30? I'd love to work Europe and possibly back
to the states if possible (barefoot).

I happened across an ad for Van Gorden Engineering baluns &
insulators, Hi-Q 1:1 or Hi-Q 4:1 Baluns. I have no clue as to how to
choose one beyond knowing they connect coax to a dipole. Is coax
length important?

Can anyone explain how I'd choose and install a balun given my desire?
1:1 or 4:1 impedance ratio?

Finally, can anyone suggest an off-the-shelf antenna based on their
experiences with it?

Thanks!
Rich
(Please don't reply via e-mail ... deed address)