On Dec 10, 7:50*am, Cecil Moore wrote:
Fred PA0FVH wrote:
Is 5/8WL on 10meters a good height or 8 meter (22')?
What I want is a low take off angle on 20 and 30 meters with high efficiency
and an impedance which my remote ATU can handle.

Yes, you don't want to get much longer than 5/8WL on
10m and you don't want to get much shorter than 3/16WL
on 40m. 22 feet is a good compromise length. At my
previous QTH I used a 22' monopole with the feedpoint
elevated at 22' with four 22' radials sloping down
at 45 degrees (also used as guy wires) and fed with
an SG-230. It worked like a charm for transmitting -
noisy on receive. Here's some information from
simulations:

22' Monopole with 22' elevated sloping radials:

Band: Gain: Take Off Angle: Feedpoint: ~Tuner Loss
40m: 0.53 dBi: 22 deg: * 24-j229 ohms: 0.9 dB
30m: 0.94 dBi: 19 deg: * *46-j31 ohms: 0.2 dB
20m: 1.47 dBi: 16 deg: *128+j233 ohms: 0.1 dB
17m: 1.91 dBi: 14 deg: *556+j583 ohms: 0.2 dB
15m: 2.47 dBi: 12 deg: 1315-j372 ohms: 0.3 dB
12m: 3.40 dBi: 13 deg: *373-j560 ohms: 0.3 dB
10m: 4.21 dBi: 11 deg: *885-j290 ohms: 0.2 dB
--
73, Cecil *http://www.w5dxp.com

Experimenting with a too long antenna on 10M can be fun. I did a 1.25
wl antenna and got some interesting results during band openings. You
get to talk to where everyone else isnt. I felt like the band had
opened just for me. Of course this isnt the norm.

Jimmie

Yes, you don't want to get much longer than 5/8WL on
10m and you don't want to get much shorter than 3/16WL
on 40m.

Cecil: I compared your simulation against what I found and the results are
simular. I'll use your tips about the height and simulate some more lenghts
based on the materials I can get.

Unless you already have the materials I suggest you build with ten
foot lengths of chain link top rail. The last time I priced it at the
home improvement store it was $11 per section.

John: I had to use google to figure out the "chain link top rail" but it is
clear to me now. I'll check the DIY stores over here on garden and fences
stuff.

Experimenting with a too long antenna on 10M can be fun. I did a 1.25
wl antenna and got some interesting results during band openings.

Jimmie: My thoughts too, get good 10m performance and as a bonus the other
bands

Thanks to all for your helpful reply's.
73's Fred


got and
"Cecil Moore" wrote in message
...
Fred PA0FVH wrote:
Is 5/8WL on 10meters a good height or 8 meter (22')?
What I want is a low take off angle on 20 and 30 meters with high
efficiency and an impedance which my remote ATU can handle.

22 feet is a good compromise length. At my
previous QTH I used a 22' monopole with the feedpoint
elevated at 22' with four 22' radials sloping down
at 45 degrees (also used as guy wires) and fed with
an SG-230. It worked like a charm for transmitting -
noisy on receive. Here's some information from
simulations:

22' Monopole with 22' elevated sloping radials:

Band: Gain: Take Off Angle: Feedpoint: ~Tuner Loss
40m: 0.53 dBi: 22 deg: 24-j229 ohms: 0.9 dB
30m: 0.94 dBi: 19 deg: 46-j31 ohms: 0.2 dB
20m: 1.47 dBi: 16 deg: 128+j233 ohms: 0.1 dB
17m: 1.91 dBi: 14 deg: 556+j583 ohms: 0.2 dB
15m: 2.47 dBi: 12 deg: 1315-j372 ohms: 0.3 dB
12m: 3.40 dBi: 13 deg: 373-j560 ohms: 0.3 dB
10m: 4.21 dBi: 11 deg: 885-j290 ohms: 0.2 dB
--
73, Cecil http://www.w5dxp.com

Fred,

You may find my article "An unloaded elevated vertical as a multi-band HF
antenna" a source of some ideas.

The article is at http://www.vk1od.net/multibandunload...ical/13mEV.htm
..

Owen

Owen,

Your article was of good help. I will start with half the size (6.5m) for
10-40m.

Thanks,
Fred

I read that article, and enjoyed it. I don't have much room here in Tampa, so a vertical may be the best I can do.

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