Hi all...
I have a 32 ft aluminum mast that I want to feed at the bottom with an
extensive radial system laying on or just below the ground.
I plan on homebrewing a matching network at the base, with tuning stubbs on
the vertical radiator and plan to use the antenna on 30 thru 10 meters.
Before I get too into the project, I am wondering if I would have a better
antenna if I simply purchase a Gap Titan, butternut or something of their
irk. Thanks in advance.

On Wed, 3 Nov 2004 09:39:49 -0800, "denton"
wrote:

Hi all...
I have a 32 ft aluminum mast that I want to feed at the bottom with an
extensive radial system laying on or just below the ground.

Hi Denton,

Sounds like a good start.

I plan on homebrewing a matching network at the base, with tuning stubbs on
the vertical radiator and plan to use the antenna on 30 thru 10 meters.

Do you really want to run outside to change bands?

Before I get too into the project, I am wondering if I would have a better
antenna if I simply purchase a Gap Titan, butternut or something of their
irk. Thanks in advance.

Not particularly, except maybe for the higher frequencies. Your 10M
of radiator being used on a 10M wavelength portends difficult tune up
(perhaps part of your motivation for the matching box). However,
being one wave long, it also has major radiation lobes pointing up
rather than out.

It is most suited for 40M (quarterwave) through roughly 15M (5/8'ths).

73's
Richard Clark, KB7QHC

Well I am planning on the matching network to be a remote....something
tweekable from the shack.
"Richard Clark" wrote in message
...
On Wed, 3 Nov 2004 09:39:49 -0800, "denton"
wrote:

Hi all...
I have a 32 ft aluminum mast that I want to feed at the bottom with an
extensive radial system laying on or just below the ground.

Hi Denton,

Sounds like a good start.

I plan on homebrewing a matching network at the base, with tuning stubbs
on
the vertical radiator and plan to use the antenna on 30 thru 10 meters.

Do you really want to run outside to change bands?

Before I get too into the project, I am wondering if I would have a better
antenna if I simply purchase a Gap Titan, butternut or something of their
irk. Thanks in advance.

Not particularly, except maybe for the higher frequencies. Your 10M
of radiator being used on a 10M wavelength portends difficult tune up
(perhaps part of your motivation for the matching box). However,
being one wave long, it also has major radiation lobes pointing up
rather than out.

It is most suited for 40M (quarterwave) through roughly 15M (5/8'ths).

73's
Richard Clark, KB7QHC

This is roughly what I have - a 40 foot vertical from about a foot above the
ground and a few radials mainly buried ranging in length from about 10 feet to
about 100 feet, three four foot ground rods about a foot apart, and, in the gap
between the bottom of the pole and where all the radials come together..... a
SGC 230 Smartuner.. which all works rather well !

Nick

I am pleased to hear it, for this is similar to what I have in mind,
although I will have a Radio Ham's manually-operated ATU rather than the
CBer's Auto ATU that you describe.(Perhaps this will be the
final arbiter as to who is a Radio Ham and who is merely a
CBer-in-disguise?)

"nick smith" wrote in message
...
This is roughly what I have - a 40 foot vertical from about a foot above
the
ground and a few radials mainly buried ranging in length from about 10
feet to
about 100 feet, three four foot ground rods about a foot apart, and, in
the gap
between the bottom of the pole and where all the radials come
together..... a
SGC 230 Smartuner.. which all works rather well !

Richard Clark wrote:
On Wed, 3 Nov 2004 09:39:49 -0800, "denton"
wrote:

Hi all...
I have a 32 ft aluminum mast that I want to feed at the bottom with an
extensive radial system laying on or just below the ground.

Hi Denton,

Sounds like a good start.

I plan on homebrewing a matching network at the base, with tuning stubbs on
the vertical radiator and plan to use the antenna on 30 thru 10 meters.

Do you really want to run outside to change bands?

Before I get too into the project, I am wondering if I would have a better
antenna if I simply purchase a Gap Titan, butternut or something of their
irk. Thanks in advance.

Not particularly, except maybe for the higher frequencies. Your 10M
of radiator being used on a 10M wavelength portends difficult tune up
(perhaps part of your motivation for the matching box). However,
being one wave long, it also has major radiation lobes pointing up
rather than out.

It is most suited for 40M (quarterwave) through roughly 15M (5/8'ths).


It will make an excellent antenna for the bands Richard indicates: down
to 40m, and up to about 15m.

You do seem to be prepared to spend some money, so if you don't want to
run outside to change bands, a remote auto-ATU would be a very good buy.

That is exactly what I am using now - a 32ft mast with an auto-ATU at
the bottom. If you can tilt the mast over easily, you can also plug in a
horizontal loading wire at the top to make an inverted-L for 80m and
even 160m.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

You might try feeding it with open wire line, have a tuner in the shack, and
see what it does...

an update on this little project...
I have tried various lengths from 32 to 42 feet and have settled on 32 feet.
I currently have 30 radials from 20 feet to over 30 feet. I am undecided to
add more but can do so before putting in a new lawn next spring.
I am currently feeding it at the base with a 4 to 1 voltage balun and 30
feet of Belden RG8-U 50 ohm coax to a little ldg auto tuner in the shack.
SWR at the base of the antenna is 6 to 1 on 40 meters, 3.5 to 1 on 30 meters
and drops from then on to 1.2 to one on 10 meters.
Even with the high swr on 40 meters (I plan on bypassing the balun for that
band) an online coax calculator for my particular feedline indicates I am
loosing at most 8-10 watts in the feedline. I have no way of calculating or
estimating the losses in the little auto tuner or the balun and can only
guess at the ground losses.
I am not too worried about 10 meter operation.
The antenna apparently works...if the band is only partly open I can work
just about anyone I can read on psk on any band 40 thru 15 meters. Comparing
it with my 80 meter twin led fed doublet, the vertical is doing its job
rather nicely.
One little suprise...in the shack, without the ant tuner in line, the swr on
80 meters is quite low...below 3 to 1 on most of the band...wonder what
causes that?
I have also given thoughts to raising the base of the antenna to 12 feet,
and run 4 radials for each band, and am wondering if I would see much
difference. I suspect the swr would be a bit different, but on the air??



"denton" wrote in message
...
Hi all...
I have a 32 ft aluminum mast that I want to feed at the bottom with an
extensive radial system laying on or just below the ground.
I plan on homebrewing a matching network at the base, with tuning stubbs
on the vertical radiator and plan to use the antenna on 30 thru 10 meters.
Before I get too into the project, I am wondering if I would have a better
antenna if I simply purchase a Gap Titan, butternut or something of their
irk. Thanks in advance.