On 3/8/2012 8:08 AM, Tuuk wrote:
Come on hams

You know the antenna I am talking about. I seen its specs online about
10 years ago. It is a single omni aluminum antenna with three traps in
it. About 19 or 21 foot long. Made for ground use, no ground planes or
radials, and old style. This is an older style antenna. Regular coax
hook up. I need to remember the name of this antenna so I can make sure
its lenghth and specs are correct. Gotta be an old ham out there that
remembers these old style omni antenna.
Thanks

There were many versions of trapped verticals sold in the last 30
years. Without pictures of the base or traps, hope of identification is
fairly slim.
Sounds like the typical Cushcraft or Hustler. Or at least those were
the most popular versions.
Also, ground mounted verticals will still need radials if the antenna
is to live up to it's expectations. And there is nothing to stop one
from using one elevated, if one uses resonant radials for each band to
be used.
Look at the tubing and see if it has any marks on it from it's previous
assembly. Often, the clamping will leave marks on the tubing, and one
that was used for a long time will usually show discoloration between
the tubing exposed to the air, and the part that was covered due to
the overlap.

On Thu, 08 Mar 2012 08:51:20 -0600, NM5K wrote:

Also, ground mounted verticals will still need radials if the antenna is
to live up to it's expectations. And there is nothing to stop one from
using one elevated, if one uses resonant radials for each band to be
used.

My GAP Titan DX requires no radials; it is a center fed, asymmetric
vertical dipole.

The OP should try using Bing or Yahoo. Here's the Yahoo Ham Antenna group:
http://groups.yahoo.com/group/ham-an...guid=353505133

On 3/8/2012 11:09 AM, dave wrote:
On Thu, 08 Mar 2012 08:51:20 -0600, NM5K wrote:

Also, ground mounted verticals will still need radials if the antenna is
to live up to it's expectations. And there is nothing to stop one from
using one elevated, if one uses resonant radials for each band to be
used.

My GAP Titan DX requires no radials; it is a center fed, asymmetric
vertical dipole.


Well, ground mounted monopoles in his case..
Being a "complete" antenna, it's true that the center fed vertical does
not require radials for proper operation, but you would still likely
show lower ground losses if it were over radials.
For instance, broadcast stations that use 1/2 wave radiators still
use a set of radials under the antenna. Usually 1/2 wave radials, when
used with a 1/2 wave radiator.
You will still see some ground loss with the ground mounted 1/2 waves
over poor ground, but being as the max current point is 1/4 up from the
ground, it's not near as severe as the ground mounted 1/4 wave where
maximum current is at the base.

Thanks for the ideas

When I find it I will post it.

73s





"NM5K" wrote in message
...
On 3/8/2012 11:09 AM, dave wrote:
On Thu, 08 Mar 2012 08:51:20 -0600, NM5K wrote:

Also, ground mounted verticals will still need radials if the antenna is
to live up to it's expectations. And there is nothing to stop one from
using one elevated, if one uses resonant radials for each band to be
used.

My GAP Titan DX requires no radials; it is a center fed, asymmetric
vertical dipole.


Well, ground mounted monopoles in his case..
Being a "complete" antenna, it's true that the center fed vertical does
not require radials for proper operation, but you would still likely
show lower ground losses if it were over radials.
For instance, broadcast stations that use 1/2 wave radiators still
use a set of radials under the antenna. Usually 1/2 wave radials, when
used with a 1/2 wave radiator.
You will still see some ground loss with the ground mounted 1/2 waves
over poor ground, but being as the max current point is 1/4 up from the
ground, it's not near as severe as the ground mounted 1/4 wave where
maximum current is at the base.

On Thu, 08 Mar 2012 12:35:58 -0600, NM5K wrote:

On 3/8/2012 11:09 AM, dave wrote:
On Thu, 08 Mar 2012 08:51:20 -0600, NM5K wrote:

Also, ground mounted verticals will still need radials if the antenna
is to live up to it's expectations. And there is nothing to stop one
from using one elevated, if one uses resonant radials for each band to
be used.

My GAP Titan DX requires no radials; it is a center fed, asymmetric
vertical dipole.


Well, ground mounted monopoles in his case.. Being a "complete" antenna,
it's true that the center fed vertical does not require radials for
proper operation, but you would still likely show lower ground losses if
it were over radials. For instance, broadcast stations that use 1/2 wave
radiators still use a set of radials under the antenna. Usually 1/2 wave
radials, when used with a 1/2 wave radiator.
You will still see some ground loss with the ground mounted 1/2 waves
over poor ground, but being as the max current point is 1/4 up from the
ground, it's not near as severe as the ground mounted 1/4 wave where
maximum current is at the base.

I don't think a ground screen is needed if you are 1/2 wave.

If you elevate a short vertical you only need a few "ground" radials
(think CB groundplane antenna), btw. My whole transmit antenna system
floats on my roof. The only "ground" is the panel where the RF goes
through the wall. I receive on a balanced 30m horizontal loop, also
floating except for the point of entry. I have an automatic tuner at the
feedpoint under the eave by my kitchen window. (FWIW) I have lived here
14 years and have never seen lightning at the shack.

On Fri, 09 Mar 2012 09:58:45 -0600, dave wrote:

On Thu, 08 Mar 2012 12:35:58 -0600, NM5K wrote:

On 3/8/2012 11:09 AM, dave wrote:
On Thu, 08 Mar 2012 08:51:20 -0600, NM5K wrote:

Also, ground mounted verticals will still need radials if the antenna
is to live up to it's expectations. And there is nothing to stop one
from using one elevated, if one uses resonant radials for each band
to be used.

My GAP Titan DX requires no radials; it is a center fed, asymmetric
vertical dipole.


Well, ground mounted monopoles in his case.. Being a "complete"
antenna, it's true that the center fed vertical does not require
radials for proper operation, but you would still likely show lower
ground losses if it were over radials. For instance, broadcast stations
that use 1/2 wave radiators still use a set of radials under the
antenna. Usually 1/2 wave radials, when used with a 1/2 wave radiator.
You will still see some ground loss with the ground mounted 1/2 waves
over poor ground, but being as the max current point is 1/4 up from the
ground, it's not near as severe as the ground mounted 1/4 wave where
maximum current is at the base.

I don't think a ground screen is needed if you are 1/2 wave.

If you elevate a short vertical you only need a few "ground" radials
(think CB groundplane antenna), btw. My whole transmit antenna system
floats on my roof. The only "ground" is the panel where the RF goes
through the wall. I receive on a balanced 30m horizontal loop, also
floating except for the point of entry. I have an automatic tuner at the
feedpoint under the eave by my kitchen window. (FWIW) I have lived here
14 years and have never seen lightning at the shack.

WABC on the rocks

http://www.musicradio77.com/transm.html

On Fri, 09 Mar 2012 10:00:10 -0600, dave wrote:

On Fri, 09 Mar 2012 09:58:45 -0600, dave wrote:

On Thu, 08 Mar 2012 12:35:58 -0600, NM5K wrote:

On 3/8/2012 11:09 AM, dave wrote:
On Thu, 08 Mar 2012 08:51:20 -0600, NM5K wrote:

Also, ground mounted verticals will still need radials if the
antenna is to live up to it's expectations. And there is nothing to
stop one from using one elevated, if one uses resonant radials for
each band to be used.

My GAP Titan DX requires no radials; it is a center fed, asymmetric
vertical dipole.


Well, ground mounted monopoles in his case.. Being a "complete"
antenna, it's true that the center fed vertical does not require
radials for proper operation, but you would still likely show lower
ground losses if it were over radials. For instance, broadcast
stations that use 1/2 wave radiators still use a set of radials under
the antenna. Usually 1/2 wave radials, when used with a 1/2 wave
radiator. You will still see some ground loss with the ground mounted
1/2 waves over poor ground, but being as the max current point is 1/4
up from the ground, it's not near as severe as the ground mounted 1/4
wave where maximum current is at the base.

I don't think a ground screen is needed if you are 1/2 wave.

If you elevate a short vertical you only need a few "ground" radials
(think CB groundplane antenna), btw. My whole transmit antenna system
floats on my roof. The only "ground" is the panel where the RF goes
through the wall. I receive on a balanced 30m horizontal loop, also
floating except for the point of entry. I have an automatic tuner at
the feedpoint under the eave by my kitchen window. (FWIW) I have lived
here 14 years and have never seen lightning at the shack.

WABC on the rocks

http://www.musicradio77.com/transm.html

Bird's Eye View: http://www.bing.com/maps/default.aspx?
v=2&cp=40.880654933621~-74.069307757843&style=a&lvl=15&sp=Point.40.8806549 33621_

On 3/9/2012 10:13 AM, dave wrote:


WABC on the rocks

http://www.musicradio77.com/transm.html

I bet their halfwave is sitting on a bed of 1/2 WL radials.
Most 1/2 wave BC antennas tend to use 1/2 wave radials I'm fairly sure.
Part of this is due to FCC requirements for stability in performance,
etc..
A 1/2 WL radiator on the ground is not immune to ground losses.
It just suffers less than the 1/4 WL.
And a 1/2 wave elevated, really should be decoupled from the feed line
for best performance. Of course, it's not required, but they will
perform better if you use decoupling. Less skewing of the pattern
off the horizon, from feed line currents.

On 3/9/2012 9:58 AM, dave wrote:


I don't think a ground screen is needed if you are 1/2 wave.

It's not required to provide the lower half of the antenna, but
they will still reduce ground losses if the antenna is ground mounted.



If you elevate a short vertical you only need a few "ground" radials
(think CB groundplane antenna), btw. My whole transmit antenna system
floats on my roof. The only "ground" is the panel where the RF goes
through the wall. I receive on a balanced 30m horizontal loop, also
floating except for the point of entry. I have an automatic tuner at the
feedpoint under the eave by my kitchen window. (FWIW) I have lived here
14 years and have never seen lightning at the shack.

The number of elevated radials needed to equal certain number on
the ground will depend on the wavelength above ground.
IE: to equal 120 1/4 WL radials on the ground, at 1/8 WL, you will need
appx 60 of them. At 1/4 WL, appx 8-10.. At 1/2 WL, 3-4..
And if the radiator is short, the radial system is a bit more
critical than with a full size 1/4 wave radiator.

Found it

Actually, I found some very old schematics , the paper is yellowish tea
like. Japanese I think . Hidaka.

http://www.hidaka.com/e-a_multi-v.html#VS-41W

I am pretty sure the one I have now is the VS-80KR.

I am going to clean it up and try it out. Don't know what will happen when I
put it on a 50 ft tower in these windy days. Will have to calculate the
length of gnd planes. I suspect they will be too long.

Any recommendations?

Thanks

73




"NM5K" wrote in message
...
On 3/9/2012 9:58 AM, dave wrote:


I don't think a ground screen is needed if you are 1/2 wave.

It's not required to provide the lower half of the antenna, but
they will still reduce ground losses if the antenna is ground mounted.



If you elevate a short vertical you only need a few "ground" radials
(think CB groundplane antenna), btw. My whole transmit antenna system
floats on my roof. The only "ground" is the panel where the RF goes
through the wall. I receive on a balanced 30m horizontal loop, also
floating except for the point of entry. I have an automatic tuner at the
feedpoint under the eave by my kitchen window. (FWIW) I have lived here
14 years and have never seen lightning at the shack.

The number of elevated radials needed to equal certain number on
the ground will depend on the wavelength above ground.
IE: to equal 120 1/4 WL radials on the ground, at 1/8 WL, you will need
appx 60 of them. At 1/4 WL, appx 8-10.. At 1/2 WL, 3-4..
And if the radiator is short, the radial system is a bit more
critical than with a full size 1/4 wave radiator.