6M stacked loops - best height above ground?
 

On 28 Dec 2005 17:00:28 GMT, Allodoxaphobia
wrote:

On Wed, 28 Dec 2005 02:33:45 -0500, Hal Rosser wrote:

"Charlie" wrote in message
...
Currently the top loop is at only 20ft but I am making many contacts.
Soon
however they will be placed off a sidearm on the tower.
The top loop could then be as high as 80 ft.

I have read and read about this topic. Does anyone have any first hand
knowledge of 6M height above ground comparisons especially for stacked
loops? Thanks....


6m is line-of-sight, so higher is better than lower.

IT IS??? !!! Then, I guess my confirmed QSO's with Japan, Australia,
Greenland, Chile, and others -- plus all states except R.I. (sigh...)
from western Colorado (while running just 9.5 watts) simply never
happened.

Jonesy

It is if the propagation isn't there or the moon is not a good shot.
;)

Then again I only have 14 countries on under 20W in the last 3 years.
I need KH and Alaska for WAS. RI is next door for me being in MA.
Even with the off peak years there is a lot of propagation
that pops up at odd times.

Allison

6M stacked loops - best height above ground?
 

On Wed, 28 Dec 2005 08:25:18 -0600, Bob Bob wrote:

Hi Charlie

I have read some of the responses you have received already. As you
asked for first hand experience I hadnt commented initially.

I wonder if you have tried modelling your configuration with height
variables and applying the resultant radiation pattern to propagation
modes? I'd suggest ground conditions for your area also need to be
entered. I seem to remember from my dim dark past that ground
reflections (and hence undesirable skyward radiation - often not usually
an issue on VHF) are more of a problem when using a lower gain antenna.
Maybe the loop in that respect might be worse than a quad/yagi?

You'd be able to see the dB per foot height changes that occur and make
a judgement from that.

Real simple. He's so close to the ground he has a lot of high angle
gain. As he goes up that will go down and the low angle gain will
improve.

I have never used horiz loops on 6m.

Handy for local stuff like a 100 ore more miles in all directions.
I use one for the listening as I miss stuff with beams.

Allison

6M stacked loops - best height above ground?
 

"Charlie" wrote in message
...
Currently the top loop is at only 20ft but I am making many contacts.
Soon however they will be placed off a sidearm on the tower.
The top loop could then be as high as 80 ft.

I have read and read about this topic. Does anyone have any first hand
knowledge of 6M height above ground comparisons especially for stacked
loops? Thanks....

--

Charlie-AD5TH



First off, what do you mean by LOOP? A Halo kind of antenna, or a vertically
mounted loop? I suspect you mean a Halo (or M2). I ran an EZNEC simulation
on a stacked pair, and it was not great. Minimum stacking distance is a bout
13 feet, with a gain 2db less than a single 3 element beam. Get the bugger
up to 80 feet. A friend of mine had bought 2 M2 loops. Never bothered to put
up the second one when he realized that you can't just stack them 3 feet
apart.

Remember, 20 feet is already a wavelength up. If you really want high angle
radiation, it would have to be a lot lower than that. That will work for E
skip, not very good for F2, or locals. Even at 80 feet, you will still have
multiple lobes, with a good part of the energy going almost straight up.

Tam/WB2TT

6M stacked loops - best height above ground?
 

"Allodoxaphobia" wrote in message
...
On Wed, 28 Dec 2005 02:33:45 -0500, Hal Rosser wrote:

"Charlie" wrote in message
...
Currently the top loop is at only 20ft but I am making many contacts.
Soon
however they will be placed off a sidearm on the tower.
The top loop could then be as high as 80 ft.

I have read and read about this topic. Does anyone have any first hand
knowledge of 6M height above ground comparisons especially for stacked
loops? Thanks....


6m is line-of-sight, so higher is better than lower.

IT IS??? !!! Then, I guess my confirmed QSO's with Japan, Australia,
Greenland, Chile, and others -- plus all states except R.I. (sigh...)
from western Colorado (while running just 9.5 watts) simply never
happened.

Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
Pueblo, Colorado | @ | Jonesy | OS/2 __
38.24N 104.55W | config.com | DM78rf | SK

OOPS! - sorry, I forgot about 50M DX - skip does happen at 50mhz sometimes
I hear its an enjoyable pass-time to attempt long-distance short-duration
contacts on 50mhz.
Does ducting also occur on 50 ?

6M stacked loops - best height above ground?
 

On Wed, 28 Dec 2005 17:34:33 -0500, Hal Rosser wrote:

"Allodoxaphobia" wrote in message
...
On Wed, 28 Dec 2005 02:33:45 -0500, Hal Rosser wrote:

"Charlie" wrote in message
...
Currently the top loop is at only 20ft but I am making many contacts.
Soon
however they will be placed off a sidearm on the tower.
The top loop could then be as high as 80 ft.

I have read and read about this topic. Does anyone have any first hand
knowledge of 6M height above ground comparisons especially for stacked
loops? Thanks....


6m is line-of-sight, so higher is better than lower.

IT IS??? !!! Then, I guess my confirmed QSO's with Japan, Australia,
Greenland, Chile, and others -- plus all states except R.I. (sigh...)
from western Colorado (while running just 9.5 watts) simply never
happened.

OOPS! - sorry, I forgot about 50M DX - skip does happen at 50mhz sometimes

Propagation to Japan, Australia, Greenland, Chile... ain't skip.
It's F2 -- or Es-connected F2. Gets Real Crazy every 11 years or so.

Does ducting also occur on 50 ?

There's little that doesn't occur on 50 MHz. I have completed QSO's by
Es, F2, Au, meteor, tropo ducting, and weird flavors and combinations
of more than one of'em. Fellers also do EME on 6M - tho' not I.

When the band is wide open on an Es opening -- maybe a 2X Es event --
you'll find the FB-OP-to-Jerk ratio Real High. It's one of the reasons
I've all but given up on the 'popular' HF bands.

And, to steer it back On Topic:
Fiddl'in with antennas on 6M is SO EASY.

73
Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
Pueblo, Colorado | @ | Jonesy | OS/2 __
38.24N 104.55W | config.com | DM78rf | SK

6M stacked loops - best height above ground?
 

Propagation to Japan, Australia, Greenland, Chile... ain't skip.
It's F2 -- or Es-connected F2. Gets Real Crazy every 11 years or so.

Worked GB from MA only 2 years ago well off the solar peak. During the
summer (2005) I got a few Carib stations and Brermuda.

Does ducting also occur on 50 ?

There's little that doesn't occur on 50 MHz. I have completed QSO's by
Es, F2, Au, meteor, tropo ducting, and weird flavors and combinations
of more than one of'em. Fellers also do EME on 6M - tho' not I.

A local does the EME thing. I do low power (20W PEP max) off solar
power. But I like the band as it's easy for antennas and fun to
design radios for.

When the band is wide open on an Es opening -- maybe a 2X Es event --
you'll find the FB-OP-to-Jerk ratio Real High. It's one of the reasons
I've all but given up on the 'popular' HF bands.

There have been times when it's like a 20m pileup.

And, to steer it back On Topic:
Fiddl'in with antennas on 6M is SO EASY.

;)

Allison
KB!GMX FN42HH

6M stacked loops - best height above ground?
 

And to complicate matters further the max antenna height being talked
about being around 3-4 wavelengths off the ground is going to break the
radiation pattern up into a number of lobes at various vertical angles.

For that reason alone I think it is still worth modelling. There will be
specific heights where the horizontal radiated component is at a maximum
and this is likely the most desirable. It will also give a good
indication of what takeoff angles will be like for ionospheric
propagation modes. You'd also see the spacing/height effect on
undesirable straight upwards radiation.

Then again a crank up/down tower and maybe inter element spacing
adjustment mght be a good empirical way to get the right data as well.

Bob VK2YQA

wrote:

Real simple. He's so close to the ground he has a lot of high angle
gain. As he goes up that will go down and the low angle gain will
improve.

6M stacked loops - best height above ground?
 

How is that you have your Forte Free Agent set up that you do not do
attributions?

On Thu, 29 Dec 2005 12:47:41 GMT, wrote:

When the band is wide open on an Es opening -- maybe a 2X Es event --
you'll find the FB-OP-to-Jerk ratio Real High. It's one of the reasons
I've all but given up on the 'popular' HF bands.

There have been times when it's like a 20m pileup.

Ya, but... For the Greater Part, _everybody_ acts like Ladies And
Gentlemen. You don't see that on 20M.

Jonesy W3DHJ

6M stacked loops - best height above ground?
 

Bob Bob wrote:
And to complicate matters further the max antenna height being talked
about being around 3-4 wavelengths off the ground is going to break the
radiation pattern up into a number of lobes at various vertical angles.

For that reason alone I think it is still worth modelling. There will be
specific heights where the horizontal radiated component is at a maximum
and this is likely the most desirable. . .

Modeling will show that at great distances from the antenna, the
horizontally radiated field is zero from any horizontally polarized
antenna over ground.

Roy Lewallen, W7EL

6M stacked loops - best height above ground?
 

On 29 Dec 2005 15:48:27 GMT, Allodoxaphobia
wrote:

A fair amount of stuff turned off and..

Delete key. ;)


Allison