[2m] Re: 2M HT Antenna

Mon, 30 Jun 2003 19:36:03 -0700 (PDT)

Craig: Premier makes an excelent rubber duck antenna and very low profile slimline for 2 meter/and 440 and can be found in either Ham Radio Oulet: http://www.hamradio.com or Amateur Electronics Supply at: http://www.aesham.com try those places.

Eric

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Today's Topics:

1. Antenna questions..... (David Hinton)
2. Re: [VHF] Antenna questions..... (R J Carpenter)
3. 2M HT Antenna (Craig Mangrum)
> ATTACHMENT part 3.1 message/rfc822 From: "David Hinton" 
To: , ,
<[email protected]>
Date: Sun, 29 Jun 2003 10:55:47 -0400
Subject: [2m] Antenna questions.....

Last week during the 2 meter e's opening I noticed a similar experience with
my antennas that I noticed during the last meteor scatter storm. I asked
about it then but no really good answers.

Anyway, here goes again. I have located on the side of my tower several
stacked 4 element end mounted beam arrays. These are separate systems
pointed at 4 different directions which are switchable using an Ameritron
RCS-8V Remote Coax Switch. Three of the systems are stacked pairs and the
other is four antennas stacked. In each system the antennas are end mounted
on the sides of the tower, stacked vertically, horizontally polarized.
Their heights are between 50 and 65 feet above the ground. On the top of
the tower at 70 ft is a C3I K1FO 12 element yagi that is rotatable.
Extensive testing on ground wave and tropo signals show the 12 element yagi
to out perform the stacked pairs by 1 to 2 S units and the four stack by
1/2 to 1 S unit.

During the last meteor storm I found a stacked pair pointing northwest out
performed my 12 el yagi pointing in the same direction by a couple S units
more often than not.

During the last 2 meter e's opening I worked several station in Texas and
found again that either the stacked pair pointing west or the stacked pair
pointing northwest out performed the 12 el yagi by 1 to 2 S units. I have
worked some of those same stations in the past on tropo and the 12 el yagi
was superior then.

Question, why does the stacked pairs of 4 element yagis with theoretical
less gain out perform the 12 element yagi under meteor scatter and e's???

I have thought about radiation angle being the answer but I thought the
vertical stacking of antennas lowered the radiation angle.

David Hinton
KE4YYD

> ATTACHMENT part 3.2 message/rfc822 From: "R J Carpenter" 
To: "David Hinton" , ,
, <[email protected]>
Date: Sun, 29 Jun 2003 12:55:41 -0400
Subject: [2m] Re: [VHF] Antenna questions.....

----- Original Message -----
From: "David Hinton" 
>
> Question, why does the stacked pairs of 4 element yagis with theoretical
> less gain out perform the 12 element yagi under meteor scatter and e's???

Except at maximum range, the meteor "hot spots" are off to the side of the
great circle path. The long antenna may not be illuminating them as well as
the shorter ones.

Radiation angle might also be the answer.

The antenna at the top of the tower will have a lower main lobe due to
ground reflection if you have a smooth foreground. The lower antennas will
have a higher-angle main lobe due to ground reflection, which may suit Es
and meteors better. Most any antenna/propagation book will show you the
desired take-off any vs. distance for the E layer (100 km) - meteors are
about the same height. These books will also show you the vertical pattern
due to ground reflection, which is related to antenna height in terms of
wavelengths. Your long antenna is WAY up, and may have an unfortunate
ground-reflection null at an angle corresponding to an attractive Es
distance. Even 65 ft is very high for Es on 2-m - we used about 45 ft on 40
MHz for a meteor link to get the first lobe at a good angle for 1000 km
distance. Of course your foreground is probably not very smooth, so the
reinforcements and cancellations from ground reflection won't be as good/bad
as theory would say. We had an Illinois corn field.

Stacking antennas does NOT lower the radiation angle. Never has. What it
does is narrow the beam in the vertical plane, ie. increases vertical
directivity. But stacking 4 is probably not enough to be noticeable on Es.

As a side note, those 12-bay FM broadcast antennas on 1500-ft towers have
too sharp a vertical pattern - not enough signal near in - and nulls
close-in. So they fudge the feed system a bit to tilt the beam down, not
straight at the horizon, and also to fill in the near-in nulls. WB5ITT
could say more about this.

> ATTACHMENT part 3.3 message/rfc822 Date: Sun, 29 Jun 2003 22:53:03 -0500
From: Craig Mangrum 
To: [email protected]
Subject: [2m] 2M HT Antenna

I have an HTX-202 2M HT.  Does anyone have a good rubber duck antenna
they could recommend I use, other than the one that came with it?  Needs
to be a BNC connection!

--
Craig Mangrum KD5UXK
[email protected]

For as long as I can remember I've had amnesia.

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