# [amsat-bb] Re: Mount an Arrow on rotator with 2m vertical orhorizontal

Art McBride kc6uqh at cox.net
Tue Apr 16 22:13:26 PDT 2013

```RT,
It is done all the time. Each antenna is 50 Ohms A 1/4 wavelength or any
other odd multiple will transform impedance. Two 100 Ohm impedance ends are
combined make 50 Ohms. The impedance of the transforming line = 50 Ohms
times 100 Ohms = 5000 to the 1/2 power is 70.7 Ohms. So 75 OHM (closest to
70.7 Ohm line) is the line of choice for the power divider section. If you
put 1/2 the power into each antenna the gain for two antennas is 3 dB over
the total power into one antenna. The gain comes from the narrowing of the
pattern for a net gain of 3dB if the antennas are identical, pointed the
same direction, same polarization, and separated by at least 1/2 wave
length.

Art,
KC6UQH

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Douglas Phelps
Sent: Tuesday, April 16, 2013 11:31 AM
To: R.T.Liddy; amsat-bb at amsat.org
Subject: [amsat-bb] Re: Mount an Arrow on rotator with 2m vertical
orhorizontal

Any reason why, using identical coax lengths, you could not transform the
impedance to 100 ohms and then use a T connector to sum both antenna signals
and
achieve 50 ohms to the radio?  I know Transmit power will be 3 dB down at
either
antenna but is there any reason it will not work?  Any antenna gurus out
there?

________________________________
From: R.T.Liddy <k8bl at ameritech.net>
To: amsat-bb at amsat.org
Sent: Tue, April 16, 2013 11:46:35 AM
Subject: [amsat-bb] Re: Mount an Arrow on rotator with 2m vertical or
horizontal

For the Satellites, it completely doesn't matter. At any given moment,
you only have 1 chance in 90 that you will have matching polarization.

So, if you plan to use the antenna for other than Satellites, set your
polarization
for that purpose (V for FM or H for SSB/CW).

My plan is to install 2 Elk antennas, one V and one H. Then, have a relay
that
I can switch between the two and choose the best downlink signal at any
given moment. This arrangement will also give me optimum flexibility for
terrestrial operation on 2 & 440.

Now, where can I find a relay to do that function?????

73/GL,    Bob K8BL

--- On Tue, 4/16/13, Lee Maisel <maisel at lobo.net> wrote:

From: Lee Maisel <maisel at lobo.net>
Subject: [amsat-bb] Re: Mount an Arrow on rotator with 2m vertical or
horizontal
To: "Don Hoover (WS4E)" <ws4e at arrl.net>
Cc: amsat-bb at amsat.org
Date: Tuesday, April 16, 2013, 12:24 AM

Hi Don,

I have mine mounted with 2m elements horizontal, because that's how it
seems I used it most when it was handheld.

Lee
W5LMM

Don Hoover (WS4E) wrote:
> Just wondering, should I mount my arrow with the 2m elements oriented
> vertical or horizontal?
>
> I am planning on putting it at 15deg and just using a az rotator.
>
> Does it even matter which way its oriented since the polarity of the sats
> are always changing?
>
> Maybe I should mount it like this: / instead.
>
> Just curious what some thought was the best way to go.
> _______________________________________________
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>

--

ΜΟΛΩΝ ΛΑΒΕ

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Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

```