Looking to build a decent 6 mtr antenna ... probably a loop...

space no problem indoor out out...

want to hit local repeater 50 miles away...

Have you had experience and can you recommend a good one..!!!
THX in advance

Tony

Most if not all Six meter repeaters use vertical antennas -- hence vertical
polarization
When looking at loops -- choose a suitable one.
Lots of 6M antenna projects at AC6V's site -- URL:
http://ac6v.com/antprojects.htm#6M

--
The Anon Keyboard
I doubt, therefore I might be



"tonester" wrote in message
...
Looking to build a decent 6 mtr antenna ... probably a loop...

space no problem indoor out out...

want to hit local repeater 50 miles away...

Have you had experience and can you recommend a good one..!!!
THX in advance

Tony

"tonester" wrote in message
...
Looking to build a decent 6 mtr antenna ... probably a loop...

space no problem indoor out out...

want to hit local repeater 50 miles away...

Have you had experience and can you recommend a good one..!!!
THX in advance

Tony

I don't think you want horizontal polarization for a repeater- everyone
(except ATV) I am familiar with is vertically polarized.

Dale W4OP

Tony wrote:
"Looking to build a decent 6 mtr antenna... probably a loop... Space no
problem indoor or out..."

I suppose vertical polarization is used in the repeater you would like
to reach 50 miles away, so that it is compatible with mobiles.

Hopefully your repeater antenna is at high altitude on a TV tower or
some such lofty perch. You need about 1250 feet of elevation to provide
a horizon 50 miles away.

Height of the station antenna on your end reduces the repeater antenna
height required. A vertical loop antenna is fed in the middle of a
vertical side and makes an array of two 1/4-wave vertical dipoles,
separated in space by 1/4-wave. It has slightly more gain in the
direction of the plane of the vertical sides. The ground quality
surrounding the antenna affects its performance but radials are not
worthwhile.
There is a slight gain versus a groundplane antenna.

In free space, the radiation resistance of a square quad loop of one
wavelength circumference is about 120 ohms. It would work best with
balanced feed.

ON4UN`s "Low-Band DXing" has a chapter "Large Loop Antennas" which would
likely be worth a look.

Best regards, Richard Harrison, KB5WZI

On Tue, 16 Nov 2004 18:44:38 +0000, tonester
wrote:

Looking to build a decent 6 mtr antenna ... probably a loop...

space no problem indoor out out...

want to hit local repeater 50 miles away...

Depends on how high the repeater antenna is and how much power you're
running -- to hit a repeater at that distance your best bet is
probably a small beam, regardless of polarization issues.

A beam would also be your best bet for general 6 meter work.

Six meter beams aren't all that expensive -- if you really want to
homebrew one, do a google search.

bob
k5qwg



Have you had experience and can you recommend a good one..!!!
THX in advance

Tony

Someone wrote
"your best bet is
probably a small beam, regardless of polarization issues.


However, a yagi can be rotated 90 deg to have vertical polarization thereby
avoiding the cross polarization attenuation which can be significant. Just
be careful of interaction between the yagi elements and the mast.
AND
A quad can be fed to have vertical polarization

--
The Anon Keyboard
I doubt, therefore I might be



"Bob Miller" wrote in message
...
On Tue, 16 Nov 2004 18:44:38 +0000, tonester
wrote:

Looking to build a decent 6 mtr antenna ... probably a loop...

space no problem indoor out out...

want to hit local repeater 50 miles away...

Depends on how high the repeater antenna is and how much power you're
running -- to hit a repeater at that distance your best bet is
probably a small beam, regardless of polarization issues.

A beam would also be your best bet for general 6 meter work.

Six meter beams aren't all that expensive -- if you really want to
homebrew one, do a google search.

bob
k5qwg



Have you had experience and can you recommend a good one..!!!
THX in advance

Tony

From URL:
http://www.astronantennas.com/polarization.html

On line-of-sight (LOS) paths, it is most important that the polarization of
the antennas at both ends of the path use the same polarization. In a
linearly polarized system, a misalignment of polarization of 45 degrees will
degrade the signal up to 3 dB and if misaligned 90 degrees the attenuation
can be 20 dB or more.

--
The Anon Keyboard
I doubt, therefore I might be



Someone wrote
"your best bet is
probably a small beam, regardless of polarization issues.


"Keyboard In The Wilderness" wrote in message
news:jTvmd.145327$hj.28281@fed1read07...
Replied
However, a yagi can be rotated 90 deg to have vertical polarization
thereby avoiding the cross polarization attenuation which can be
significant. Just be careful of interaction between the yagi elements and
the mast.
AND
A quad can be fed to have vertical polarization

--
The Anon Keyboard
I doubt, therefore I might be



"Bob Miller" wrote in message
...
On Tue, 16 Nov 2004 18:44:38 +0000, tonester
wrote:

Looking to build a decent 6 mtr antenna ... probably a loop...

space no problem indoor out out...

want to hit local repeater 50 miles away...

Depends on how high the repeater antenna is and how much power you're
running -- to hit a repeater at that distance your best bet is
probably a small beam, regardless of polarization issues.

A beam would also be your best bet for general 6 meter work.

Six meter beams aren't all that expensive -- if you really want to
homebrew one, do a google search.

bob
k5qwg



Have you had experience and can you recommend a good one..!!!
THX in advance

Tony

Difficult to answer your question until you say what Tx power you intend to
use and the sort of obstructions along the radio path.

=================================

want to hit local repeater 50 miles away...

Looking to build a decent 6 mtr antenna ... probably a loop...

space no problem indoor out out...

want to hit local repeater 50 miles away...

==================================

The line-of-sight performance on a 50 mile path, at 50 MHz, with a Tx power
of 50 watts and similarly polarised half-wave dipoles, is approx as
follows -

Tx to Rx transmission loss = 100 dB.
50-ohm Rx input volts = 500 micro-volts.
Equivalent to S9 + 20 dB.

Which is a very loud signal level.

However, due to Earth curvature, at 50 MHz the radio horizon at ground level
is only about 14 miles. And as Richard says, at least one of the Tx and Rx
antennas must be elevated to more than 1250 feet above the other to achieve
a line-of-sight condition without any high ground obstructions in between.

Attenuation beyond the horizon increases rapidly due to diffraction. But you
might just about make it with 50 watts and a 3-element vertical antenna. (A
dipole with 1 reflector + 1 director.) (Or a dipole + 2 directors.) (Or you
could try just 1 director.) Expect some fading depending on weather
conditions.

On the other hand, if you were lucky when you chose your QTH, you may come
booming through. Enjoy yourself experimenting with a vertical antenna as
high as possible above the roof tops.
----
Reg, G4FGQ

Your main aim with this antenna - is to get it as HIGH as you can and use
good feedline
Use a 5/8-wave vertical - or a quad (side fed)

"tonester" wrote in message
...
Looking to build a decent 6 mtr antenna ... probably a loop...

space no problem indoor out out...

want to hit local repeater 50 miles away...

Have you had experience and can you recommend a good one..!!!
THX in advance

Tony


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