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Off Topic -- Yagi Antenna SWR measurement ?

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Phil Hystad-3

Off Topic -- Yagi Antenna SWR measurement ?

I know this is OT but there are so many knowledgable people on this reflector
that I can't pass it up.

A friend has a Yagi antenna (HF tri-bander) that he wants to measure the SWR
before he raises the antenna up on the tower.

Question: is this accurate or does the proximity of ground (maybe two feet high)
so strongly affect the SWR reading that the measurement is not accurate.

73, phil, K7PEH

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daleputnam

Re: Off Topic -- Yagi Antenna SWR measurement ?

Two feet high.. is way too close to the ground.....
However, if the beam is 10 foot high.. or maybe 15... that would be so much better and more accurate..
Expect some change when it gets top of tower.. but at 15 ft.. adjustments can me made reliable, with little change
seen.
Good Luck, be careful, ladders are more dangerous than towers,

Have a great day,

--... ...--
Dale - WC7S in Wy

> From: [hidden email]
> Date: Fri, 12 Jul 2013 07:50:43 -0700
> To: [hidden email]
> Subject: [Elecraft] Off Topic -- Yagi Antenna SWR measurement ?
>
> I know this is OT but there are so many knowledgable people on this reflector
> that I can't pass it up.
>
> A friend has a Yagi antenna (HF tri-bander) that he wants to measure the SWR
> before he raises the antenna up on the tower.
>
> Question: is this accurate or does the proximity of ground (maybe two feet high)
> so strongly affect the SWR reading that the measurement is not accurate.
>
> 73, phil, K7PEH
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

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mcduffie

Re: Off Topic -- Yagi Antenna SWR measurement ?

In reply to this post by Phil Hystad-3

On Fri, 12 Jul 2013 07:50:43 -0700, Phil Hystad wrote:

> Question: is this accurate or does the proximity of ground (maybe two feet high)
> so strongly affect the SWR reading that the measurement is not accurate.

Not accurate at all. Most manufacturers say to stand the beam up so it
is pointed straight up into the sky, reflector down, to do such checks.
I still don't trust that, but is better than having it parallel to the
ground. Keep everything (including yourself) away from the elements
during the test. Get it out in a clear yard, as far from wires and
buildings as possible and point it into the sky.

Gary
--
http://ag0n.net
3055: http://ag0n.net/irlp/3055
NodeOp Help Page: http://ag0n.net/irlp
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WM3M

Re: Off Topic -- Yagi Antenna SWR measurement ?

What I have done is clamp it to my wooden deck railings on a 8 foot mast,
the higher your deck is the better.
That worked pretty well for me, little change once it was up in position.
73 good luck
Emory WM3M

-----Original Message-----
From: AG0N-3055
Sent: Friday, July 12, 2013 10:58 AM
To: elecraft
Subject: Re: [Elecraft] Off Topic -- Yagi Antenna SWR measurement ?

On Fri, 12 Jul 2013 07:50:43 -0700, Phil Hystad wrote:

> Question: is this accurate or does the proximity of ground (maybe two
> feet high)
> so strongly affect the SWR reading that the measurement is not accurate.

Not accurate at all. Most manufacturers say to stand the beam up so it
is pointed straight up into the sky, reflector down, to do such checks.
I still don't trust that, but is better than having it parallel to the
ground. Keep everything (including yourself) away from the elements
during the test. Get it out in a clear yard, as far from wires and
buildings as possible and point it into the sky.

Gary
--
http://ag0n.net
3055: http://ag0n.net/irlp/3055
NodeOp Help Page: http://ag0n.net/irlp
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Jack Smith-6

Re: Off Topic -- Yagi Antenna SWR measurement ?

In reply to this post by Phil Hystad-3

You might get a somewhat more representative SWR value if the yagi is
vertically mounted so that the reflector is closest to ground and the
director at the top.

The idea is that the reflector will partially decouple the close in
ground surface from the antenna. I've done this with VHF and UHF
antennas and found it works well, but at HF while it's better than
making a measurement with the antenna parallel to the ground but I would
expect noticeable changes when it is mounted atop the tower.

Jack K8ZOA

On 7/12/2013 10:50 AM, Phil Hystad wrote:

> I know this is OT but there are so many knowledgable people on this reflector
> that I can't pass it up.
>
> A friend has a Yagi antenna (HF tri-bander) that he wants to measure the SWR
> before he raises the antenna up on the tower.
>
> Question: is this accurate or does the proximity of ground (maybe two feet high)
> so strongly affect the SWR reading that the measurement is not accurate.
>
> 73, phil, K7PEH
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Phil Hystad-3

Re: Off Topic -- Yagi Antenna SWR measurement ?

In reply to this post by Phil Hystad-3

Thanks guys who answered the question -- good convergence. I had already
told my friend that his readings would not be very accurate but he is concerned
about putting an old beam antenna up that had been out of service and laying
out on the ground in the open for some time (years?).

I think I have a good assessment so far that matches what I had thought
so the Off Topic Q can be closed unless someone has something completely
different to say.

73, phil

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Mel

Re: Off Topic -- Yagi Antenna SWR measurement ?

In reply to this post by WM3M

I used a 12 foot tall four leg scissor ladder. Close but no cigars. The lower bands will probably show the higher SWR, and a lower shift in freq response. As long as the pass band is close it will probably be OK.

Mel, K6KBE

________________________________
From: WM3M <[hidden email]>
To: [hidden email]; elecraft <[hidden email]>
Sent: Friday, July 12, 2013 8:09 AM
Subject: Re: [Elecraft] Off Topic -- Yagi Antenna SWR measurement ?

What I have done is clamp it to my wooden deck railings on a 8 foot mast,
the higher your deck is the better.
That worked pretty well for me, little change once it was up in position.
73 good luck
Emory WM3M

-----Original Message-----
From: AG0N-3055
Sent: Friday, July 12, 2013 10:58 AM
To: elecraft
Subject: Re: [Elecraft] Off Topic -- Yagi Antenna SWR measurement ?

On Fri, 12 Jul 2013 07:50:43 -0700, Phil Hystad wrote:

> Question: is this accurate or does the proximity of ground (maybe two
> feet high)
> so strongly affect the SWR reading that the measurement is not accurate.

Not accurate at all. Most manufacturers say to stand the beam up so it
is pointed straight up into the sky, reflector down, to do such checks.
I still don't trust that, but is better than having it parallel to the
ground. Keep everything (including yourself) away from the elements
during the test. Get it out in a clear yard, as far from wires and
buildings as possible and point it into the sky.

Gary
--
http://ag0n.net
3055: http://ag0n.net/irlp/3055
NodeOp Help Page: http://ag0n.net/irlp
______________________________________________________________
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John Santillo

Re: Off Topic -- Yagi Antenna SWR measurement ?

The lower the frequency the harder it is and I found standing the antenna up
on end didn't work well either.

What I do especially at the lower bands is put the antenna up in the air
around 10 to 12 feet and adjust it to just below the bottom of the band.
For example for 40M I would tune for best VSWR at 6.95MHz. Then when the
antenna was raised the resonant point moved up in frequency to 7.1MHz. I
know it's not the best way but it worked.

73,

John
N2HMM

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Mel Farrer
Sent: Friday, July 12, 2013 11:42 AM
To: WM3M; [hidden email]; elecraft
Subject: Re: [Elecraft] Off Topic -- Yagi Antenna SWR measurement ?

I used a 12 foot tall four leg scissor ladder. Close but no cigars. The
lower bands will probably show the higher SWR, and a lower shift in freq
response. As long as the pass band is close it will probably be OK.

Mel, K6KBE

________________________________
From: WM3M <[hidden email]>
To: [hidden email]; elecraft <[hidden email]>
Sent: Friday, July 12, 2013 8:09 AM
Subject: Re: [Elecraft] Off Topic -- Yagi Antenna SWR measurement ?

What I have done is clamp it to my wooden deck railings on a 8 foot mast,
the higher your deck is the better.
That worked pretty well for me, little change once it was up in position.
73 good luck
Emory WM3M

-----Original Message-----
From: AG0N-3055
Sent: Friday, July 12, 2013 10:58 AM
To: elecraft
Subject: Re: [Elecraft] Off Topic -- Yagi Antenna SWR measurement ?

On Fri, 12 Jul 2013 07:50:43 -0700, Phil Hystad wrote:

> Question: is this accurate or does the proximity of ground (maybe two
> feet high)
> so strongly affect the SWR reading that the measurement is not accurate.

Not accurate at all. Most manufacturers say to stand the beam up so it
is pointed straight up into the sky, reflector down, to do such checks.
I still don't trust that, but is better than having it parallel to the
ground. Keep everything (including yourself) away from the elements
during the test. Get it out in a clear yard, as far from wires and
buildings as possible and point it into the sky.

Gary
--
http://ag0n.net
3055: http://ag0n.net/irlp/3055
NodeOp Help Page: http://ag0n.net/irlp
______________________________________________________________
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Jim Brown-10

Re: Off Topic -- Yagi Antenna SWR measurement ?

On 7/12/2013 9:12 AM, John Santillo wrote:
> What I do especially at the lower bands is put the antenna up in the air
> around 10 to 12 feet and adjust it to just below the bottom of the band.
> For example for 40M I would tune for best VSWR at 6.95MHz. Then when the
> antenna was raised the resonant point moved up in frequency to 7.1MHz. I
> know it's not the best way but it worked.

I tried this with a 4-el 10M Yagi on a push-up at about 10 ft, and the
resonance actually moved down when I raised it to 20 ft, which is where
I run it.

73, Jim K9YC
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Keith Heimbold

Re: Off Topic -- Yagi Antenna SWR measurement ?

In reply to this post by John Santillo

I ran into this issue with my Mosley Super 33 where it looked fine on 40m at 12' at 7.14 mhz resonance and then when I put it up in the tower it shifted up 100 kHz. Not good.

I have been able to improve resonance slightly by extending the tower all the way up to 50' but eventually I will need to rent a scissor lift and extend the elements to position 1 versus position 2 on the Mosley. Still it works great on the edge of my 150' canyon but still need to eventually take care of it.

Good luck!!

Keith
AK6ZZ

Sent from my iPhone please excuse typos

On Jul 12, 2013, at 9:13 AM, "John Santillo" <[hidden email]> wrote:

> The lower the frequency the harder it is and I found standing the antenna up
> on end didn't work well either.
>
> What I do especially at the lower bands is put the antenna up in the air
> around 10 to 12 feet and adjust it to just below the bottom of the band.
> For example for 40M I would tune for best VSWR at 6.95MHz. Then when the
> antenna was raised the resonant point moved up in frequency to 7.1MHz. I
> know it's not the best way but it worked.
>
>
> 73,
>
> John
> N2HMM
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Mel Farrer
> Sent: Friday, July 12, 2013 11:42 AM
> To: WM3M; [hidden email]; elecraft
> Subject: Re: [Elecraft] Off Topic -- Yagi Antenna SWR measurement ?
>
> I used a 12 foot tall four leg scissor ladder. Close but no cigars. The
> lower bands will probably show the higher SWR, and a lower shift in freq
> response. As long as the pass band is close it will probably be OK.
>
> Mel, K6KBE
>
>
>
>
> ________________________________
> From: WM3M <[hidden email]>
> To: [hidden email]; elecraft <[hidden email]>
> Sent: Friday, July 12, 2013 8:09 AM
> Subject: Re: [Elecraft] Off Topic -- Yagi Antenna SWR measurement ?
>
>
> What I have done is clamp it to my wooden deck railings on a 8 foot mast,
> the higher your deck is the better.
> That worked pretty well for me, little change once it was up in position.
> 73 good luck
> Emory WM3M
>
> -----Original Message-----
> From: AG0N-3055
> Sent: Friday, July 12, 2013 10:58 AM
> To: elecraft
> Subject: Re: [Elecraft] Off Topic -- Yagi Antenna SWR measurement ?
>
> On Fri, 12 Jul 2013 07:50:43 -0700, Phil Hystad wrote:
>
>> Question: is this accurate or does the proximity of ground (maybe two
>> feet high)
>> so strongly affect the SWR reading that the measurement is not accurate.
>
> Not accurate at all. Most manufacturers say to stand the beam up so it
> is pointed straight up into the sky, reflector down, to do such checks.
> I still don't trust that, but is better than having it parallel to the
> ground. Keep everything (including yourself) away from the elements
> during the test. Get it out in a clear yard, as far from wires and
> buildings as possible and point it into the sky.
>
> Gary
> --
> http://ag0n.net
> 3055: http://ag0n.net/irlp/3055
> NodeOp Help Page: http://ag0n.net/irlp
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Elecraft mailing list
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>
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>
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N5GE

Re: Off Topic -- Yagi Antenna SWR measurement ?

In reply to this post by Phil Hystad-3

All,

There is an antenna reflector that would be more appropriate for the
is post. Try it out.

Welcome to the [hidden email] mailing list! Antennas is a
mailing list (reflector) devoted to discussing, comparing,
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especially for amateur radio, SWL, scanning, and monitoring.

* Design and Evaluation
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* MF, HF, VHF, UHF, SHF
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This list (reflector) is devoted entirely to the topic of antennas.
Anything related to antennas operation is appropriate.

On Fri, 12 Jul 2013 07:50:43 -0700, Phil Hystad <[hidden email]>
wrote:

73,
Tom
Amateur Radio Operator N5GE
Licensed since 1976
ARRL Lifetime Member
QCWA Lifetime Member

>I know this is OT but there are so many knowledgable people on this reflector
>that I can't pass it up.
>
>A friend has a Yagi antenna (HF tri-bander) that he wants to measure the SWR
>before he raises the antenna up on the tower.
>
>Question: is this accurate or does the proximity of ground (maybe two feet high)
>so strongly affect the SWR reading that the measurement is not accurate.
>
>73, phil, K7PEH
>
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html

Amateur Radio Operator N5GE