[VHFcontesting] Tech Help needed

Sun Jan 3 13:19:57 EST 2021

I'd be a little more interested in what was done to resonate the Cushcraft
yagi.   I have the newer 6 element version and using the "factory
recommended "  settings my resonate point with the best SWR is just above 52
MHz.   I'm currently using a tuner and have been able to live with it, but
I'd like to get SWR reasonable at 50.100 to 50.313 where it is currently
2.5:1.

de K3SK

----------------------------------------------------------------------

Message: 1
Date: Sun, 3 Jan 2021 04:58:18 +0000 (UTC)
From: nosigma at aol.com
To: chetsubaccount at snet.net, vhfcontesting at contesting.com
Subject: Re: [VHFcontesting] Tech Help needed
Message-ID: <1663620010.6568776.1609649898988 at mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8

Interesting thread.? I face a similar band width problem but fortunately
conquered it with a lot of help. 

 I need to run SSB, FT8 at the low end (50.125-50.313) and FM (52.525) at
the high end.? With the Gamma match Cushcraft (go ahead, hate on me for
using it) 5 element I was able to get well under 1.5:1 except from 51.100 to
51.800.? It was a full days work with a blue tooth wireless head on a
spectrum analyzer that let us test with the mast up and down (fold over on
Jeep).

The Gamma match settings are way off the mfg spec to make it work.? The
critical tuning was to the reflector and first two directors.? The reflector
is marginally asymmetric (probably due to 45 deg polarization with mast
interference) and much wider than the SSB spec with the first two directors
being a bit narrower than the SSB spec.? FM to 400mi and SSB (running W4IY
KW amps & heliax) going from Va to? Europe and the Pacific Northwest.?
4000ft elevation didnt hurt.

The ability to slide the reflector? and directors in and out to change width
was the enabling capability of the antenna that allowed the silly wide
bandwidth to be achieved.? 

I know the M2's are fixed width elements, but if you the time to experiment
playing with sleeves of tubing on the reflector and first couple directors
you might get good results.

73
John
KM4KMU
On Saturday, January 2, 2021 chetsubaccount <chetsubaccount at snet.net> wrote:
This brings up again the age old question: do I want to DX or contest?

A high gain, narrow band antenna does not send a CQ in a wide azimuth. But
today's rules allow you to call someone on your cellphone and ask them to
get on and give you their grid while you beam there way. 

Vs.

Less elements on the yagi (but you can stack them? for more gain or have
multiple yagis) and call CQs that may be heard over a wider coverage
azimuth. 

Kind of like fishing- try by yourself to read the areas to fish vs. other
boats telling you where to go. Either way you will catch fish and have fun.

Your station, your choice!

Hoping to catch many fish this January.

73,
Chet, N8RA

-----Original Message-----
From: VHFcontesting
<vhfcontesting-bounces+chetsubaccount=snet.net at contesting.com> On Behalf Of
Dan Evans via VHFcontesting
Sent: Saturday, January 2, 2021 7:59 PM
To: 'Jim Worsham' <wa4kxy at bellsouth.net>; Paul Rollinson
<Paulrollinson at sbcglobal.net>
Cc: 'VHF Contesting Reflector' <vhfcontesting at contesting.com>
Subject: Re: [VHFcontesting] Tech Help needed

Hi Paul,No help here with the issue, but I wanted to thank you and the list
for the topic.
I currently have a CC 6 element on a small tower.? I have a bigger tower I
hope to put up soon, and I've been wanting to upgrade to the 6M7 if I ever
get the tower project off the ground.? So I will likely face the same
issues.
I've been following with interest.
73Dan
-- K9ZF? President, Clark County Amateur Radio Club,Amateur Radio Emergency
Service, Clark County Indiana. EM78el The once and future K9ZF /R no budget
Rover? ***QRP-l #1269 Check out the Rover Resource Page at:? List
Administrator for: InHam+grid-loc+ham-books? Ask me how to join the Indiana
Ham Mailing list! 

? ? On Saturday, January 2, 2021, 11:55:03 AM EST, Paul Rollinson
<paulrollinson at sbcglobal.net> wrote:? 

 Good morning all,

It appears that I'm not alone with this issue. It's a great antenna until
you try to push up the band for the digital modes, with potential for more
to come.

So far I've learned this from this list and other friends in the VHF
spectrum:

The theory behind moving the shorting bars out to more the freq up the band
may be based on simple J pole type design, when you short higher up the
driven element, it increases in resonate freq.
The 70 ohm (RG-6) phasing line might be able to raise the center freq if
shortened. If anyone has done this, please reply with length to attempt.
The driven element might be able to be sleeved increasing the diameter and
potential bandwidth, which is the biggest problem with this design.
Electrically lengthening the T match bars using? retaining rings at the end
may create an aching point at hi power and wet environment. This may be
catastrophic for an amp and will not be explored.
Repositioning D1 may help but this has unknown effect of performance.
Finding a better, free space test range will be first on the list. I have
90Ft trees here so spanning 2 trees and hanging the antenna in the middle
show be effective.
I still plan on calling M2 on Monday to see if I'm missing something

I will say this, great responses from the VHF community. Thanks to all.

73,

Paul Rollinson, KE1LI
Rollinson Associates
860-928-5147
860-208-8814 Cell/Text
Paulrollinson at sbcglobal.net

Representing Component Part
Manufacturers for over 35 years

info/vhfcontesting
? 
_______________________________________________
VHFcontesting mailing list
VHFcontesting at contesting.com
http://lists.contesting.com/mailman/listinfo/vhfcontesting

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------------------------------

Message: 2
Date: Sun, 3 Jan 2021 12:35:02 +0000 (UTC)
From: mikflathead at aol.com
To: "wa4kxy at bellsouth.net" <wa4kxy at bellsouth.net>,
	"chetsubaccount at snet.net" <chetsubaccount at snet.net>
Cc: "VHFcontesting at contesting.com" <VHFcontesting at contesting.com>
Subject: Re: [VHFcontesting] Tech Help needed
Message-ID: <1762347524.5016996.1609677302387 at mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8

Why was a frequency so far from 50.125 chosen for FT8? Mike

-----Original Message-----
From: Jim Worsham <wa4kxy at bellsouth.net>
To: chetsubaccount at snet.net
Cc: VHFcontesting at contesting.com
Sent: Sat, Jan 2, 2021 10:45 pm
Subject: Re: [VHFcontesting] Tech Help needed

That is my thinking also. You can have a single really large antenna with a
narrow beam width or stack two (or more) smaller antennas.

73
Jim, W4KXY

Sent from my iPad

> On Jan 2, 2021, at 8:46 PM, chetsubaccount at snet.net wrote:
> 
> ?This brings up again the age old question: do I want to DX or contest?
> 
> A high gain, narrow band antenna does not send a CQ in a wide azimuth. But
today's rules allow you to call someone on your cellphone and ask them to
get on and give you their grid while you beam there way. 
> 
> Vs.
> 
> Less elements on the yagi (but you can stack them? for more gain or have
multiple yagis) and call CQs that may be heard over a wider coverage
azimuth. 
> 
> Kind of like fishing- try by yourself to read the areas to fish vs. other
boats telling you where to go. Either way you will catch fish and have fun.
> 
> Your station, your choice!
> 
> Hoping to catch many fish this January.
> 
> 73,
> Chet, N8RA
> 
> 
> 
> -----Original Message-----
> From: VHFcontesting 
> <vhfcontesting-bounces+chetsubaccount=snet.net at contesting.com> On 
> Behalf Of Dan Evans via VHFcontesting
> Sent: Saturday, January 2, 2021 7:59 PM
> To: 'Jim Worsham' <wa4kxy at bellsouth.net>; Paul Rollinson 
> <Paulrollinson at sbcglobal.net>
> Cc: 'VHF Contesting Reflector' <vhfcontesting at contesting.com>
> Subject: Re: [VHFcontesting] Tech Help needed
> 
> Hi Paul,No help here with the issue, but I wanted to thank you and the
list for the topic.
> I currently have a CC 6 element on a small tower.? I have a bigger tower I
hope to put up soon, and I've been wanting to upgrade to the 6M7 if I ever
get the tower project off the ground.? So I will likely face the same
issues.
> I've been following with interest.
> 73Dan
> -- K9ZF? President, Clark County Amateur Radio Club,Amateur Radio
Emergency Service, Clark County Indiana. EM78el The once and future K9ZF /R
no budget Rover? ***QRP-l #1269 Check out the Rover Resource Page at:? List
Administrator for: InHam+grid-loc+ham-books? Ask me how to join the Indiana
Ham Mailing list! 
> 
>? ? On Saturday, January 2, 2021, 11:55:03 AM EST, Paul Rollinson
<paulrollinson at sbcglobal.net> wrote:? 
> 
> Good morning all,
> 
> It appears that I'm not alone with this issue. It's a great antenna until
you try to push up the band for the digital modes, with potential for more
to come.
> 
> So far I've learned this from this list and other friends in the VHF
spectrum:
> 
> The theory behind moving the shorting bars out to more the freq up the
band may be based on simple J pole type design, when you short higher up the
driven element, it increases in resonate freq.
> The 70 ohm (RG-6) phasing line might be able to raise the center freq if
shortened. If anyone has done this, please reply with length to attempt.
> The driven element might be able to be sleeved increasing the diameter and
potential bandwidth, which is the biggest problem with this design.
> Electrically lengthening the T match bars using? retaining rings at the
end may create an aching point at hi power and wet environment. This may be
catastrophic for an amp and will not be explored.
> Repositioning D1 may help but this has unknown effect of performance.
> Finding a better, free space test range will be first on the list. I have
90Ft trees here so spanning 2 trees and hanging the antenna in the middle
show be effective.
> I still plan on calling M2 on Monday to see if I'm missing something
> 
> I will say this, great responses from the VHF community. Thanks to all.
> 
> 73,
> 
> Paul Rollinson, KE1LI
> Rollinson Associates
> 860-928-5147
> 860-208-8814 Cell/Text
> Paulrollinson at sbcglobal.net
> 
> Representing Component Part
> Manufacturers for over 35 years
> 
> info/vhfcontesting
> 
> _______________________________________________
> VHFcontesting mailing list
> VHFcontesting at contesting.com
> http://lists.contesting.com/mailman/listinfo/vhfcontesting
> 
> _______________________________________________
> VHFcontesting mailing list
> VHFcontesting at contesting.com
> http://lists.contesting.com/mailman/listinfo/vhfcontesting

_______________________________________________
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VHFcontesting at contesting.com
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