[VHFcontesting] Tech Help needed - Cushcraft 5el 6m Yagi

Sun Jan 3 15:37:14 EST 2021

Couple of things to remember when testing 6m beams close to the ground.
Unless you can get a horizontal 6m beam 20 ft off the ground, your results
will not be consistent, tie a rope between two trees and point the antenna
straight up and at least 4-5 feet off the ground. Be sure you are using
multiples of a half wavelength between the antenna and whatever you are
measuring SWR with.

I've found with all our antennas using tee matches, the length and position
of the tee arms past the shorting bars relative to the driven element makes
a huge difference. Dave Olean, K1WHS, wrote a nice paper on understanding
tee matches and is available on our website.
https://directivesystems.com/information/tech-notes/t-matching-tuning-notes/

Terry Price - W8ZN
Directive Systems and Engineering
703-754-3876

On Sun, Jan 3, 2021 at 2:06 PM Lloyd - N9LB <lloydberg at tds.net> wrote:

> I've got a CushCraft 5el 6m Yagi too, it was not a high performing antenna
> right out of the box.  Also optimum pattern and gain are not directly
> related to SWR.
>
> You need to make some modifications with element length and spacing.
>
> Bill Van Alstyne - W5WVO came up with some improvements for the A50-5
> antenna:
> http://www.bigskyspaces.com/w7gj/A50-5S_w5wvo.pdf
>
> Justin Glasener - K9MU also has some significant improvements for this
> antenna.
> http://www.k9mu.com/a50-5.html
>
> BTW the Cushcraft 6el Yagi is computer optimized and is a far better
> antenna
> right out of the box.
>
> 73
>
> Lloyd - N9LB
>
>
> -----Original Message-----
> From: VHFcontesting
> [mailto:vhfcontesting-bounces+lloydberg=tds.net at contesting.com] On Behalf
> Of
> k3sk at hiddenacresfarm.com
> Sent: Sunday, January 03, 2021 12:20 PM
> To: vhfcontesting at contesting.com
> Subject: Re: [VHFcontesting] Tech Help needed
>
> 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
>
> _______________________________________________
> VHFcontesting mailing list
> VHFcontesting at contesting.com
> http://lists.contesting.com/mailman/listinfo/vhfcontesting
>
>
> ------------------------------
>
> 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
>
> _______________________________________________
> VHFcontesting mailing list
> VHFcontesting at contesting.com
> http://lists.contesting.com/mailman/listinfo/vhfcontesting
>
>
> ------------------------------
>
> Subject: Digest Footer
>
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> VHFcontesting mailing list
> VHFcontesting at contesting.com
> http://lists.contesting.com/mailman/listinfo/vhfcontesting
>
>
> ------------------------------
>
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