On Wed, 16 Jun 2010 10:24:26 -0700 (PDT), "R.Scott"
wrote:

I see all kinds of crazy matching sections in posts about 6 meter
beams. How about direct connect. I have an A4S that has major issues
in the traps and I cant find the problem (IE I opened them and cant
find anything) SOOO I have a new A4S coming.

Has anyone taken an old 3 elem tribander and converted it to 6 meter
monobander using the direct connect.

Any Issues.

Would a 4 elem be better since its a long boom ?

I'm pretty sure I know the answers. Just want to confirm and see if
there is any reason not to direct connect rather than through a
hairpin or a gamma match.


Scotty W7PSK

I have an old Radio Shack 11 meter 3 element beam that I plan to put
on 6 meters. I once did the EZNEC modeling with the boom length being
the only constraint. It was possible to come up with a model that
would work with a direct match for 50 ohms to the driven element. I
hope to try to construct it soon.

The problem with holding a few parameters constant is that you have to
accept whatever gain, patterns and such that come with the deal.

I also have a very old Mosley 15 meter 3 element beam that I want to
modify to 17 meters. I am having a lot of fun with PSK31 there with
poor antenna setup now.

Tower space is a limiting factor in my case and I am not interested in
anything that compromises my A3S!

I wish you were close to me rather than 2306.9 miles, I am looking for
an old bargain tri band to tinker with. There is a lot there I don't
understand!


John Ferrell W8CCW

The problem with holding a few parameters constant is that you have to
accept whatever gain, patterns and such that come with the deal.

Well I did find plans for a 6 elem on a 17.5ft boom. The boom on the
old A4S is 18Ft. If I use the parts off my old A3
and my A4 I should be able to come up with all the parts for the 6
element. And its direct connect.


I wonder how far above the A4 the 6 meter needs to be. I only have a
5ft mast.

my DX800 rotor should handle it.

Since no one stepped up who has the experience and knowledge, I will
offer an opinion:

Further would be better but the more practical decision will be based
on what is reasonable and maintainable.

Everything is a compromise!

On Thu, 17 Jun 2010 09:05:11 -0700 (PDT), "R.Scott"
wrote:

The problem with holding a few parameters constant is that you have to
accept whatever gain, patterns and such that come with the deal.

Well I did find plans for a 6 elem on a 17.5ft boom. The boom on the
old A4S is 18Ft. If I use the parts off my old A3
and my A4 I should be able to come up with all the parts for the 6
element. And its direct connect.


I wonder how far above the A4 the 6 meter needs to be. I only have a
5ft mast.

my DX800 rotor should handle it.

John Ferrell W8CCW

On 6/17/2010 11:05 AM, R.Scott wrote:
The problem with holding a few parameters constant is that you have to
accept whatever gain, patterns and such that come with the deal.

Well I did find plans for a 6 elem on a 17.5ft boom. The boom on the
old A4S is 18Ft. If I use the parts off my old A3
and my A4 I should be able to come up with all the parts for the 6
element. And its direct connect.


I wonder how far above the A4 the 6 meter needs to be. I only have a
5ft mast.

my DX800 rotor should handle it.



I have plans for a very good 6 element beam which is 15.53 feet from
reflector to D4. I could scale it to the element taper you have if needed.

It will not be a direct connect however, as those are almost never
optimal designs for gain, F/B or pattern. They are optimized to be 50
ohms with the rest subservient to that. Most of the designs I have
would be around 22 ohms so this one is probably in that area. A gamma
match is easy to make.

tom
K0TAR

On 6/19/2010 8:33 PM, tom wrote:

I have plans for a very good 6 element beam which is 15.53 feet from
reflector to D4. I could scale it to the element taper you have if needed.

It will not be a direct connect however, as those are almost never
optimal designs for gain, F/B or pattern. They are optimized to be 50
ohms with the rest subservient to that. Most of the designs I have would
be around 22 ohms so this one is probably in that area. A gamma match is
easy to make.

tom
K0TAR

Sorry, I should have looked before leaping, it's 5 elements on 15.5 feet.

tom
K0TAR

On Jun 19, 7:28*pm, tom wrote:
On 6/19/2010 8:33 PM, tom wrote:



I have plans for a very good 6 element beam which is 15.53 feet from
reflector to D4. I could scale it to the element taper you have if needed.

It will not be a direct connect however, as those are almost never
optimal designs for gain, F/B or pattern. They are optimized to be 50
ohms with the rest subservient to that. Most of the designs I have would
be around 22 ohms so this one is probably in that area. A gamma match is
easy to make.

tom
K0TAR

Sorry, I should have looked before leaping, it's 5 elements on 15.5 feet.

tom
K0TAR

Id be interested in the plans.
Hard part is making the strap, Ive no shop tools/materials handy to do
it easy. Ive the tubing and
the RG8 .

Scotty W7PSK.

On 6/21/2010 12:08 PM, R.Scott wrote:

Sorry, I should have looked before leaping, it's 5 elements on 15.5 feet.

tom
K0TAR

Id be interested in the plans.
Hard part is making the strap, Ive no shop tools/materials handy to do
it easy. Ive the tubing and
the RG8 .

Scotty W7PSK.

Send me an email at . It will be valid until
tomorrow morning.

tom
K0TAR

On Jun 21, 5:19*pm, tom wrote:
On 6/21/2010 12:08 PM, R.Scott wrote:



Sorry, I should have looked before leaping, it's 5 elements on 15.5 feet.

tom
K0TAR

Id be interested in the plans.
Hard part is making the strap, Ive no shop tools/materials handy to do
it easy. *Ive the tubing and
the RG8 .

Scotty W7PSK.

Send me an email at . *It will be valid until
tomorrow morning.

tom
K0TAR

Guess I was too slow.

On Thu, 17 Jun 2010 09:05:11 -0700 (PDT), "R.Scott"
wrote:

The problem with holding a few parameters constant is that you have to
accept whatever gain, patterns and such that come with the deal.

Well I did find plans for a 6 elem on a 17.5ft boom. The boom on the
old A4S is 18Ft. If I use the parts off my old A3
and my A4 I should be able to come up with all the parts for the 6
element. And its direct connect.
I'm a bit late to the party, but...

To me that seems like a lot of elements on a short boom, (I use 7L on
a 29' boom) but properly adjusted they can give more band width rather
than gain as gain is more a function of boom length. Also, how do they
get 50 ohms at the feed point of a dipole driven element in a 6L
Yagi?

Direct connect can work, but how well is another question. It may
give a good match, it may transfer the power efficiently, but again
the question is, how well does it work.

Jim Brown's (K9YC), A Ham's Guide to RFI, Ferrites, Baluns, and Audio
Interfacing ...
www.audiosystemsgroup.com/RFI-Ham.pdf is well worth reading. when it
comes to using toroids and the old "coil of coax" as a rather
inefficient current balun (which I used for years).

I worked a station down in Central America (on six) who had his new
rig on the bench testing it with a short piece of wire stuck in the
coax connector...I'm in Michigan. He could have said, that short piece
of wire on the bench was a good antenna...at that moment.

But given you get a good match, the pattern is still going to be
distorted. You can take 4 2.4" OD toroid cores with 4 or 5 turns of
coax through them to make a very good current balun (bout 5,000 ohms
isolation) and center feed a split driven element, then the antenna
is not really "direct connect" as the "matching device" is between the
feed line and antenna even though it can be the end 5 to 8' of coax
wound on the cores.

BTW, run the coax through the toroids before installing the connector



I wonder how far above the A4 the 6 meter needs to be. I only have a
5ft mast.

Should be and what you can get away with are often quite different. A
friend has a bunch of antennas on one tower that are all way closer
than they *should* be, but he gets acceptable performance, at least to
him and that's all that counts. Having said that, 5' would be
considered very close and 10' would be much better. OTOH you will
probably be satisfied with the performance over a simple antenna.
All antennas are a series of compromises as are installations. IOW we
use what we have and hope for the best. You only have a 5' mast, so I
assume that a taller mast is out of the question which makes "how far
apart do they need to be" a moot question. Then the real question is:
Will they work with only 5' of spacing? The answer is ... Probably and
they probably will work fairly well.

One element to keep in mind (no pun intended) is with the antennas
only 5' apart they may tend to detune one or both a bit and also lower
the feed point impedance. But it's what you have and you won't know
until you try.

Getting things to work is half the fun, at least it is to me...as long
as getting the project to work does not run into frustration. :-))

73 & Good Luck.

Roger (K8RI)

my DX800 rotor should handle it.