Dave Platt wrote:
Does anybody have a copy of K1BQT's article from the Summer 1997 issue
of Communications Quarterly, on a method for constructing a 2-meter
extended double zepp antenna with a novel feed/matching arrangement?

Is it better than just feeding it with about 15 inches of ladder-line?
--
73, Cecil http://www.qsl.net/w5dxp

In article ,
Cecil Moore wrote:

Does anybody have a copy of K1BQT's article from the Summer 1997 issue
of Communications Quarterly, on a method for constructing a 2-meter
extended double zepp antenna with a novel feed/matching arrangement?

Is it better than just feeding it with about 15 inches of ladder-line?

Better? Dunno - maybe so, maybe no.

The K1BQT design creates an EDZ using a pair of 38"-or-so rods or
whips, and two just-under-10" lengths of RG-58 solid-core coax
(conductor and braid shorted at the outer end, braid left open at the
center where the antenna connects to the feedline). The lengths of
RG-58 act as inductive stubs, cancelling out the capacitive reactance
of the radiators; the lengths of the rods/whips are adjusted to yield
a 50-ohm-per-side resistive impedancea at the feedpoint. The
resulting 100-ohm impedance is matched to the feedline by a 3/4-
wavelength piece of RG-59 75-ohm coax which is coiled around the
center support... it serves both as an impedance transformer and a
choke balun.

If I were going to feed a 5/4 with ladder line, for tower
side-mounting, I suppose I'd probably put the ladder line inside the
PVC support arm, and then connect it to some 50-ohm coax which was
wound around the outside of the arm to create a choke balun.




--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Dave Platt wrote:

Cecil Moore wrote:
Is it better than just feeding it with about 15 inches of ladder-line?

If I were going to feed a 5/4 with ladder line, for tower
side-mounting, I suppose I'd probably put the ladder line inside the
PVC support arm, and then connect it to some 50-ohm coax which was
wound around the outside of the arm to create a choke balun.

Cebik's stuff is probably for HF. EZNEC sez an 8 foot long, one
inch diameter dipole at 36 ft. height has a feedpoint impedance
of 86-j91 on 146 MHz. Heck, that's already better than some rubber
duckies. All it takes to resonate that impedance to a 50 ohm SWR
of about 1.6:1 is about 2.5 inches of 450 ohm ladder-line in
series. What could possibly be simpler than that?
--
73, Cecil http://www.qsl.net/w5dxp

On Sat, 12 Nov 2005 22:30:44 GMT, Cecil Moore wrote:

Dave Platt wrote:
Does anybody have a copy of K1BQT's article from the Summer 1997 issue
of Communications Quarterly, on a method for constructing a 2-meter
extended double zepp antenna with a novel feed/matching arrangement?

Is it better than just feeding it with about 15 inches of ladder-line?

No perfomance difference. Construction difference may favor one of
the other.

Allison

On Sat, 12 Nov 2005 23:31:27 GMT, Cecil Moore wrote:

Dave Platt wrote:

Cecil Moore wrote:
Is it better than just feeding it with about 15 inches of ladder-line?

If I were going to feed a 5/4 with ladder line, for tower
side-mounting, I suppose I'd probably put the ladder line inside the
PVC support arm, and then connect it to some 50-ohm coax which was
wound around the outside of the arm to create a choke balun.

Cebik's stuff is probably for HF. EZNEC sez an 8 foot long, one
inch diameter dipole at 36 ft. height has a feedpoint impedance
of 86-j91 on 146 MHz. Heck, that's already better than some rubber
duckies. All it takes to resonate that impedance to a 50 ohm SWR
of about 1.6:1 is about 2.5 inches of 450 ohm ladder-line in
series. What could possibly be simpler than that?

With EDZ or it's evil twin in the other plane the 5/8 wave the
electrical length affects feed point R while the X is fairly large.
So you use some form of matching magic to transform that
unrulely X to R and thereby a match to a 50 ohm source and line.

If you looked at the Cebik article you will see how and why
plus it's result at 2m. I scaled his work for 6m and it worked
to the the decimal point.

Allison
KB1GMX

Does anybody have a copy of K1BQT's article from the Summer 1997 issue
of Communications Quarterly,

He used to hang around here, but haven't seen him in ages...
Seems like I heard he was doing some work for cushcraft,
or someone, but I may be thinking of someone else...
He's the only person on this newsgroup I've actually talked
to on the air...:/ Was on 10m, and I was using a 1/2 wave
vertical at 20 ft...Yakked for a good while.. I do hear W8JI
on 160m loads of times, but I've never actually called him.
He's always busy working all that far off dx, and I hate to
bug him.... :/ Heck, most the time, I can't even hear the
stuff he works...It's fairly disgusting... He works mostly
CW.
MK

I'll try the long wire antenna attached to the coax center conductor. I can
put around 60ft of #12ga single conductor insulated wire. Should this be at
right angles to the stations I want to receive or parallel? What do I do
with the shield on the coax?

wrote in message
oups.com...

Jeff Dieterle wrote:
I've ran RGU-6 coax from my office to the factory roof,
(appx.75ft) as I doubt if the loop would pull these in from inside my
office
which is inside the factory.

Is there a less expensive alternative than the loop since I have coax
installed ?

Thanks
Jeff

Did you connect the coax to anything at all, or is it just coax
going outside to the roof,
Connecting it to the metal gutters or something like that might really
help the reception.
If there are no metal gutters or anything like that, connect a long
piece of wire to the center conductor of the coax and lay it out on the
roof.

You might also try just taking a piece of wire and connecting it to
the back of the GE SRIII, connect it to the AM screw terminal on the
back of the radio and take that wire over to the window and see if that
works, or you can continue that wire all the way from the back of the
radio all the way out to the roof.

I also remember something like winding wire around something like a
Quaker oatmeal container, contecting both ends of this wire to a small
air variable cap and just placing this antenna right behind the GE SR,
near its internal antenna. You can then tune the cap for peak reception
and then turn it and the radio to get the stations you want, this coil
of wire enhances the internal antenna of the GE SR.

Craig