Buddipoles and KX1

[John Harper AE5X]

Mike / KK5F:
>I often erect at least two antenna types at a site for
>side-by-side comparisons.  That is the *only* way one can determine how
>one antenna performs against another under otherwise identical site and

I'll be doing that myself next Saturday during QRPTTF. My main antenna will
be an 80m dipole fed with 450-ohm ladder line (for use on 20 & 40m with
tuner) that I want to compare with a camera tripod-mounted hamstick on 20
and 40 meters. I already have an idea how they will compare - the only
reason for the test is that I have a camping spot in mind for some time in
the future where there are no "organic supports" for a dipole and any radio
operation will necessitate a small vertical as described. I just want to
know how much more poorly the vertical will be. I plan to have four 33'
radials for it. The dipole will be up about 40 feet & the rig will be a KX1.

John Harper AE5X
http://www.ae5x.com




_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Vic K2VCO]

John Harper wrote:

> My main antenna
> will be an 80m dipole fed with 450-ohm ladder line (for use on 20 & 40m
> with tuner) that I want to compare with a camera tripod-mounted hamstick
> on 20 and 40 meters. I already have an idea how they will compare - the
> only reason for the test is that I have a camping spot in mind for some
> time in the future where there are no "organic supports" for a dipole
> and any radio operation will necessitate a small vertical as described.
> I just want to know how much more poorly the vertical will be. I plan to
> have four 33' radials for it. The dipole will be up about 40 feet & the
> rig will be a KX1.

I suggest that you try something like 16 radials of, say, 8 or 10 feet
(somewhere there is a table of the optimum number/size of radials for a
given length of wire).

If the radials are on the ground, a large number of short ones is better
than a few long ones.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Vic K2VCO]

Vic K2VCO wrote:

> (somewhere there is a table of the optimum number/size of radials for a
> given length of wire).
>
> If the radials are on the ground, a large number of short ones is better
> than a few long ones.

Here it is: <http://www.ncjweb.com/k3lcmaxgainradials.pdf>

They recommend fewer radials than I did. For average soil, they
recommend using 9 radials of 14 feet each. I suspect that -- since your
vertical is so short, it might be advantageous to have more and shorter
ones.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[John Harper AE5X]

I will re-think my radial configuration. It is more of a pita to carry,
untangle, deploy and repack 16 of anything and I may decide to stick with 4
even at the price of some efficiency. I will have height above average
terrain on my side though. Here is the camping area I have in mind (for
either June or September):
http://www.summitpost.org/images/medium/274856.JPG

John Harper AE5X
http://www.ae5x.com




----- Original Message -----
From: "Vic K2VCO" <[hidden email]>
To: "John Harper" <[hidden email]>
Cc: "Elecraft" <[hidden email]>
Sent: Thursday, April 17, 2008 4:36 PM
Subject: Re: [Elecraft] Buddipoles and KX1

> Vic K2VCO wrote:
>
>> (somewhere there is a table of the optimum number/size of radials for a
>> given length of wire).
>>
>> If the radials are on the ground, a large number of short ones is better
>> than a few long ones.
>
> Here it is: <http://www.ncjweb.com/k3lcmaxgainradials.pdf>
>
> They recommend fewer radials than I did. For average soil, they recommend
> using 9 radials of 14 feet each. I suspect that -- since your vertical is
> so short, it might be advantageous to have more and shorter ones.
> --
> 73,
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco
>
>
> --
> No virus found in this incoming message.
> Checked by AVG. Version: 7.5.524 / Virus Database: 269.23.0/1383 - Release
> Date: 4/17/2008 9:00 AM
>
>

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[AC7AC]

CONTENTS DELETED

The author has deleted this message.

[Vic K2VCO]

John Harper wrote:
> I will re-think my radial configuration. It is more of a pita to carry,
> untangle, deploy and repack 16 of anything and I may decide to stick
> with 4 even at the price of some efficiency. I will have height above
> average terrain on my side though. Here is the camping area I have in
> mind (for either June or September):
> http://www.summitpost.org/images/medium/274856.JPG

Well, if you only want 4 radials, you can make them shorter. The
additional length won't get you anything.

What I would do at a location as pictured (although in my case I would
need a helicopter to get there) is to use your tripod vertical as the
center support for an inverted V near (not too near) a sharp dropoff in
the direction that you want to work. Bring some duct tape and tape the
ends to the ground. Even if the V is only a few feet above the rock, it
will be a *very* high dipole in the direction of the dropoff.

By the way, another problem of a vertical in such a location, is that
even if you get a good counterpoise, the reflection from the Fresnel
zone (a few wavelengths) will be poor because igneous rock is a very,
very poor ground!
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com