KAT100 Tuner and a Longwire

I am not sure that this has been discussed before on the reflector, but will the KAT100 tune a longwire?  Really, it should, but how does one connect the longwire to the tuner?  Banana plug to the center pin with the counterpoise clipped to the ground lug?  That is what I did with the old DX-40...but that was 40 years ago.
 
Comments to such a dumb question?
 
Lee - K0WA
 


Common sense is in short supply - get some and use it  - Lee Buller
_______________________________________________
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

[wayne burdick]

On Mar 10, 2005, at 9:17 AM, Lee Buller wrote:

> I am not sure that this has been discussed before on the reflector,
> but will the KAT100 tune a longwire?

Yes. You can connect it directly to the ATU using a binding-post
adapter, or just wire up a PL-259's center pin to an alligator clip or
to the wire itself. Counterpoise goes to the ground lug -- use a very
high-quality ground to maximize transmit efficiency. (House electrical
ground is marginal from both all angles -- noise, efficiency, and
safety.)

A better alternative than direct feed is to use balanced feedline (and
a low-loss 4:1 balun such as our BL1 at the tuner) to get the radiating
part of the antenna *out* of the shack and away from computers, kids,
pets, TVs, portable phones, etc. If you use a random wire without
feedline, you'll likely have to stick with QRP power levels to avoid
RFI.

73,
Wayne
N6KR

_______________________________________________
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]

Lee Buller wrote:

> I am not sure that this has been discussed before on the reflector, but will
> the KAT100 tune a longwire?  Really, it should, but how does one connect the
> longwire to the tuner?  Banana plug to the center pin with the counterpoise
> clipped to the ground lug?  That is what I did with the old DX-40...but that
> was 40 years ago.

You can do this.  I would avoid lengths of wire that are an exact multiple
(within about 6 inches or so) of a half wavelength on one of the frequencies on
which you want to operate, since the impedance will be very high under such
conditions and may be difficult to match.  Good counterpoise lengths are odd
multiples of a quarter-wavelength. Remember that the end of the counterpoise
will be at high RF potential.

If the counterpoise is ineffective, you may have the well-known RF-in-the-shack
problem.  Another issue is that the antenna will be very prone to pick up noise
from computers, monitors, etc., that are nearby.

Someone will probably say something about RF exposure.  I believe that at HF and
KAT100 power levels there is no a safety problem.  According to the calculator
at <http://n5xu.ae.utexas.edu/rfsafety/>, assuming 50% duty cycle, 0 DBd gain,
100 watts at 28 MHz, (this works for either 50 watts RTTY/PSK or 100w SSB/CW),
and a distance to the center of the antenna of 7 feet, you are cool according to
the [flame on] ridiculous, lawyer-driven, idiotic, stupid [flame off] FCC
requirements.

--
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