[Elecraft] Getting ready to buy a K2. Request your input

Frank Nikolajsen elecraft at warpspace.com
Fri Mar 25 18:29:41 EST 2005


On Mar 25, 2005, at 18:07, Robert Jones wrote:

> Hello all,
>
> I just upgraded to General class and have zero
> experience on HF bands.

[Snip.]
> Since I live in an apartment, I want a low power rig.

   Hi Robert,

   Having also only quite recently joined the ranks of Elecraft owners I 
cannot sensibly comment on which options might be right for you and 
your family.

   However as a fellow apartment dweller I would like to use the 
opportunity to pass along a simple piece of advice that I learned only 
fairly recently and which I wish someone had told me 20 years ago. I 
strongly suspect it might have a large influence on your success in 
operating from an apartment, so ignore this at your peril:

   ** Only ever use physically symmetric and electrically balanced 
antennas. **

   The reason is that by using symmetric and balanced antennas like 
tuned or untuned horisontal dipoles, magnetic loops etc., you are most 
likely to not exprience problems with BCI/TVI/RFI. Seen in hindsight my 
own experience spanning 23 years as an active ham on HF while living 
mostly in apartments reflects this, but unfortunately for most of that 
time I was blisfully unaware of the potential problems with asymmetric 
antennas.

   Mind you, you *can* work the world successfully on the proverbial 
random wire and the central heating pipes, but your neighbours will 
most likely not be happy. Been there, done that. Scrap the vertical 
groundplane too, even if it has tuned radials.

   When I heard about this not too long ago, a lightbulb went off in my 
head. Since then I have searched the 'net for more info on this issue, 
and I can only advice you to do likewise. You shouldn't take my word 
for it, research this yourself.

   If you do decide to use a symmetric antenna, then you will most 
likely not want to use an antenna tuner built into your rig, as it will 
not be able to provide the symmetric match required. You may hear 
people suggesting putting a balun after the tuner, but this doesn't 
work very well at all either. You will probably end up with an 
inherently matched antenna like a magnetic loop, which doesn't need a 
tuner, or something like an untuned dipole fed via open wire feeder 
connected to a purpose built balanced antenna tuner. Such a beast is 
not hard at all to make, though I admit it is less convenient than a 
computer controlled and fully integrated unit.

   Good luck  es 73 de

     Frank, OZ1IOC (donning asbestos suit).



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