[TowerTalk] Dorm room antenna?

[Jim Lux]

>From: bill rubin <brubin2010 at gmail.com>
>Sent: Oct 27, 2008 7:50 AM
>To: Greg Davis <n3zl.radio at gmail.com>
>Cc: towertalk at contesting.com
>Subject: Re: [TowerTalk] Dorm room antenna?
>
> Use the cold water pipe from the bathroom if you can for a ground.
>73 Bill

I don't know about Clemson, but at UCLA in the 70s, the bathroom was down the hall, so running a wire to it wouldn't be all that great.

And, anyway, if you hook up to the water pipe or the greenwire ground, you're just asking for RFI complaints (or your received signal will be full of RFI from others.. or both).

The restriction of no tuner makes life pretty complex. 

You might wander over to the HFPACK group on Yahoo.  Your problems are much like those faced by folks doing portable operations.

One approach is to do the "pair of mobile whips" scheme as a dipole. 
Another is the "mobile whip on the window ledge sticking out" working against an untuned counterpoise of a bunch of wires hanging down the outside the building or strung to your neighbor's room.

A wire suspended from an inexpensive collapsible fishing pole is another idea. You can adjust the wire length for tuning. Cabelas sells 20 foot "panfish poles" for <$20 that collapse to <4' in seconds. 

So, something like a wire hanging down the outside of the building, and another wire sticking straight out, perhaps with a bit hanging down off the end (for tuning) might work pretty well.  Watch out for problems with HV at the end of your hanging counterpoise.


Watch out for RF exposure limits!  This isn't a situation covered by the "safe harbor" tables for dipoles etc, in OET Bulletin 65.  You'll need to do some real analysis work to be legally compliant.


>
>On Sun, Oct 26, 2008 at 6:35 PM, Greg Davis <n3zl.radio at gmail.com> wrote:
>
>> Hello:
>>
>> adjusted to college life. My room is on the third floor of the dorm,
>> so I have a bit of room to work with. At first I was thinking about
>> trying an end fed sloper to a tree about 30 feet diagonally out from
>> my window, but I am not sure how well that would work out since I
>> don't have anything to ground it to up here.
>>
>> I am wondering if anyone could give me any suggestions on an ultra
>> simple antenna (no matchboxes, etc. required hopefully - directly fed
>> with just a few feet of coax to the radio without a tuner would be
>> fantastic) that I could quickly deploy from out of my third floor
>> window, ideally end-fed. I would like to work 40M and 20M mainly. I
>> know that's a lot to ask!
>>