[Elecraft] Attic Antenna Tradeoff?

[kc4kgu@ENTERZONE.NET]

On Sat, 21 Sep 2002, Greg White wrote:

> I am currently building a new home and have many challenges regarding the
> use of a traditional outside antenna.  I know that an "indoor/attic" antenna
> is a compromise, but how much of one??  All things being equal, what amount
> of attenuation (receive and transmit)can I realistically expect?  I am just
> trying to figure out if I would be happy with an attic antenna for the time
> being.  I will use a trap dipole in the attic (about 25-30 feet) with my K2.
> Thanks!
> Greg, N9EYO


Greg,

When I first started working HF, I was more worried about the YL than any
neighbors. (I have thick woods all around the back yard so, they would
never see an antenna.)  Not wanting to get on the bad side of SWMBO "She
Who Must Be Obeyed" I put up a "slinky" antenna in the attic.

I worked L.A. on 75m phone with that antenna from here in Ohio, during the
daylight hours even if I remember correctly.

Now, that said, let me go on to say that the antenna was still _terrible_
and I mean *BAD*!

The noise floor was a good 3 s-units above the current dipole I
use.  Additionally, the RFI (tv, phone, etc) was bad, even at 30-40w and
it was a bear to tune up the thing.  I'm pretty sure that the noise/tuning
problems can be attributed to HVAC ducting (metalic) and power wiring that
lay below the insulation in my attic.

After a few months of frustration, I put up a 135' dipole at about 20ft in
the back yard and carefully hid the coax run coming into the house.  The
guys I had been talking to for a month or so in the evenings accused me of
buying an amplifier and man did the dipole hear better, on every band!

So, IMNSHO, attic antennas (or at least slinky's) are _serious_
compromises.  I think I could have done better by loading up the rain
gutters!

If you've got _anything_ to use as supports, you can put up an antenna
that is very hard to see.  I use 12guage wire for my antennas and I have a
hard time finding them in the air, and I know _exactly_ where to look!


73 de John - KC4KGU
K2/100 #2490