Attic Antenna

[busher12]

Looking to put an antenna in the attic, anyone have any tips? suggestions on what type of antenna to get? thank you.

[Rt169Radio]

Are you looking for a scanner antenna? How tall is your attic?

[busher12]

looking to recieve mainly, would like the abbility to transmit, but probably wont transmit much, and in the middle of the attic i have 10 or so feet.

[popnokick]

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We can answer for receiving, but to help us provide better info, what band(s), service(s), frequencies will you be transmitting on? Answering that question is a whole other animal in terms of antennas.

[LtDoc]

There are two problems with any indoor antenna no matter where it is indoors. One is that the structure surrounding the antenna will attenuate the received signal (to some extent). The other is that since you are nearer to all the electrical devices in your home they will tend to 'hear' you, as in RFI. That works in both directions, your radio may hear those electrical devices too. So, it amount to evaluating the antenna's surroundings and then handling the interference you WILL get/produce.
Think of the antenna's size in relation to the wave length of the frequency(s) of use. In general, the bigger the better until it get's ridiculous.
Not much specific help but this can make things easier... or harder depending on how you look at it.
- 'Doc

[popnokick]

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There are two main reasons people want to use attic antennas: they can't put anything on the roof, and the attic is better than a back-of-the-set antenna. I'm assuming the OP knows the best place to put an antenna is outdoors/on the roof.... both for better signal and to get away from RFI in the house. And that the OP cannot use the roof. That leaves the attic as the next best choice.
So what can be done in the attic? Lots of posts on this topic already here on RR. Search forums using "attic" as your search term.

[busher12]

frequency is in the 153.000's

[Rt169Radio]

How wide and long is your attic?

[busher12]

around 25' by 35'

[kc9buh]

This is what I did,your mileage may very.
Bought the cheapest antenna I could(read radio shack 19 in quarter wave,three radial antenna about $25 and bought 30 ft of rg58 coax and connectors)
I ran my coax thru the wall and into the attic.
Then I put the antenna together,went to the attic and hooked up the coax.
now this is the tricky part.
I set the antenna down on the ceiling insolation and the ceiling joist,resting on the radials.
check the swr on 2 mtr @1.5
you might have to trim the vertical radiator(cut the end).
Mike
KC9BUH

PS worst part was fishing the coax down the wall.

[benbenrf]

If you intend to monitor on a fixed freq or relatively narrow frequency band, choosing an antenna which is as resonant as possible for that frequency range is a good starting point, no matter what the brand name is.

But antenna choice aside, filtering can be as important. Filtering can improve SNR by 6dB - 9dB (or more).

Typical off-the-shelf consumer type scanners/receivers, as a rule have front ends comprimised by budget and volume - both these criteria impact demodulated audio quality.

Investment in a good quality pass band filter - mounted directly to the antenna - will make a big big difference by way of removing all the trash in the air that would otherwise saturate your scanner/receiver front-end with noise.

Don't underestimate the difference a good quality pass band filter can make. My personal favorite are cavity type pass band filters - they can be obtained for as broad, or narrow a bandwidth as desired while still retaining decent shape and roll-off characteristics. never be too concerned about the signal strength loss/es that cavities incurr. The improvement in SNR they provide will always off-set signal strength loss - and anyway, scanners/receivers are nowadays as a rule plenty sensitive enough (which is no small part of the problem in that they saturate easily).