Help with Antennas

wdancer · Oct 12, 2013

I am cutting my cable and am going to install 2 antennas in my attic (HOA does not allow exterior antennas) pointed towards Tuscon and Phoenix. I am aware that I need to put the antennas at least a quarter wave apart, not a problem since they will be on opposite ends of the attic.

My question is; when I get them installed and run them through a combiner, I will almost certainly have signal loss on some channels due to multi-path and I do not want to install a select switch. Does anyone have schematics and or PCB layout plus advice? I never have been good at RF circuits.

duke37 · Oct 12, 2013

What is HOA?

You have not said the frequency that each antenna is intended to be used for. If the frequencies are similar then there will be interactions between signals from each antenna. A resistive combiner will reduce the interaction at the cost of loss of signal. You could use an amplifier in each antenna cable before the combiner to compensate for the loss.

The simplest solution would be a change over relay, fed from the bottom, using the co-ax cable for both signal and DC voltage.

davenn · Oct 12, 2013

What is HOA?
Click to expand...

presumably he's in some sort of housing / apartment complex and the strata manamgement ( as they are called in Australia) dont allow external antennas .... a common hassle, been through that myself in yrs gone bye

I am aware that I need to put the antennas at least a quarter wave apart, not a problem since they will be on opposite ends of the attic.
Click to expand...

that's only a requirement if they are stacked directly above or beside each other and pointing in the same direction....
if pointing in different directions its not a consideration

firstly more info from you....
as duke said, you havent said the freq.
also, are these yagi's ?
are they receive only or transceive ?
OHHHh and most importantly .... what is the roof made of ? if its metal, attic antennas wont work!!!

Dave

davenn · Oct 12, 2013

wdancer

I have renamed your thread to Help with Antennas
"notch filters" was misleading

Dave

wdancer · Oct 13, 2013

Clarification

Okay, an HOA is an "Home Owners Association" in the US. It is basically a lot of guidelines that pertain to appearances to the property and whatnot. I would have preferred to live somewhere there wasn't one, but you have to either spend a lot of money, or live in a bad neighborhood it seems.

As for the freqs, I did not specify since I do not know yet what channels I need to filter until I get both antennas installed. I just wanted to get ahead of the game and build an adjustable filter or two just in case. If I do not need them, oh well, good exercise

The frequencies are spread across the entire North America TV bands. I have about 60 channels, some are duplicates.

davenn · Oct 13, 2013

OK we just needed to know if you were referring to the 88-108 FM band or something else so it appears you are referring to TV

so my other Q was are you using Yagi's ? have yopu got ones that receive specific to the channels being transmitted from the 2 different locations ?
if not, you need to find what channels are used from those locations
find out if they are low VHF band Hi VHF or UHF or a mixture there of

You dont need any filters in the antenna feedlines, you just combine the coax feeds from each antenna and then a single feed to your TV.
There are coax splitters readily available to split a coax feed to feed 2 TV's, these can be used in reverse to combine 2 antennas to a singe line and TV

Dave

wdancer · Oct 13, 2013

More Info

Dave,

Here is data with headings and signal strengths at ground level in my location;
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=46aeaa38862cbb

The Yagi Antenna I am using;
http://www.amazon.com/gp/product/B0024R4B5C/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

Help with Antennas

wdancer

duke37

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wdancer

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wdancer

Antennas

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