Roof antenna help

[minasha]

Hi,
I need a little advice on using an antenna for base station scanner reception.
I will be using my BCd536 Uniden receiver with a roof mounted antenna.
The frequencies I will be monitoring are some vhf 136-174mhz, a lot of Uhf 430-512mhz, and lots of the 800 mhz band for digital trunking.
The antenna I intend to us is a vhf/uhf yagi with amplified booster and 360 degree rotation it's for TV channels but also covers all the scanner frequencies I listed, I intend on using RG 6 quad shield cable. 100' Here are my questions:
1- Will the fact that the antenna and cable are 75 ohm impedance and the scanner calls for 50 ohm impedance make a "big deal" I mean not in terms of measured theory but in real life reception.
2-Should I mount it vertically or horizontally.

Thank You

 

[KC4RAF]

The 75 ohm to 50 ohm won't matter that much. Some will ague that there's great loss, others will agree with me.
Since most of what you will be listening to will generally be vertically mounted antennas. Go vertical.
Back in the early '90s I experimented with tv antennas for scanner listening and found that those antennas work remarkably well.
Do you really need all 100 feet of that cable? Use only what length you need and no more. The longer the run, the more you suffer in loss.
hth

 

[popnokick]

To read all about using TV antennas for scanners, scroll down in this RR thread to the post from zonian149 which was originally written by Bill Cheek titled "TV Antennas for Scanners?"
https://forums.radioreference.com/scanner-receiver-antennas/63421-tv-antenna-scanning.html