let's talk antennas

[mikehaugen]

Well I know there are a lot of tou ham operators and others out there that know about radio waves and such. I have a tv antenna that isn't being used anymore because of the dish. I would like to utilize it for fm reception. There is a receiver in the house and in the garage that need better reception.

For whatever reason there are 2 different types of antennas up there (see pic) pointed east. I live about 80-90 miles west of Chicago and about 40 miles south of Rockford, both of which transmit. I would prefer Chicago, and that is where the antenna is pointed it seems. The two antennas feed into some kind of box, which then has a coaxial cable running down the tower. I can split that cable and run coax to both places using rg6. The question I have is how do I connect it? The receiver in garage has both a 75 and 300 ohm input. I see 300 ohm adapters, but do I really need that since I have the 300 ohm input? I don't see any just straight coax adapters to wire to the screw terminals, so how do I wire into those unless I use the transformer?

Also, what do you suggest with the antennas? Keep using them both, or just one? Airwave transmission is quite confusing and what I am trying to do seems pretty simple. Thanks for any suggestions.

 

[Jimbrown]

The two antennas are top UHF bottom VHF. The box is a combiner. Leave all that alone.

Put a 75 ohm to 300 ohm transformer on the end of the coax and connect to the 300 ohm terminals on your radio.

Receivers are not near as picky as transmitters it should work very well.

The FM radio band fits in approxametely the middle of the VHF TV band.

You can buy the transformer in any home store, wallmart, or hardware store.

Indoor Matching Transformer - UHF/VHF/FM | ShowMeCables.com

 

[buickanddeere]

There is probably a FM trap in there which reduces FM interference to TV signals in the CH2-CH6 area in particular. FM radio is in the spectrum between TV CH6 and Ch7. I would retain the ability to receive TV from the antenna.

 

[mikehaugen]

Thanks everyone for the replies. I will run the coax and use the transformer for the reciever and see what happens. If everything works out I will be happy. If I need to get into amplifiers or anything I will probably be back on here asking. I am pretty confident because I can usually get reception in my car up until about a mile or two from my house.

Okay, maybe I do have another question. The inside of the garage is lined with steel panels on all walls and ceiling. I believe this is why I have a hard time getting reception in there now, even with some of the very close (under 20 miles) small local stations. I think the metal shouldn't be a problem as I am pulling the signal from an outside antenna, but thought I would bring it up in case there are any other considerations I need to be aware of with it.

 

[Pete Judd]

The metal building is blocking your FM. Run coax from your old outside tv antenna, to your radio, and you should be good to go.

 

[mikehaugen]

Okay, so an update if anyone was wondering... I got the coax ran last week and it definitely helped a lot. I can probably get acceptable reception on about a dozen stations, versus the 1 from before. They are all local stations (like within 40 miles). I am still confident I can get Chicago stations though. My thinking is that I can get them in my car until about a mile or two from home, also since the previous owner had the antenna pointed that way I assume he was getting tv from there. I will still probably go up there and check out that box to see if has a trap, though that may wait until next spring.

I am happy with the stations I have though. It's funny how out here I get about six country stations, out of about 12. Chicago and suburbs have 2, out of probably 20 or more. I like country music, but with all that crap mixed in now it's nice to have another station to switch to.

Thanks again for the help guys.

 

[locknut]

You should get much better reception than the car radio.The ants on the tower are being fed into a preamp which I assume is not being fed any power from a transformer.Won't get much of anything from the ants without the transformer.If you go up the tower,take some new coax and a new outdoor balun transformer and hook it to the bottom ant.It looks like a channel master crossfire and may have a builtin balun.If so,hook the new coax up to that.A dedicated FM antenna will work better.

 

[locknut]

The tower setup is UHF/VHF seperates with a dual input preamp.With no transformer to that preamp not much of anything will come through.you need to run coax directly to the lower VHF antenna without a preamp for best FM reception.Can't see the pic well enough but looks like a CM crossfire and might have a built in 300/75 ohm balun that you hook the coax directly to.If not,install a new outdoor balun on the terminals then coax on down.For best reception a dedicated FM antenna would be ideal.Never use a preamp for FM.

 

[Coyote machine]

You'll get better reception if the antenna points toward the sky instead of toward Chi town.

 

[mikehaugen]

You'll get better reception if the antenna points toward the sky instead of toward Chi town.

I wondered about that actually. Seems I remember from somewhere that radio waves bounced off the ionosphere or something. I always wondered if it had something to do with why it seems on super clear nights I get worse reception. Maybe it's my imagination though.