OT Bizarre receiver operation

[632 Regal]

K, I have an old receiver in my barn/shop. reception was real bad so I installed an antenna on the roof (old car antenna with coax).

Well... the tuner squished all the stations between 92-104MHZ. like 101 fm is at 98... So I went out and picked up one of them high quality 120.00 antennas, risked my life crawling way up there again and hooked that one up...same freaking deal with the squished stations.

If I disconnect it and hook the old antenna up with a wire in the barn the stations correct themselves. I used 1 peice of shielded coax cable to do the long run to the peak of the roof if that matters any.

I dont mind or anything, I get a few stations now VS 1 staticy religeous talk show, just wondered WTF caused this.

[whiskychaser]

K, I have an old receiver in my barn/shop. reception was real bad so I installed an antenna on the roof (old car antenna with coax).

Well... the tuner squished all the stations between 92-104MHZ. like 101 fm is at 98... So I went out and picked up one of them high quality 120.00 antennas, risked my life crawling way up there again and hooked that one up...same freaking deal with the squished stations.

If I disconnect it and hook the old antenna up with a wire in the barn the stations correct themselves. I used 1 peice of shielded coax cable to do the long run to the peak of the roof if that matters any.

I dont mind or anything, I get a few stations now VS 1 staticy religeous talk show, just wondered WTF caused this.

It may have something to do with the physical length of the coax you are using not being 'tuned' to the frequency you are using. The coax may now be acting as the antenna itself but as you dont have a big lump of flat metal, like a car roof, into which your antenna is bolted, you are missing a big part of the antenna system (ground plane). Hence weak reception. Sorry if you fell asleep half way through that :-)

[632 Regal]

the coax is ran along the side of the barn up to the roof and the barns walls are steel so would that count as a ground plane?

It may have something to do with the physical length of the coax you are using not being 'tuned' to the frequency you are using. The coax may now be acting as the antenna itself but as you dont have a big lump of flat metal, like a car roof, into which your antenna is bolted, you are missing a big part of the antenna system (ground plane). Hence weak reception. Sorry if you fell asleep half way through that :-)

[Jr ///M5]

How many beers did it take to get the courage to crawl up on the roof?

[attack eagle]

it has to be analog tuner then right?
I have 0 technical idea on this but to float an Idea:

Prerhaps in adding the long coax run you somehow affected the inpedence the unit was designed to have on the antenna, and thus the tuning is off?

[632 Regal]

just an old stereo hooked to a stage system amp and 4 speakers.

the coax is the same as a direct sheilded wire and the antenna is supposed to be dead nuts on (full FM hertz range) Maybe I do need a ground block or some ****. I guess this is one advantage of living in the stix but not sure why yet.

it has to be analog tuner then right?
I have 0 technical idea on this but to float an Idea:

Prerhaps in adding the long coax run you somehow affected the inpedence the unit was designed to have on the antenna, and thus the tuning is off?

[Vanguard]

Jeff,

I suspect that your problem is in the receiver itself. Many old recievers use a wire, a rubber band or a cord to tie the analog indicator to the dial. It's likely that yours has slipped or stretched and while the tuner is at 98 the indicator is 3 steps off. I used to have an old Marantz tuner that this happened to.

[ryan roopnarine]

what is the ohm-age of the cable that you are doing this with (colloquially, rg-58, rg-59, rg-6). did the antenna you bought have a balun or transformer to convert from twinlead to coax? having done far too much of this mess between the ages of 10 and 14, it sounds like it is a receiver problem, not a decoupling or antenna problem.

[632 Regal]

naww, works right on if I hook a lamp cord into the car antenna inside the barn, dont get good reception in here tho.

Jeff,

I suspect that your problem is in the receiver itself. Many old recievers use a wire, a rubber band or a cord to tie the analog indicator to the dial. It's likely that yours has slipped or stretched and while the tuner is at 98 the indicator is 3 steps off. I used to have an old Marantz tuner that this happened to.

[632 Regal]

RG-6 cable. The antenna came with a length of cable (RG-6) but it was about 15 feet too short so I had to make a longer one.

The receiver I have has only 1 lead for antenna and 1 ground, I hooked the coax direct and with a filter tieing both together and made NO difference.

Im thinking the new antenna is making the receiver stoned and not able to comprehend a good antenna.

You are probably onto something with a transformer and my receiver only having 1 antenna lead. Maybe it's just too old but it sounds freaking awesome with the current setup....maybe its just the combination of amp and speakers.

Just too weird how it "compresses" the dial into a smaller range. Its all there just compact now...lol

what is the ohm-age of the cable that you are doing this with (colloquially, rg-58, rg-59, rg-6). did the antenna you bought have a balun or transformer to convert from twinlead to coax? having done far too much of this mess between the ages of 10 and 14, it sounds like it is a receiver problem, not a decoupling or antenna problem.