Antenna height, is this possible?

[Swingin]

Quick question, I just raised my ST2 antenna about 6' higher than it used to be, same orientation as before. Now it doesn't pick up my local police station as well as it used to, about two bars compared to five. To begin with, I had it just above the roof line and it worked great for local, and could pick up many miles away. Is it possible to have an antenna to high? Has this happened to anyone else?

I know the logical thing to do is lower it to where it was, but I just wanted to know if this has happened to anyone else?

Thanks, Don.

[n5ims]

It now could be high enough to pick up a strong enough signal from another source (paging, radio/TV, cell phone, etc.) to overload your radio's front end, causing it to receive desired signals worse than before.

[popnokick]

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Check your coax and connectors to be certain they're tight, no water, no nicks, no shorts, no corrosion, etc.
How old is the cable on your ST-2, anyway? Did you have to extend it somehow to raise the antenna? How did you do that?

[Swingin]

Originally Posted by n5ims

It now could be high enough to pick up a strong enough signal from another source (paging, radio/TV, cell phone, etc.) to overload your radio's front end, causing it to receive desired signals worse than before.

Edit, I just noticed I am getting the five bars still, but the voice is scratchy.

Thanks, n5ims, I think your right. Guess I'll climb back on the roof to lower it. Heck at this rate i'm going to wear a trail on my shingles, lol.

[Swingin]

Originally Posted by popnokick

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Check your coax and connectors to be certain they're tight, no water, no nicks, no shorts, no corrosion, etc.
How old is the cable on your ST-2, anyway? Did you have to extend it somehow to raise the antenna? How did you do that?

It's all brand new, I also have everything sealed with liquid tape so there's no water in anything. I made sure of that.

I made myself a 30' extension pole with three 10' galvanized poles one inside the other, then put two bolts through the pipes, criss cross to hold it tight.

Thank you..

[Swingin]

Well apparently you hit the nail right on the head n5ims, I just lowered it and wala, five bars and clear voice, Thank you very much!!

[rfradioconsult]

I would be suspect of the joints where each section join, even a small amount of play can create static sounds in yogur reception, your joints need to be electrically solid.

[Swingin]

Originally Posted by rfradioconsult

I would be suspect of the joints where each section join, even a small amount of play can create static sounds in yogur reception, your joints need to be electrically solid.

Lowering the ST2 did the trick, I also have the poles grounded with an 8' copper rod, and I also wrapped electrical tape where the poles slide into each other just to make a tighter fit. Working like a charm now, Thanks..

[ab3a]

It would have been informative if you had used an attenuator in front of your scanner first, before lowering the antenna. The attenuator would confirm that there was indeed some overload or whether something else might be at work.

[kb2vxa]

IMS had it right, sort of, but it was not another signal causing overload, it was the same signal and not overload. Multipath reception is the culprit, raising the antenna allowed it to hear a reflection as well as the direct. Should they arrive at the antenna in phase they reinforce and signal increases, out of phase they tend to cancel, signal decreases. Sometimes height isn't might and this is one of those.

[k3cfc]

Did you ever try to tune in an fm station and just can't quite get it and then you move the antenna or the radio just a bit and it works just fine? this is the same thing you put the antenna in the signal path. it has nothing to do with anything else just the signal getting to the antenna.

hope this helps.

K3CFC

[Cataddict]

I spent several days (part time) informally "characterizing" my rooftop. My elevation is high relative to many of the stations I listen to, however I am down in a hole, with the streets around me about one block away being 150 to 200 ft. higher than me except for one direction. My house is even about 40 ft. down from the top of my driveway. Most houses on the higher streets around me have metal roofs. There is a tall water tank about two streets over (line of sight from my roof) that has a couple VHF public service repeaters on it.

The bottom line is that I am probably living off of multipath, diffraction, and assorted scattering de jour. While listening to several strong PD repeaters in surrounding counties, I put my discone on a extendible mast and moved it up and down and right and left. With fairly small movements (several feet), some stations would get much stronger and others would basically go away. Move a few feet or change antenna height a little and the strong stations became weak and the weak became strong. I finally found a place that was the best compromise I could get, which ended up being <10' above the roof. I tried a 1/4 wave ground plane and got similar results.

The only way I could "fix" the problem was to try a 10 element homebrew Yagi. I get excellent results with it on all stations of interest (plus some) if I go to the trouble of turning the rotor. Just because of the directions the stations I'm interested in are located, I've found a compromise azimuth for it also that normally exceeds the discone.

Most of this exercise was to see if it was worth putting up a 2m base station at my crummy location and what type of antenna would be suitable. (It should finally be on the air by Christmas. Ran the LMR-400 today).

So yes, your problem exists for other people too.

[Swingin]

Originally Posted by ab3a

It would have been informative if you had used an attenuator in front of your scanner first, before lowering the antenna. The attenuator would confirm that there was indeed some overload or whether something else might be at work.

Didn't know a thing about these things, i'm a rookie. Would something cheap like this work?
Antennas Direct 20dB Variable Attenuator for VHF UHF HD Off-Air Reception 1296F from Solid Signal

It's never to late to try one, just don't want to spend a lot of $$$

Thanks for the input...

[Swingin]

Originally Posted by k3cfc

Did you ever try to tune in an fm station and just can't quite get it and then you move the antenna or the radio just a bit and it works just fine? this is the same thing you put the antenna in the signal path. it has nothing to do with anything else just the signal getting to the antenna.

hope this helps.

K3CFC

Oh yes, I noticed plenty of this while doing adjustments to both antennas. So it's just a matter of compromise then?

Thanks man..

[ridgescan]

Reaffirming here too. I had to move the d130j about 15' from the original mountpoint on the roof to get that compromise on uhf. I also raised it 5'. Now for what I use it for, it's ok.

[wingmaker]

How did you have your poles like along the side of your house, i know i had 2 galvanized poles from menards used as fence top rail and had it in a 5ft tripod ontop of my house and had good winds one day and over it went onto my neighbors power feed line to there house NOT GOOD needless to say i did get it down without getting shocked now the stupid part was i knew i shouldnt touch the pole and what did i do went up on the roof and grabbed it to pull it then realized. LOVE AND BLESSINGS

[Swingin]

Originally Posted by wingmaker

How did you have your poles like along the side of your house, i know i had 2 galvanized poles from menards used as fence top rail and had it in a 5ft tripod ontop of my house and had good winds one day and over it went onto my neighbors power feed line to there house NOT GOOD needless to say i did get it down without getting shocked now the stupid part was i knew i shouldnt touch the pole and what did i do went up on the roof and grabbed it to pull it then realized. LOVE AND BLESSINGS

lol, that sounds a bit dangerous. Luckily for us, we live in the woods and all our power lines are under ground, Also we live in a rural area where our neighbors are not even close, we like that. My poles are attached to the side of the house with heavy duty wall mounts, I also put in two pipe straps at the top of the eves, that way I can use a pair of vice grips to turn my antennas pretty easily.

[wingmaker]

I also live in BFE/ the woods i wish our power was underground. There only 1 house other than me on my road, but my neighbor right next door. Sounds pretty good though your setup whatever works, I had one similar before i put it up on the roof i had it along site sitting in a tripod concreted in the ground and straped at the top but there was to much movement for me to pick up 800mhz without signal going up and down. Yeah it was dangerous the whole situation. LOVE AND BLESSINGS

[Swingin]

I guess I forgot to mention that I have three guy wires on my poles also. From what I hear on the weather, today will put them to the test.

[wingmaker]

Hope and Pray for the best for you and all my BROTHERS AND SISTERS on this beautiful planet. LOVE AND BLESSINGS.