750-806 Yagi Antenna

[brian86]

ok so i'm not a rocket scientist but....

I bought a PSR-800, 750-806mhz 9db gain Yagi Antenna & 45' of LMR-400 Cable to listen to PG Counties NEW X2-TDMA Trunking System. Where i'm setting this antenna up has a ground elevation of 118' above sea level (ASL) and the antenna is 30' Above ground level (AGL) so lets say 148' ASL. The tower is 6 miles NNW from my location and the antenna on that tower is mounted 340' ASL (40' Ground Elevation ASL and 300' tower). I can practically see the red light flashing from my antenna mount point. According to Google Earths Ground Elevation Profile Feature from Point A to Point B (A= My Yagi, B= Transmitter) its a total distance of 5.918 miles and the highest land point between A & B is 131'... I looked the whole line between Point A &B and there are no large buildings or any other obstructions between the Yagi & The X2-TDMA Site.

WHY CANT I GET A CLEAR LOCK ON THIS SYSTEM??? IM OUT IN THE STICKS NO OTHER TRANSMITTERS AROUND AND CERTINALLY NO OTHER TRANSPITTERS IN THE 770MHZ RANGE.

The owners manual for this antenna says to mount vertically but i have noticed that when I hold this antenna horizontly it performs better is there a diffrence because this system is TDMA?

Please Help!!!!

[n5ims]

Neither TDMA nor it being digital will affect what antenna works. To an antenna a signal is a signal is a signal. It doesn't matter if it's a signal modulated using AM, FM, TV, digital, garage door tones, dog collar 'electronic fence' signals, or even radar pulse signals, if the antenna is tuned to work effeciently on that frequency it'll work effeciently on it.

What you're probably having is issues with Simulcast Distortion (Simulcast digital distortion - The RadioReference Wiki) where you're picking up signals from mutiple towers and the signals are mixing together degrading the signal. Often this looks like you're getting too little signal, when in reality you're actually getting too much signal. This is reinforced by your getting a better signal horizontal than you are vertical.

Start by turning on any attenuator your scanner may have to see if that helps. Next try aiming your antenna around the area to see if you can isolate a single tower (it doesn't have to be the closest, only that your antenna can isolate it from all of the others in your desired system). You may also try using an antenna with less gain and/or lower on your tower. You may even have success by pointing your yagi away from the desired system to see if that will help reduce the signal or isolate the towers.

[brian86]

Its funny because standing on the roof with the portable i can't get a lock on the control channel at all with the yagi I can get the control signal but only a 80-90% quality reception. This tower is the furthest south tower to my location and to be getting 2 towers I don't even think is possible because were my antenna is located no other 700 PG tower around it in fact the next closest tower is 6 more miles directly north of the tower I'm aiming at... its not like there are two towers around me at all only the one so i don't thing the fading in and out is caused by two many signals at nice. I think PG counties system is crap. There department issued portables don't even work in parts of the county or more then a mile out of the county. Its just crazy.

[awal]

Originally Posted by brian86

Its funny because standing on the roof with the portable i can't get a lock on the control channel at all with the yagi I can get the control signal but only a 80-90% quality reception. This tower is the furthest south tower to my location and to be getting 2 towers I don't even think is possible because were my antenna is located no other 700 PG tower around it in fact the next closest tower is 6 more miles directly north of the tower I'm aiming at... its not like there are two towers around me at all only the one so i don't thing the fading in and out is caused by two many signals at nice. I think PG counties system is crap. There department issued portables don't even work in parts of the county or more then a mile out of the county. Its just crazy.

And you wonder why you can't pick PG up in freakin' St Mary's - after acknowledging it's hard to pick up WITHIN the county?

Dude

[brian86]

It just seems that if i can see the tower from the roof a yagi should get the signal. im just surprised that the portable antenna couldn't... I know it seems stupid, but this is a stupid system with some stupid problems.

I'm going to try some Att. settings next time and a diffrent antenna and see if that changes anything.

Thanks for everyones input.

[zz0468]

Are you sure you're pointed at the correct site? Have you tried sweeping the antenna around to see if the signal sounds better in a different direction? Are you sure your radio is programmed up correctly? Are you sure that the system you're trying to listen to is even radiating any signal in your direction? Many systems are specifically designed NOT to radiate in certain directions. You may be in one of those directions.