clear reception help

[tanzie21]

Hi all,I would appreciate your help. When listening to police traffic in my vehicle, reception is perfect as long as the vehicle is stopped, but as soon as I am moving the reception turns real bad. I am useing one of those common pre tuned 477MHZ antennas with the spring at the base attached to the bullbar. It cost about $90 from Dick Smiths. Do the larger fiberglass antennas work better? Is it bacause the current antenner is moving around in the wind? How do the police avoid this problem? Thanks for any assistance.

[ziggybyrne]

You might be lisening to a more distant repeater. As i'm sure you know the police use a linked repeater system using 6 to 10 or more sites. They use signal strength voting to automatically select the strongest signal and lock on it. Police fire and ambulance among others use this system. Maybe choose a closer repeater for more reliable reception. Check out the freq database for the most appropriate site. Also dont forget to set your squelch appropriately.
Cheers Rowan

[Comint]

Hi all,I would appreciate your help. When listening to police traffic in my vehicle, reception is perfect as long as the vehicle is stopped, but as soon as I am moving the reception turns real bad. I am useing one of those common pre tuned 477MHZ antennas with the spring at the base attached to the bullbar. It cost about $90 from Dick Smiths. Do the larger fiberglass antennas work better? Is it bacause the current antenner is moving around in the wind? How do the police avoid this problem? Thanks for any assistance.

Could be the electrical system in your vehicle, ie, the ignition system, the engine management system, etc. Maybe you need to mention the type of vehicle.

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Comint

[tanzie21]

It's a 99 Toyota Landcruiser and the cable winds along the side of the engine bay, then along the back of the engine bay and then goes through the fire wall near the steering column. Thanks for the help.

[AIRMAN]

Sounds like a loose connection. When you become mobile the vibration or wind causes the reception to break-up. Check your connection to the antenna first, then along the cable where it goes into the radio.

If its a noise when the engine is running indicates you may need a suppressor.

[tanzie21]

I keep hearing people talking about Yagi antennas. Do these antennas improve the reception or only improve the transever ability?

[Stretch]

I keep hearing people talking about Yagi antennas. Do these antennas improve the reception or only improve the transever ability?

Not sure what you meant by "Do these antennas improve the reception or only improve the transever ability?" but yagi's are generally if not completely directional. Ie they're only good for a base radio where you can choose to point the antenna towards a particular site (eg a mountain, or a building with a repeater on it). The downside to Yagi's as per my understanding is their receiving capability from what's behind them (the opposite way to the way it's facing) is very very limited hence why they're not suitable for vehicles.

Hope this helps


Cheers,
Mitch
Sent from my iPhone using Tapatalk

[Comint]

I keep hearing people talking about Yagi antennas. Do these antennas improve the reception or only improve the transever ability?

Yes, Yagis can improve reception, as they are GAIN antennas.

However, they are very directional, usually with a Beamwidth of no more than 60 degrees, and often with a Beamwidth of only 30 degrees, and the gain drops off, the closer you get to the edges.

And as Stretch pointed out, they have poor response from the rear, a feature which can be utilised to reduce interference.

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Comint

[tanzie21]

Just an update for anyone interested. I put a rubberducky antenna dead smack in the center of the roof and it has improved the reception.

[AIRMAN]

Just an update for anyone interested. I put a rubberducky antenna dead smack in the center of the roof and it has improved the reception.

Was this mounted thru the roof or on a magnet base?