WHAT ANTENNA WOULD YOU RECOMEND?

[ems46pa]

Hello,

Our buisness is putting a gr1225 repeater in service and was wondering what antenna model would best suite our situation.
We are licensed for 50 watts. on 468.71250 Our terrain is foothills and valleys. right now we have a roughly 48" cheapo uhf antennas no db gain that sits on top of a 80 foot tower with 1/2 hardline that works somewhat ok but was wondering what everyone would recomend. Right now we can only hear the repeater only about 4-5 miles away. I live about 9 miles away and can not hit the repeater with a cdm1250 mobile. We are using a mix of CDM's and MTS2000's with MTVA's. The transmitter was bench checked by a tech and all was good so it makes me belive the antenna needs changed. The coax and connectors are only 4 years old.
would like to get the most bang for our buck without breaking the bank

Thanks
John T

[tvsjr]

First, you need to be careful with gain... from the sounds of your terrain, you may not want the limited vertical bandwidth of a higher-gain antenna.

If you're running 50 watts into even a semi-decent antenna, you should be able to work it from 9 miles away mobile. I'd be looking at the overall system, RF conditioning, etc. to find the problem. Has the duplexer been checked? Feedline swept?

[RKG]

I'd check that license again; 468 is generally limited to repeater INPUT use.

[Jim2121]

I'd check that license again; 468 is generally limited to repeater INPUT use.

I was just going to post the same

[RKG]

Great minds think alike?

[escomm]

Depending on where you live.

Southern California uses a negative offset as a perfect example.

[libuff]

im see your already licensed, but lower frequencies, maybe more like the 46mhz band would better suit your needs... however, my guess, is very low gain antennas to extend the "bubble" into the valley better. im very sure that the 468mhz band will most likely NOT propigate over the hills like a 46mhz band would.

my area, NYC metro & Long Island is VERY flat with one prominant large hill cutting down long island length-wise. most of the transmitters are ontop of that very tall hill, and use fairly low gain antennas, which allow the singal to propigate down the hill into the low-lying grounds. those transmitters that wish to only hit 1/2 the island, use high gain antennas in the low lands, and cover the plains quite well. and transmit VERY far.

[ems46pa]

FYI, the transmit is 463.7125 with a rx of 468.7125
I am not sure what type of gain is on the antenna now,
i will have a tech comeout and check the line and duplexer
I can hit the repeater at about the 7 mile mark with a cdm but I am on the other side of one of the largest hiolls we have to deal with
I looked into seeing if we can find a new spot for the antenea but no luck yet.

Where this antenna was used to be the Fire Dept repeater they just moved about 150 feet higher on a county owned tower and that system now kicks but at 50 watt output!!

We bought our radio equipment from the federal surplus so it was just about practicly free
this is going to be used for special events for an ambulance company and talk betwen the ambulances

I do have the frequency coordinator looking to see if we can get any more wattage added to our license.

Is there anything I can do to help the recieve issue on the repeater?

[Will]

Depending on where you live.
Southern California uses a negative offset as a perfect example.

"negative offset" ????? In comercial systems, 450-512, the repeaters, and base stations, transmit on the LOW freq.

So ems46pa's repeater transmits on the 463.7125, while the mobiles and handhelds transmit on 468.7125, the "Input" to the repeater.

Only in So. California is the ham band bas ackwards, the repeaters transmit 445-449.975 range. "negative offset" for the mobiles..................

[Will]

My recomendation, the orig poster is looking for, is:

Comtelco 4.5dbd gain, BS450U-C 60" OAL.
You can have the antenna fine tuned for your frequencies at no extra charge.