Lowband antenna question

Post by **Code3Response** » Mon May 19, 2003 7:50 am

OK - Just got in a Lowband Syntor X9000 and there is now way Im putting a 6 foot long whip on an 03 Tahoe - already ripped an antenna off going in a parking structure - lol. It will be a receive ONLY radio - so a proper lowband antenna isnt necessary, is it? What antenna could I use? Thanks

jim · Post by **jim** » Mon May 19, 2003 9:13 am

Comtelco A1801-(frequency)-S works great!
also.. Antenex C30 to C47 works great.

I do alot of lowband in my area and use both of these often.

There's still NO substitute for a 7' whip and a 500W mobile amplifier! All lowband radios should almost stall the engine when keyed

Radio_Cowboy · Post by **Radio_Cowboy** » Mon May 19, 2003 9:34 am

jim wrote: There's still NO substitute for a 7' whip and a 500W mobile amplifier! All lowband radios should almost stall the engine when keyed

Damn Jim....U tryin to talk skip all the way to red china or what?

Agreed on the 1/4 antenna....makes a HUGE difference!

-RC-

jim · Post by **jim** » Mon May 19, 2003 10:57 am

No- just Argentina!

Really though, in the western PA terrain, you need power. If you aren't packin' at least 110W, you aren't gonna be heard too far.

Post by **Code3Response** » Mon May 19, 2003 11:01 am

No Jim - I think you misunderstood. I only need the radio to receive, so I DONT want to put a regular long Lowband antenna on. What would happen if, lets say, I connected a UHF 450-470 antenna to the LB X9000? Remember, its receive only, a mic isnt even hooked up - would I still be able to receive decently? I just dont want to have to do a ball mount or similar large antenna on there. Thanks!

nmfire10 · Post by **nmfire10** » Mon May 19, 2003 11:45 am

Well, I know a few people in my dept that use a simple 1/4 wave VHF (19") antenna for their scanners and it works just fine within a few towns on low band.

firemanbatt · Post by **firemanbatt** » Mon May 19, 2003 12:57 pm

Matt,

What about a antenna specialists glass mount lowband, or even a scanner antenna? i would think a glass mount scanner antenna, since you dont want a tall antenna (I prefer AS MON-51's myself) would work.

I dont think the uhf would, but maybe a vhf 1/4 might...

Tim

Max-trac · Post by **Max-trac** » Mon May 19, 2003 1:39 pm

Anything will "work", but if you want decent recieve, at least put a base loaded 1/4 wave. Larsen, Motorola (Spectrum), Maxrad make them with NMO mount...to name a few.
They will be about 45" long.
You could try a NMO VHF 5/8 wave also. They will work on lowband it the coil is of the right kind.....

007 · Post by **007** » Mon May 19, 2003 1:55 pm

jim wrote:There's still NO substitute for a 7' whip and a 500W mobile amplifier! All lowband radios should almost stall the engine when keyed

Hell yeah, baby! I'm picking up the Antenna Specialists ball mount on Wednesday. Nothing says "I love you" like a ball mount!

007 · Post by **007** » Mon May 19, 2003 2:11 pm

Matt-

If you use a Larsen NMO150 for receive, it will work great. If you use any 50 MHz loaded 1/4 wave NMO antenna, it will work great - other than Antennex (they suck on lowband).

144 MHz 1/4 wave....ehhhh...probably not worth the time to think about it...go with a 50 MHz antenna.

Glass mount? I hate to sound like Jim here, but how about NO? Use a 144 MHz 1/4 before a glass mount.

007 · Post by **007** » Mon May 19, 2003 2:27 pm

Code3Response wrote:OK - Just got in a Lowband Syntor X9000 and there is now way Im putting a 6 foot long whip on an 03 Tahoe - already ripped an antenna off going in a parking structure - lol. It will be a receive ONLY radio - so a proper lowband antenna isnt necessary, is it? What antenna could I use? Thanks

After reading you post again, it would actually be better if you had a lowband ball mount....follow this logic:

You drove into a parking garage and ripped a roof mounted antenna apart, right? So why put another 52" whip on the roof?

If you put the ballmount on the rear fender behind the wheelweel, not only will it only stick up above the roof line 30" or less, but you could let it smack the ceiling all you want! Unless you shut the garage door on that AS whip, you aren't going to hurt it. Besides that huge 6" spring will absorb all the shock you could throw at it.

I'm sure you won't do this, but it's something to think about

Granted, the ball mount is not the most aesthetically pleasing antenna, but it's still the only "real" antenna for lowband. Why do you think 9 of 10 state police agencies that are on lowband still use them?

See here for a visual aid:

http://chpcars.tripod.com/chp1030.jpg

http://www.anzwers.org/free/policecars/state.html

nmfire10 · Post by **nmfire10** » Mon May 19, 2003 2:44 pm

I think your still missing the point. He doesn't want a big antenna ANYWHERE!

007 · Post by **007** » Mon May 19, 2003 2:58 pm

No, I got the point. Really I did.

The problem is the words "lowband" and "small antenna" are not found in the RF dictionary together.

jim · Post by **jim** » Mon May 19, 2003 4:59 pm

Lowband won't receive very well with anything less than a 1/4 wave lowband antenna. A 1/4 VHF MAY work okay at close range, however.

I say just mount a 50' air tower on the roof and use a trombone groundplane!

Actually, I use a Motorola Spectrum (Scrotomola Rectum?) lowband antenna on my own vehicle. It's shorter than the Comtelco or Antenex and works well on 33 MHz. It even held 400 watts and didn't burn up! The amp's gone now. It was only to prove a point for one weekend. The point was proven. Westmoreland dispatch heard me from Nesquehoning, Pa!

tiredfireman · Post by **tiredfireman** » Tue Jul 22, 2003 11:40 am

My 2c is to buy a roof mount 1/4 wave, uncut. If you go with aircraft whip, you'll get an extra couple of inches for your bux. Remember, lots of folks use the factory whip on their scanner on the seat in low band territory (yeah, the horror). As long as it is truly receive only, your only problem will be portables, which are only 6watts and in my experience will only talk a mile or less unit to unit. If everyone else is 'romping' around with the motor stalling ["I'm givin 'er all shes got Cap'n"] 100+ watt radios, bases will be at least that, and your receive problems will be nil.
Seems like a waste of a good xmitr tho. Why not just a scanner, or spring for a "bus" type(riot type, or is that not PC?) low profile and be able to talk too --- assuming you're authorized to.
Happy listening.

USPSS · Post by **USPSS** » Tue Jul 22, 2003 11:58 am

I think he is trying to listen to the CHP. They use different systems in different area's of CA, So CA is 39MhZ repeated 42MhZ, most of the state is 42MhZ not repeated. They do use simulcast and it has real problems with phase distortion so a little cheappie antenna will not work, I put on a 148 MHZ 1/4 today and it sucks on CHP LA. and they are running off high mtns.

Matt you need to use a loaded 1/4 wave, you might be able to cut the whip shorter by a few inches, (actually use a 30-33 Meg coil) and cut the whip to about 34" and it might work OK, but DO NOT TRANSMIT or you will have blue smoke coming out of your truck.

I put a COMPROD am/fm sidguise antenna on the Impala and it works very well at 42.5 for TX and RX. Maybe you should look at that one but they are not cheap. $200.00 or so, STi_Co's suck.

mastr · Post by **mastr** » Tue Jul 22, 2003 5:41 pm

The UNtenna CR109 ARD is less than 6 inches high, and can be tuned for any center freq. 30-85 mhz. It is a helical antenna under a radome, and would be suitable as a receive antenna over a decent freq. range. It is just as ugly as a ball mount whip, but won't bang around in trees and parking structures. PM if you would like more info.

Post by **Code3Response** » Tue Jul 22, 2003 5:58 pm

Stan - thanks for the help - it is VERY much appreciated. Mastr - Ive seem those radomes and they are large, correct? Like 6 inches tall and 6 inch diameter, in a cylindrical shape? A CHP Expedition has one and I would ratheri have a 50m whip then one of those! Thanks for the help though. Right now I am just running a base loaded Antenex whip cut to 43 Mhz whip. I may upgrade when I get my ham license so I can TX on 6m, but for right now RX only it seems to be doing the job fine. Thanks for the help guys!

kd9000 · Post by **kd9000** » Thu Jul 31, 2003 8:22 pm

I'm using an Antennex Genisis wide band cut for 47-54 MHz mounted on my Dodge truck. It's pretty flat, SWR goes up to about 1.7 at the extreme ends. I use a 100W SX-9000 and transmit in the 6m band from a low of 50.3 and up into the 53 MHz range with NO problems.

It also receives the CHP fine.

The Antennex works great for me.

Ken

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