VHF but use CB Antennas?

[sepura]

My local police department is VHF, they only have one antenna on the car so this couldn't be used for CB. But their car antennas are very long:

WallaWalla county sheriff | Flickr - Photo Sharing!

Like in this photo. Any ideas why they'd be using low band antennas for VHF? Or do they make some VHF antennas longer or something?

 

[kayn1n32008]

Wirelessly posted (BlackBerry9630/4.7.1.57 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/109)

I could not see the antenna in the photo, if the antenna is in the 3.5-4ft range for length with a coil that is about 1.5 inches tall it may be a 5/8wave antenna that they are using on their cars

 

[davidzimmerman]

i dont see the antenna?? get a little more brave to a better one

 

[ve9jmc]

Looks to me like a 5/8 wave VHF antenna. vhf could be as short as 17 inches for a quarter wave.. or as long as 4 feet if used with a coil for a 5/8 wave.

 

[cgriggs]

Looks like one of these to me.

B1443

 

[SCPD]

its probably vhf what ever is in the 150 mhz because ive medical transport ambulances with that style of antenna and i thought they were cbs but i pressed scan on my scanner and i heard them on 159.9900

 

[W2NJS]

Sepura:

Look at the catalog at www.Comtelco.com and you'll see all kinds of different length antennas for VHF. If you're not familiar with antennas now you will be after you run through the Comtelco catalog.

 

[kayn1n32008]

i dont see the antenna?? get a little more brave to a better one

could not see it due to using a BB.

Now that I have looked at the photo I am going to say that it is a 5/8wave.

 

[KG4INW]

So I clicked on your full size photo and to me it looks like a Larsen LM150C 5/8 wave antenna with a 51 3/4" whip. See here and scroll down: http://www.larsen-antennas.com/docfiles/ASB10/Mobile136to174MHz.pdf

 

[FFPM571]

It is a larsen I have the same one.VHF 5/8 wave

 

[mrweather]

So I clicked on your full size photo and to me it looks like a Larsen LM150C 5/8 wave antenna with a 51 3/4" whip. See here and scroll down: http://www.larsen-antennas.com/docfiles/ASB10/Mobile136to174MHz.pdf

The whips that go with the NMO150 coils are only 49" long max. Combined coil + whip is around 51" tall.

 

[KG4INW]

Ah, OK. I was just quoting the spec sheet but thanks for the clarification as I don't personally own one.

 

[Murstech]

Im using a heavy duty radio shack magnetic mount CB antenna for VHF MURS . The antenna was given to me only after I bought a half wave magnetic mount VHF antenna. I think I spent $40 for it. I actually wanted to find a CB antenna in the first place so I could modify it to 5/8 wave VHF as per ARRL manual instructions. I done that before and it was easy to make it work.
Sooo.. The first thing I noticed about the RS CB antenna is its got this huge magnet. I mean 6 inches in diameter. I then measured the length of the stick and it was about 57 inches or something like that. Hey thats 3/4 waves on VHF I thought. So I took the base apart of wich I only needed to remove the stud to do so.
I found it was only a plastic cover... I also found a PC board type coil in there. I bypassed that, put the antenna back together, check the SWR and it was near 1 to 1!
Ive been using that antenna ever since. My $40 VHF antenna is in the corner of the room just sitting there. I know the radiation pattern for 3/4 wave may not be optimal but it works a treat for me! Someday I may compare it to a true 5/8 wave antenna but I bet I notice very little difference between the two.

 

[mrweather]

Yep it'll work. Just like some hams like to use a 1/4 wave 2M antenna as a 3/4 wave 70CM antenna.