Wide Band, Dual Band Mobile Antenna

[N0GX]

I currently use a Maxrad MWV1322 for my vhf radio, so I can cover my ham stuff and our farm stuff. My question is, does anybody make a dual band version that would cover vhf and uhf that is widebanded? I see Comtelco makes some, but they are only around 19" long, I'm looking for something a little longer, similar in length to my 1322.

Thanks, NZ0J

 

[WB4CS]

Any dual band antenna you find should work as long as the frequencies you're using are not too far away from the resonant point of the antenna.

An antenna will be tuned to a certain frequency, that is to say the one frequency where it is resonant. At that frequency the antenna should have an SWR of 1:1. As you move away from that resonant frequency in either direction, the SWR will go up. As long as the SWR isn't above 2:1 you should be okay.

I would recommend either:
1) Tune the antenna for the best SWR of the frequency you use the most, or
2) Find the midpoint between all of the frequencies you use and tune it for that midpoint frequency. You won't have optimum SWR at any of the frequencies, but as long as they're not too far apart the SWR should be acceptable.

I haven't tested the SWR of any antennas outside of 2 meters or 70cm ham bands, but I would imagine that you could get away with using any dual band ham antenna up to around 150 MHz and up to 470 MHz with decent SWR. That's just my opinion, your mileage may vary. Whichever antenna you use, check the SWR on all the frequencies you use just to be sure.

 

[N0GX]

Thanks, I'm needing to cover from 2 meters up to 160 Mhz though. I'm not sure tuning for around 152 Mhz is going to give me a good enough swr where I need it to work.

 

[WB4CS]

You're welcome.

About the only other thing I can come up with is use 2 separate antennas, one tuned for ham and the other tuned for the higher frequencies, and use a coax/antenna switch to change between the 2 antennas as needed.

Maybe someone else here can come up with a better solution, or recommend an antenna that has the bandwidth you're looking for.

Good luck!

 

[N0GX]

You're welcome.

About the only other thing I can come up with is use 2 separate antennas, one tuned for ham and the other tuned for the higher frequencies, and use a coax/antenna switch to change between the 2 antennas as needed.

Maybe someone else here can come up with a better solution, or recommend an antenna that has the bandwidth you're looking for.

Good luck!

I had three antennas on my old truck, the 1322 for vhf, a quarter wave for uhf, and a lowband antenna for 6 meters. I just got a new truck, so I'm trying to get away with drilling as few holes as possible.

 

[xxdanielt3]

I had three antennas on my old truck, the 1322 for vhf, a quarter wave for uhf, and a lowband antenna for 6 meters. I just got a new truck, so I'm trying to get away with drilling as few holes as possible.

Mag mounts, bed lip mounts?

 

[mmckenna]

I see Comtelco makes some, but they are only around 19" long, I'm looking for something a little longer, similar in length to my 1322.

Thanks, NZ0J

The 1322, being a half wave antenna, is giving you a pretty good mix of gain and bandwidth. While there are "gain" dual band antennas, they will have less useable bandwidth that what you are likely looking for.

So, while I understand you want the additional gain, you might need to give that up to get the wider bandwidth you desire. A general rule is:
As gain goes up, bandwidth goes down.
As bandwidth goes up, gain goes down.

A 1/4 wave antenna is going to give you better bandwidth that the higher gain models.

I've put my 1/4 wave VHF antenna on the analyzer at work and the bandwidth of a basic 1/4 wave is pretty impressive. I had 1.6:1 (or better) across 144MHz to 174MHz.

Also, a 1/4 wave VHF antenna is going to work at UHF frequencies. I used to use a simple 1/4 wave NMO whip for my dual band hammy radio with excellent results. The pattern for UHF gets a bit "odd", but it was never an issue. Certainly something you could try in your case.

 

[kayn1n32008]

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Agreed, unless you use a Vhf 1/4 wave, I do not think you will get the bandwidth on Vhf you are needing once you go to a dualband antenna. I have used a 1/4 wave Vhf on Uhf and found it works Ok. I currently use a 1/2 wave antenna on my 45w TK-760HG-1, and it is on a magmount, on the passenger back corner of my roof, the radio has transmit frequencies from 144.8100-173.3700MHz and it will draw less than 10A(what it is fused at) across the whole range with out any problems.

 

[N0GX]

Thanks for the info guys. Take a look at this antenna and tell me what you think. I've never used Comtelco antennas before, don't really know much about them.

http://www.comtelcoantennas.com/html/Show_Part_Number.php?Inv_ID=52

 

[Rt169Radio]

Would the Larsen NMO150 and NMOQ series be what your looking for?

 

[kayn1n32008]

Wirelessly posted (Mozilla/5.0 (BlackBerry; U; BlackBerry 9900; en-US) AppleWebKit/534.11+ (KHTML, like Gecko) Version/7.1.0.746 Mobile Safari/534.11+)

Thanks for the info guys. Take a look at this antenna and tell me what you think. I've never used Comtelco antennas before, don't really know much about them.

http://www.comtelcoantennas.com/html/Show_Part_Number.php?Inv_ID=52

That would work.

 

[W3DMV]

Might look at the Comet CA-2X4SRB. I have two them and they held up well for the
past 5 years of use. Dual band, a good match over almost of both bands.

The antenna has a UHF base, so if your going to use it with a NMO mount, you will need the adapter
which has worked well with mine.. Good luck