Will a dual band mobile antenna receive VHF as well as a straight VHF antenna?

[JoshuaHufford]

Most of my scanning is for railfanning, and I have a 5/8 wave antenna tuned to 160-161MHz for my scanner.

I've recently learned about monitoring EOT and DPU frequencies which are UHF 452-457MHz, and it has proven very useful in rural areas for knowing when a train is nearby, however in cities not so well if there is a train parked somewhere.

Obviously my current antenna isn't the best for UHF, so this has me thinking about getting a dual band antenna so I can monitor both the VHF voice communications and EOT and DPU frequencies.

If I go with a quality unit such as a larson, I'm just curious if I will be sacrificing any reception with a dual band as opposed to the current tuned antenna that I'm using now.

Thanks!

 

[krokus]

Most of my scanning is for railfanning, and I have a 5/8 wave antenna tuned to 160-161MHz for my scanner.

I've recently learned about monitoring EOT and DPU frequencies which are UHF 452-457MHz, and it has proven very useful in rural areas for knowing when a train is nearby, however in cities not so well if there is a train parked somewhere.

Obviously my current antenna isn't the best for UHF, so this has me thinking about getting a dual band antenna so I can monitor both the VHF voice communications and EOT and DPU frequencies.

If I go with a quality unit such as a larson, I'm just curious if I will be sacrificing any reception with a dual band as opposed to the current tuned antenna that I'm using now.

Thanks!

That depends on the antennas. There are broadbanded antennas, but do not have much gain. A dual band antenna can be made with gain, in the targeted frequency ranges.

Did you have a specific antenna in mind?

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[JoshuaHufford]

Not really, I'm open to suggestions. I don't mind paying for quality if it is worth it, but I don't want to get carried away with the price.

I'd like it to be NMO mount as I have 2 NMO magnetic bases, and if there is a no ground plane version of a dual band I might be interested as I have a vehicle I'm planning on buying a luggage rack mount for. I realize it won't perform as well but I don't wan't to use a mag mount on this vehicle.

I drive 3 different vehicles so at this point I don't want to install anything permanent. I'd like the ability to move the antenna between vehicles.

 

[kayn1n32008]

Not really, I'm open to suggestions. I don't mind paying for quality if it is worth it, but I don't want to get carried away with the price.

I'd like it to be NMO mount as I have 2 NMO magnetic bases, and if there is a no ground plane version of a dual band I might be interested as I have a vehicle I'm planning on buying a luggage rack mount for. I realize it won't perform as well but I don't wan't to use a mag mount on this vehicle.

I drive 3 different vehicles so at this point I don't want to install anything permanent. I'd like the ability to move the antenna between vehicles.

There is a LMR band tuned version of the Larsen NMO2/70. I use the ham band version and have been very satisfied with it. Had it for around 10 years so far.

There is a slight difference in gain, but I doubt you will be able to tell the difference.


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[mmckenna]

A 1/4 wave VHF antenna will be 3/4 wave on UHF. I used a simple 1/4 wave VHF whip for my dual band radio for years.

But, if price isn't a concern and you don't mind the taller antennas, the Larsen would be a good choice.
Larsen NMO 150450C https://www.theantennafarm.com/catalog/larsen-nmo150450c-865
Larsen NMO 150/450/800 would be a good lower profile option https://www.theantennafarm.com/catalog/larsen-nmo150-450-800-1050

If you use your scanners for anything else other than monitoring railroads, the 150/450/800 might be a good choice.
Or, if you have more than one scanner, use one for VHF and one for UHF and just use a VHF antenna and a UHF antenna.

 

[JoshuaHufford]

A 1/4 wave VHF antenna will be 3/4 wave on UHF. I used a simple 1/4 wave VHF whip for my dual band radio for years.

But, if price isn't a concern and you don't mind the taller antennas, the Larsen would be a good choice.
Larsen NMO 150450C https://www.theantennafarm.com/catalog/larsen-nmo150450c-865
Larsen NMO 150/450/800 would be a good lower profile option https://www.theantennafarm.com/catalog/larsen-nmo150-450-800-1050

If you use your scanners for anything else other than monitoring railroads, the 150/450/800 might be a good choice.
Or, if you have more than one scanner, use one for VHF and one for UHF and just use a VHF antenna and a UHF antenna.

Thanks, I don't really want to run more than one scanner, at least for now.

So one thing I'm still curious about, will their be much if any performance trade off with VHF reception if I get the dual band that you suggested as compared to the VHF antenna that I'm currently using?

 

[mmckenna]

I doubt it, but I've never done anything to confirm that. Would be something I'd need to test for myself. The coil on the dual band antennas should be essentially invisible to VHF, but I'd be surprised if there wasn't some impact.
If VHF is all you need, nothing else, then a VHF only antenna will be cheaper.

I usually prefer lower profile installations, and stick with the thin 1/4 wave whips for my own personal vehicles. A simple 1/4 wave VHF antenna has always served me well for my needs. I've played around with half wave, 5/8th's wave, dual band, etc. but always come back to the 1/4 waves as the best solution for my own needs. My needs on my own truck are just VHF. I don't have a need for anything else. I don't run multiband radios. When I did have other radios in the truck, I had dedicated antennas for each radio.

For what you are doing, the dual band 150/450 antennas sound like a good solution. It'll work well on VHF. Even if there was the slightest amount of impact, I doubt you would be able to hear it. Things like antenna location make a much bigger difference.

 

[JoshuaHufford]

OK great, that is what I needed to know. I just wanted to make sure there wasn't a big impact before I spent the money and then end up disappointed.

I always appreciate your input.

 

[mmckenna]

I think you are on the right track (no pun intended).

There are things that will impact performance, like where you put the antenna, unnecessary adapters, etc. As always, put the antenna in the center of the vehicle roof to give it the best ground plane you can. Get the coaxial cable terminated with the connector that matches your scanner.

Other than that, enjoy.