Dual Band VHF/UHF Commercial Antenna

[ericthenerd]

Hey all,

I've looked around the forums to try and find someone else who's run a similar setup, with no luck.

I'm going to be installing a Kenwood TK-7180 and a Kenwood TK-8180 in my new pickup. I'm hoping to only drill one hole in the roof and was looking to use a single antenna for both radios. I was exploring options and think the best match for my needs is a Laird AB150/450C (Listed here: http://www.theantennafarm.com/catalog/laird-technologies-ab150-450c-7023.html) used with a diplexer like the Comet CF-416A (http://www.theantennafarm.com/catalog/comet-cf-416a-1642.html).

What are the disadvantages of this setup vs running separate quarter-wave antennas for each band? The antenna would be mounted to an NMO just forward of the third brake light on a 2017 F-150.

 

[rescue161]

Disadvantages would be the loss, but 0.15 dB insertion loss is not much at all. I'm using a similar setup for my base station by using a triplexer connected to three Desktrac (lowband, UHF and VHF) radios that are wirelined to a single tone remote (MC2500). All connected to a single tri-band antenna. It works great and I only have the one antenna for those three radios.

I have used that antenna before, but like this one much better.

http://www.theantennafarm.com/catalog/pctel-pctwslmr-8504.html

 

[ericthenerd]

I have used that antenna before, but like this one much better.

http://www.theantennafarm.com/catalog/pctel-pctwslmr-8504.html

Awesome, thanks for the input. Any particular reason you prefer this antenna? I have no need for the 700-900 band so would the extra money be worth it on UHF/VHF?

 

[12dbsinad]

Being in Vermont, I'd opt for separate 1/4 waves. I am sure you'll need all the bang for your buck in a hilly terrain state. You will compromise some with combining antennas, there is no way around it vs dedicated antennas drilled in with a good ground plane. You'll probably notice more of a difference in "range" with UHF. If range is a concern and you want the best there is, go with 2 holes with V and U 1/4 waves. If it isn't really a big deal, go with a dual band. They do work OK, just not optimal.

 

[Project25_MASTR]

I haven't ran multiple antennas in the last few years. I've been running the Panorama Sharkee with their Tri-Band whip for about 2.5 years now. It's been a solid performer on both VHF and UHF. Living in the Texas Hill Country it's been a pretty solid performer. Even when I had the opportunity to compare it to some of the Sandia Peak repeaters (which had previously been accessed when driving my old DD with separate 1/4 waves) on a trip to Las Vegas there were not noticeable differences in performance.

 

[mmckenna]

I'd run separate antennas if you can. While the 0.15/0.25dB loss in the diplexer isn't a big deal, it is an extra $40.

The nice thing about running separate 1/4 wave antennas is that the 1/4 wave's are very broad banded. The UHF side of the dual band antennas will be narrower bandwidth. Might not be an issue if you are just sticking to the ham bands, but if you are going to try to cover amateur, GMRS, LMR, etc. the wider UHF bandwidth is helpful. Probably not a huge deal, but something to be aware of. The cost of a second NMO mount and a the cheaper costs of the 1/4 wave antennas will save you some money.

Nothing wrong with the dual band antennas if that's what you want to do. The diplexers work fine, I ran one in the opposite direction, dual band hammy radio with a separate VHF and UHF antenna.

The Sharkee's are nice. A few of our Ford SUV police cars have those and they seem to work well.

As for the F-150, directly in front of the third brake light works well, but getting it more in the center of the cab gives a more ideal ground plane.
I just did an install on a 2017 F350 regular cab, and I was surprised at the difference in drilling the aluminum compared to the previous steel bodies. Seemed to actually take a bit more effort on the aluminum than the older trucks. Nice thing is that these newer full size trucks are really easy to install in. I've got a 2011 F150 crew cab and it was an easy install.

 

[methusaleh]

What are the chances...unless you purchased those radios and the Comet combiner/duplexer from AF in Underhill?

I am in Vermont, I ran the same two radios, with the same antenna consideration, for several years ending in 2014. Sold my entire setup to the aforementioned gentleman in Underhill.

That being said, I went through a friend's radio shop and purchased a (Larsen? Maxrad?) antenna that for the life of me I can't recall the model number or features. It was an NMO mount, total length about 26 inches, most unusual of all was the center coil load was encased in some sort of black painted metal and was about six inches long. The paint wore off over just a few years, exposing bare metal. Never seen a coil that long or encased in metal.

Edit to add....oh yeah, in response to the topic at hand...I am guessing (emphasis on that word) that antenna was probably nearly full wave on VHF and, what would that be, something like 7/8 wave on UHF...either way, it worked fantastic everywhere I traveled!

 

[ericthenerd]

Sorry I'm late to the conversation! Just noticed I had more replies on here.

I'd run separate antennas if you can. While the 0.15/0.25dB loss in the diplexer isn't a big deal, it is an extra $40.

The nice thing about running separate 1/4 wave antennas is that the 1/4 wave's are very broad banded. The UHF side of the dual band antennas will be narrower bandwidth. Might not be an issue if you are just sticking to the ham bands, but if you are going to try to cover amateur, GMRS, LMR, etc. the wider UHF bandwidth is helpful. Probably not a huge deal, but something to be aware of. The cost of a second NMO mount and a the cheaper costs of the 1/4 wave antennas will save you some money.

Nothing wrong with the dual band antennas if that's what you want to do. The diplexers work fine, I ran one in the opposite direction, dual band hammy radio with a separate VHF and UHF antenna.

As for the F-150, directly in front of the third brake light works well, but getting it more in the center of the cab gives a more ideal ground plane.

That makes a lot of sense. The bandwidth shouldn't be huge deal. I run with a couple public safety agencies, most of them VHF, but one is primarily UHF at 460/465MHz and that's what the 8180 will be primarily used for. I appreciate the cost savings, but having a clean and tidy installation of one antenna is going to be my main focus, and if it costs slightly more to be more aesthetically pleasing, it's worth it to me.

I was poking around the truck the other day and found that theres a clear shot to the center rib in the roof accessed by pulling the rear dome light. It's about 21 inches from the back glass, and looks like there would be a good path for the coax to run to the third brake light then down one side. I plan on running both radios remotely mounted behind the rear seat so I think I'm good there. The more central positioning on the roof also makes me happier, plus I don't want to drop the headliner for my install.

What are the chances...unless you purchased those radios and the Comet combiner/duplexer from AF in Underhill?

I am in Vermont, I ran the same two radios, with the same antenna consideration, for several years ending in 2014. Sold my entire setup to the aforementioned gentleman in Underhill.

That being said, I went through a friend's radio shop and purchased a (Larsen? Maxrad?) antenna that for the life of me I can't recall the model number or features. It was an NMO mount, total length about 26 inches, most unusual of all was the center coil load was encased in some sort of black painted metal and was about six inches long. The paint wore off over just a few years, exposing bare metal. Never seen a coil that long or encased in metal.

Edit to add....oh yeah, in response to the topic at hand...I am guessing (emphasis on that word) that antenna was probably nearly full wave on VHF and, what would that be, something like 7/8 wave on UHF...either way, it worked fantastic everywhere I traveled!

Ha! I'm on the other side of Mansfield, and bought both radios online. I've had them around for a bit but just got a new truck to put them into. I'm glad to hear you had success with the dual-bander! I didn't notice the replies to this thread and actually ordered the parts yesterday. I'll do my best to update with performance and you'll be seeing an install thread hopefully in the near future!

 

[cmdrwill]

The antenna would be mounted to an NMO just forward of the third brake light on a 2017 F-150.

You will need 18 inches from the edge of the cab roof to to the center of the antenna to get the required groundplane. Minimum of 18 inches in all directions.

The a Laird AB150/450C antenna is a good choice.

I would use a commercial diplexer, the one listed is only hammy grade.

 

[ericthenerd]

You will need 18 inches from the edge of the cab roof to to the center of the antenna to get the required groundplane. Minimum of 18 inches in all directions.

The a Laird AB150/450C antenna is a good choice.

I would use a commercial diplexer, the one listed is only hammy grade.

Drilling over the dome light gives me 21 inches from the rear of the cab and more than that in all other directions.

Any recommendations on a commercial-grade diplexer? I wasn't able to find a ton of options, the one listed is what seemed like the best choice.

 

[KK6ZTE]

Did they get rid of the stupid moulding down the dead center of the roof on the later F-150s? The one I did Tuesday (an 07) had a roof line that prevented a dead center mounting... had to go to the rear in order to center it. Thankfully it was a UHF customer.

https://www.tessco.com/products/displayProductInfo.do?sku=309599

 

[ericthenerd]

Did they get rid of the stupid moulding down the dead center of the roof on the later F-150s? The one I did Tuesday (an 07) had a roof line that prevented a dead center mounting... had to go to the rear in order to center it. Thankfully it was a UHF customer.

https://www.tessco.com/products/displayProductInfo.do?sku=309599

I drilled directly over the rear dome light and there was nothing in the way, took me 5 minutes. Gives me dead center horizontally and about 22" from the rear of the cab.

 

[ericthenerd]

Here's some photos of the antenna install:

 

[KK6ZTE]

Looks very nice! It appears they made the roof more radio friendly!

 

[SentinelVT]

Here's some photos of the antenna install:

ericthenerd,

How did that antenna end up working out for you reception and transmission wise? I live in Chittenden County and am considering something similar. I am not a fan of the other larger multi-band antennas being sold at the moment as I am looking for something slim, if even possible.

 

[ericthenerd]

ericthenerd,

How did that antenna end up working out for you reception and transmission wise? I live in Chittenden County and am considering something similar. I am not a fan of the other larger multi-band antennas being sold at the moment as I am looking for something slim, if even possible.

The antenna has been great. I don't do a ton of transmitting with it, but when I have, I've had no complaints. As far as reception, I've been very impressed. It picks up everything I've needed with good ranges. I haven't tried anything else with this setup to compare, but compared to my last setup (mag mount 1/4 wave), it blows it out of the water.

I live in Lamoille county and work in Burlington so I make the commute regularly and monitor many agencies along the way. Feel free to PM me for specifics and I'd be glad to help in any way I can.