Dual band antenna help/recommendations

[OhioJeff]

I have recently passed my test for the Technician class license and am awaiting my call sign. While I wait I’ve been shopping for a mobile setup for the 4Runner and have decided on the Icom IC-2730A. Due to occasional height restrictions I’m looking at the Comet CA-2x4SRNMO antenna because it has the fold over design. Anyone use one of these? I like the idea of a fold over but unsure on how durable it will be. Planning to use a lip mount on the rear hatch so no ground plane. I’m not sure how to tell if this antenna is designed for a ground plane or not, showing my ignorance here. I’m completely new to Amateur radio so feel free to chim in if this is a bad choice or mismatched to my radio.
Thanks in advance.

 

[WareWolf MoonWall]

I have recently passed my test for the Technician class license and am awaiting my call sign. While I wait I’ve been shopping for a mobile setup for the 4Runner and have decided on the Icom IC-2730A. Due to occasional height restrictions I’m looking at the Comet CA-2x4SRNMO antenna because it has the fold over design. Anyone use one of these? I like the idea of a fold over but unsure on how durable it will be. Planning to use a lip mount on the rear hatch so no ground plane. I’m not sure how to tell if this antenna is designed for a ground plane or not, showing my ignorance here. I’m completely new to Amateur radio so feel free to chim in if this is a bad choice or mismatched to my radio.
Thanks in advance.

I've currently got the CA-2x4SR mounted to the light bar of my truck. Before that, I had a diamond with the fold over feature. Both will give you great TX/RX, but I'll add that you may prefer the Comet solution as they have a spring kit available for another few bucks that will help with it.

The fold over design is more for planned convenience., such as garages and drive through needs. A spring is to ensure the antenna survives tree limbs and when you forget its up.

That all being said, take a look at eham reviews: https://www.eham.net/reviews/detail/2082

 

[WareWolf MoonWall]

A pic of it with the spring kit installed, folded over on my truck. It essentially keeps the profile below the height of the XM antenna, which is perfect in my case.

I can add that the folding spring is a bit stiffer to work on the Comet than the Diamond. In my case, that was a consideration because I have the climb up the truck and reach other the center and try and fold it over with 1 hand. It's tricky, and I'm 6'4... :)

 

[OhioJeff]

I've currently got the CA-2x4SR mounted to the light bar of my truck. Before that, I had a diamond with the fold over feature. Both will give you great TX/RX, but I'll add that you may prefer the Comet solution as they have a spring kit available for another few bucks that will help with it.

The fold over design is more for planned convenience., such as garages and drive through needs. A spring is to ensure the antenna survives tree limbs and when you forget its up.

That all being said, take a look at eham reviews: https://www.eham.net/reviews/detail/2082

Thanks for the link, reviews seem pretty good, no red flags. I think the optional spring as you suggest is a good idea, I’ll add that to my shopping list.

 

[OhioJeff]

A pic of it with the spring kit installed, folded over on my truck. It essentially keeps the profile below the height of the XM antenna, which is perfect in my case.

I can add that the folding spring is a bit stiffer to work on the Comet than the Diamond. In my case, that was a consideration because I have the climb up the truck and reach other the center and try and fold it over with 1 hand. It's tricky, and I'm 6'4... :)

View attachment 85246

Looks good. Can you tell me if the antenna only folds over in one direction? I guess what I’m asking is when it’s folded over, can it rotate around the base or will it stay put?

 

[WareWolf MoonWall]

It's essentially a rotating hinge that has a spring to keep both ends from slipping apart if that makes sense.

It will only fold over one way, but it will sweep like a turret.

On my truck, I always fold it over the bed of the truck. It can and does 'drift' slightly to the left or right at times (which drives my OCD crazy), but it has never become a propeller or slapped around.

 

[WareWolf MoonWall]

It's essentially a rotating hinge that has a spring to keep both ends from slipping apart if that makes sense.

It will only fold over one way, but it will sweep like a turret.

On my truck, I always fold it over the bed of the truck. It can and does 'drift' slightly to the left or right at times (which drives my OCD crazy), but it has never become a propeller or slapped around.

Best analogy I can provide is think of a flexible straw in a cup with a lid. Imagine the straw only flexed in one direction, but could still rotate in the straw hole of the lid on the cup.

 

[OhioJeff]

It's essentially a rotating hinge that has a spring to keep both ends from slipping apart if that makes sense.

It will only fold over one way, but it will sweep like a turret.

On my truck, I always fold it over the bed of the truck. It can and does 'drift' slightly to the left or right at times (which drives my OCD crazy), but it has never become a propeller or slapped around.

That’s good to know, in my application I was planning to fold it over to the side, but from what you have told me it will weathervane. I will need to rethink my plan.

 

[WareWolf MoonWall]

That’s good to know, in my application I was planning to fold it over to the side, but from what you have told me it will weathervane. I will need to rethink my plan.

I had considered making a small teether line to hold it in place using a slipknot, but have never found it necessary with it aimed towards the back.

In your setup, I could see it drifting towards the driver behind you and possibly getting snagged and broken off.

They are not that big, so you may be able to just remove it when not needed and slip it behind or under a seat etc...

 

[94Cruiser]

I love mine. But as someone said above, it's meant for planned folding. It doesn't do well with branches... Unlike the spring-loaded Firestik for the CB

 

[Prerunner1982]

Planning to use a lip mount on the rear hatch so no ground plane. I’m not sure how to tell if this antenna is designed for a ground plane or not, showing my ignorance here. I’m completely new to Amateur radio so feel free to chim in if this is a bad choice or mismatched to my radio.
Thanks in advance.

I can't comment on the fold over antennas but as far as the no ground plane antenna goes you would want a 1/2 wave antenna. They are typically about 36" tall (+/-). However unless the rear hatch is fiberglass it should provide enough ground for a VHF/UHF antenna.

 

[OhioJeff]

The antenna I’m planning on is 40”. Just not sure how to tell the difference between an antenna designed to work without a ground plane. Is it simply the length?

 

[Prerunner1982]

The antenna I’m planning on is 40”. Just not sure how to tell the difference between an antenna designed to work without a ground plane. Is it simply the length?

It's the wavelength that determines if it's not ground dependent, 1/4 wave, 1/2 wave, 5/8 wave.... a 1/2 wave antenna is not ground dependent. It does relate to length of the antenna but 1/2 wave antennas from different manufacturers may be slightly different lengths due to size of loading coils or mounting bases, etc.

The Comet CA-2x4SRNMO is a 1/2 wave antenna, Universal Radio has it listed incorrectly as both a 5/8 wave on 2m and 5/8 on 70cm. DXEngineering has it correct at 1/2 wave for 2m and 5/8 wave for 70cm.

 

[OhioJeff]

It's the wavelength that determines if it's not ground dependent, 1/4 wave, 1/2 wave, 5/8 wave.... a 1/2 wave antenna is not ground dependent. It does relate to length of the antenna but 1/2 wave antennas from different manufacturers may be slightly different lengths due to size of loading coils or mounting bases, etc.

The Comet CA-2x4SRNMO is a 1/2 wave antenna, Universal Radio has it listed incorrectly as both a 5/8 wave on 2m and 5/8 on 70cm. DXEngineering has it correct at 1/2 wave for 2m and 5/8 wave for 70cm.

Thanks, that clears it up for me. I’ll make sure to stay with 1/2 wave or longer for my installation, little or no ground plane available.

 

[RadioRick]

Is the hatch you are mounting to fiberglass or metal? If it is fiberglass you will want to consider some additional grounding. If it is metal run a ground strap from the door to the body. The roof of the vehicle will actually make a decent ground plane although it will be decidedly forward-patterned. Would drilling a hole in the roof and using an NMO kit be out of the question? We actually get reasonably good performance using this style of mount on the patrol Tahoe and Explorers.

 

[OhioJeff]

Is the hatch you are mounting to fiberglass or metal? If it is fiberglass you will want to consider some additional grounding. If it is metal run a ground strap from the door to the body. The roof of the vehicle will actually make a decent ground plane although it will be decidedly forward-patterned. Would drilling a hole in the roof and using an NMO kit be out of the question? We actually get reasonably good performance using this style of mount on the patrol Tahoe and Explorers.

It is metal, was planning on running a ground strap to take care of the hatch but I’m not confident that the actual clamp on lip antenna mount will get a good ground connection to the hatch. It’s got a rubber back to protect the paint and a small plate on the set screw side. Do I need to make sure the mount itself is grounded? The manufacturer didn’t seem to think it was needed. Unfortunately mounting to the roof is out, I have a full length aluminum roof rack loaded up with the usual overlandy stuff.