Amateur Radio Antenna Applications

[xlaxx]

Recently acquired a 2006 V6 SE 4Runner with the tubular boards and rack,...last night as a matter o' fact!

I am an amateur radio enthusiast and am curious as to where I could potentially mount a single, 2m/70cm Diamond antenna. Please note that I have seen the thread on the CB custom mount (attached to the tailgate section) on this website.

The issue I have with these custom jobs are that most antenna mounts that one discusses on this forum, are for CB use. CB/11m antennas are much longer, as the frequency is lower, hence a driver tends to bump into lower-roofed parking garages and the drive-thru at McDonalds. Therefore, the antenna is mounted lower on the vehicle. 2m antennas need to be mounted higher on vehicles to reach repeaters in the area but are shorter in length for the most part (still effective at 1/4 wavelength).

Mounting the antenna on the hood or drilling a hole in the roof are not good options for me,... there is no way I am taking a drill to my new T4R!

Does anyone have a decent suggestion? I believe Diamond has an automatic mount that can raise and lower an antenna but where could I bolt it on to as to make it a clean install?

Thank you for the help.

xlaxx

 

[lexmedic157]

Could do a Comet RS-720 on the edge of the lift gate. Seen a couple of that type of mount on here and the 120 forum.

 

[lexmedic157]

 

[xlaxx]

Nice pic, thanks for the reply and info.
Had a 93 P/U 22RE 4X4 ExCab Delux previously,...could never find a place to mount the VHF/UHF ant. or lil' Tarheel II HF except in the bed. Not even high enough for my standards. Thanks again. Will look up your call and see what your qth is.

xlaxx

 

[xlaxx]

What is the 120 Forum?

xlaxx

 

[lexmedic157]

toyota120.com

 

[xlaxx]

ATAS 120,... had one of those until the rollers and motor went on the blink. Nice option for VHF/UHF/HF (single antenna to mount),...no 80m tho. What are you driving into the yazu?

 

[lexmedic157]

I got a SS-460SBNMO, been thinking of getting something with a little more gain, but can't complain with what I run currently. Have a Larsen NMO CB antenna too.

 

[beeftube]

Nice location, I think I may be mounting my 2m antenna in the same spot. How did you manage to snake the coax into the cab, however? I've been looking for a spot, but don't see anything obvious.

 

[lexmedic157]

This is a hijacked picture, not actually my truck (I drilled NMO mounts into mine). It seems that most feed the coax into the wiring harness entering the cab from the hatch.

 

[xlaxx]

Saw an Urban Runner last week with what looked to be an automatic/motorized antenna mount located on his nerf bar roof rack. He pulled a quick U-turn at the light and I missed the hardware he had it attached to. I am thinking it was some sort of Diamond or Comet motorized unit but the mouting hardware is key. Be nice to see how the wiring is done inside if it is going behind the plastic or under a carpet,....?

 

[xlaxx]

toyota120.com

When the gate is lifted here,... that whip on the Yaesu screwdriver has got to be whacking the roof rack!

 

[USA591]

This is a hijacked picture, not actually my truck (I drilled NMO mounts into mine). It seems that most feed the coax into the wiring harness entering the cab from the hatch.

Would love to see a pic of your NMO mount placement if this thread re-activates!

73

 

[Bumbo]

I don't have a CB, but I have two Amateur radios in the truck... both are rear hatch mounted and I very much like the hatch mounts.

Yaesu FT-2900 (shorter 1/4 wave flexible antenna)
Kenwood TM-v71a (dual band 1/2 wave antenna)

I have more than one antenna for both radios (stored in the truck)... In the city 95% of the time I actually use 1/4 wave short flexible antennas because I never have to worry about clearance in and out of garages. It takes no more than 20-30 seconds to change an antenna so it's not a big deal, plus it gives me backup/spares in the truck.

Off-road, I generally put a better antenna on it like the 1/2 wave shown.

Getting into a repeater even with the 1/4 wave antennas has never been a problem especially in the city... and even with a less than ideal ground plane its a non issue where I go. Its only when you are on the fringe of coverage the antenna swap becomes a useful gain.

 

[Krayziekid]

I have the Comet CP5NMO mount near the top of the hatch on the trunk. I daily drive with a flexible Comet SSB1 antenna that bends pretty darn easily. I've hit it on a few parking garages and haven't had any issues with it, although I can't imagine it can be good for it in the long run :lalala:

For trips that are longer and won't involve tight trails, I simply swap over to a Comet CA2x4SRNMO. That's a way bigger antenna, but the bottom of it has a joint that allows it to fold over 90 degrees. It's not automatic, but it is an option for you if you know where you are going and plan accordingly.

 

[USA591]

Thanks for the responses!

Do these "clip on" types suffer from lack of a ground plane? I'm sure truck-to-truck and repeater operation is fine, but I'm hung up on thinking that I need a sheetmetal (roof) ground plane for maximum effectiveness, which is what I'm going for.

I've been told that it's tough because of the sunroof on the T4R's... has anyone out there done it?

I love doing simplex on the road (or in the city) and I have an NMO drilled dead center on the roof of Jeep Liberty with a 1/4 wave fold-over that I drive around most of the time. I also have a hood-lip mount that I switch to when I'm constantly driving in an out of parking garages.

73

 

[Bumbo]

Thanks for the responses!

Do these "clip on" types suffer from lack of a ground plane? I'm sure truck-to-truck and repeater operation is fine, but I'm hung up on thinking that I need a sheetmetal (roof) ground plane for maximum effectiveness, which is what I'm going for.

I've been told that it's tough because of the sunroof on the T4R's... has anyone out there done it?

I love doing simplex on the road (or in the city) and I have an NMO drilled dead center on the roof of Jeep Liberty with a 1/4 wave fold-over that I drive around most of the time. I also have a hood-lip mount that I switch to when I'm constantly driving in an out of parking garages.

73

ANY style mount can suffer from a lack of a ground plane... it's the location and material. If you had a fiberglass or plastic roof, like on a race truck or UTV then even a center roof mounted NMO won't have a ground plane.

For setups with less than ideal ground the most popular antenna is a 1/2 wave antennas which isn't dependent or doesn't require a ground plane for performance.

A 1/2 wave antennas is essentially a dipole antenna... it basically consists of two 1/4 wave elements to get its job done.

There is plenty of reading to do on the subject, 1/4 wave, 1/2 wave, 5/8 wave... the key take away is picking the right antenna for the setup. Hatch style mounts used in a corner of the car benefit from 1/2 wave antennas.

Now... Center of the roof is always going to give the best results regarding radiation pattern and all that good stuff, but for most the differences with the right antenna are marginal at best.

Maximum effectiveness is great... but if im getting into every repeater I need to get into, even with a less than ideal setup like my city setup (hatch style mount with a 1/4 wave), I am not really loosing out on anything except perhaps a bit of power from a higher SWR. I can simply change the antenna if I need more performance.

Not trying to talk you out of drilling a hole in your roof, because there is a difference, but for most people, it doesn't matter.

You literally have to be on a fringe of performance for it to even matter and even then I am generally in a place (deep in canyons or something) where my radios either work, or they don't. No amount of power or antenna tuning is going to fix that especially when working a repeater.

Simplex can be a totally different deal when working ground units over long distances.

 

[having fun]

Glad this post popped up. I have a 10/11 meter antenna setup on mine, use of a whip for power and flexibility due to the terrain I get into.
I now tend to run trails with guys on 2meter. I'm still on hand held unit (inside the cab) and can get the adaptors to plug in using my 11 meter setup.

My question, and hopefully can get help from you guys is, Is there, and what type of antenna that can mount to my setup, removable like I have and is flexible to take a beating.

Help please.

 

[Bumbo]

[MENTION=88231]having fun[/MENTION]

I can't answer your specific question about which antenna... but if it was me running trails where antenna damage can happen I would just take it off until I actually needed it.

You have a solution already... you mentioned you generally run 2meter handheld for car to car simplex, so I presume the 10/11 meter setup is more for emergency anyways. At least you still have coms without an external antenna.

I have a long 5/8 2meter whip and it can actually take a good amount of abuse. It would take a low branch towards the base to really break anything.

Jokingly... perhaps its time to install an NMO mount under the truck, so when if/when I roll over I can just pull an antenna out of the cab and screw it to my skid plate haha. Perfect ground plane too. :bounce:

 

[USA591]

My question, and hopefully can get help from you guys is, Is there, and what type of antenna that can mount to my setup, removable like I have and is flexible to take a beating.

Now that you're into 2M and the VHF/UHF world, I'd go for a hood lip mount if you feel that overhead clearance is an issue (trail or parking garages).

Using a handheld is ok and does the trick, but having an in-vehicle mounted radio is so much better after a certain point. Your top-of-vehicle mount is awesome, by the way. Very helpful to see where you put it.

Here is a link to a nice fold-over antenna (one answer to your question):

Mobile Antenna

You could put this or something similar on that mount. And use the low profile hood mount when clearance is an issue--I just swap the feed lines to the back of the radio when I do this. My radio main unit sits under the driver's seat--it takes about 10 seconds.