When your car is aluminum...

[HCCFCA]

I use HT's when my car club goes on drives. Depending on the number of cars, the line can get pretty long. I recently purchased a 20 watt mobile unit to gain some distance. The dilemma is this: the car is completely aluminum so no mag mounts (or those base plates with the double sided tape) and I will not use a lip mount that might mar the paint or drill holes. Where could I mount an antenna and what antenna would it be. Does such an animal exist? 

[wayoverthere]

12 minutes ago, marcspaz said:

 

Tram 1126-B works fantastic and is very low profile.  I have been using it for years and love it.

Nice wide tuning too..1/4 wave was my thought also...the Laird 1/4 wave ive used/was thinking of is around the same size, but rated much narrower (450-470mhz).

[marcspaz]

@HCCFCA This looks like a great source and advertiser/supporter of the site, too.

 

https://www.buytwowayradios.com/tram-1126-b.html

 

@wayoverthere no doubt.  410MHz-490MHz is outstanding.

[gman1971]

You do have a sharkfin antenna on the car, I would remove that and put an NMO there, then a simple 1/4 wave 6 inch whip will do the trick. No drilling. I've done that on two of my cars and it works perfect.

[Sshannon]

6 hours ago, HCCFCA said:

Chapter 3:

Why didn't I see this earlier, Steve? I have LOTS of glass... 

Do any of these work guys?

 

 

Yeah, I would think so! Good job!

[BoxCar]

13 hours ago, HCCFCA said:

IAntenna suggestions (I want to keep the antenna relatively short)

What do y'all suggest

Tram 1174? Midland Ghost? Other candidates?

Continue to appreciate all your help. We're almost done.

Laird. My Laird is less than 7" including the NMO base.

[wayoverthere]

4 hours ago, BoxCar said:

Laird. My Laird is less than 7" including the NMO base.

Had a picture laying around for this, actually. The mount is the one Midland used to send with one of the bundles, alongside the Laird 450-470 1/4 wave

https://imgur.com/a/6bHYPOh

[HCCFCA]

Well, that is exactly what I was looking for. Appreciate the photo and suggestions!

[HCCFCA]

Epilogue...

It's a happy ending.

Thanks for everyone's advice and links to radio and antenna mounts and an antenna, All was installed and tested to 8 miles Simplex to base this morning. I was amazed that this tiny Tram antenna bested the roof magnetic mount Nagoya UT-72G on my SUV with the same radio (I need to check the SWR on that install). And no drilling or other alterations to the Ferrari were necessary and it's all temporary. The car will be ready for the caravan drives with the car club.

1. Tram 1126-B

2. Rugged Radio suction cup antenna mount

3. NMO mount & RG58 cable

4. Rugged Radio/Scosche cup holder mount (modified to work)

[n4gix]

Nice!

[Sshannon]

That worked well! 

[marcspaz]

Looks like a great, non-invasive install. I hope you have a good time with it!

[tcp2525]

20 hours ago, HCCFCA said:

Epilogue...

It's a happy ending.

Thanks for everyone's advice and links to radio and antenna mounts and an antenna, All was installed and tested to 8 miles Simplex to base this morning. I was amazed that this tiny Tram antenna bested the roof magnetic mount Nagoya UT-72G on my SUV with the same radio (I need to check the SWR on that install). And no drilling or other alterations to the Ferrari were necessary and it's all temporary. The car will be ready for the caravan drives with the car club.

1. Tram 1126-B

2. Rugged Radio suction cup antenna mount

3. NMO mount & RG58 cable

4. Rugged Radio/Scosche cup holder mount (modified to work)

Nice job!! Sometime the easiest solution is the most elusive.

[WRKC935]

Kinda surprised that everyone is going on about aluminum as if it were less of a conductor to RF than steel.

How many steel tube case antenna's have you ever seen, as opposed to the number of aluminum ones. 

Truth is that they use aluminum coated steel cable for high power transmitter antennas at HF and below.  Most commercial base antenna's like the DB series are all aluminum construction.  Aluminum conducts RF well.  And reflects it well too, since most microwave dishes are spun aluminum.  The trick will be getting a mount to connect to it with your specific application.  But your idea of a mount that fastens to the body under the hood and comes out between it and the fender is a good plan. 

 

[MichaelLAX]

2 hours ago, WRKC935 said:

Kinda surprised that everyone is going on about aluminum as if it were less of a conductor to RF than steel...

Conductor?

Let's refresh our memories with the Original Post:

On 2/10/2022 at 4:41 PM, HCCFCA said:

I use HT's when my car club goes on drives. Depending on the number of cars, the line can get pretty long. I recently purchased a 20 watt mobile unit to gain some distance. The dilemma is this: the car is completely aluminum so no mag mounts (or those base plates with the double sided tape) and I will not use a lip mount that might mar the paint or drill holes. Where could I mount an antenna and what antenna would it be. Does such an animal exist? 

 

[WRKC935]

4 hours ago, MichaelLAX said:

Conductor?

Let's refresh our memories with the Original Post:

 

Yep,,, this is a good reason to not post at night.  You don't see everything you need to, say something wrong and Micheal gets to up his post count.

 

[MichaelLAX]

On 3/14/2022 at 3:48 AM, WRKC935 said:

Yep,,, this is a good reason to not post at night.  You don't see everything you need to, say something wrong and Micheal gets to up his post count.

 

Nightime only, Kieth? 

[HCCFCA]

Not to beat a dead horse...

But, here are some further observations for more forum insight into identifying ways to reduce the SWR:

In testing my previously described set up on the Ferrari with the Tram 1126B, I'm getting an SWR of 2.78 on Ch 25 (15 W) to SWR of 4.21 on Ch 17 (18W). On the same mount in the same position on the glass by the roof (previous posted photo) a different antenna has different results. 

With a Tram 1174 the SWR on Ch 25 is 1.75 (18W) to 1.80 on Ch 17 (21W). The 1174 has transmitted about 2 miles further than the 1126B although it was at least 6 miles simplex for the 1126B. The 1174 hit a repeater 40 miles away, the 1126 couldn't hit the repeater.

Does this have something to do with the ground plane effect or lack thereof? Ways to reduce the SWR?

 

[marcspaz]

@HCCFCA, the Tram 1174 is a half wave antenna and the bare minimum for an antenna with no ground plane.  The 1126B is a quarter wave and requires a ground plane.

 

Based on the pictures you shared, you would need to move the suction cup mount closer to the roof line, center the mount on the window's leading edge and rotate the upper potion that holds the antenna 180 degrees in the mount... making it so the 1126B antenna is over the roof.  That may improve the SWR, but the quarter wave will never work as good as the half wave in that type of mount.  Even if you put the suction cup on the roof instead of the glass, I think that mount is entirely too tall for a quarter wave antenna.

 

The only other option would be to buy or make an NMO UHF ground plane kit/adapter. 

[HCCFCA]

Thank you Marc. I will play around with the suggestions. 

[tweiss3]

I agree with @marcspaz, you need a half wave antenna if you don't have a direct RF ground.

[HCCFCA]

Any suggestions for a half wave that'll be ok with the suction cup mount? I'm still getting acquainted with the antennas and all their different flavors. And how power output is affected by a ground plane (or not). I could see radiation pattern but output power?

I was perfectly happy with the Tram 1126B's performance. If I hadn't checked the SWR we wouldn't be having this conversation(!)

Appreciate the help as always.

[tweiss3]

This would be a good one https://theantennafarm.com/shop-by-categories/shop-all/mobile-antennas/300-512-mhz-uhf/no-ground-plane-antennas/3230-laird-connectivity-bb4502n-detail

 

 

[marcspaz]

@HCCFCA  The Tram 1174 (taller of the two) is a half wave antenna and should work fine with the suction cup mount.

 

The 1126B (shorter of the two) will require a ground plane.  That means you are going to need to buy a ground plane kit or you are back to a mag mount or lip mount for the shorter antenna. 

As I mentioned earlier, you may have some luck flipping the upper bracket 180 degrees and getting the antenna over and as close to the roof as possible.

[BoxCar]

Here's some other options:

Amazon.com: Wishring Re-02 Mobile Antenna Ground Uhf-f 10-1300mhz for Car Radio Motorola Icom : Electronics

Amazon.com: TRAM(R) 1192 Pre-Tuned 150-154 VHF / 450-470 MHz UHF Dual-Band Land Mobile Glass Mount Antenna, Black : Electronics

[axorlov]

Results are expected: half-wave antenna performed better in a situation with questionable or non-existing ground plane. I would go with half-wave. SWR is better, efficiency is better, that was confirmed by test in the field. Half-wave antennas do not require ground plane and [almost] not affected if you have a ground plane nearby. But if you are satisfied with quarter-wave, it's all good.

With regards to quarter-wave vs half-wave for power and efficiency: quarter-wave with good ground plane is identical to half-wave with no ground plane.