Antenna plain…mobile solid or perforated?

[WSAZ909]

I’m intending to use this 3rd light antenna/led light mount/plate for many different antennas. (Pics below) 
Will this plate work as properly as a flat solid metal plate used as a plain?(as I have heard of folks using a o sheet. 
Next…will multiple antenna installed on this plate or a solid plate cause interference or feedback into a different radio in the same vehicle when multiple radio installed  are on ion the same vehicle?

UPDATE : Radios and antennas to be installed…

Radios being installed:

Radio 1:   Abbree AR2520  
https://a.aliexpress.com/_mMk93iw

Antenna: Diamond Antenna SG-M507 Dual Band 144/430MHz Mobile Antenna

Radio 2:  Wounxun KG-1000G-plus v1

Antenna: BROWNING 450MHz-470MHz UHF 3dBd Land Mobile NMO Antenna  https://a.co/d/7fqbE76

or

Midland® MXTA25 3DB MicroMobile® Compatible Gain Ghost Antenna – 3.5” Tall with 1.5” Base Diameter – Low Profile GMRS NMO Connection  https://a.co/d/jlFHsxJ

 

 

UPDATE ON PLATE SIZE 

21” left to right 

10.25” front to back 

 

Edited March 24 by WSAZ909
Measurements of plate, radios, and antennas to be installed

[WRYZ926]

I would love to run longer antennas but I need to be able to park in my garage and also fit into low parking garages at my doctors appointments. I might end up getting another Comet 2x4SR for when out and about.

[WRYZ926]

Yes that should work as a ground plane.  I have my Comet 2x4SR with a magnetic mount on an expanded metal rack on the back of my SxS and it works just fine for 2m, 70cm, and GMRS. I modified one of those trailer hitch cargo racks to fit my SxS.

[kidphc]

Next…will multiple antenna installed on this plate or a solid plate cause interference or feedback into a different radio in the same vehicle when multiple radio installed  are on on the same vehicle?
 

Yes, it could. Especially, if the frequencies in use overlap or are harmonics.

Even if they aren't overlapping or harmonics of the same frequency, the fact they are close to each other will effect performance. Rule of thumb is try to keep separation of antennas at least one wavelength apart of the lowest.

You won't really know the effects till you try.

Sent from my SM-S901U using Tapatalk

[WSAM454]

  I imagine that the entire plate is something like 8x12 inches in size?   If so, you might find that tuning the antennas will be difficult, since being so close to each other they might interact, even though they are on different frequencies.  As far as use, I agree with kidphc; I would not be comfortable transmitting 20-40 Watts on one antenna while another radio (even on another band)  antenna is so close.   Possibly OK if only one radio was on at a time, but I would opt for putting only one antenna on that plate.  

Also the cable you show in one photo looks to be a very small diameter. so hopefully it will be a very short run to the radio, since losses will be great.

[WRYZ926]

I totally missed the part about having two antennas. Not enough . Half a wave length for 70cm band and GMRS is about 12 to 13 inches. Half a wave length of 2m band is around 40 inches. I am running a Comet SBB-1 dual band antenna and a Nagoya UT-72G GMRS antenna on top of my Ford Escape. The antennas are approximately 2 foot apart (full wave length for 70cm/GMRS). I haven't had any issues with that setup. I haven't tried having the antennas any closer than that.

[kidphc]

I should add I have a ham radio with the antenna mounted almost in front of the driver on a hood hinge mount. The other antenna for gmrs is about 9" in front of the rear hatch on the roof. Roughly about 6 feet of separation and not even on the same plane.

Welp, I have blasted the ham radio with the gmrs radio and vice versa, remember 70cm is real close but far also from gmrs frequencies.

The Yaesu xtm400 (ham on fender) doesn't seem to care when I use the 70cm portion on the Motorola xtl5k (gmrs and ham p25).

But the other way around the Motorola gets pissed (overloaded). It seems the Motorola is a lot more sensitive than the Yaesu. So normally I shut down the Xtm400 when using the Motorola and vice versa.

Makes sense to me about the sensitivity. I mean new the Xtl5k were like $3k new and the Yaseu was about $500 new.

Curious to see if the Harris 100m is going to be the same situation. Especially, since the harris will be on a triplexer with 3 different antennas.

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[WSAZ909]

3 hours ago, kidphc said:

 

 

Yes, it could. Especially, if the frequencies in use overlap or are harmonics.

Even if they aren't overlapping or harmonics of the same frequency, the fact they are close to each other will effect performance. Rule of thumb is try to keep separation of antennas at least one wavelength apart of the lowest.

You won't really know the effects till you try.

Sent from my SM-S901U using Tapatalk
 

 

What would be the least and ideal distance these antennas should be apart on a truck. I do have some optional mounts that can be placed on the fender/tailgate area. But these will not have any plane to work with.

[WSAZ909]

3 hours ago, WRYZ926 said:

I totally missed the part about having two antennas. Not enough . Half a wave length for 70cm band and GMRS is about 12 to 13 inches. Half a wave length of 2m band is around 40 inches. I am running a Comet SBB-1 dual band antenna and a Nagoya UT-72G GMRS antenna on top of my Ford Escape. The antennas are approximately 2 foot apart (full wave length for 70cm/GMRS). I haven't had any issues with that setup. I haven't tried having the antennas any closer than that.

So, with your antenna set up, any bleed over , one into another radio when tx? 
A distance of 14”, but on the same plain, would be ok?

 

[WSAM454]

3 hours ago, WRYZ926 said:

......... Half a wave length for 70cm band and GMRS is about 12 to 13 inches. Half a wave length of 2m band is around 40 inches. I am running a Comet SBB-1 dual band antenna and a Nagoya UT-72G GMRS antenna on top of my Ford Escape. The antennas are approximately 2 foot apart (full wave length for 70cm/GMRS). I haven't had any issues with that setup. I haven't tried having the antennas any closer than that.

As above, about 2 feet separation would be ideal for UHF freqs, and about 4 feet for  VHF.   Also, if the antenna(s) all have good solid connections to the body of the vehicle, (not mag mounts!) then the entire vehicle would act as the 'ground plane.'   (it does not necessarily need to be an actual 'plane'  or metal sheet just below the antenna, although that would be ideal, and why the optimal location for antennas is the vehicle roof!)    If the antennas are mounted on separate body panels, (hood and trunk) it is often suggested that they be 'bonded' together.   This is usually done by using flexible 3/4"-1" wide braid.  for example, running a piece of braid from the hood hinge (or door hinge) to the body of the car; running braid from the trunk/hatch back to the body and not just relying on the hinge to maintain continuity.

[WSAZ909]

4 hours ago, WSAM454 said:

  I imagine that the entire plate is something like 8x12 inches in size?   If so, you might find that tuning the antennas will be difficult, since being so close to each other they might interact, even though they are on different frequencies.  As far as use, I agree with kidphc; I would not be comfortable transmitting 20-40 Watts on one antenna while another radio (even on another band)  antenna is so close.   Possibly OK if only one radio was on at a time, but I would opt for putting only one antenna on that plate.  

Also the cable you show in one photo looks to be a very small diameter. so hopefully it will be a very short run to the radio, since losses will be great.

That cable came with the NMO mount( Midland – MXTA24 Low Profile Antenna Cable with NMO Connector , https://a.co/d/2InzGkf )  It is being changed out for a different mount. 
Do you have a nmo mount recommendation!

[WSAZ909]

23 minutes ago, WSAM454 said:

   If the antennas are mounted on separate body panels, (hood and trunk) it is often suggested that they be 'bonded' together.   This is usually done by using flexible 3/4"-1" wide braid.  for example, running a piece of braid from the hood hinge (or door hinge) to the body of the car; running braid from the trunk/hatch back to the body and not just relying on the hinge to maintain continuity.

The body of my truck is all aluminum alloy. Finding  ground continuity can be a challenge. Could I use some10 awg or 18awg insulated wire to accomplish this?

[WSAZ909]

To everyone that has pitched in with all the help, thank you! I am a newbie to anything but cb radio, old school.

Can I mount two different gmrs antennas on that same plate and switching out to radio as needed, being are both for the same frequency use?

Then mount a cb antenna on one side of the tailgate and a ham radio antenna to the other side to have all antennas/frequencies separated far enough anyway to alleviate or help with these issues?

[kidphc]

To everyone that has pitched in with all the help, thank you! I am a newbie to anything but cb radio, old school.
Can I mount two different gmrs antennas on that same plate and switching out to radio as needed, being are both for the same frequency use?
Then mount a cb antenna on one side of the tailgate and a ham radio antenna to the other side to have all antennas/frequencies separated far enough anyway to alleviate or help with these issues?

It is really no different then cb. Just really the wavelengths. Hence why we jokingly call it uhf cb. Hopefully, it doesn't get as bad.

Yes you can mount two gmrs antennas on the same plane. I would recommend unplugging (antenna port on radio) / turning one off when the other is in use. Rf will still leak into the other radio's finals.


11m/cb is not a damaging harmonic (not even sure if it a harmonic, to lazy to check) of 2m/70/gmrs.

As long as the antennas aren't too close shouldn't be a problem.

My 11/10m antenna is on the rear hatch (driver side of hatch). The 2m/70cm on the hood and the gmrs on the center rear hatch about 3 ft from the cb antenna. Never had problems with it even when using 10m at 50w.



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[WSAZ909]

41 minutes ago, WSAM454 said:

As above, about 2 feet separation would be ideal for UHF freqs, and about 4 feet for  VHF.   Also, if the antenna(s) all have good solid connections to the body of the vehicle, (not mag mounts!) then the entire vehicle would act as the 'ground plane.'   (it does not necessarily need to be an actual 'plane'  or metal sheet just below the antenna, although that would be ideal, and why the optimal location for antennas is the vehicle roof!)    If the antennas are mounted on separate body panels, (hood and trunk) it is often suggested that they be 'bonded' together.   This is usually done by using flexible 3/4"-1" wide braid.  for example, running a piece of braid from the hood hinge (or door hinge) to the body of the car; running braid from the trunk/hatch back to the body and not just relying on the hinge to maintain continuity.

Understood, maki sure there is a proper grounding of each antenna for the truck to act as the plain.

As far as the separation/distance is best at 4ft. I have considered mounting GMRS antennas on the roof plate, then a cb and ham antennas on opposite sides at the tailgate.

[WSAZ909]

5 minutes ago, kidphc said:

 

 

It is really no different then cb. Just really the wavelengths. Hence why we jokingly call it uhf cb. Hopefully, it doesn't get as bad.

Yes you can mount two gmrs antennas on the same plane. I would recommend unplugging (antenna port on radio) / turning one off when the other is in use. Rf will still leak into the other radio's finals.


11m/cb is not a damaging harmonic (not even sure if it a harmonic, to lazy to check) of 2m/70/gmrs.

As long as the antennas aren't too close shouldn't be a problem.

My 11/10m antenna is on the rear hatch (driver side of hatch). The 2m/70cm on the hood and the gmrs on the center rear hatch about 3 ft from the cb antenna. Never had problems with it even when using 10m at 50w.



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Looks like I will be using tailgate mounts for separating and reserve the roof plate for GMRS, they are the shorter type ( nmo browning br-176s, and midland mxta-25 ). I will check continuity of each for mounting grounds/connections. 

[WRYZ926]

1 hour ago, WSAZ909 said:

So, with your antenna set up, any bleed over , one into another radio when tx? 
A distance of 14”, but on the same plain, would be ok?

 

I don't get any bleed over at all with the antennas being 2 foot apart. The only way to know if 14" (half a wave length) would work is to try it. A full wave length of separation would be better.

I am using a TYT TH-7800 and Wouxun KG-1000G Plus in my Escape. Here is a photo showing the antennas.

[WSAZ909]

On 3/24/2024 at 1:43 PM, WRYZ926 said:

I don't get any bleed over at all with the antennas being 2 foot apart. The only way to know if 14" (half a wave length) would work is to try it. A full wave length of separation would be better.

I am using a TYT TH-7800 and Wouxun KG-1000G Plus in my Escape. Here is a photo showing the antennas.

I have these for interchangeable for different terrain/areas:

•Midland 5/8 wave mxta-25, 5/8 wave, 3db gain, nmo
•Browning 5/8 wave br-176s, 3db gain(tunable), nmo … not sure on the wave spec
•Midland mxta-26, 6 db gain, (tunable), nmo

probably going to get a 4 or 6” pvc pipe with bottom cap and top screw lid. for storing them in so they don’t receive damage when not in use.

Just received my kg-1000g today. Weather sux today, but hope to get it in truck later this week, run wires power/antenna, and check/tune swr.

I’m probably going to place my ham antenna at the back tailgate, I have left/right side mounts for ham/cb and center the gmrs mount on top of the roof.

Edited March 26 by WSAZ909