Portable Ground Plane for Mag Mount Antenna
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Credit to Monty Northrup = N5ESE
Credit to Monty Northrup = N5ESE
Adding a ham radio antenna to an RV or Trailer
[This is my version of the portable group plane as outlined in the article by N5ESE
I am a ham radio operator, call sign K7BTU, and like to have my radio equipment with me when traveling and camping. When I am at the campsite, I usually set up my portable rig and a temporary J-Pole base antenna for my communication needs. More power and a better antenna makes a big difference. I have considered installing a mobile in the RV but I often like to set up under the awning and kick back in the chair to communicate rather than sit in the drivers seat.
A handheld ham radio (HT) is lightweight and convenient while traveling down the road. Unfortunately, the lower power of the radio and rubber duck antenna performance diminishes the signal. Add to that, the potential interference and signal blockage by all the stuff in the RV, and your signal will suffer even more. Putting an antenna on the roof is the solution.
For the time being, I like the simplicity of the handheld radio and putting a better antenna on the roof seems like a logical solution to improving the signal. Regardless of the type of radio, it is still best to have a good antenna on the roof. So, I decided to figure out a way to install an antenna on the roof of the motorhome to allow for better communications while on the road.
My RV roof is a plywood/foam and aluminum rib frame composite construction with a rubber membrane cover. This type of construction greatly impacts the installation of such equipment. This type of roof construction does not act as a ground plane to help the antenna propagation pattern. That being the case, I needed to come up with a plan to create a ground plane on the roof. I thought about a piece of sheetmetal but it would have be about 30 inches square and then there was the problem of securing it to the roof. I was concerned about the possibility of the wind stress while traveling could rip it off. So I went to the internet to look for a solution.
I came across a system on a ham website [n5ese.com] by Monty Northrup] showing a possible solution. (Thanks Monty for the great idea). I decided to try this method to see if it would work on my RV. I built a ground plane using his outline and then placed it on the roof of my RV for a test.
The unit consists of a shallow electrical box as the base and the radials are made up of 1/8” all-thread rod, covered with heat shrink tubing to protect the roof from abrasion from the threads. I used a 1/4 wave magnetic antenna with a SMA male connection to match my handheld radio. The use of the 1/4 wave helped to keep the antenna height lower for clearance purposes. I then hooked up the HT and asked for a radio check on a local repeater. I received a response saying my signal was strong and readable. I then asked the responding operator his location, which was about 15 miles away and asked if he would contact me on a “simplex frequency” to see how that would work. We made contact and he said my signal was still good and readable. I was satisfied with that and thanked him for his help. Life was good!
Now I needed to figure out how to mount the system to the roof without drilling holes to do so. I was prepared to route the cable through the roof with a roof mounted cable cover but that was all the drilling of holes in my roof I was going to do. After some thought, It came to me that I could use some roof repair tape called “Eternabond RV repair tape” . It is available from many sources but I got mine from Amazon. This tape is made for repairing the type of roof material I have and I had used it when I attached my solar panels down. Very strong adhesive and no holes required. It is not cheap but is very useful for many RV purposes.
Before putting the ground plane “electrical box” base down, I put a piece of the Eternabond tape down on the roof to protect the roof from any abrasion by the box. I then attached the antenna to the roof by taping down the radials down using pieces of the Eternabond tape. As the picture shows, it makes for a pretty solid installation with very little wind resistance.
After drilling one hole through the roof for the cable. I pushed the connector through the hole and into the cabinet that was immediately behind the driver location. I then sealed the opening in the roof with a cable plate and RV roof sealant making sure the cover and attaching screws are completely sealed.
The antenna cable was then routed from the cabinet to the dash by utilizing the door trim moulding to hide it This allows me to attach the antenna cable to my handheld and then use it with the roof mounted antenna. I attached a bracket to my dash to hold the radio and have a remote speaker microphone attached to the radio to use for communication. This leaves the radio clipped to the dash bracket and allows me to use the lightweight speaker/mic in my hand. It’s just like having a mobile but much smaller footprint. I use a charger/power supply plugged into the lighter port to keep the battery charged up.
I have used this setup on three outings and it has worked just fine. Keep in mind that you have to be within range of a repeater or the other party if using simplex but it has performed very well for me. If i need more power for communication when camping, I set up my mobile rig and J-Pole antenna.
If you have questions, contact me through my website hamradioworks.org
Go to the “Contact us” tab. My email address is listed there or you can fill out the form.
[This is my version of the portable group plane as outlined in the article by N5ESE
I am a ham radio operator, call sign K7BTU, and like to have my radio equipment with me when traveling and camping. When I am at the campsite, I usually set up my portable rig and a temporary J-Pole base antenna for my communication needs. More power and a better antenna makes a big difference. I have considered installing a mobile in the RV but I often like to set up under the awning and kick back in the chair to communicate rather than sit in the drivers seat.
A handheld ham radio (HT) is lightweight and convenient while traveling down the road. Unfortunately, the lower power of the radio and rubber duck antenna performance diminishes the signal. Add to that, the potential interference and signal blockage by all the stuff in the RV, and your signal will suffer even more. Putting an antenna on the roof is the solution.
For the time being, I like the simplicity of the handheld radio and putting a better antenna on the roof seems like a logical solution to improving the signal. Regardless of the type of radio, it is still best to have a good antenna on the roof. So, I decided to figure out a way to install an antenna on the roof of the motorhome to allow for better communications while on the road.
My RV roof is a plywood/foam and aluminum rib frame composite construction with a rubber membrane cover. This type of construction greatly impacts the installation of such equipment. This type of roof construction does not act as a ground plane to help the antenna propagation pattern. That being the case, I needed to come up with a plan to create a ground plane on the roof. I thought about a piece of sheetmetal but it would have be about 30 inches square and then there was the problem of securing it to the roof. I was concerned about the possibility of the wind stress while traveling could rip it off. So I went to the internet to look for a solution.
I came across a system on a ham website [n5ese.com] by Monty Northrup] showing a possible solution. (Thanks Monty for the great idea). I decided to try this method to see if it would work on my RV. I built a ground plane using his outline and then placed it on the roof of my RV for a test.
The unit consists of a shallow electrical box as the base and the radials are made up of 1/8” all-thread rod, covered with heat shrink tubing to protect the roof from abrasion from the threads. I used a 1/4 wave magnetic antenna with a SMA male connection to match my handheld radio. The use of the 1/4 wave helped to keep the antenna height lower for clearance purposes. I then hooked up the HT and asked for a radio check on a local repeater. I received a response saying my signal was strong and readable. I then asked the responding operator his location, which was about 15 miles away and asked if he would contact me on a “simplex frequency” to see how that would work. We made contact and he said my signal was still good and readable. I was satisfied with that and thanked him for his help. Life was good!
Now I needed to figure out how to mount the system to the roof without drilling holes to do so. I was prepared to route the cable through the roof with a roof mounted cable cover but that was all the drilling of holes in my roof I was going to do. After some thought, It came to me that I could use some roof repair tape called “Eternabond RV repair tape” . It is available from many sources but I got mine from Amazon. This tape is made for repairing the type of roof material I have and I had used it when I attached my solar panels down. Very strong adhesive and no holes required. It is not cheap but is very useful for many RV purposes.
Before putting the ground plane “electrical box” base down, I put a piece of the Eternabond tape down on the roof to protect the roof from any abrasion by the box. I then attached the antenna to the roof by taping down the radials down using pieces of the Eternabond tape. As the picture shows, it makes for a pretty solid installation with very little wind resistance.
After drilling one hole through the roof for the cable. I pushed the connector through the hole and into the cabinet that was immediately behind the driver location. I then sealed the opening in the roof with a cable plate and RV roof sealant making sure the cover and attaching screws are completely sealed.
The antenna cable was then routed from the cabinet to the dash by utilizing the door trim moulding to hide it This allows me to attach the antenna cable to my handheld and then use it with the roof mounted antenna. I attached a bracket to my dash to hold the radio and have a remote speaker microphone attached to the radio to use for communication. This leaves the radio clipped to the dash bracket and allows me to use the lightweight speaker/mic in my hand. It’s just like having a mobile but much smaller footprint. I use a charger/power supply plugged into the lighter port to keep the battery charged up.
I have used this setup on three outings and it has worked just fine. Keep in mind that you have to be within range of a repeater or the other party if using simplex but it has performed very well for me. If i need more power for communication when camping, I set up my mobile rig and J-Pole antenna.
If you have questions, contact me through my website hamradioworks.org
Go to the “Contact us” tab. My email address is listed there or you can fill out the form.