Lightning arrestors and ground planes

[Elbowmac]

DB20g mobile radio as base and a midland mxta26 antenna on a midland nmo magnetic mount base. It is currently on a cookie sheet extended  outside by the installed 16' coax on the mag base. I have been advised to get a lightning arrestor between the radio and the antenna cable connector. Ground the arrestor to a house ground. Then to drill a hole in the cookie sheet to allow the nmo base electrical connections to pass through the hole and then screw the antenna back onto the nmo mount. It was explained that this would give a ground plane to the antenna as the metal cookie sheet would contact the ground of the antenna and mounts coax ground and then to the ground wire on the lightning arrestor, to earth ground via the house grounding system. I hope I explained it adequately. This would turn the metal reflector (cookie sheet) into a real earth ground. What benefits will this provide in protection and reception?

Thanks

 

[SteveShannon]

3 hours ago, Elbowmac said:

DB20g mobile radio as base and a midland mxta26 antenna on a midland nmo magnetic mount base. It is currently on a cookie sheet extended  outside by the installed 16' coax on the mag base. I have been advised to get a lightning arrestor between the radio and the antenna cable connector. Ground the arrestor to a house ground. Then to drill a hole in the cookie sheet to allow the nmo base electrical connections to pass through the hole and then screw the antenna back onto the nmo mount. It was explained that this would give a ground plane to the antenna as the metal cookie sheet would contact the ground of the antenna and mounts coax ground and then to the ground wire on the lightning arrestor, to earth ground via the house grounding system. I hope I explained it adequately. This would turn the metal reflector (cookie sheet) into a real earth ground. What benefits will this provide in protection and reception?

Thanks

 

For a permanently mounted antenna up in the air a properly installed lightning arrester is a good thing to have, but for a mobile antenna on a steel cookie sheet stuck out the window it’s really not necessary.

Nor do you need to change to a through hole NMO connector. The magnetic base establishes a good enough ground plane with the cookie sheet without needing direct connection. And as @Socalgmrs pointed out a ground plane isn’t the same as an earth ground. Also, that metal cookie sheet is not a reflector; it should be kept horizontal and the antenna should be vertical.

[Socalgmrs]

The cookie sheet is the ground plane. A ground plane has nothing to do with an earth ground.  Your ground plane is already totally fine.  Now if you want to put a lightening arrestor in your system or an earth ground incase of a lightning strike that’s totally different and totally removed from the ground plane.   Is the antenna up higher than any other metal in the area?   It is likely to get struck by lightning?   Do you have home owners insurance?   I’m f you do you may want to check with them.   If lightning is an issue most likely the insurance will want an electrician to Atleast check your work. 

[Elbowmac]

12 hours ago, Socalgmrs said:

The cookie sheet is the ground plane. A ground plane has nothing to do with an earth ground.  Your ground plane is already totally fine.  Now if you want to put a lightening arrestor in your system or an earth ground incase of a lightning strike that’s totally different and totally removed from the ground plane.   Is the antenna up higher than any other metal in the area?   It is likely to get struck by lightning?   Do you have home owners insurance?   I’m f you do you may want to check with them.   If lightning is an issue most likely the insurance will want an electrician to Atleast check your work. 

I apparently have run out of reactions.... Thanks for the information and explanation. The antenna is currently on a table on the inside of a screened patio. The procedure and posted explanation was the reasoning for the grounding scheme. THANK YOU FOR EXPRESSING THE INSURANCE CONCERN! Have offers to mount an antenna on the highest part of the roof along with the cable. With the current setup I am hitting a good repeater @ 18 miles on low power on the db20g. SWR on high power 1.5 and low 1.02. From what I have gathered here and on the air, this is doing well. I take the mobile antenna in at night. I would like to get a better simplex setup. I can only hit about 7 miles to an operator using his yagi antenna. Threw n9tax gmrs up a tree about 20 feet and was able to get and talk on the repeater with the ht GM-30. Daunting is the learning experience. Many are the contradictory answers! Glad I found this forum, though it produces much possible ambiguity. Anyway thanks for the heads up.

[Elbowmac]

8 hours ago, SteveShannon said:

For a permanently mounted antenna up in the air a properly installed lightning arrester is a good thing to have, but for a mobile antenna on a steel cookie sheet stuck out the window it’s really not necessary.

Nor do you need to change to a through hole NMO connector. The magnetic base establishes a good enough ground plane with the cookie sheet without needing direct connection. And as @Socalgmrs pointed out a ground plane isn’t the same as an earth ground. Also, that metal cookie sheet is not a reflector; it should be kept horizontal and the antenna should be vertical.

Again, I have run out of reactions to you guyz help. It seems that I am good for now. Possibly put up a cheap yagi on a temporary pole and see if I can transmit to operators around me who are using them. Actually I should get back to studying for the technicians license. That will explain much in a structured way!! The suggestion was to use the magnetic base and antenna... placing the cookie sheet in between where the two items connect. Thanks