Base station antenna -- ground plane addon kit

[TXRiverRat]

Can the radials of a ground plane kit be mounted pointed upwards instead of downwards?

I'm not a Ham or radio expert, just a CB dummy.

I have a Procomm, Patriot 12, Omnidirection 1/2 wave fiberglass antenna mounted on a 16' mast, mounted against the side of my house. I have height limitations. I am considering adding the ground plane kit to this antenna, but the 6' fiberglass radials will not clear the roof at my current mounting height, and I cannot go much higher due to Home Owner Association (HOA) regulations.

My question is, can the radials be mounted pointing upwards instead of downwards? Will I defeat all transmission abilities?

 

[jessejamesdallas]

pointed up would put them right next to the antenna itself....think you're going to have SWR issues... Be like these guys who mount their antenna right behind the cab of their pick-ups on the bed rail, then wonder why they can't get the antenna to tune.

 

[Marconi]

TXRiverRat, if you can flip the radial hub over and put the radials slanted up at about the same angle as they are currently slanted down...you might find the antenna still works OK but with a bit less gain maybe. Not enough as you could tell just working your radio though.

When I did the same on an A99 free space model I saw the match improve, but the gain dropped from 2.16 dbi @ 5* degrees above the horizon to 1.97 dbi as @ 0* degrees above the horizon. A pretty good result on slanting the radials up.

The change seems pretty simple with a little effort. Why don't you take the chance and see in you get the clearance you need while maintaining a workable match. Then Keep us posted.

 

[Robert Buttle]

Can the radials of a ground plane kit be mounted pointed upwards instead of downwards?

I'm not a Ham or radio expert, just a CB dummy.

I have a Procomm, Patriot 12, Omnidirection 1/2 wave fiberglass antenna mounted on a 16' mast, mounted against the side of my house. I have height limitations. I am considering adding the ground plane kit to this antenna, but the 6' fiberglass radials will not clear the roof at my current mounting height, and I cannot go much higher due to Home Owner Association (HOA) regulations.

My question is, can the radials be mounted pointing upwards instead of downwards? Will I defeat all transmission abilities?

Hi I was wondering if you had not bought the ground plane kit, you could try some wire tilted down towards the roof and see if it is better.

 

[Marconi]

TXRiverRat, hold off a bit on my idea posted above. I got to thinking that something else may be going on with your setup.

I should have asked why you decided to put radials on your PCP #12. If you don't mind, were you having issues with your antenna?

 

[SIX-SHOOTER]

Had a local who installed a ground plane kit on his Antron 99 & it worked so well about 2 weeks later he removed it & gave it away.I had one New in the box that came from an Estate & I gave it away as well & never installed it.The Antron 99 talks all over the world as it is so why would I mess with it?

SIX-SHOOTER

 

[S&W357]

That right there

 

[357magnum]

Six & Ralph , same here ! I don't need " No Stinkin' GP Kit " !

 

[Marconi]

I agree with my pistol packing buddies.

Long ago I thought the A99, without radials, worked great for me, and I still do. I never did anything but stick my A99 in the air, and then Bob85 'splaned to us about Common Mode Currents (CMC) on the feed line. I've had questions ever since, but was always afraid to ask.

This is why I told TXRiverRat to hold off a bit before he wasted his time making the changes by adding radials and slanting them UP...that I encouraged him to consider and try the idea.

His Procomm sounds like it is acting bad possibly due to CMC, and IMO adding radials may not be enough to mitigate the problem, slanted up down or horizontal.

 

[Marconi]

Here is a model of my A99 at 18' feet to the feed point, with radials slanted down at 45* degrees, and with a mast that is Isolated (ISO) by 4" inches from the antenna. This post is only intended as a simulation of an antenna with very little to no Common Mode Currents flowing on the mast.

The 2nd model is the same model as #1 above...except I connected the mast directly to the antenna, no more Isolation between the mast. I did this just to help show the possible effects of CMC. This model shows considerable CMC on the mast and that skews the pattern, lowers the gain, and raises the TOA a bit.

Both models are match well at the feed point as noted in the Source Date Report.

Neither of these models has a feed line attached, and that would change these results as compared here. So, even with an ISO mast CMC could still flow and cause problems. This is what I think, in part, is likely going on with TXrr Procomm setup up close to his house.

We just don't know enough about TXrr's setup to be sure.

 

[Shockwave]

Some things to consider are that the 1/2 wave end fed antenna is the least dependent on ground radials for performance as compared to any other ground plane. In other words, adding radials to this antenna should not cause any noticeable improvement in signals.

I hate to be blunt here but that 12 foot 1/2 wave is one of the worst performing base antennas I've ever tested because it's "loaded". I helped a friend install one with similar height limitations on a 10 foot pole. He can't wait to cut 5 feet off the pole and get an unloaded Antron 99 in its place. It works about as good as a 102 inch whip on a car in his driveway, 20 feet lower.

Bang it around a little during shipping or installation and the solder connections to the matching coil inside will pop right off with a near infinite VSWR. Luckily the glue holding it together was just as cheap and pulled apart to resolder the broken connection. Good VSWR now but poor signal.

There is so much compromise going on inside that antenna in order to remove 5 or 6 feet of length, that it's not worth the sacrifice. Trade a few feet of mast height for the full length antenna and you'll be pleased with the results. Something you can actually see.

 

[357magnum]

I just like my A-99 & Iv'e had a few ( only because I had a newer one to replace the old from a rental ) My 1/4 RS $12.95 antenna received better . (IMO) But I'll keep my A-99 for what it put's up with her in the North East and hopefully get my 27-4 Sirio up soon . Metal is better IMO ! Heck the TV people made antenna's out of it for years for receive .