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Author Topic: 2m Ringo Ranger counterpoise radials  (Read 1609 times)

Posts: 700

« on: March 10, 2013, 08:23:50 AM »

I've got a Ringo Ranger ARX-2B up on the side of the house (antenna base is about 4ft above peak of roof), sans counterpoise radials. I did not install them because at its current height, the radials would have been below the eave, touching aluminum cowling, and because it would have been difficult to mount the antenna with them.
That said, the SWR measured at the radio is flat, about 1.5:1 across the 2m band.
I have two questions:

1) How much am I losing by not having the radials, in terms of output power.
2) Would three radials really be sufficient as a counterpoise?

I am considering building a new set of radials from copper tubing, if I can come up with the right plumbing fittings to do the job. I would think that in terms of radials acting as a counterpoise, more is better, as long as they are evenly spaced, and the correct length. So I figure I would go with 4 copper pipes radiating from the mast below the antenna at 90 deg spacing.

The radial kit that came with the antenna is damaged; one or more of the radials has stripped threads, so if I were going to use it again, I need a die to put new threads at the other end.
The whole kit is very cheaply made; aluminum, which is too soft to hold a good thread.

Of course i could just replace the entire antenna; that is also a consideration, except that I am on a very tight budget.

Thanks for any ideas/help on this.

Frank; KE2KB

Posts: 102

« Reply #1 on: March 10, 2013, 12:17:57 PM »

As I recall, the purpose of the radials on this antenna is an attempt to minimize common mode current on the coax shield.  This can have an adverse effect on the radiation pattern of the antenna, and RF in the shack.  The original antenna mounted the radials on the supporting mast below the bottom of the antenna, and a coax "jumper" was provided between the radials and the antenna feedpoint.  New radials made from other material such as copper, would be OK, but they should maintain the same length (and approximate diameter) as the original aluminum ones.  They should also be connected to the coax shield the same distance from the feedpoint as the original design.  This will help ensure the low common mode impedance desired.  Or, you could just use the antenna as is, and live with any common mode problems that result, ala J-Pole :-)

73 de wb0ksl, John

Posts: 700

« Reply #2 on: March 10, 2013, 12:26:11 PM »

Since I posted, I took a closer look at the radials and collar, and found them to be usable after all. I just need to bring the antenna down and see how difficult it will be to handle it in swinging it clear of the eave so I can shove it up above the roof with the radials installed. I want to add another section of EMT, which I am using as the mast. I figure to get a large enough diameter so the top piece will slip into the bottom, and then be bolted (through holes I will have pre-drilled) together.
I'm also considering relocating the ICE lightning arrestor to the ground rod (it is currently located up on the mast with about 30ft #4 THWN wire from it to the ground rod), and then running the coax from there back up to the radio.

It's a bit of a problem only having access to the antenna by reaching out the attic window. If I had a ladder long enough, I would just climb and hoist it up and onto the brackets from the outside.

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