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Latest Topics

Topic Created Posts Views Last Activity
HF Antenna Advise Aug 21st 2012, 06:35 4 3,847 on 22/8/12
Grounding a Travel Trailer & Antenna Jul 29th 2012, 22:41 5 5,877 on 22/10/12
Wires, is it worth it ? Jul 27th 2012, 04:30 2 3,919 on 3/8/12
Inside antenna and grounding Jul 24th 2012, 21:14 3 3,505 on 27/7/12
Battery Charging May 27th 2012, 17:12 5 8,279 on 23/10/12
2 Meter Inverted V Antennas May 27th 2012, 16:37 7 6,138 on 20/11/12

Latest Posts

Topic Author Posted On
HF Antenna Advise kf7vxa on 22/8/12
Thank You,good reply. As for the HF antenna, without a tower, is something like the Buddypole put on top of the van, horizontal going to be better than the vertical. Either case we would use a good automatic antenna tuner.I'll look for the radial system using the tape measures.
There are few roads the van can get up, the mountains are steep and many trees and rocks and in winter, it's not any kind of option at all.
I also intend to use straps to go from the body to frame, etc.
It's really kind of a unique situation.
I'm going to suggest a second HF radio on the 4 story court house with a larger antenna with a rotor if the county will let go of the money.
At least we are finally working on good ECOMS as far as radios go. The Emergency Coordinator really wants to do the best he can with what we have to work with.

Thanks, John
HF Antenna Advise kf7vxa on 21/8/12
It would be best to lay out the senerio first.
We are in a valley at 6200" sourounded by mountains on better than 3 sides that are from 8000' to in excess of 10,000' with the average being approx. 9000'. We have among others a HF radio in our Emergency Communications van, an Icom IC 7000 running 100 watts.

Right now it is equipped with a streight vertical long wire HFantenna attached to the top rear of the van. At present, it does not even have an antenna tuner, but that will change no matter what we end up with. (The antenna looks like something Army surplus)

The question is,what is going to be the best antenna to get the furtherest distance given the equipment we now have and the bowl we are in.

The problem will be getting a signal over the mountains. In many places the angle would not be too bad, but in others when close to the mountains, it's going to be a rather steep angle.

I was thinking about something like a Buddy Pole that could be set up and taken down in little time, but am looking for suggestions for something that could be deployed fairly rapidly without a lot of effort and a lot of complicated tuning to get a signal out of the valley further than just a signal going upward and coming down 400 to 500 miles away. I think the less technical, the better.
Something with a range of 6 meters to 40 meters would be ideal.
Horizontal polerization is most likely going to be the best. Something along the lines of the Buddy Pole or similar might be ideal if it would work.
We are in Idaho and not looking at getting outside of the USA, but would like more distance than the current set up is going to give us.

As an example, on UHF/VHF, repeaters are just about the only reliable way to get out of the valley, with simplex and some power being the exception sometimes if your in the right spot or have a good antenna on a tower and did I mention extra power?
The ECOM van is kind of cobbled togather (I'm being kind), I'm trying to get some other issues streightened out now also. They don't even have an SWR meter anywhere, not just in the van. I've got some work to do. They have got some nice radios, they just have antenna issues for the most part.
Also, with 2 different areas with radios, what is going to be the best way to ground. At this point I was going to ground each group of radios to a common buss bar, then run ground wire between the two areas and the temp ground rod, hooking both groups of radios up so they would all go to the common point of the ground rod. I'm trying to avoid grn. loops and want to insure static is bleed off. As to lightning, I'm going to seek some professional help on that one unless you have a solution.
It's never easy is it, but I volenteered.

73's, John

Grounding a Travel Trailer & Antenna kf7vxa on 30/7/12
Thank You for the reply. My main concern is that I want to bleed off static from the antenna and coax before it gets to the power supply and radio and I was concerned that if I put a ground rod in the ground and hooked it up to the lightning arrester that I would create a ground loop between the coax hooked to the radio and power suppy and the ground (third pin) in the 120 v electrical socket attached to the built in generator, it's not a portable, which makes this different somewhat.
I want to make sure my equipment is protected, from what I read, as the generator is a built in unit and is grounded to the frame of the travel trailer, it looks like I should ground the lightning protector to the frame of the travel trailer to bleed off static and have no other ground other than the 3rd pin ground in the plug and electrical socket.
In the case of any storms approaching, the antenna will be taken down and all connections disconnected. My main worry is damage to my equipment as I ruined a power suppy once because I put up a temp antenna and static from a far away storm was inducted into the antenna and coax. I don't want that to happen again.
Lightning is not the worry, static and not having a ground loop by grounding the frame of the trailer is the worry. From what I saw, I should not ground the trailer frame to a ground rod, but let the grounding in the trailer 3rd pin in the outlet and a ground wire from the lightning arrestor to the frame of the trailer take care of bleeding off any induced static.

I just want to get it right. I take grounding and safety seriously and want to do it right. I know what to do at home, this is something different. The articals were good.

73's John
Grounding a Travel Trailer & Antenna kf7vxa on 29/7/12
I'm going camping next week and for the first time will be taking my 2M/440 radio and power supply with me.
I have a fiberglass pole about 10 feet taller than the trailer with a J Pole antenna.
My plan is to put 2 four foot ground rods into the ground which is moist and pour some rock salt in as I go and keep the ground wet.
I will have a Diamond 3000 lightning arrestor connected to the coax going to the ground rods and will ground the power supply and radio to the ground rods also, at least that is the plan.
This is not the best of grounds, but any sign of lightning and the antenna comes down and all is disconnected.

My main question is should I also run a gound wire from the rods to the frame of the trailer also, or no grn wire to the trailer at all. With the built in generator powering the power supply, I'm not sure how it might work out with no ground.
I don't have a good 12V hook up inside the trailer so I planned on using the generator which is built into the trailer and my power supply to power the radio.
I might be better off putting in a 12V ten guage wire and running just off of the batteries and not using the power supply with the generator.
Any thoughts on which way to go. Is there more risk of trouble using the generator. I'd like to be able to use the generator because I will be using the trailer in some ECOM situations and would like the generator to help power the radio equip. I have a 37 gallon fuel tank for the generator, so I have a long run time with it.
The generator is a factory built in 4K and is grounded to the ground pins of the electrical outlets.

Thanks, John KF7-VXA
Lightning Arrestors KapAceHigh on 29/7/12
Thanks for the reply Bill. My grn to the radio and buss bar runs a very short distance to the main grn to the electrical panel. 2 more grn rods, 8' long have been driven into the ground and also connected to the main grn for the electrical panel. My equipment each has a seperate grn which is run to a thick copper buss bar behind the equipment which runs to the mains and the coax is grounded with a Diamond 3000 lightning arrester, connected to the same grn wire that comes from my station.
All equipment has the 3rd grn terminal on the plugs.
My window board also has a sheet of copper on it that the through fittings are bolted to and it is grounded to the same ground wire that runs from my equipment to the mains grn. I don't think I can do too much better. Have some tall electrical poles about 150 yds away, with any luck, lightning would hit them and I would be left to deal with the electrical pulse, with everything grounded to the common mains, I should be OK, but never say never.
Does this sound about right?

My Best, John

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