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Re: [TowerTalk] Help Needed for my First Tower --Coax Grounding

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Subject: Re: [TowerTalk] Help Needed for my First Tower --Coax Grounding
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
Date: Wed, 16 Oct 2013 15:27:10 -0400
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On 10/16/2013 8:21 AM, Pete M wrote:
I would agree, normally, but I have sold many ground kits here for $3-$5 each (new). And have seen many for sale on ePay an other places for low and close to these prices. I am not trying to sell any here and now. Please do not ask if I have any "???" for sale ... I will not reply too those.

Bottom line ... the grounding of the Heliax should be done per Mfg's recommendation ... they have more experience than we do ( I hope) and I do believe there are certain NEC codes that are applicable to this.

I agree with the Heliax even when used on HF, but it's because of cost. They save you nothing as far as loss. IOW there is no practical reason for using them at HF other than they can leave the coax at a curve.

The reason for grounding kits is a simple one. They avoid additional connectors and their losses. At HF and Amateur power levels, ( even most QRO) this is not a problem, even when using UHF connectors. The loss per connector is miniscule and I'd not be concerned until well into the UHF range. When we see these loss figures for connectors, they are at the upper frequency limit for the connectors.

I have, on average, about 10 connectors between the amp and antennas. The measured loss, at the operating frequency(s), when added for a total is still a tiny fraction of a db. I do run QRO. I also use regular coax consisting of RG8X, LMR-400, and LMR-600 and gain nothing on HF or even VHF by using grounding kits over bulkhead connectors. Were I using hard line and/or operating in the upper UHF range, then I'd us grounding kits.

If you really do want to use grounding kits, buy one and duplicate it. They are very simple to make and can be made without cutting any holes in the copper. I just don't figure they are worth the effort in most cases.


73

Roger (K8RI)


Look around you will find complete new ground kits ( with sealants, etc)

Pete WA2ODO


On 10/15/2013 7:09 PM, Roger (K8RI) on TT wrote:
On 10/15/2013 4:34 PM, Richard Solomon wrote:
I have 8 never used Grounding Kits for Coaxial Cable (their title), that
will fit
anything from 1/2" up. Made by Radio Frequency Systems (but look a lot like
Andrew).

I posted them here some time ago, but got no interest. Any interest now ??

73, Dick, W1KSZ

You can use the grounding kits, which are very effective although they do require some work and weatherproofing. There is also the simple way, but expensive. Two coax connectors and a bulk head connector.

I'd use the bulkhead connector with less expensive coax on HF. All 3 connectors cost less than one hard line connector and about the same as 1 grounding kit. They are also very effective. I use it up through LMR-600

73,

Roger (K8RI)



On Tue, Oct 15, 2013 at 1:14 PM, Pete Smith N4ZR <n4zr@contesting.com>wrote:

I have used stainless shim stock from McMaster-Carr to address this
problem. The Andrew kits are nice if you can find them, but not cheap.

73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

On 10/15/2013 8:27 AM, Wayne Willenberg wrote:

Hello.  I am making good progress on my new (and first) tower.

I am connecting my RF signals to the Yagis on my new tower using 7/8”
Andrew Heliax. I would like to ground the top and bottom of the Heliax to
one of the galvanized legs of the tower.

I am concerned about putting 2 dissimilar metals together (i.e., the
corrugated shield of the Heliax and the galvanized steel leg of the
tower).

What type of metal is used to make the outermost shield of Heliax?

And, do I need an intermediate metal (like stainless steel) between the
Heliax shield and the tower leg?

Thanks for your help.
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