HF Radio earthing advice please

Submitted: Sunday, May 10, 2015 at 14:46

ThreadID: 117791 Views:3901 Replies:5 FollowUps:4

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HF Radio Installation

In this article, we discuss the procedures for installing a HF radio and the modifications that can be considered for a successful installation.

Tim F3

Those that have hf radio,can you advise if there is any practical difference between using flat braided copper strap (either 12mm or 25mm wide ) for earthing compared to using very heavy round multi strand copper wire for earthing.

Thankyou in advance for any advice.

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Reply By: TomH - Sunday, May 10, 2015 at 15:40

Sunday, May 10, 2015 at 15:40

My Codan was earthed with a length of round braided wire similar to 8 Gauge electrical wire. Was more flexible and had transparent brown plastic sheathing on it.

It came with the radio

AnswerID: 553539

Follow Up By: TomH - Monday, May 11, 2015 at 08:10

Monday, May 11, 2015 at 08:10

The 9350 aerial had a flat braided earth strap. the radio box had the round cable

FollowupID: 839458

Reply By: Peterbilt - Sunday, May 10, 2015 at 15:41

Sunday, May 10, 2015 at 15:41

According to one techie on the Codan Outback Radio forum, "The reason it is a flat braid rather than a round one is that RF travels better over the surface area as the RF flows on the “skin” of the braid." Another technical guy reckoned round or flat didn't make much difference. There seems general consensus though that the better earthing you have will improve the radio's performance, something I need to do on mine.

AnswerID: 553540

Follow Up By: Member - P and JM - Sunday, May 10, 2015 at 18:13

Sunday, May 10, 2015 at 18:13

I second that, either does the job. I have used both since 1994 with no problems.

P&J

FollowupID: 839431

Reply By: Member - ACD 1 - Sunday, May 10, 2015 at 21:45

Sunday, May 10, 2015 at 21:45

Hi Ti

my Codan 3040 has a round earth and was factory fitted. Never noticed any performance difference.

My 9350 had flat cable and when they serviced it, it came back with a round one. Again no noticeable performance issues

Cheers

Anthony

AnswerID: 553562

Reply By: Tim F3 - Monday, May 11, 2015 at 09:06

Monday, May 11, 2015 at 09:06

Thanyou for the above replies, I am in the illawarra nsw and can send and receive to charters towers ,alice springs,south aust ,vic,and the telephone interconnect through Reids Radio Data works well.

Would you consider this to be normal performance for a barrett 950 ???

AnswerID: 553572

Follow Up By: Bob Y. - Qld - Monday, May 11, 2015 at 09:35

Monday, May 11, 2015 at 09:35

Haven't used HF since mid-90's Tim, but if you're getting that sort of Tx/Rx, and you're happy with it, then all is well.

As I recall, we didn't always use an earth strap/cable directly off the transceiver, as they seemed to be adequately earthed by the power lead and the co-ax cable. We always had good Tx/Rx, though we were mostly using 2020khz, RFDS on 5 & 6 MHz and Radphone on 4 & 7 MHz.

The old Codan user manual recommended flat straps, and also showed the straps being used on such vehicle panels as doors, bonnets etc, to reduce any RF interference.

Knew a couple of vets in the Isa area, who were running HJ45 Landcruisers, with 2H engines, and they had earth straps literally "everywhere", to keep interference at a minimum. But they used the HFs like we use mobile phones these days.

Bob

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FollowupID: 839462

Follow Up By: Isuzumu - Monday, May 11, 2015 at 19:32

Monday, May 11, 2015 at 19:32

Yes Tim that is a good, I have 959 also.

FollowupID: 839480

Reply By: Allan B (Member, SunCoast) - Monday, May 11, 2015 at 18:43

Monday, May 11, 2015 at 18:43

As most of you know, radio frequency signals travel predominantly near the surface or 'skin' of a conductor. That is, on the surface of individual strands, not on the outside of a bunch of conductors. So it is of no significance whether that collection of strands is in the form of a flat, round, or any other form of cable.
What matters is that there are many strands rather than a few.

The reason that earth straps were often manufactured in a flat form is that the strands can easily be woven into a flat braid and do not require any overlaying insulation to maintain the form of the cable thus saving the cost in manufacture. Once, all battery earth straps were of this flat un-insulated form for cost saving but in more recent times auto makers have changed to a circular form PVC cable with fewer strands as it better suits their costs.

So no, it matters little whether your RF earth strap is circular or flat.