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What cable to use

PostPosted: Tue Oct 25, 2016 9:08 am
by timcooper55
Hi All,

Got to the stage now where I am going to build my own hf antennas,
As it's cheaper to buy cable in bulk, I will buy a 100 m reel but want toke sure it is fit for the job.
Am I right in saying that go hf work, a thinner cable such as mini 8 would be suitable?

Thanks

Tim

Re: What cable to use

PostPosted: Tue Oct 25, 2016 10:02 am
by m0lsx
Mini 8 would work yes, but it does depend upon length.
25 meters of reasonable quality Mini 8 at 7 mhz would only lose around 15% which is low & it would only lose 5% more at 29 mhz.

Min 8 or RG-8X is a reasonably low loss coax for HF & although some call it low loss, it is only very marginally better than RG-58. RG-58 would lose around 5% less at 29 mhz & around the same 15% at 7 Mhz. So the alledged low loss tag on Mini is not always what it seems. But yes it's a good choice on HF.

When you get above 30 MHz, Both RG-8X & RG-58 become poor even at 50 mhz, where both lose approaching 40% at 25 meters.

The only place you could gain with different coax is in the matching department. If you are making things like a low impedance quarter wave. Then 75 Ohm coax is a good choice as it counter balances the antennas low impedance. And for multi band antennas balanced line is a good choice. Although that does need the right connector for your Antenna Matching Unit.

Re: What cable to use

PostPosted: Tue Oct 25, 2016 5:19 pm
by timcooper55
Many thanks for the detailed reply.

Tim