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What power will 16/0.2 wire handle in a dipole?


#1

title says it basically. I know SWR will have a bearing, but in general.
I’m looking for it to handle 100W if required, but plan to use less typically.


#2

Ohm’s Law will give you the current and Google will give you the current handling for 16/0.2 cable.

I think 16/0.2 is 05mm^2 so 100W should be fine. Do the numbers yourself to be sure.


#3

Hi,
No problems with 100 W below 30 MHz. Similar wire is advertised as handling 1 kW at HF. Skin depth effects will derate it as frequency rises so dc and mains frequency ratings are only a rough guide.

At the end of the day the rating is limited by the temperature rise. This should not be enough to soften or melt any covering or plastic supports. If bare it should not discolor.

In the old days 12 gauge hard drawn copper was considered necessary for wire dipoles on HF but we tend to run things harder. The old 1,000 A dc per square inch rule of thumb causes chuckles amongst designers now.

73
Ron
VK3AFW


#5

Hello,
This is very good stuff albeit a bit pricey - see spec.
I have a drum of it here for some new antenna work in the next month or so.
http://www.nevadaradio.co.uk/antenna-accessories/antenna-wire/nevada-nevada-ms-01d---
Good luck
Mike


#6

thanks guys.
I made it 71V(100Vpeak) and 1.41A, which is that is correct then no worries at all.

@G6TUH that stuff is expensive!!


#7

That’s why Nevada can afford to sponser DXpeditions/DXexpedtioners :wink:


#8

Steve,

You don’t need anything like that power on a SOTA activation anyway. There’s loads of us regularly working juicy DX with 5 watts from an FT-817 and a simple wire aerial.

Just get out there with a basic lightweight station and have a go. There’s plenty of easy-to-access simple summits in your area to start with. Having a go is the only real way to find the answers to many of your questions as much depends on your own preferences/operating style.

So I’d highly recommend doing 2 or 3 local activations, see how you get on, then post any follow-up questions that arise as a result on here.


#9

:smile:

Thanks Tom. I will be out trying it soon. I’m gathering up bits and pieces, just waiting for the postmen.
I’m also using what I have to hand a fair bit.
I’m sure there will be follow up threads :smile:

I do have a SOTA summit not 5 or so minutes drive from my house. If I recall correctly it’s quite heavily populated with trees, but I my have my maiden voyage there, or a dry run at least.


#10

Always worth doing a dry run (reccie) if possible. Time how long it takes to walk from where you park the car. Make some notes about the access route you take and then check when you get home, that there isn’t a better / shorter way. Check what supports for your antenna exist at the sumit and if there’s any logs suitable to put the rig on / sit on or whether you need to perhaps take a folding chair - or my preferred option, some thick plastic usually used to protect items when painting in the house. Take a small camera or your smart phone and take a few pictures - useful as a reminder for planning and also if you have no time on the activation day or the visibility has turned bad, these pictures are useful for an activation report if you want to create one later. Check whether you have cell phone coverage at the summit or close to it, so that you can self spot when you are ready to activate.

73 Ed.


#11

You can get a foam plastic garden kneeler from Poundland for a quid, or the same thing from your local garden centre for more like a fiver. They are comfortable and warm to sit on, you can put a tent peg through the handle to hold it down in a wind, and if it does blow away its only a quid!

Brian


#12

What a sound idea for us older gents, will look into that when next in there.

Karl


#13

This is one of my top tips. I have a couple of these. Always one in the rucksack for stops, and also for kneeling on for photography.
I even keep one in the studio for kneeling on!.
I think I saw in Asda this week a cheap yellow one that instead of the normal long and thin kneeler shape was more ‘bum’ shaped.


#14

Yes 100 W will be OK BUT remember that at 14 MHz the skin depth is only 0.0018 mm so the core of each 0.2 mm dia strand doesn’t carry useful rf current. This means the rf resistance at 14 MHz is about 3 times the dc resistance.

There is an upside. You can use plated steel wire (steel is strong but rotten stuff at rf) if it has only 2 micrometre of silver plating. The efficiency would be at least 65% of copper alone.

These are BOE calcs but are near enough to make the point that dc and rf are quite different when it comes to losses in a wire.

In many cases if you have something in your goodies box it’s worth trying before going out and buying something that may be no improvement on the stuff under the bench. Many a useful purse has been made out of sows ears.

73
Ron
VK3AFW


#15

Fine for your backside, but you also need to consider where to put the rig, log, etc. As I said a “reccie” visit is VERY worthwhile to sort these things out. I used to have one of those seats about 1 foot x 1 foot square - sold for outside concerts and the like in Oz. I also have two very small foldable chairs that fit easily into my rucksack but my current favorite is the thick plastic - cost €0.00 as several pieces of it were in the cellar of the house we bought. (it’s not exensive to buy in any case).

With a pre-activation reccie, you can avoid carrying what you don’t need. “Weight is the enemy”.

73 Ed.


#16

I used single strand green plastic covered, steel gardening wire in my 40m loop for several years in Australia, it only got “upgraded” to “proper antenna wire” when the antenna got put up again in Germany. I ran up to 800W into that Garden wire with no apparent issues! Not a scientific measurement, YMMV. The key thing is it worked and cost peanuts! Improvement since moving to the proper antenna wire - none apparent. The principal I follow is use what you have handy (if you have anything handy) and then improve on it if it doesn’t work. In many cases I have found the “cheap and cheerful” solution works fine and the expense of buying the “right” components can be saved.

73 Ed.


#17

yeah not quite sure about where the rig is going to go etc. I do have, and was planning to try out, one of thos pop up beach shelters. I was thinking that, and if chucking it down, maybe a bothy bag over it, or a poncho.
But haven’t got as far as somewhere for the rig as yet. For my rig I may kit out a lightweight plastic case to protect is and stop it chafing, in which case it will double as a low table for the rig.
Batteries will probably be going in a clip lock box too. Extra weight (a little) but will keep them from bashing around etc.

too true!