[OZAPRS] 10.147 MHz antenna

[Glen English VK1XX]

(this info for everyone)

Peter, on your copper straps- be sure to use a zinc based jointing 
compound between the copper and aluminium... or a large Zinc(Gal) 
washer. ...and avoid stainless in there. The Gal washer works well.

On a more practical note, on the copper straps,  given that the the 
ground you are trying to connect to is 10 to 20 ohms, an ohm of RF 
resistance wont hurt ! wide copper is not necessary... so something like 
a couple of 4mm2 wires soldered to crimp lugs (as the Cu-Zn-Al 
interface) will do the job.
Depending on the length.

3mm2, like RG213 inner is approx 132 milli ohms per meter at 10 MHz.
so you dont need much ..

1mm2 about 230 milliohms per meter at 10 MHz


glen

On 9/12/2017 10:58 PM, Peter Dodd wrote:
> Hi Andrew,
> SO239 base is mounted on approx 200 x 200 mm sheet of aluminium which 
> is bolted to the rack.
> Rack is providing a counterpoise of sorts.
> At this time rack does not have a good dc path to chassis (fibreglass 
> canopy in the way).
> In process of making earthing straps using copper strips approx 25 mm 
> wide to remedy this.
> Shifted antenna late yesterday and haven't redone sweep yet.
> Should be able to get back to it tomorrow.
> Heard by vk4mq-4 1600km so it is operational but probably not ideal
> Regards
>