23-08-2024, 12:44 PM
In amongst in in the showers I got the antenna aloft.
This first image is the sweep from 7 to 29MHz on the uncut antenna.
The next is the point where any change at either end caused the VSWR to start to go back up. This also coincided with a break in play for lunch.
"Gentlemen, that's over and lunch".
As I was packing up the NanoVNA I realised that I am going about this all wrong. I did a quick sweep of 6.5 to 7.3 MHz and found that the antenna is still way too long.
Lowest VSWR is around 6.5 MHz.
When play next recommences I will try a radical fold back.
M0MCX has a calculator that suggests that if this were a dipole it would be almost 1.8 metres too long.
https://www.m0mcx.co.uk/quick-swr-calcul...-antennas/
So I will adjust the length accordingly (after dividing by 1/3 for the OCF split ((0.9*2)/3) gives me a 1.2m and 0.6m adjustment.
To do this one of the halyards will need to be lengthened, so this is for future me to do.
(23-08-2024, 11:51 AM)VK2XAX Wrote: I'm surprised that no one has mentioned Bunnings as yet, they have electric fence insulators thus...
https://www.bunnings.com.au/o-briens-whi...k_p3040955
Bunnings say they carry them and have them in stock.
Even after ringing the store to assure they are in stock, upon arrival nothing, zip, nada!