70cm multimode activation, Thursday afternoon, 19th May
In my five years of SOTAing I feel I’ve neglected 70cm, occasionally working a few FM stations after qualifying a summit on 2m. My default VHF/UHF antenna for SOTA, a Diamond RH770 ½-wave telescopic whip, gets good reports but I thought it was time to get a 70cm Yagi suitable for portable use [via a birthday pressie].
That means being light enough (~1kg) to be handheld (as well as mounting on my 3m pole) and the boom length short enough (~50cm) to go in my 30L rucksack albeit sticking out the top a bit. Yes, a 15-el Yagi would be great for super Dx but I know I’m never gonna lug such a monster up a mountain.
I settled on a 7-element Z.L. Special which has a folded driver/dipole and a folded reflector. Assembly was straightforward enough despite woefully inadequate instructions. But it was devil to tune and I messed around over three days using coax capacitive stubs and beehive trimmers trying to persuade it to resonate at 432-433 MHz rather than 5-10 MHz higher. In the end I used a coax stub twice the length of the supplied one to get excellent SWR in the 70cm band.
Pointing the Yagi towards GB3NGI 70cm beacon 240km away in Ballymena N.I. from an upstairs bedroom and hearing its digital burble in the noise confirmed it seemed to be working. A field trial followed this morning with Rick 2E0FRS near Bleasdale Fell and me on Arnside Knott (G/LD-058) for antenna tests, both running 100mW FM and giving/getting 5/3 reports.
That convinced me to do a short-notice [sorry!] 70cm-only activation tomorrow afternoon (Thursday 19th. May) - before the rain starts again - from Gummers How G/LD-050 with my FT817 for 5W FM [vertical polarisation] and SSB [horizontal] and CW, if I can get it.
I’ll use a modest 3m pole as I don’t fancy trying to hold the Yagi, logbook & pencil and paddles in two hands. It’s only a 7-element Yagi so I’m not expecting to break any Dx records, but it should be fun. Hope to work some of you on one of those modes.
Regards Andy G8CPZ / M0ALC