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+--- Thread: Antenna Shenanigans... (/thread-1395.html)
Antenna Shenanigans... - VK2CSW - 09-03-2024
Sometimes you just wonder why.
After a hiatus caused initially by the NBN, the interruptions of Covid, moving interstate, making the new house liveable, learning to enjoy the new surroundings, coping with an awful project at work (you know, life stuff) I have dusted off some of the gear and started cobbling a temporary (for now) station together.
Our block has a largish veggie garden that has a metal frame over it with a shade cloth cover. Methinks that as an interim solution to overcome the analysis paralysis of what real antenna/s to put up, I will bung a bit of angle onto the frame, whack on a delrin base and stick my FAMPARC multi-tap helical whip and run some coax across the yard to it.
As I wasn't too fussed and the VSWR was within reasonable limits that the tuner could handle - I looked no further.
I got the radio and interfaces up and running. Lo and behold I was getting decodes on FT8 immediately. I spent a couple of evenings trying the break the duck on my VK5 callsign.
No luck. Plenty of decodes and PSKInfo said I was being heard and decoded all over the place.
Early this morning, about an hour before the sun it was over 25°C so I got up and started mucking around on 20m FT8 again. "Hang the expense, I'll do a quick tune of the helical" I said to no one in particular.
Broke out the VK5JST analyser, yup it still works so off I go to tune this thing. Back and forth, up and down the ladder, you know the drill. From one end of the adjustment to the other. Best I could do was 2.63:1.
Seems odd to me.
Once the sun had risen and I could see more clearly I decided further investigate the groundplane/veggie garden sun shade. It is all 40x20mm gal section in a grid, held up by treated pine posts. I grabbed a DMM and started to check continuity amongst the frame members.
Mostly good. Except the cross member I had chosen to attached to. It must have been an afterthought, added for bracing. It is screwed to the pine uprights, but air gapped where it passes the other metalwork. To quote Adam Savage from Mythbusters "There's your problem". The groundplane was a single 40x20mm gal section about 3 metres long.
Back to the drawing board, I guess.
RE: Antenna Shenanigans... - VK5PJ - 09-03-2024
Hello Colin,
the answer to ALL of these situations is LONGER screws. :-)
RE: Antenna Shenanigans... - VK2CSW - 09-03-2024
(09-03-2024, 11:36 AM)VK5PJ Wrote: Hello Colin,
the answer to ALL of these situations is LONGER screws. :-)
Longer screws and maybe some jumper cables...
(But not this weekend)
RE: Antenna Shenanigans... - VK2CSW - 10-03-2024
Well I made up some short jumper cables and grabbed some tek screws - it is all bonded together now.
Does it make any difference?
Who knows? it's hit 38°C at the garden bed and 35° inside the shed, so I have called it a day.
Lunch at Club Tanunda in the A/C might be in order (If I can convince SWMBO).
RE: Antenna Shenanigans... - VK5TM - 11-03-2024
Wot, no #8 fencing wire to wrap around it
RE: Antenna Shenanigans... - VK2CSW - 11-03-2024
(11-03-2024, 09:28 AM)VK5TM Wrote: Wot, no #8 fencing wire to wrap around it
If I am being honest, there was a couple of rolls of fencing wire on the bench and they were pressed into service...
So a bit more playing this morn, before that sun came up and chased me away (geez I have gotten soft).
Couldn't get the thing to tune on 20m, nothing under 2.5:1.
I even tried longer and shorter adjustment rods (made from fencing wire...) but no joy.
Reinserted the original rod, put it about halfway through the adjustment, moved the wander lead to the 40m position.
Analyser showed me 49Ω and 1.02:1. Good enough.
Had a play on 40m well after sun up, probably around 8:00 AM local. Lots of decodes, I was showing up on PSKReporter and had one incomplete QSO with a VK6 POTA station (honestly it was just the RR73 message that didn't get through!).
Moved to 17m. Plenty of decodes and appearances on PSKReporter. So it is, on the whole working.
As I was packing up I did notice one issue. WSJT-X had the wrong maidenhead locator in it. Not doubt a typo on my behalf. It could explain why I was getting few responses. It had PL51 which put me some where NE of the Philippines. When I tried to correct it to PF95LN, it wouldn't save it and kept reverting to PL51. I had to restart WSJT-X and re-enter the location before it would accept it.
I need to have a look at the 20m tap on the antenna to work out why it is so far out.
Sadly it's back to work tomorrow, so the window to fiddle is diminishing...
RE: Antenna Shenanigans... - VK2CSW - 12-03-2024
To round it out, I got it to tune on 20m (cleaned out the tap point).
Even got some log entries.
Now that it is working, it's time to work on my other antenna analysis paralysis issues. ??
RE: Antenna Shenanigans... - VK2CSW - 17-03-2024
So the palaver continues
I ordered one of the bullbar antenna mounts that has a spring loaded pin that lets you lay the antenna down - in my case this is the facilitate moving the wander lead on the multi-tap vertical.
Good grief, I have had to almost entirely re-engineer the thing - adding jumpers and scraping paint to get any sort of ground connections through the various pieces!
Then, as a kicker, the antenna base has an SO-235 connector, except the design of the mount doesn't allow enough room to actually connect and disconnect the PL-259. So out with the angle grinder, hammers, spray paint etc. to reshape a few things.
Waiting on the paint to dry before I reassemble it and test it...
At least it's a cooler day with a bit of rain, so not a bad day to be getting tooly around the workbench.