Saturday, 8 August 2015

40m dipole with skyhooks

Beauty, as we all know, is in the eye of the beholder, and a 40m dipole never looked so beautiful...
It is now the case that the antenna wire and the supporting cord are about the same "conspicuity", so if you do not notice the cord you will not notice the antenna either. So that's great then.

Full marks to an outfit called Antenna Engineering for handling this via eBay, and when I ordered it on Thursday, it arrived with me on Friday. It is proper Mastrant guy rope.

I visited Pearsons of Duns today to use their coffee shop (it is the local garden centre/ coal merchant/ hardware supplier/ builders supplier/ everything else). There I also acquired two "Rawlbolts" (well cheaper Rawlbolt-alikes) for wall fixings (at the moment the antenna is relying on cuphooks) and some cable tensioners. Cheap and cheerful, that should move it all from a lash-up to a proper fixing.
The pole is nicely held by the two "guy ropes". It is not actually guyed as it can support itself, but there are two ropes which balance out the forces from the antenna which is strung from one side.

What is missing is the 70MHz vertical which used to be above it. After having mysterious problems, I changed the antenna, the coax and switched from the rig to the antenna analyser. Whatever was wrong with the rig/ coax/ antenna is still wrong after changing all three of them. Now that is even more mysterious and needs some resolving. However, I am fed up with all this and it will need to wait.

I wrote a while ago about whether 4m FM is worth bothering with around here. I am still unsure about that.

Without the 4m antenna on the top, the pole is at its full height, making the 40m dipole a bit higher than it was. And it is working brilliantly, given that it is a modest wire antenna not very high up.

Still to be changed over to the new guy rope is the coax which feeds the Sirio 10m antenna. This passes over a path using a support made of old bathroom light switch cords. I suspect that the new guy rope would look better (and be better at holding up the coax). The Domestic Authority might prefer dark grey to white. Problem is, I need to change the cable ties, and it is too windy anyway.

A further job is replacing polyprop rope on another support which carries the 6m beam and 2m vertical coax plus rotator cables across to the T and K brackets which hold that antenna system up. Too windy today for that too.

Once those are done, all the supporting ropes will be the new, low profile, almost invisible type.

Grrr.

Right, today I was actually running WSPR on 4 bands at once. 4m, 6m, 10m and 40m. There is a problem with this.

For some reason my PC goes daft if the Flex is running any WSJT programme at the same time as WSJT runs on either the Yaesu 450 or the Icom Ic-7100. I cannot fathom that all all. Nasty audio appears, and if you turn the PowerSDR off and turn it on again that either cures it or I get a horrible buzzing noise on the PC audio, requiring a reboot to clear. Closing the WSJT on the other rigs stops it immediately.

I cannot see why this happens. I used to have the Flex on a separate computer in the past, and that worked as far as it goes. Having two computers is a bind for keeping the RF noise down.

Oh dear, more delving needed.

73

Jim
GM4FVM

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