Breaking budgets.. and ladders
Yesterday's post was about using an X-Phase style QRM eliminator that I'd decided I was going to get in a few months until I rejigged a couple of things and decided that I should just get it over and done with.
I ordered the QRM Eliminator clone on eBay. Job done. Then I had to sort out the switching cable issue. I found one in the UK that was reasonably priced and will ship reasonably fast. I did look at wiring it myself given it should be trivial, but I've never done well soldering 5 pin DIN cables much less a 13. The mob selling it look to know what they're doing. I've read nothing to suggest that this version of the QRM Eliminator has the VOX detection mechanism, so I'll just assume that not wiring the cable right first time could be expensive.
I'd read some posts about the idea of using a short wire in shack as the QRM detection antenna being inadequate, and that great results were had in using an active antenna, such as a "miniwhip". Pretty straight forward, and aimed at sticking it outside where it can pickup some serious noise. I don't know if this is entirely needed as yet - the antenna could have other uses, particularly connected to an SDR. There's a TV mast on the side of the house next to the flag pole. I'd left on there with the intention of building a 6m antenna and mounting it off there (nothing else I have seems to receive on 6m... ). I'm inclined to make a shortish PVC mount adapter on the top with a T piece, and some spare schedule 80 (thick) PVC piping to get some height away from the mast. It should be all reasonably light, and properly glued should hopefully hold up OK. It's not going for any great height. This would probably be as good a place as any to pickup stray RF coming from outside, should I determine that's where I'm picking up a lot of it from. There will definitely be some experimentation to see whether I'm getting more noise inside or out. In a perfect world, it'll all be outside, but I doubt I'm quite there yet.
In other news, I replaced the coax on the flag-dipole today. It's now ladderline. I didn't expect 450Ohm cable to be quite so wide. Definitely not like that stuff they used to use on TV antennas when I was a kid!
The balun is now near ground level. I've got about a mile of coax to remove still, and do something with to make it less obtrusive.
Should the NanoVNA I ordered ever get here, it'll be interesting to test this antenna out and see if that balun is as useful as I'd like to think it is (I can't even remember if it's a 9:1 or a 4:1 now!).
In terms of the original plan - to cut the droop caused by the weight of the balun being inline with the dipoles, it's certainly worked. It's substantially higher through the centre. The only downside now is that the width of the ladderline makes it a sail. Luckily the fence under it is lattice and gives me plenty of points to cable tie the cable directly under it, leaving enough slack to reduce the weight on it further and let it blow around just enough that perhaps my solder joints will hold.
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