the doctor who and japan channel, part 2

[solarbird]

After posting that previous bit of antenna wankery, I had a thought that maybe I could gain a little more signal by bulking up the reflector on the back of the UHF antenna from a thin wire grid to a continuous foil reflector using ordinary aluminium foil backed with plastic for stability.

Being an outdoor antenna, the reflector needs to be thin wire and moderately sparse. Otherwise it wouldn't survive wind. But this installation is in an attic so I don't have to care about that at all.

The goals would be:

1: Improve reception of the on-axis KBTC/NHK World channels, since signal strength is okay but kind of borderline by the numbers and will definiely be impacted by anything bad, and

2: Boost the off-axis UHF stations so that they'd stay glitch-free during bad weather. Plus, of course,

3: Not screw up what's already working.

So I foiled the current antenna's built-in reflector. While that didn't make a big difference, it did seem to help a little - maybe a couple of points, enough that it might be there and might not be there.

But most importantly, doing this didn't screw anything up.

So I thought "okay, let's try stage two." Stage two was to build frames out of some thick aluminium wire^* and line those frames with foil in order to extend the reflector and provide opportunity to shape specific angles based on where I know the transmitters - and Tiger Mountain - are.

Basically, stage two is building a bigger and more specialised reflector.

So I did! It was pretty easy and it worked great. It boosted the KBTC/NHK World signal a good solid 15 points, way more than I was expecting, and did similar amounts of good for the other UHF signals that would normally be very strong here but are weak because of hills and from having to have the antenna so far off main transmission axis. I'm not generally getting into the mid-90s (tho' I am on a couple of stations) but I am regularly getting into the 80s, and that's plenty.

It didn't even screw up VHF reception! At least, not as far as I can tell so far. KCTS 9 hasn't budged - if anything it's a little stronger somehow? - and virtual 46/RF 12 might be a little weaker, but I didn't do timely enough A/B comparisons to be sure. If it is weaker it's not by much - it's so all over the place normally so it's hard to be sure regardless, plus weather is moving in so if there is something it could be that. So I'm not sure. It's still entirely watchable so far so I think I'm fine, and I'll figure it out over the next few days.

But the big result here is that I'm getting enough extra signal on the channels I really care about (and lots that I kind of don't care about lol) that I don't think I have to worry about weather from now on. Like I shouldn't have to, really, but, you know, I've made antenna angle position compromises to get all the stations I want and all that.

Anyway, in terms of meeting goals, this is a big success. It definitely worked. Yay! ^_^

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*: It's like 8 or 10 gauge? I honestly don't know, I literally found it somewhere. It's rigid enough to hold a shape, but easy enough to shape freely by hand.

Comments

[sistawendy]

That aluminum wire sounds like armature wire that sculptors use.

[solarbird]

That sounds right. I bet that's it. I was thinking it might be tig wire but it's too bendy. (Tig is also kinda bendy but not this bendy.)

[vatine]

Yay doing things! Yay things being improved. On this end, it is a LOT of "unscrew a British plug, install a Swedish plug". Apparently, I have acquired a lot of electrical equipment over the previous two decades.

[solarbird]

I did some more fiddling last night (because some real weather came in and revealed problems that I solved, I might write it up) and along the way discovered that the channel that required a separate VHF-High antenna is in fact a low power station, like maybe a kilowatt in our direction tops? So now I’m both completely cool with it being kind of a fair-weather station and kinda surprised I’m getting it at all xD