Finished up the stackbox for the 40 stack

Yesterday I had some time over at work, so I spent an hour mounting the 40m stackbox into a weatherproofed box which will be mounted between the top and lower Yagi in the 60m tower. The box contains a few W2W Russian vacuum relay and allows us to switch between both in phase and out of phase. With no voltage to the box the Top Yagi only is connected (because of the relays just being SPST) but through the L-match, so SWR will be a bit bad. The L match converts the 25 ohms we get when connecting the Yagis in parallel to the 50 ohms we wish to have to the radio. The capacitors are Russian doorknob 220pF capacitors. When I measured the box I pretty much a perfect match and about 3.04dB insertion loss measuring on one port, which means the insertion loss is 0.04dB to each antenna which is very little.

The thing left to do is to make a mount so that we can attach U-clamps to it which are attached to the tower legs. This will hopefully be done on Friday or Saturday morning, so we can get the box up the tower on Saturday or Sunday.

No real effort in SAC SSB this year, we don’t have the time for it. The tower work will probably take quite some time and after that we will start finishing up the 18m tower which we want to get up before the snow arrives, which can be any day now.

Here is the old picture gallery from when I built the box. Ignore the measurement values since those have been greatly improved now with a bit of tuning. I have a feeling too that the network analyzer during those pictures were not calibrated, because it seem to be a bit too much insertion loss.

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