Microwave Day.

 In the past week end I went to the Microwave Day in the town of Horsens, Denmark.

Although I have not really built any microwave equipment yet, everyone interested is welcome, and I did also go to the previous one 3 years ago - the ones in the last two years were canceled due to the COVID situation.

I wanted to take things easy, so I did the drive there on Friday, and home again on Sunday.

There were two presentations, one about the Norwegian beacon LB2SHF and the other about the 122GHz experiments. 

After the presentations there was social gathering and microwave talk, as well as Ole, OZ2OE demonstrating his 122GHz equipment. 

There was a small flea market, and I got just a few things. Two N-connector to WR90 waveguide transitions and some ancient 12GHz LNBs with WR75 waveguide inputs.

Because I have some horn antennas for both sizes of waveguide I wanted to have this. The WR90 transitions can be used as they are, and the LNBs can be used in different ways:

1) As a simple down converter, used as-is.

2) As an "active antenna". This requires a modification, taking the output of the 10-12GHz (pre)amplifier to an SMA connector.

3) Removing all the electronics and grinding a bit of material away, the LNB can also be used as a waveguide to SMA transition.

At the flea market I also saw transverters. There was an old version of the DB6NT transverter, complete with a horn antenna for a reasonable price, even if the output power was limited to 30mW. I did not bring it home, but I should probably have bought it, as I do have another 10GHz amplifier module that could have increased the output to about 200mW. A bit of a regret, but there may be other opportunities.

A 24GHz transverter, also at a reasonable price, was seen, but again, I did not bring it home. I know the seller, however, so I could probably still find it for sale.

Then there is test equipment. I had an appointment with another participant, that he would bring a 26GHz spectrum analyzer to check and possibly buy, and I did bring it home. I can now see what the things I build and buy are doing, signal-wise.

In the afternoon there was a demonstration of the 122GHz equipment at a longer distance (5km). Not that far, but not so easy. Signals were heard both ways, though.

Some time ago I purchased a CBNL 10GHz link transceiver module, but there is not much information, so I asked if any of the others had more information.

I have found a bit, but I am worried about the simple stuff: How critical is the order in which I connect the power supply. On the on6ll.be website I found the following:

Since it is used in a remote link the "base supply voltage is 48V (see the two connections at the right side of the connector). Then I see that there is a +8V connection The question is now - do I connect the 48V first, or the 8V? What I cannot easily see is where the negative bias for the GaAsFETs is generated. From the 48V converted to 7V, or from the 8V? It is not even clear if the 8V is generated on board when the 48V is connected. 

The other parts I have found sufficient information about to proceed. The LO should be somewhere around 7.5-8GHz, and the IF for the "RF/microwave" section then uses an IF of about 2.4GHz.

The T/R switching is clear enough from the description on the website, even the illustration above.

If any reader knows I would appreciate the information. I simply do not want to make a potentially destructive test, as the GaAsFETs simply will self destruct if the drain voltage is applied before the negative gate bias, as those familiar with GaAsFETs will know. If no reader knows I will have to extend the search.

Good to be back doing social activities again, there will be a few more coming up in the next months. Some of them will be outdoors, and others indoors. The next one is only a few weeks away.