PA Transistors Found at the Rally.

 There was one more thing I found at the rally.

1.9GHz PA transistors capable of about 60W linear output, apparently LDMOS. 

I found a set of 14 pieces packed in an antistatic container.

The transistors come from CREE Microwaves and are marked LGA19060-171. Does this relate to 1.9GHz and 60W output? 

I do not know if they are internally matched. If they are not they could be interesting for a number of PA constructions for different frequency ranges.

My main interest will be to see if I can get those running on 1296MHz. Two of those should be capable of generating 100W. If they have internal matching an external impedance matching circuit should be made.

Since they came at a low price I can do some experimentation without being afraid of destroying a transistor, and with 14 of them I should be able to make a workable amplifier with them.

I was recommended contacting a local amateur, as he may have some tips for overcoming the possible internal matching, so I can use the transistors well outside the design frequency.

As there most likely will be a lot of experimentation, this will be a future project, as there are already so many ones already to be made.

If anyone knows more about these transistors, please let me know.

Rally in a Local Club. Got Some Stuff.

Yesterday I went to a local rally/flea market.

I made one relatively large purchase, a microwave frequency counter, the Anritsu MF76A specified up to 18GHZ.

This is a very nice piece of equipment, and looks well calibrated. The 10MHz reference oscillator is about 0.7Hz off from my 10MHz GPS reference output, after a warm-up of 1/2 to 1 hour. 

There seems to be one fault. When I switch the 10MHz connector to reference input, the counter seems to simply stop. No lights at all. As I would like to use the counter with the best possible reference (GPF locked) This needs to be corrected.

As an intermediate solution (the counter is otherwise fully functional) I can attempt a fine calibration of the internal reference oscillator. If I can bring it within 100-200mHz on 10MHz (after warm up) that is a quite acceptable accuracy.

I will contact the seller to see if he has more information than I could find in an internet search. My searching for about an hour did not even yield a user manual. The seller (a local radio amateur) has already indicated that I should contact him in case of any trouble, and I will do that.

But as the counter stands I can measure 10GHz signals with an accuracy of less than 1kHz, which is quite acceptable for daily use.

The second thing I brought home was a swap. I had two Rubidium 10MHz standard modules, and the first thing I got out of this swap was an old 2m multimode transceiver, the FT-290R. I was particularly looking for the original (mk 1) model, as the Mk 2 model has a "feature" that would drive me crazy. When switching  from CW to SSB, or from SSB to CW the mode would rotate via the FM mode and jump from the original frequency to the nearest FM channel frequency - and STAY there. That is simply not workable for SSB/CW work.

This looked in good condition, the only thing needed is a microphone.

A quick test of the FT-290R showed a functional transceiver with a signal of -135dBm easily heard in the SSB/CW mode, and about 2.5W output, as specified.

This transceiver, as it is, will be usable for controlling some microwave transverters, such as the Kuhne/DB6NT ones, via the VHF control cable, as there is a 7V DC signal at the antenna port when in transmit mode.

In the swap there was also an old AM/SSB CB transceiver. It came without cover, but as I intend to convert it into a 10m SSB/AM (CW?) transceiver it does not matter too much, as it will likely be heavily modified and mounted in another casing. This is a project for much later, but it is good to have some decent raw material. Yes, I need to make a rough test of this radio, that is also for later.

All in all a good day, meeting a lot of old friends and some new hams. There was an exam at the event, and 10 people passed, among them a young man of 13 who passed the exam for the highest class license.

New (Old) Radio in the Shack.

 I just picked up a bit of a museum piece in the week end.

On the local ham radio site someone sold a Heathkit HW-9. Yes an oldie. 

This one had a WARC band expansion, so yes, 8 bands available. 

Running abpout 3W on 10m up to 4-5W on 80m it is a capable QRP radio.

The set does need a bit of maintenance. Switches are a bit unstable, although the volume potmeter sounds OK. A fresh alignment will also be a good idea, as the (analog, of course) frequency dial is a bit off.

For now I set up the HW-9 as a receiver (without connecting a key), with the audio output connected to a computer speaker. Using the radio for transmitting will come later, after the fresh alignment.

The only real drawback for me is that the tuning is a bit fiddly, I have got used to modern rigs with a nice slow tuning, but this one will do nicely.

Sensitivity is sufficient on all bands, as the noise clearly increases when the antenna is connected, even on 10m. Selectivity is sufficient for my use. Wide is about 1kHz at 6dB and narrow is about 250Hz. The narrow filter is audio based.