Busy day – the pre-amp story continues.

Hi all

So I have been having big problems trying to get a pre-amp working inline.

The problem is that it has to be sequenced in and out correctly. Then the grand plan was to introduce a big linear amplifier into the equation.

I had several issues – I had no good relays, except for some big 24AC relays I bought by mistake on Ebay. Budget does not allow some cool vacuum relays – so I decided I would use what I have.

As I’m pretty lousy in designing proper DC circuits – I decided to use a project that was already underway, my Amplifier + rotor controller + sequencer that I have been working on. I had already put a vero bord into a small chassis and hooked a LCD + rotary encoder + some push-buttons. I even had some 7 port darlinton relay drivers on hand.

So toady I have put the relay into the chassis – built a relay buffer -with some relays to switch on 28V AC going into the BIG RF relays (not really RF relays) and gotten everything to work.

This is mainly because I use a small board called Teensy2++ – that houses a really powerful Atmega microcontroller. It has numerous in and out ports – 8 A/D converters and runs on 16Mhz – so you can be really sloppy programming it – wont notice it to much. And the best part is the bootloader that comes with the teensy – you have a small program running – it will detect when you press the reset button on the teensy and upload a new code in 1-2s via USB. This is so much faster than ANY ICSP programmer I have tried and is perfect for someone like me. trial and error!

So I could just plow through writing the sequencer code upon my “testbed” with the LCD and everything hooked up. So now I have a working sequencer.

Only really bad hack was to intercept the PTT line from Signalink USB to the Kenwood. Time was short – I did a ugly thing… look at the picture. Probably have to order a new cable from Signalink.

Here are some pictures – This will hopefully be finished some day – preamp is working – now just the big test – try to xmit!

Finally – 2m EME success!!

I’m not a single yagi station anymore! After a really disappointing night – only be able to decode one signal I decided to get the other yagi and mount it horizontally. This meant for some last-minute fixing. I found a small carpenter shop that made solid shafts out of oak. I got some cosmetically flawed shafts for little money and they now make the tips of the horizontal boom. I made trusses to strengthen the boom. This is a bit hard for the small rotor but he can manage this. During last night we had pretty strong winds and the antennas where bouncing quite a bit – I was mildly concerned if the wind force would increase as I would not be able to lower the antenna.

I can now add one JT65B QSO to the “long” list of 2M EME contacts!

This was my 2M EME contact #1 and EME contact #4 !!

This could possibly the first 2M eme contact from a TF native station. There are rumors that a another TF station was active some decades ago – but I have never gotten that 100% confirmed.

I finished the QSO with K5QE pretty much without any issues – just sent a wrong sequence once. But from there I could not decode anything – got some shorthands but it was like a total blackout. I visually inspected the heading of the antenna repeatedly – I did a CQ CQ run and got good reports on 100W – But I was unable to hear anything. This was either some issue with my RX or a very bad case of faraday rotation. I did not have a pre-amp installed but that could not explain the really bad RX as I was getting quite good reports -21 to -25dB.

I will use the day to try to get the pre-amp working .

The station is now:

  • TS-2000 – 100W -internal pre-amp
  • 25m CableExperts feedline X-1318
  • 2x 2m5wl
  • Yaesu G-5600 rotor system AZ/EL
  • Pre-amp to be used is from WA2ODO

here are pictures:

QRV on 2m EME … just slightly

I decided to jump the gun as the weather is so good now…

I put up a 2m5WL yagi, have to have it vertical polarized. I have a view from ca 100° east to 250° – Got az/el  control.

Having issues getting the pre-amp inline and the power amp to work togeather. coax is from “cable experts”.