9cm (3.4GHZ)

My 3.4GHz system is a Khune mku34 G3 transverter built into a Yaesu FT736R in the position of a removed 6meter module. With IF tap pan adapter. See the 13cm page for more details of integrating with FT736R. The transverter is now GPS locked.

The Amplifier

100w amplifier 2x 50w Stealth Microwave amps combined. I couldn’t mast mount an amp due to there being too much on the mast already. So needed extra power to compensate. The combiner on the output is a Narda high power Hybrid coupler 3033. On the input is a Wilkinson splitter I used this instead of a hybrid because I needed a little more attenuation on the input and this did the job nicely. There is also a 20db attenuator connected to the amp input fit directly on the change over relay. The fans are a little noisy and will be changed out for arctic white silent fans. I’ve added a speed control which helps to quieten them down for now. The case is repurposed from an old Air-span WiMAX base station original having two smaller amps installed.

100w amplifier. 2x 50w stealth microwave SM3436-47 amplifiers

Mast head preamp is a Sam Jewell DDK. VLNA9 design 27db gain <0.5db NF

Antenna Initially was a panel claimed 20db gain. If the amp was to be driven hard I don’t think the panel would survive. Its rated at 50w But I’m sceptical a PCB antenna could survive that. Feeder was 20mtrs of Westflex 103. Very lossy at 3.4GHz I know but it was already there installed to the mast, so tried it. The DDK preamp more than makes up for the losses and no significant loss of RX signal was noted compared to direct connection to the antenna. I am hearing GB3CSB North and GB3OHM South both in excess of 250km at good audible levels all of the time flat band . So happy with the panel performance on RX for now, TX Power reaching the antenna is an other story. (now replaced with a loop yagi and better coaxial cable)

91 element JVL Loop Yagi Construction.

3m boom length 91 element

I made a wood jig to manufacture the loops which made the job quick and easy. Loops were formed by bending around sockets from a ratchet socket set. The loops were soldered to slot head brass bolts. all mounted on a 3 meter 15mm boom. split in the middle for easy transport if needed in future. A trombone support finished it off.

After giving the loops a coat of clear varnish spray. I used the new mini VNA2 which covers up to 4GHz to tune the antenna. ” Worked Great”. There was very little I could do to improve it the JVL design software was accurate.

Feeder was upgraded to 20meters of Genuine Times Microwave LMR-600 . This feeder only has 1.7db loss for a 10 meter run at 3.4ghz. This is only a 1/4 of the loss of the cable I was using which had around 6-7db! loss. Quite stiff though but beautifully quality.

2020-08-20GB3MHZ3400.830051jo02pb<tr>io94eq 51349
2020-08-20GB3LPC3400.935052io91fr<tr>io94eq 52328
2020-08-20GB3ZME3400.910055io82rp<tr>io94eq 55233
2020-08-20GB3OHM3400.900057io92aj<tr>io94eq 57255
2020-08-20GB3CSB3400.985059io75xx<tr>io94eq 59212
First test looks promising I’m now hearing more.

Top 3 places were a close contest.

I was thrilled to be placed 1st in the 2022 UKAC 3.4GHz Open Section.

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