Welcome on DL4UNY's Radio-Page!

...DL4UNY on 2m/70cm...

I didn't focus much on bands higher than 50MHz because I never had an outstanding QTH for VHF operation and the bit of 2m contest activity I did was just for fun, to work some friends. Therefore, I never used any special equipment to make QSOs on 2m, just used what was available.
I'm an RF engineer, working at Rohde&Schwarz, developing RF frontends and synthesizer for high class spectrum analyzers. Therefore of course I'm quite familiar with frequencies beyond 50MHz ;) and after some time I felt the strong desire to design my own VHF/UHF Radio equipment. From the engineering point of view, a simple 28-144 transverter is very easy, but I didn't want anything thats already available on the market. I wanted to build my own high class bidirectional converters.
First, I wanted to design and build a stable low phase noise 116MHz source with high power output (> 17dBm output power) to work as LO for the following converter. It took me a while to find the right crystalls to do the job and eventually ordered customized 116MHz quartz crystalls from Axtal.
I designed a oscillator circuit for low phase noise and made a PCB which can be used as a submount or separate module for the next stage (converter, in my case)

Oscillator, heater and crystall are enclosed in a thick alloy enclosure:

By now, I have completed about 25 116MHz oscillator units and the plot below shows the typical phase noise of them:
1 Hz: > -50dBc
10 Hz: > -85dBc
100 Hz: > -115dBc
residual noise: > -165 dBc

Just message me in case you are interesed in purchasing an oscillator or parts.

10m <-> 2m Transverter
In order to extend the frequency range of my TS-590 and FT-1000MP I needed a transverter. I didn't want to buy a ready-made solution for several reasons:
- the commercial high-performance transverters are too expensive to me, neither I'm a passionated VHF contester nor DXer, I just 'want to be active' but I want best performance possible
- I wanted to make my own gear
- focus on parameters that are important to ME, such as bandwidth (for an SDR), compatibility to other bands (using 6m/4m/70cm ... with minor circuit but no layout changes)
- I'm an RF-engineer ;)

After developing the 116MHz signal source for LO I could continue designing the up- and down converter stages. Checking the list of MMIC amplifiers I have availabe at home, I quickly computed the expected dynamic on 2m:

A noise figure of about 2dB and OIP3 of about 33dBm doesn't sound so bad for the beginning. So I started designing the filters according to my block diagram.

The result can be seen here: (interactive BOM is here)

PCB of the May 2019 version

1st time power up and tuning

tuning and measuring the proto-type @ home

assembly of the DL4UNY transverter

Output IP3

Noise Figure Measurement @ corner temp (40℃)

Not bad: 2dB noise figure and 31dBm output IP3 @ 27dB gain. Physics works
Assembly instruction and Description (in German) is available here.
Just message me in case you are interesed in purchasing a complete transverter or parts.