Another G4DDK VLNA on the workbench. 13cm this time…..
Remember the “Shambolic Shack” feature of the 1980s? Is this just a slightly higher-technology version? This is the Engineering side of the G4DBN radio room, the operating position is to the left. Repaired Kuhne 13cm transverter and Anglian 144MHz transverter on the operating table in front of the testgear rack
Tropo and aircraft scatter from GB3BSS in IO81SR32 on 2320.924923 MHz (GPSDO locked). 14:25 on May 14, 2016. Elad FDM-DUO/G4DDK Anglian/DB6NT MKU23 G4/40-ele Wimo. Aircraft scatter around +10dB peak over noise, tropo is 2dB or so over noise. Beacon running 40W EIRP at 248km on 13cm. Pretty much normal conditions.
Bought a pair of Broadern 33GHz transceivers to use as an LO source for 134GHz bare diode harmonic mixer transverters. Should be a bit of fun for those cold, dry winter days. 2300 IF on 134 would work, so would 432 IF. Not really any good for 241GHz though, x7 in one step doesn’t sound feasible…
I finally cracked and decided my eyeballs were not up to SMD work, and holding a magnifying glass was just too clumsy, so yet another bit of kit has appeared. 7x to 45x binocular microscope from AmScope. Very nice working distance and excellent clarity, at full zoom an 0805 resistor looks like a house-brick. FOV at 45x is about 4mm. At 7x zoom, full frame is about 25mm diameter, with 100mm working distance.
I bought an eBay Spectrian 75W amplifier for 13cm to go with the Kuhne transverter. Spec says 26V at 16A, so the efficiency is extremely low, but it was cheap. 7 amps or so standing current. Thinking of watercooling it. It has a thin copper heat spreader bonded to the underside of the PCB, so maybe OK just mounting it on an aluminium cooling plate, but I have a bit of copper bar that I can solder the water pipe to directly, so might go for that instead. Transverter has not arrived yet, so having to test it with a CW signal from my Agilent E4421B
After seeing the Anglian on Sam G4DDK’s stall at the Martlesham Microwave Round Table event, I bought one of the last of the batch and built and tested it as the IF for the upcoming 13cm and 3cm transverters. Great fun and it works extremely well with a 116MHz GPSDO locking reference at -10dBm. Output is very clean at 13dBm output, and receiver is performing as per spec.
Treated myself to a DB6NT 10GHz G2 transverter kit to get back on to 3cm after 35 years. Nice project on which to try out the new binocular microscope. Brilliant kit, just hope my SMD skills are still up to scratch.
The parts are coming together. Nice isolators direct from RFCI in CA, peak 1kW, 200W continuous, built in 100W dummy load
FETs. At six quid each, the MRFE6S9160HS makes a nice cheap 23cm PA, cellphone technology instead of broadcast devices
Hybrids. OK, I could use a printed Wilkinson as the input splitter, but hey…
Relays. The R570113030 is rather over-specified for this, but has 85dB isolation up to 1GHz and 80dB up to 2GHz and should handle up to 500W at 23cm very easily.
Tinplate boxes to screen the individual DF9IC PA boards
27V 18.6A switchmode PSU
Three runs with a VBW/RBW ratio of 0.01, total run time about four minutes. HP E4421B at 1296.200 MHz 0dBm into HP8652A using KE5FX PN. Brings out the 50kHz interval spurs very nicely. Now I need to find if they are from the 4421 or the 8652!