DG0VE Kon146-1100 2m upconverter

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DG0VE Kon146-1100 2m upconverter

Post by g8vpg » Tue Jun 07, 2016 2:22 pm

I have a couple of the DG0VE Kon146-1100 2m upconverters here at present, one for me and one for GB3ZZ. When we tried it at GB3ZZ, we were not getting any results, so I had it back here to look at. It is difficult testing a frequency converter with my spectrum analyser, because you cannot set an offset between the tracking generator output and the spectrum analyser. However, I have a signal generator that can be set to provide a swept output, and so I set that running from 100-200MHz and the analyser from 1200-1300MHz with a max hold trace.
The upconverter allows you to set four local oscillator frequencies by means of internal jumpers; 1100, 1115, 1130 & 1145MHz. Purely for ease of arithmetic and round numbers, I set 1100MHz. Big mistake! Although it still works, it puts the output someway down the output bandpass filters curve. By setting the local oscillator to 1130MHz, I am getting 10-12dB more conversion gain at around 50dB, the claimed figure and the output is close to the curve peak. I suppose if you wanted, you could tweak the helical filter cores, but since both are brand new, I don't want to do too much yet! Both examples here were consistent in their results.
The moral of the story for anyone who has one of these devices is to use 1115 or preferably 1130 as the local oscillator frequency!
73 Shaun.
PS: Roberto has now advised that the two helical filters on the output can be tuned in the range 1240-1300MHz. It would seem the factory default is in the middle, 1270MHz, so choose the LO to output as close to this as possible for maximum gain.

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