- OH2MT approached me with an intriguing question: is it possible to use and R&S EZP panorama display with an EK070 receiver ?
- of course the answer is yes - the only real question is what level of challenge is one ready to accept
- I wonder what the guys at RF Tuote in Teijo, Finland think of their CATV modulator (108kb) in its new application ? The VCO was modifed to run a decade lower than designed... ;-)
- swapped the crystal to 3.2 MHz to get 100 kHz steps, tweaked the loop filter a bit...
- I chose to use a low side 70.7 MHz LO rather than the high side 92.1 MHz to avoid BCI and extra spurs
- and most dramatically modified the VCO (112kb) to about a decade lower to around 70 MHz
- the DBM modulator now acts as a DBM mixer again, converting the broadband EK070 first IF to 10.7 MHz
- as the mixer is low-side, the spectrum needs to be inverted by joining pins 16 and 17 on the multipin D-type connector
- after about 25 years of operation, the EZP sweep inverting relay still works perfectly ;-)
- OH2MOK scrounged a LAN switch box that OH2LH made a new front panel for making this a snazzy RFI shielded converter enclosure
- found a suitable replacement power supply in my junk box to provide 17 V (12 + 5 V) for the converter
- added a red PLL alarm LED, green power LED and PLL tuning voltage monitoring meter to the front panel
- also modified the original high IP3 PIN diode attenuator and equippent the box with a front panel Gain Control knob
- EZP level can now easily be calibrated with this Gain Control using the EK070 accurate level meter
- rear view (28kb) of the converter box, L to R: 81.4 MHz IF input (+-0.9 MHz), 10.7 MHz output, Mains input, fuse, ON/OFF switch
- inside view (92kb) of the box with power supply on the left, modified CATV modulator a.k.a. HF converter
- testing the package (112kb): converter on top, EZP in the middle and the EK070 at the bottom
- a typical IF panorama display (80kb) from the EK070 first IF
- and finally a short video (3Mb) of the 15 MHz BC band showing a typical live IF panorama display
- also fixed the trace rotation cabling more professionally as the original was cut, resoldered and taped for some obscure reason
