Sunday, September 20, 2015

Return to 70MHz Portable Contests after 30 Years

Having Completely re-engineered the 70MHz MRF151G Amplifier after the disaster in February , it was time to try it. The opportunity arose in the form of the the RSGB 2nd 70MHz contest. Again the Blorenge is no place to go on a Sunday morning , so it was time to visit Dorstone and again use G5NF/P

Having disposed of my pair of 5 ele 70MHz MET antennas 30 years ago I had looked for a portable antenna. I found a Powabeam 5 ele on the DX Shop web site, They had a lightweight version of the 5 ele , but that was on a round boom which I avoid based on previous experiences. So they made it on a 2 piece square boom so it would fit in my car (only just,... the elements are one piece!)

The K3 was used to drive the 70MHz Anglian Transverter then into the MRF151G. 160W was easily reached with 2W into the PA module.As the amplifier is so compact, there is no room for an LCD display on the front panel, so a remote LCD is used to display the Amp Status (flashbacks to the KLM amps with remote display). As a precaution, should I forget to Pack the display the error LED flashes an error code if there is one in the style of Harris TV Amplifiers

K3 and Anglian Transverter

Amplifier and remote LCD display

The band suffered from the usual QSB but some interesting DX was worked to the East and North. PA4VHF was the best DX at 671km

The good news is the amplifier survived the whole contest, and we got a runners up certificate. To do well in this contest you need to be well away from the centre of activity!

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