How to exchange the GU74b / 4CX800 tubes on your Alpha91b (Alpha99) Amplifier

it finally happend…. After a decade of reliable service, my Alpha91b amplifier broke. Most likely on it’s way to Spain one of the tubes broke. During the comissioning at ED1R contest station, fire & smoke shot out of a chimney. The first shock was big, but a few measurements confirmed that just the tubes were broken. In this blog post I will share the knowledge I gained during during debugging, comissioning and breathing new life into the amplifier.

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5 must have productivity tools for Hams

Productivity toolsDuring the last few years the internet enriched greatly our lives. In this blog post I will share the five best tools how to increase your personal productivity. Regardless if you are just a passive ham browsing the web, actively building Ham Radio equipment or organizing the next Fieldday, these tools will help you to organize your hobby, save time and hazle. I’m using all of them on a daily basis!

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When antennas come down

During CQWW CW we had a shootout from ED1R with our friends from the Bavarian Contest Club. The group around DQ4W organized a Contest-Expedition to Corsica (TK) to get on the air as TK4W. Considering the available antennas, (two A3S, and three verticals) they generated a great score. For details comparisons between ED1R and TK4W click here.

Ulf, DK5TX created a serious of cool stop motion videos of the antenna work. Unfortunately, including the moment when one of the 17m tall masts came down and damaged the mounted A3S severely.

Fortunately nobody was injured and the A3S still worked, even being a bit deformed.

Building a beverage switching box

Listening on Beverage Antennas on the LowbandsThis year we wanted to seriously compete in CQWW CW from ED1R contest station. While the station is equipped reasonably on all bands with Yagis and verticals, there were no dedicated receiving antennas available – yet. Out of my former contest participations from other stations I know that when it come down to winning a CQWW, dedicated receiving antennas are a must have. Beverages provide great directivity and reduce the EU clutter significantly.

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