Ham Radio, Summits On The Air (SOTA), Making and Hacking and Vintage Electronics are hobbies that I enjoy. This website covers my activities in these hobbies. See my personal website to learn about my IOT garden and photography. You may also visit my QRZ.com page for my Ham Radio profile.

Interested in learning more about Me?

Listen to the Hamdom Thoughts podcast by AD6DM interviewing me about Ham Radio, Making, Hacking and SOTA

Dan Koellen AI6XG

Making the KD1JV Tri-Bander More SOTA Friendly

This post outlines the modifications made to reduce receive current consumption, reduce weight and size, and change the controls and readout

Dan Koellen AI6XG

QRP Tube: High Voltage DC to DC Supply Evaluation

The high voltage supply for the vacuum tube transmitter needs to be low noise in the 40 meter band, efficient for battery operation and...

Dan Koellen AI6XG

QRP Tube: T/R Switch and QCX Interface and Modification

A Modified QCX and TR Switch for Vacuum Tube SOTA transmitter

Dan Koellen AI6XG

QRP Tube: Single Tube SOTA Transmitter

A single tube transmitter is developed for portable and Summits on the Air (SOTA) use. The SOTA transmitter had to be relatively...

Dan Koellen AI6XG

QRP Tube: Vacuum Tube, Battery, Lightweight, Compact, Portable: Can They Coexist?

Using vacuum tube equipment for SOTA activations? Why not! A portable battery operated vacuum tube transmitter is part of a SOTA system.

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Dan Koellen AI6XG

All Wound Up About EFHW Transformer Winding

After successfully using an End Fed Half Wave (EFHW) antenna for SOTA, I decided to build a 10 to 80 meter EFHW antenna for my home...

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