Vintage Electronics

Making and Hacking

SOTA

Looking over Donner Lake

Vintage Electronics

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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

May 2
6 min

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...

146 views0 comments

T/R Switch and QCX Interface and Modification

Dan Koellen AI6XG

May 2
6 min

T/R Switch and QCX Interface and Modification

A Modified QCX and TR Switch for Vacuum Tube SOTA transmitter

44 views0 comments

Dan Koellen AI6XG

May 2
14 min

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...

117 views0 comments

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

Dan Koellen AI6XG

May 2
5 min

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.

863 views0 comments

All Wound Up About EFHW Transformer Winding

Dan Koellen AI6XG

Feb 28
5 min

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...

907 views0 comments

Evaluating efficiency, transformer and mismatch losses in toroid transformers - some observations.

Dan Koellen AI6XG

Jun 17, 2022
5 min

Evaluating efficiency, transformer and mismatch losses in toroid transformers - some observations.

Two methods for transformer loss are evaluated. We learn that mismatch loss must be accounted for.

579 views0 comments

Reactive Component Measurement With the NanoVNA

Dan Koellen AI6XG

May 16, 2022
6 min

Reactive Component Measurement With the NanoVNA

Exploration of using the nanoVNA to measure inductance and capacitance at frequency of use.

1,047 views0 comments

Toroid Transformers - How Hot Will It Get?

Dan Koellen AI6XG

Mar 2, 2022
11 min

Toroid Transformers - How Hot Will It Get?

There are a number of factors in choosing a toroid for a RF transformer. While one may model electrical performance, calculate predicted...

1,302 views0 comments

Leg Benchmark W7Y/EW-017 Activation - An Alternative Route From the West

Dan Koellen AI6XG

Jul 30, 2021
2 min

Leg Benchmark W7Y/EW-017 Activation - An Alternative Route From the West

Pole Mountain From My Operating Position Summit Trip Summary Distance: ~ 2.6 mi one way Transport: Hiking Elevation Gain: ~500 feet...

69 views2 comments

Electrostatic Discharge (ESD), Does it Matter for Makers and Hackers?

Dan Koellen AI6XG

Jul 20, 2021
9 min

Electrostatic Discharge (ESD), Does it Matter for Makers and Hackers?

Electrostatic Discharge (ESD) is a subject that can inspire a lot of discussion, head shaking and some misunderstanding. ESD damaging...

610 views0 comments

Dan Koellen AI6XG

Jun 16, 2021
13 min

Don't Fear the Smith Chart

Like many radio amateurs I was initially intimidated by the Smith chart. Transmission line and antenna theory, unfamiliar terms and...

1,045 views3 comments

Schallenberger Ridge W6/NS-213 Activation - An Alternative Route

Dan Koellen AI6XG

Apr 26, 2021
3 min

Schallenberger Ridge W6/NS-213 Activation - An Alternative Route

A different approach to Schallenberger Ridge from the west. A nice hike through historic train tunnels.

54 views0 comments

Dan Koellen AI6XG

Apr 25, 2021
9 min

How I Killed a Microcontroller

This blog outlines the steps taken to determine why a microcontroller no longer works, and the journey to find the damage on the chip.

236 views0 comments

The Digi-Disco, a 1970's Light Controller

Dan Koellen AI6XG

Jan 25, 2021
2 min

The Digi-Disco, a 1970's Light Controller

This is a light system that I designed and built in 1978 to control large flood lights of different colors, synchronized to disco music...

139 views1 comment

Dan Koellen AI6XG

Jan 25, 2021
1 min

Heathkit IT-28 Capacitor Checker

After building the Pico C-Super capacitor tester that was published in Elektor Magazine I decided to revive an old Heathkit IT-28...

695 views0 comments

Dan Koellen AI6XG

Dec 15, 2020
2 min

Mount Rose W7N/WC-001 Activation

Lake Tahoe and Tamarack Peak From Mount Rose Summit Trip Summary Distance: ~ 4.9 mi one way Transport: Hiking Elevation Gain: ~1800...

249 views0 comments

Dan Koellen AI6XG

Dec 13, 2020
2 min

Tamarack Peak W7N/WC-003 Activation

Lake Tahoe From Tamarack Peak Summit Trip Summary Distance: ~ 1.3 mi one way Transport: Hiking Elevation Gain: ~960 feet Time: ~ 0.75...

139 views0 comments

Dan Koellen AI6XG

Dec 10, 2020
3 min

Mount Houghton W7N/WC-002 Activation

Operating Position on Mount Houghton, Mount Rose W7N/WC-001 in Background Summit Trip Summary Distance: ~ 4.8 mi one way Transport: ...

80 views0 comments

Dan Koellen AI6XG

Dec 3, 2020
2 min

Scott Peak W6/NS-153 Activation

Operating Position on Scott Peak Summit Trip Summary Distance: ~ 4.2 mi one way Transport: Hiking Elevation Gain: ~1700 feet Time: ~2...

92 views0 comments

Dan Koellen AI6XG

Nov 29, 2020
5 min

Granite Chief W6/NS-115 Activation

Operating Position on Granite Chief Summit Trip Summary Distance: ~ 4.6 mi one way Transport: Hiking Elevation Gain: 2748 feet Time:...

54 views0 comments

Dan Koellen AI6XG

Nov 23, 2020
1 min

Wishing You a Very Random Christmas

Being the holiday season I decided to post this article from the December 2014 issue of Nuts & Volts magazine www.nutsvolts.com that I...

73 views0 comments

Dan Koellen AI6XG

Oct 4, 2020
8 min

Trapped 20/30/40 Meter EFHW Antenna

An End Fed Half Wave (EFHW) antenna for operation on 20, 30 and 40 meters was built for SOTA operation. By using traps, the antenna...

7,124 views0 comments

Big Font Clock Update: Dimmer-Interface PCB and Setup Instructions.

Dan Koellen AI6XG

Jun 29, 2020
7 min

Big Font Clock Update: Dimmer-Interface PCB and Setup Instructions.

A prior post described the development and build of a clock to display time and date for UTC and Local. The clock characters are large,...

182 views0 comments

End Fed Half Wave Antennas: More About the Primary Capacitor

Dan Koellen AI6XG

Jun 6, 2020
4 min

End Fed Half Wave Antennas: More About the Primary Capacitor

I recently posted a blog claiming that a capacitor in the primary of the matching transformer is not needed for end fed half wave (EFHW)...

6,315 views1 comment

End Fed Half Wave Antennas: Is a Primary Capacitor Really Needed?

Dan Koellen AI6XG

May 27, 2020
3 min

End Fed Half Wave Antennas: Is a Primary Capacitor Really Needed?

In my research on End Fed Half Wave (EFHW) antennas I found that nearly all have a capacitor in the primary (rig) side of the transformer....

14,771 views3 comments

Dan Koellen AI6XG

Apr 5, 2020
3 min

Auto Run for your Raspberry Pi - how to have your Rpi boot up in the desired configuration.

The Raspberry Pi (Rpi) is a great single board computer (SBC) that can be used in many projects and comes in different configurations. I...

74 views0 comments

Dan Koellen AI6XG

Feb 9, 2020
9 min

Big Font Clock - Relieve for Old Eyes

Recently the Maker Space that I frequent received a number of 4 line 40 character (4 x 40) LCD displays. They asked me to figure out how...

657 views0 comments

Dan Koellen AI6XG

Jan 12, 2020
3 min

Castle Peak W6/SN-038 Activation

Operating Position on Castle Peak Looking Southwest Summit Trip Summary Distance: ~ 3.5 mi one way Transport: Hiking Elevation Gain: ...

118 views0 comments

Dan Koellen AI6XG

Jan 12, 2020
4 min

Sand Ridge W6/NS-155 Activation

Operating Position Looking South From Sand Ridge Summit Trip Summary Distance: ~ 6.5 mi one way Transport: Hiking Elevation Gain: 1200...

74 views0 comments

Dan Koellen AI6XG

Jan 11, 2020
2 min

Mount Lincoln W6/NS-149 Activation

Looking east from Mt. Lincoln, Tinker Knob W6/NS-121 is hiding behind Anderson Peak Summit Trip Summary Distance: ~ 3 mi one way...

77 views0 comments

Dan Koellen AI6XG

Jan 11, 2020
2 min

Signal Hill (7751) W6/NS-393 Activation

Looking east from Signal Hill, Donner Lake is in the background and Lake Angela in the foreground Summit Trip Summary Distance: ~ 2 mi...

139 views0 comments

Dan Koellen AI6XG

Jan 9, 2020
3 min

Tinker Knob W6/NS-121 Activation

Summit Trip Summary Distance: 7.2 mi one way Transport: Hiking Elevation Gain: 1870 feet Time: ~3.5 hours one way Route: Via Pacific...

76 views0 comments

Dan Koellen AI6XG

Jan 6, 2020
6 min

How to do a SOTA Activation

SOTA activations are challenging and with risk, be sure you are experienced in hiking, navigation and survival skills.

221 views0 comments

Dan Koellen AI6XG

Dec 23, 2019
3 min

SOTA - What is it? Why I do it

What is SOTA? SOTA, or Summits On The Air, is basically an activity where ham radio operators take their radio equipment to a hill or...

146 views0 comments