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Saturday, July 11, 2026

My Parks 2 meter Nuvistor Converter, a QST review, and Bio Info on the Tektronix Hams who Designed It (Who is W7UHF now?)

 






Denton E. Nelson (amateur radio callsign W7UHF) was an electronics engineer and a notable figure in mid-century amateur radio history, best known for co-founding Parks Electronics alongside fellow operator Loren Parks (K7AAD) [3.1.3].

Tektronix Background

Nelson spent part of his career in the 1950s working at Tektronix in Oregon, where he moved through various roles from assembly into test and production engineering [1.2.2, 3.2.3]. During his time there, he was also an active member of the Tektronix Employees Radio Amateur Club [3.1.2].

Parks Electronics and VHF Converters

In the 1960s, Nelson (W7UHF) and Parks (K7AAD) partnered to build high-performance VHF (Very High Frequency) converters, initially starting their production in Parks's garage [3.1.3]. At the time, amateur radio operators who wanted to operate on the VHF or UHF bands often relied on outboard converters to shift those higher frequencies down so they could be tuned on standard shortwave communication receivers.

Leveraging their rigorous professional backgrounds at Tektronix, Nelson and Parks applied strict commercial test-equipment standards to their amateur gear [3.1.3]. Parks Electronics quickly became famous for its superior "little black boxes" [3.1.3]. Unlike much of the consumer equipment of the era, every converter Nelson and Parks produced was individually tested for precise gain, bandwidth, and low noise figure before it was shipped [3.1.3]. This commitment to quality made their equipment highly sought after by VHF and UHF enthusiasts worldwide [3.1.3, 4.1.6].

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One question about W7UHF:  If you go to QRZ.com, you will see that there is still a listing for W7UHF, under the name of Denton E. Nelson.  But it is for a Technician license.  And it lists a previous call as KD6EFF.  Who is that?  Could that be OM Nelson's son?  The holder is in Silicon Valley, and the license seems like it is about to expire. 

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Loren Parks (1926–2023), who operated under the amateur radio callsign K7AAD, was a man of three distinct legacies: he was a skilled electronics engineer who built highly respected amateur radio gear, and a pioneering manufacturer who made millions in the medical device industry. [3.1.1, 3.1.6].

Tektronix and Amateur Radio (K7AAD)

After serving in the U.S. Navy and earning a degree in psychology, Parks moved to Oregon and took a job in the 1950s with Tektronix, the pioneering test equipment manufacturer [3.1.1, 3.1.6]. He was heavily involved in the local amateur radio scene and the company's ham radio club [3.2.1].

Recognizing that operators needed better ways to tune into the VHF and UHF bands, Parks partnered with his Tektronix colleague Denton Nelson (W7UHF) to build outboard receiving equipment [3.2.2]. What started as a garage project became Parks Electronics [3.2.2]. By applying rigorous commercial test-equipment standards to their amateur gear, their VHF converters became famous for their high performance and exceptionally low noise figures. Parks was also a dedicated supporter of the wider ham community, at one point stepping in to purchase and run the VHF'er magazine to ensure the publication survived [2.3.2, 3.2.2].

The Medical Device Fortune

While his amateur radio converters were a critical success among hobbyists, Parks found his vast fortune in the medical field. In 1961, he founded Parks Medical Electronics in Aloha, Oregon [3.1.1, 3.1.7].

Pivoting his electronics expertise, Parks designed some of the world's first impedance plethysmographs and Doppler ultrasound systems [3.1.1, 3.1.7]. These devices are used by doctors to measure blood flow in vascular studies, detect faint pulses, and monitor patients during surgery [3.1.1, 3.1.5]. His company became a global pioneer in vascular diagnostics—making Parks a multi-millionaire in the process—and it remains one of the oldest manufacturers of Doppler systems in the world today [3.1.5, 3.1.7].

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