The Super Senior has been on the market since 2012, initially only as a dual band model for 160/80 meters. A few years later, around 2015, Bruce began the production and sales of the 40/80 meter Super Senior.

He did not respond to my question as to which model is more popular, or whether the three-year head start for the 160 meter variant means there's more of them out there, today.

Significant upgrades have taken place along the way.

Bruce said "The original version used a PLL synthesizer of my own design with the phase detector, dividers and logic implemented on a CPLD programmable logic array. It used 5KHz steps. The introduction of the Si570 synthesizer chip obsoleted my design and made it easy to do 1KHz steps."

It was at that point the Super Senior's tuning became much more practical. Newly produced examples came with the 1Kc tuning, and owners could send in the older 5Kc step version for a retrofit.

Other refinements followed, including an effort to mitigate some component failures as more and more Super Senior transmitters got a shakedown in the wide variety of environments operators would configure.

"The original design used leaded silver mica capacitors in the low pass filters, Bruce explained, saying "they worked fine in preproduction testing but after about a year started failing in the field" during daily use. New production got higher rated RF chip capacitors, and Bruce offered to upgrade the existing transmitters over a two-year period.

The connectors are another way to tell a newer from older example of the Super Senior. The newer models have what Bruce considers a more durable connector than the earliest versions for "Aux" and receive antenna.

Bruce is reluctant (for business reasons) to disclose production numbers, declining to cite a vague numerical tally, or any sense of monthly sales presently. While the Super Senior has been on the market for more than a dozen years, Bruce plans to continue production indefinitely.

Not everyone is aware that each transmitter is built when a customer places an order. They are not on a shelf ready-to-ship. "I am currently building the Super Senior to order with 30 days lead time. Sales have been steady and I plan to continue offering the product for the foreseeable future," Bruce said.

Earlier this year, he told me he was exploring possible substitutions for certain MOSFET chips that appear to be going out of production. In his most recent correspondence, he said he had not found any alternatives but that he has plenty of stock on hand for production and repair support.

He did not say whether he considers the current design "mature," or whether we might anticipate an overhaul with some of the suggestions owners have expressed. I am aware of interest in a better fault display than "HIGH SWR," which may or may not actually be the cause of a protection circuitry trip. I would like a more obvious fault indicator, like a bright red LED to get my attention.

I've also expressed support for the idea of moving the cooling fans to the rear of a lengthened frame and panel behind the existing modules, with top and bottom covers for air flow. The same back panel would then have room for a terminal strip to supplement the densely-packed multi-pin connector.

One of the project consultants on the Super Senior has been Janis, AB2RA. She was instrumental in both the design and the development as Bruce moved ahead from earlier projects, and she has provided substantial feedback from users that helps Bruce with technical support and what marketers would call "user engagement" regarding the transmitter's value to our part of the hobby.

Janis is credited with the upgrade that brought adaptive tuning speed for the Super Senior. In a practical sense, the feature is used most often after changing from one band to the other, since the typical AM corridors are often some distance apart (e.g. 7290 & 3885).

She explains the rate of kilocycle change temporarily changes to a faster tuning step during QSY. When the knob is turned at a normal rate, it returns to 1 KHz steps."

Janis also convinced Bruce to automatically mute the audio input of the transmitter when a user selects the low power "Tune." Originally this caution was in the instructions, and left up to the user to avoid applying audio in that mode.

Bruce is most tightly connected with the AM community in the Pacific Northwest. Selected operators in that region were among the first to get prototype Super Seniors, according to Janis, prompting final pre-production tweaks.

Historically, Bruce has deep roots in this part of the hobby. He wrote:

"My primary amateur radio business prior to the high efficiency AM transmitters was the Index Laboratories QRP+ Transceiver which I designed and manufactured during the 1990's.

I started working on high efficiency RF amplifier design around 2006. The first effort was a kit called the K7DYY Junior which I sold primarily to the AM group here in the Pacific Northwest. It was a crystal controlled 80 meter 100watt class E transmitter. This was a good way for me to get real field experience with the technology and was a fun project for regional AM group.

The next amateur product was the K7DYY Senior which was also 80 meters only with 6 user selectable fixed frequencies. It ran about twice the power of the Junior. This was sold as a completed unit rather than a kit.

At about the same time I introduced a commercial version for the 49 meter shortwave broadcast band that was sold primarily to European customers and an RF generator for use with plasma chambers."

This last point amends an earlier account that I had misunderstood. I thought there has been a monoband version of the Super Senior, de-tuned to 250 watts for continuous duty, marketed to "European customers."

He did not repeat his earlier assertion that the U.S. Department of Defense has purchased some of his transmitters for information broadcasts in mountainous areas with unsettled geopolitics.

In summary, Bruce wanted it to be known that his technical support is available for the asking. He concluded by saying "As a member of the amateur radio community I think I am obligated to publish all the technical details of my designs and especially to provide support and encouragement for experimenters who want to use that data."

Written up by WA3VJB 23 Oct 2023

DISCLAIMER

I, Janis Carson AB2RA, am not an employee of, nor do I receive any compensation from, Index Labs. The above is an interview by WA3VJB, published unedited to mirror a similar Facebook page, as a service to K7DYY Super Senior users.