Many thanks to Joshua (KO4AWH) who shares the following guest post:
Ten-Tec Argonaut 509 Acquisition
by Joshua (KO4AWH)
My club president sent me a text on Sunday before our Monday club meeting. He wanted to know if I was interested in a Vintage 80s QRP Radio. He knows I have an affinity for QRP. Honestly, I think he is still amazed at how I managed to get through piles ups on his hexbeam during summer field day with my TX-500. Boy was that fun.
The deal was a Ten-Tec 509 with the microphone and CW filter, the matching 251 power supply with meter, and the 504 matching 50W amplifier. He sent me a photo, I had to look it up. I have heard of Ten-Tec, thanks to Thomas K4SWL, but certainly was not familiar with their Argonaut 509. I was intrigued. I don’t have a single vintage piece of equipment. I have only been a Ham for less than 3 years.
We had some equipment from a club member SK donated for auction to raise funds for some club repeater upgrades. This was a good excuse to purchase an old piece of equipment that I likely would not have purchased otherwise. After looking over the 509 and accessories, all of which were in great condition, I brought them home. Of course I couldn’t help but hook everything up and turn on power. Everything powered up but no movement of the frequency indicator, not a great sign, and no audible hint of changing reception frequency. After further inspection it seemed the dial tuning mechanism was seized up. Looks like another project.
The next morning, as I had a few minutes to spare I started taking things apart. I have never pulled apart an old transmitter before so I took my time as I studied all the components and marveled at the simplistic yet complex circuitry found under the covers. Once I was down to the tuning mechanism, a few desoldered wires later, it was removed and ready for cleaning. I don’t know if the grease was original, but it sure was hard. After carefully cleaning, greasing, and reassembling all the components, soldering a couple wires back, and reassembling the housing, I was ready to power it back up. I don’t want to understate the work involved, it can be quite tricky, but I really enjoy this type of thing.
After tuning around a bit and working with the controls on the Radio, I found a POTA operator to zero beat. I needed something to reference in order to adjust my knob indicator so I would know what frequency the radio is on. I actually received the manual for the radio and each of the components. Reading through a few key points the night before really helped out when I was ready to start tuning in and transmitting.
I had the amplifier on, I set the DRIVE to about half way guessing that was okay and called back to the Activator. First call, he called me back with a 59! WOW, I was excited. I let him know I was on an old Ten-Tec that I had just repaired and he came back and said the audio and signal were great. How exciting! So, naturally, I hunted a few more stations and then listened to a few rag chews as I got familiar with the Radio.
Not only was I excited to have repaired my first radio, I am also amazed at the capability of this Radio originally released in 1973. I am not a long time SWL or radio operator but there is certainly something very appealing to me about the audio this Rig produces. I wasn’t certain what I was getting into with this rig, but I sure am happy how it worked out! I may just be on the hunt for another Ten-Tec. I even plan to take this to my local park and do at least one activation with it.
Here is a quick excerpt from the introduction in the operating manual.
“The Argonaut opens a whole new world of excitement and fun in Amateur Radio. We think you will find QRP a welcome change. Five watts are only 2-1/2 S-units below 150 watts for the same conditions. When skip is favorable and QRM light, you will not be conscious of using low power.”