Heathkit DX-60A (Part 3) Initial QSOs

Final Amp compartment with plate choke, parasitic choke and 6146 in view
Final Amp compartment with plate choke, parasitic choke and 6146 in view

Still trying to make that 1st QSO, I thought that I might be sending a bit too fast so I slowed it down to about 20 wpm. Sure enough, out of the ether comes a fairly staunch signal KV6Z, Bill from Claremont, OK. He’s pounding in at 599 so I let him know his report and all the particulars. When he comes back, he gives me a 599 as well and says the rig sounds good. Whew, finally the 1st QSO and I know the rig is working. Well, got that one under the belt now, not too shabby a signal report so I QRZ’d again and N4LQ, Steve in Charlotte, NC, replies. We’re both 599 and I tell Steve about the rig and apologize if I might be drifting a bit. Steve says “No drift and the signal tone is pure with no chirps or clicks”. I am surprised to say the least, this over 50 year old transmitter (using only 3 tubes for the CW portion) can transmit a clean CW note. Amazing!


Rear view of transmitter with octal accy socket and new Hayseed filter cap in view
Rear view of transmitter with octal accy socket and new Hayseed filter cap in view

After all the excitement, I sign with Steve and Mauro, I1MMR from Genoa calls in and gives me a 599 which was his report as well. I am elated to see everything percolating so well and I also am aware that having the 2 elements on 40 helps in putting in a decent signal at various locations.

Bottom view of the DX-60A
Bottom view of the DX-60A

I button it up for the evening and will have to wait until tomorrow to relive the 60’s era Ham Radio culture.

Heathkit DX-60A (part 2)

Waters Dummy Load - Wattmeter and DX-60A producing power
Waters Dummy Load – Wattmeter and DX-60A producing power

Getting ready for the serious RF and insuring that both the band switch of the DX-60 and the VFO were both set to 40 meters, I placed the meter switch in the PLATE position, set the Mode switch at first on AM and then to CW and using the Tune and Load caps, I was able to find a dip in the Tune and started increasing the Loading -always maintaining a resonant condition. Noticing the meter on the Waters, I saw the power starting to increase slowly (which is what I was aiming for). It initially read 12 watts and slowly increased to 35 watts. I kept taking rest periods as I was not confident of all this loading on the final (6146) and on the high voltage plate circuitry. Continuing on, I managed to get the Plate current to a resonant 100 mils  (which was a very low current according to the manual)but the power output was at 60 watts which is about the normal power out for this rig. My best guess is that the metering circuitry is off (for whatever reason) but the proof of the Drive and Final Amplifier circuitry is in the resultant output. Wow, really was not expecting that much power!

The Heathkit Lineup -  SB-303 receiver, HG-10B VFO and DX-60A transmitter.
The Heathkit Lineup – SB-303 receiver, HG-10B VFO and DX-60A transmitter.

My next task was to ensure that the signal that was being produced was a clean, stable and acceptable signal. Initially I would listen on my Icom IC7600 with no antenna and the attenuation fully on. If I tuned the receiver to a frequency 75 or 100 kHz off the transmit frequency, I knew I would be able to locate the signal on the scope of the 7600 and if it appeared too large I would not monitor it for fear of receiver overload. I packed up the rig, brought into the shack and started to connect the required cables and my paddle. Since I was not going to use my straight key or one of my Bugs, I decided to use the new Begali paddle I had purchased in May at Dayton. Since these old rigs did not have a built in keyer I would utilize my K1EL Winkeyer to key the rig which provides for grid block keying. With everything connected and my Steppir Yagi tuned for 40 cw, I set the grid drive to 2.5 mils and started loading the antenna. At 12 watts I could see the signal on my IC7600 Spectrum Scope and it was not a tremendously strong signal so I tuned the receiver to it. The sound seemed pure, the frequency was stable (I had warmed it up for over 1/2 hour) and I could not detect any key clicks or a chirp. I also monitor my RF output of my station through a Wavenode RF sensor. This sensor has a pickup that allows me to feed the signal to my oscilloscope and monitor it (I usually monitor my SSB waveform  to ensure its linearity) but I am also able to monitor the CW waveform. As my Winkeyer was running my stored CQ, I watched the CW trace on the scope. The envelope looked great- clean and even through CW pulsing. So far, so good. The next item I needed to accomplish was an actual CW QSO. So I made sure that my SB 303 receiver was on frequency and started calling CQ on 7027 Mhz. I was sending at about 27 to 29 wpm but not getting any responses. Uh oh!


New Heathkit DX-60A

Heathkit DX-60A and HG-10B


Earlier this month (July) I had the opportunity to purchase a used (obviously) Heathkit DX-60A and HG-10B matching VFO.  Since I had recently been looking for an older Heath transmitter similar to the DX-20 that I used as a Novice way back in the early 60’s, I was fortunate to come across this listing on QRZ.com. I also noticed that the listing was from a Ham about 120 miles distant from me in the town of Waynesboro, VA (just down I-81).

N4JGO, Bob McCracken, was the Ham selling both items and I found them to be attractively priced. I made contact with Bob and we spoke about the rig. I made arrangements to pick up the rig, tested it out and bought it from Bob.  All of this took place over the 4th of July weekend and although we had some things taking place here at the QTH, I gave the rig a good going over. Bob was a wonderful Ham to deal with, very flexible and accommodating, a true Southern Gentleman.

Once I placed the rig on my work bench, I removed both covers in order to inspect the components and the build quality. I found nothing burnt or over worn and surprisingly noticed that the filter cap had been changed to a Hayseed Hamfest electrolytic as well as 5 other electrolytics in the circuitry. I also noticed that one resistor had been updated with a new CER, probably to ensure adequate  dissipation  of heat. Additionally, many of the existing caps have been replaced with Sprague “orange drops”, my guess is that one of the previous owners was interested in keeping a good signal on the air. Nice to see all these replacements being done.  The build quality was good although I did notice a few extra millimeters of lead length on many of the  terminals. Oh well.  The top of the chassis did have some rust stain marks on it and I did clean everything up but that’s the way with older rigs sometimes – being left in dank basements or sheds can leave some unsightly blemishes on metal. But for the most part, the transmitter was in excellent condition. So much for the Static I needed to get to the Dynamic.

I reinstalled the covers and proceeded to turn the system on and warm it up. All the tubes glowed, the VFO also came to life and I then connected my Waters  334A Dummy Load/Wattmeter to see what the rig was capable of doing. After waiting about 30 minutes, I gingerly set the drive level to the required 2.5ma. I had no problem in obtaining copious amounts of drive so I knew that the oscillator and driver were working well. Now for the moment of truth, will this transmitter generate any power and what about the purity and stability of the signal (if any)?    



K8NY Blog Restart

Just restarting the blog from where I left off in March of this year when I had switched Hosting providers.
Am hoping to post some interesting topics and may go back through some recent events to discuss.