Hammarlund HQ-110A Ham Band Only Receive.|
When I received my ham radio licence in 1959, Hammarlund receivers were my dream. But that is what they were, only a dream as the Canadian Input Duty Tax put even the lowest cost HQ-110 beyond my reach. The HQ-110A is an 12 tube dual conversion superhetrodyne circuit with Q multiplier, a 100 KHz calirator and an AM plus a CW/SSB linear product detector. In 2011 I saw an add on eBay for a HQ-110A offered for sale as "not working" so I bid and it was soon sitting on my work bench. After close inspection I was pleased that it was cosmetically in very good condition other than accumlated dust and dirt. As well it is a late production number with the last of the Hammarlund improvements to the A model.
A picture of the back with the label shows the model number (HQ-110A), tube lay out and back panel connections.
A close inspection of the band selection knob shows the HF ham bands allowed back when it was made. It covers 160 to 10 meters as well as 6 meters which the earlier HQ110 did not have. 160, 80, 40 and 20 meters are on the left dial with dial marking every 5 KHz. The right hand dial is calibrated for 15, 10, and 6 meters with 10 KHz dial markings. This dial is also calibrated for an optional 2 meter converter.
This picture shows the dial markings on the left dial which for the day was quite a accurate frequency display for such a low cost receiver.
The first step was to take the chassic out of the cabinet and inspect it for any obvious signs of burned components or other tell tail signs of a failed component. The top looked good with no signs of rust on the steel chassic. I spent a couple of hours with a vacuum cleaner sucking up the dirt and dust then washing and buffing everything with steel wool (except for the dials). When I was finished cleaning it looked like it came directly from the factory.
I decided to take the dials off so I could clean them properly and also lubricate the dial shafts bearings. Here is a picture of the front after dials were cleaned and re-installed.
Now it was time to find out why the receiver was dead. Acutally with the RF and Audio gain control set for maximum gain there was a light hiss coming from the speaker. First I did a few resistance checks and then with the receiver turned on I checked voltages at various points and no readings were unexpected.
I hooked up my HP8640B signal generator to the receiver and when I increased the generator power to a high level I was able to hear the generaor though faintly. The generator frequency was way different than what the receiver dial indicated. This led me to believe that the whole receiver was seriously out of alighment. Following the instructions in the manual I began to methodically align the receiver, first the 2nd IF coils. Obviously some one had adjusted the IF coils but not near to the correct frequency. I followed with the 1st IF coil and then on to the VFO oscillator, mixer and RF input coils. It took me a while to realize that the manual shows the wrong HF Oscillator coil locations in Figure 7. From left to right, the correct location of the HF Oscillator coil is 54, 30, 21.6, 14.4, 7.3, 4 and 2.0 MHZ.
After I aligned the receiver I checked the sensitivity of the reciever. I was amazed how sensitive this mid 1960 low-end ham receiver was. I am able to clearly hear a CW signal with an input of -130dBm on all bands 160 to 10 meters. As well I had forgotten how sharp a Q multiplier is when properly adjusted. What a delight to tighten up the bandwith when other signal creep near by.
The HQ-110A now proudly sits on the top shelf of my operating desk. I often use it to listen to W1AW CW bulletins, to AM boatanchor hams or quickly tune across the bands to check conditions.