I need some direction with HQ-160 weak Band 6, 18-30 Mhz. Bought a clean, untouched radio, replaced filter caps, it played on two bands. Applied oleic acid to bandswitch and it played on all bands. WWV is spot on the dial on all bands, even 20 Mhz when conditions are right.

I use about 25% advance on the volume knob to receive on the lower five bands with lots of stations. 18-30 band requires maximum on the volume control to hear anything. I realize on those frequencies stations are sparse anyway, but my HQ-180 receives quite a few stations 20-30 Mhz at normal volume setting.

I can replace components and read schematics and have aligned S-38s and one SX-71, but my radio theory needs some work.

Any and all suggestions are greatly appreciated and thanks,


Bill

P.S.: visited here: http://www.ohio.edu/people/postr/mrt/ on the way home, and this museum is stunning. Curator Geoff Bourne gave a tour and it was very enjoyable. I can't wait to visit the AWA Museum in Bloomfield, NY, which is only 60 miles from home.

Have you tried it aligning it first?

Likely it needs a few new tubes, at least in the front end stages. The 6C4 is particularly troublesome and should be NOS GE or Sylvania 6C4W or a 6101.

Carl

Thanks for your help, Carl, I forgot to mention I hadn't tested the tubes yet. Forgot to test the others, too.

I did test the 6C4, and it tested weak on my Micronta tester, with two shorts. The same tube tested OK on my Hickok 539A. I did have two 6C4s, and one tested very high on the Hickok, so I put that in with no change in the radio operation. Have ten more 6C4s coming, all tested but no NOS.

Thanks again,

Bill

Got the ten 6C4s and tested them. I put one that tested very good in the HQ-160 with no change in the problem.

I discovered an IF output on the back of the HQ-160 in the form of an RCA jack. I put this output on an analog scope and measured the IF at 454.545 Khz. On a digital scope with frequency readout it reads 454.5 Khz. This is visible on the scopes on the five lower bands. When I switch to the sixth (highest) band, each scope gives a flat line.

The lower five bands all work very well, very close dial readings and plenty of volume and stations.

Any help appreciated.

Bill

Id start with a signal generator and do a band 6 alignment as well as measure sensitivity which should be around 1uV or so for a 10dB SNR on AM at 30% modulation.

Since you say you hear stations on that band but there is no IF out signal Id be concerned what frequencies you are really tuning. Possibly a switch problem as it is a double conversion band.

Carl

Carl,

Thanks very much for your help. I hadn't thought to look for a higher IF frequency if that is what is on band 6. The background noise on the weak band is as weak as the signal when listening. By "SNR" I am guessing you mean signal to noise ratio. I don't know enough radio theory to know where to measure sensitivity or SNR.

I have neglected to test all the tubes. Will do. In my HQ-145X literature, I discovered several old pages relating to Hammarlund troubleshooting field problems for HQ-170. It mentioned swapping the two 6BE6s around. I tried this on HQ-160 and thought I got a little more volume. I have several 6BE6s so will try to get a stronger one. And I will try your alignment advice.

On my HQ-145X there is an RCA jack on the chassis back, but no mention if it is IF out or some input jack, such as a phono amp input.

As to what frequency I am measuring, the IF output sent the modulated output to the scope at 1ms, and when I went to 2us, it displayed what I am assuming is the 455 kHz IF, a pretty good looking sine wave, with very little modulation.

Again, thanks very much for your help,

Bill

Carl, it was a good idea to check the switches further. Thanks.

Tested the tubes and found 4 or 5 weak, replaced them with good tubes, increasing the volume on all bands about 15%. After marking and measuring the positions of the affected components, tried aligning Band 6. No results, returned the components to their original position. Operated all the switches, resulting in another 10% increase in volume across the bands. Then just to be sure, I used a burnishing tool on all the switch contacts. Surprisingly the Calibrator switch caused the most increase in the volume. This surprised me since that switch doesn't go anywhere, especially when open. Still band 6 was very weak.

Looking at the IF output jack on the analog scope, I had not switched to CW/USB at all when looking at the scope. Very surprised when switching to CW/USB the 454.5 IF sine wave appeared on Band 6 where there had only been a flat line before. Does not appear on AVC or MAN positions of the same switch.

The weak audio on Band 6 has disappeared, no audio at all now. Bands 1-5 are normal, very loud now.

Thanks for any and all help,

Bill

Got it. A bus wire in the RF section had a slight curve and was almost touching the back side of C67 a compression cap. . It must have had about .001" clearance. When I turned the screw on the cap to attempt an alignment it must have touched, causing the loss of Band 6. Moving the wire 1/16" fully restored Band 6 which now has full volume. Still needs aligned.

Thanks, Carl,

Bill

Bill,

Glad you found your problem. Odd mostly mechanical causes like you found are often the most difficult to locate.

One note from experience is that a tube checker isn't the best thing to rely upon for gear that is picky about a particular tube like the Hammarlund HQ series receivers using a 6C4 as the HFO. The better tube testers that most of us use are transconductance types (instead of the less complex emission and short test types) but they are not testing tube performance at RF. The best way to choose a tube for these circuits is testing in the receiver. The same is very true of the 6BE6 used as mixers and converters.

I have found several cases where transmitter driver tubes that test fine in my transconductance tester have gain that drops off tremendously far below the highest transmitting frequency. Even faults that the tester can catch are often missed in testing because they don't show up until the entire tube is at full operating temperature (not just the cathode structure) or operating in its normal environment (vibration from set mounted speaker for example).

When starting a major restoration I will run all of the tubes through the tester to catch tubes with internal shorts, heater cathode leakage, gas, and extremely low transconductance. Since I am going to pull them anyway to clean the socket it makes sense to test them. But I don't use the tester as the last word and if the symptoms indicate a likely tube fault I fall back on substitution.

Rodger WQ9E

Good news Bill. There is usually no magic involved in those old radios and often good eyesite and a big hammer work the best

Seriously tho I do use a plastic or wood handle screwdriver for tapping around suspected areas and often didnt need the scope.
A GC Solder Pik with an insulated sleeve added is another good tool to pick around with looking for short, unsoldered wires, etc. I still have most of my tools from National including a few I made.

Carl

The National Service Dept didnt even have a tube tester Rodger. The old timers said they belong in the trunk of a traveling TV repairmans car simply as a way to sell tubes
If I really wanted to play around Id use the Tek curve tracer in R&D which I just happened to buy along with a Hickok 752A from the military division and several other test pieces when they went under.

Carl

Thanks for your valuable insight, both Carl and Rodger.

Since the radio plays well on five bands, I knew that the problem was in the parts which are exclusive to Band 6. I was removing the trimmer cap for testing when I found the problem.

I use a Hickok 539A, and just selected the best reading tubes, which did increase the performance. I will follow Rodger's advice and try some others in the radio.

My use of a scope is because I have been using them for other requirements for 50 years, and have about a dozen. I know almost nothing about boat anchor theory, but am learning slowly, unfortunately my progress is like watching fossils form.

Thanks again,

Bill

I wouldnt be without a scope Bill as it has reduced trouble shooting time to minutes for what might have taken days. My introduction to something above an OS-8 I used in the Navy was a brand new Tek 485 which I learned to use and love at National as I was the sole HRO-500 tech for years as well as doing special projects in R&D. Ive increased the number of scopes over the decades as I got rid of the heat generators and have at least one SS Tek on each bench plus an old SS 20MHz Leader for auto radios.

So what will be the next project?

Carl

Thanks for your reply, Carl.

I have recapped and aligned an SX-71, so next I am going to try alignment on the HQ-160. It seems like a simple question, but can I ignore the single and double conversion and just inject the frequency showing on the radio dial when aligning the RF? I.E., for the low end of the HQ-160 band 6 (18-31 mHz), set the radio dial to 19 mHz, set the signal genarator to 19 mHz and go ahead? I can set the S.G. with a choice of two digital receivers or the (cute little) Rigol scope. I have quite a bit of test equipment, including an HP spectrum analyzer, on which I hope to learn.

My favorite analog scope after my 547 quit is a pair of Tek R7844s stacked. I also favor the 465M.

If I finish the 160, I will have the boatanchors pretty well set, then have ten or so smaller radios in varying degrees of need.

I have National NC-109, NC125, and the super-duper NC-183D, They are all super clean, and the 183D is superior to my HQ-180 or SX-100.

Thanks for inquiring,

Bill

You have to at least check both conversion IF's as well as the 2nd oscillator, there is more involved than just gain in those stages.

For the RF, yes just use the specified frequencies direct to the antenna strip thru a 4:1 balun from a 50 Ohm generator. The actual input impedance varies a bit so the balun doesnt have to be exact but 50 Ohms direct will load down the antenna coils on some frequencies.

Carl

Thanks, Carl you are helping a lot. I will read the alignment instructions to try to integrate the information you gave. I will use a couple of dry runthroughs first. I want to make sure I understand and don't miss something.

Thanks again,

Bill

Now that you got it working, what is your impression of the 160 as compared to your other BA's? I have always wanted a 160 & I am curious.
Thanx - Bob

Bob,

I will step in with some comments while Bill is doing his final alignment work. I have most of the Hammarlund line from the early Comet Pro through the solid state HQ-215.

The HQ-160 is pretty close to having a HQ-180 except it doesn't have the additional 60 Khz. third IF section. Because of this it has broader bandwidth than the HQ-170/180 siblings which is preferable when conditions are favorable. The Q multiplier can be used to narrow the bandwidth and it is very effective for CW but the HQ-180 will outperform the HQ-160 when there is a lot of interference. But with a fairly clear frequency the HQ-160 will hear anything the HQ-180 can and will do so with better fidelity, especially if the "auto response" tone circuit is defeated.

I now have a Hammarlund HC-10 SSB adapter hooked up to my HQ-160 which provides the best of both receiver alternatives. The HC-10 contains the equivalent of the final mixer, 60 Khz. IF strip, detectors, and notch filter from the HQ-170/180 receivers. With this hookup the audio can be taken directly from the normal HQ-160 or from the HC-10 when more interference fighting tools are needed.

If you are looking mostly for a good general coverage receiver that performs very well except under extreme interference conditions then the HQ-160 is an excellent choice. It does a fine job on all modes. For extreme conditions, in my opinion, the HQ-170/180 are among the best of the vintage receivers. Some of the vintage Hallicrafters gear also does very well under tough conditions but the SX-96/100 don't seem as mechanically stable as the HQ-160/180 and the SX-101/115 aren't general coverage and that is probably what you are looking for if you are considering the HQ-160. I really like my SX-88 but it doesn't have switch selectable sideband. I do prefer the Hallicrafters electronic sideband switching to the system used by Hammarlund. If the SX-88 had the same style sideband switching as its later relatives in the SX-96 through SX-117 line it would be the perfect vintage receiver for me but I am not willing to modify it to that extent. Instead I will live with retuning to select the desired sideband on AM when I need to reject interference above or below the operating frequency.

Rodger WQ9E

Hi, Bob,

Thank you for your inquiry. Now that the Band 6 is fixed, it is a lot easier to align Band 6 to the exact dial settings.

To answer your question, I went to the top of my Hallicrafters collection with SX-100 Mk II, to the top of National with NC-183D. Then I got a Hammarlund HQ-145X, so bought an HQ-180.

I bought the 160 for the same reason as you, I was curious. And they seem to go for less money. The HQ-160 nicely fills the gap between the two Hammarlunds. It has the good audio, and is easy to use. To recap, you only need the filters, all the rest is disc caps. It is the only radio I have refurbed that didn't need any replacement resistors. Very easy to work on and easy to align.

I don't intend to go into Collins or Drake receiver lines, too many radios and too pricey. Right now I like the National NC-183D the best of my boat anchors.

Hope this helps,

Bill

Edit: Thanks Rodger for your help. I am not experienced enough to answer as comprehensively as you have. I am not a ham and no electronic training. My thing is SWL.

Bill,

You are welcome and it is all too easy to forget that receivers were sold for a lot of different purposes. What is great for ham use may not be so great for SWL use. I think you will be very happy with your HQ-160, I certainly like mine.

If you decide to expand into a couple of other brands the tube type Heathkit SB-310 might interest you, this is the SWL version of the ham band SB-301. It is a tube type receiver and covers most of the popular shortwave broadcast bands between 49 and 15 meters along with 80 and 20 meter ham band coverage. Tuning is in 500 khz ranges with very stable and accurate readout to 1 Khz. A 5.0 Khz. AM filter is standard and optional SSB and CW filters were also available. It is a pretty good sounding shortwave model but the frequency coverage is limited. The SB-313 was the later solid state version.

Drake's SW-4A was their tube type SWL receiver and they are pretty common and not terribly pricey. It covers the broadcast band and major shortwave bands in 600 Khz ranges and has very accurate calibration easily readable to under 1 khz. It is AM only and is a very different design than the cosmetically similar 4 line amateur gear. They sold a now expensive plug in loop that works very well for BCB dxing, it is fairly easy to make a home built replica. The SPR-4 was a followup solid state receiver that was very different than the SW-4A and could be used anywhere from VLF through 30 mhz. depending upon which range crystals were installed. It is all mode and its similarities to the SW-4A are limited to the Drake name and the use of the same plug in loop antenna.

Rodger WQ9E