The AM Forum

Hi to all:
Who are the top restoration pro's for the Hammarlund HQ-170AC VHF receiver?
Thank you.
Chuck - AA5WG

Wouldn't it just be easier to ask your technical question(s)  ???

Who is considered a top restoration pro for the Hammarlund HQ-170AC VHF?
Thank you.
Chuck - AA5WG

Chuck,

The VHF version just adds a converter for 2 meters and the 6 meter output amp of the converter doubles as a preamplifier to enhance the performance of the standard receiver circuitry for 6 meters.  The VHF version is a bit uncommon but it does not change the basic construction of the HQ-170A so you are probably better off looking for a "plain HQ-170A" restoration pro.  

Of course the C part indicates a clock and if it isn't completely dead or worn out then a noisy clock can often be cured by introducing some good quality lightweight synthetic oil into the clock motor case through an opening or around the gear shaft via heating and then cooling the case.

By the A version, the hateful open construction mica padders in the IF section were no longer used and the remaining capacitors are mostly highly reliable ceramic disc.  I did have the dubious pleasure of replacing all of the open style padders in an early model HQ-170 I own but that is not an issue with yours.  If you decide to do the work yourself the only problems you are likely to find are filter caps in need of replacement and possibly some out-of-tolerance resistors.  The biggest precaution is that you must use an accurately calibrated 60 Khz. signal generator to align the low IF section.  This multi-stage IF is what gives the HQ-170 (and 180 sister) excellent performance over a wide range of conditions and if it isn't properly aligned performance will suffer greatly.  You cannot do that part properly without an RF signal generator that goes down low enough (or some of the wide range audio oscillators like the HP-200 series will go high enough to hit the low IF).

There are a lot of us here who have worked on this family of Hammarlund receivers so I am sure you will get plenty of advice if you run into difficulty.  But as far as knowing of a specialist who does these I have no idea.

Hi Rodger:
Thank you for the very good information regarding the Hammarlund HQ-170ACc VHF.  I don't have this radio yet.  I have found one for sale but it is a rust bucket.  If I have to get a rust bucket then I am going to need lots of help, i.e. sand blasting, painting, rebuilding etc.

I am going to keep looking for this radio for a while.
Thank you.
Chuck - AA5WG

Chuck,

If it is truly a rust bucket you are probably better off to keep on looking for something better.  You will spend a lot of money repairing a radio which will likely never be reliable or perform like one that has been properly maintained.  IF the VHF converter and dials are in good shape, you could transfer the converter, properly marked dial, and volume control with switch, and additional connectors over to a good HQ-170A.  Even if you want to have the front panel redone I would still consider converting a good HQ-170A chassis over for use in your VHF version because if it was in bad enough conditions to rust out the panel and case all of the transformers and coils are likely to be compromised.  Coils don't have to be open or shorted to reduce their Q and having been exposed to excessive moisture and dirt it is likely many of the components have been compromised. 

Another quick note on the clock, this is only useful if you leave your HQ-170A plugged in at all times (which will also allow the low drift features to come into play).  I really don't believe in leaving vintage gear plugged in when I am not around because you are putting your faith in nothing going wrong with the old wiring, power switch, fuse holder, etc.  The HQ-170A will come up to normal operating temperature pretty quickly and there is at least one good source for a battery operated replacement clock to keep the unit looking stock (but the timer functions will not work with the replacement clock).  If you do want to leave it plugged in all the time, I would at a minimum: replace the power cord, make sure to use the proper AC line rated bypass caps, check all the wiring associated with the fuse holder, AC switch, and clock, and of course ensure that the proper size fuse is installed.

Since it sounds like you are trying to put together a "fully loaded" HQ-170A also keep a watch out for the IF noise silencer which is a pretty rare accessory.

Good luck with your quest!

Rodger:
Again, thank you for the very good advice.  When the day comes and I have the radio I will not leave it on all the time.
At present, I will keep looking for the radio.
73,
Chuck

I thought I should add a comment about the drift reputation. The HQ-170 in my experience is the king of drifters, practically a spread-spectrum radio.  There is a Hammarlund bulletin dealing with this and one correspondent said that changing one of the temperature compensating padder capacitors had cured the drift issue in his.  I haven't tried it yet.  Right now, from a cold start to an hour later on 40 Meters, mine drifts about 20 kHz!

The drift correction discussion was over on the Antique Radio Forums' Communications Receivers forum, but the main website is down due to having lost the hosting company, so it may be awhile before the archives there are back up.

I don't think paying someone to restore a severely-challenged HQ-170A, even a VHF, would be economically practical at the present time.  You could probably buy a nice original one for less.

Hi WB6NVH:
Thank you for the drift information.  I need to get my hands on that print info. regarding the drift improvemnt fix.  Is there any word when the Hammarlund Web site will be up and running 100%?
I agree that I should not get the rust bucket HQ-170A VHF.  I will keep looking.

Do you think any of those anti-drift boards for boatanchors would help?

Thank you.
Chuck

The Hammarlund forum on QTH.net is alive and well but not very active. There is also the general Boatanchors forum there that is very active.

Its anybodys guess when ARF will be back on a new full service server. Its limping now with only a fraction of the old membership.

Hammarlunds step 1 drift cure was to install a seperate filament xfmr and leave the 6C4 filaments on 24/7, then they called it the 170A or 180A. This worked very well for some who reported no more drift but others still complained. I made that change in my HQ-180 and its more than tolerable now but its only used for SWLing and some ham AM listening. Its also beginning to show SMD symptoms so I pulled it and put the SX-73/R-274 in its place.

Carl
KM1H

Carl:
Thank you for the tip on Hammarlund drift. 
I am still looking for the HQ-170A VHF.
73,
Chuck - AA5WG

Carl:
I tried QTH.net and could not find the Hammrlund group.  Is QTH.net the correct Web address?
Thanks.
Chuck

You didnt follow the links once you got there

http://mailman.qth.net/