Alignment Question on HQ 129X
 

A question for those with Hammarlund experience,
I have just restored my first HQ rcvr and the manual says I need a
sweep generator and a scope to align the IF. On most of my other rcvrs
(Hallicrafters), I just use a signal gen and a VTVM. Is this really
necessary or can I just peak the IF's? Mike KF6KXG

Alignment Question on HQ 129X
 

tchrme wrote:
A question for those with Hammarlund experience,
I have just restored my first HQ rcvr and the manual says I need a
sweep generator and a scope to align the IF. On most of my other rcvrs
(Hallicrafters), I just use a signal gen and a VTVM. Is this really
necessary or can I just peak the IF's? Mike KF6KXG

I have one of those, exactly, and I just peaked the IF stages. What was
interesting was getting the frequencies on the dial to be exact. I used
WWV as much as possible and A.M. radio stations that I knew the
frequency of. If you want it to be absolutely right on you will need a
signal generator (digital preferred) and a counter if you don't have a
digital generator. A sweep generator is nice to have but not that many
people have them laying around the bench.

Good luck with that, my 129X picks up the whole world quite nicely and I
think you will be very happy with it.

Bill Baka

Alignment Question on HQ 129X
 

Bill wrote in :
tchrme wrote:
A question for those with Hammarlund experience,
I have just restored my first HQ rcvr and the manual says I need a
sweep generator and a scope to align the IF. On most of my other rcvrs
(Hallicrafters), I just use a signal gen and a VTVM. Is this really
necessary or can I just peak the IF's? Mike KF6KXG

I have one of those, exactly, and I just peaked the IF stages. What was
interesting was getting the frequencies on the dial to be exact. I used
WWV as much as possible and A.M. radio stations that I knew the
frequency of. If you want it to be absolutely right on you will need a
signal generator (digital preferred) and a counter if you don't have a
digital generator. A sweep generator is nice to have but not that many
people have them laying around the bench.

Good luck with that, my 129X picks up the whole world quite nicely and I
think you will be very happy with it.

If you're lucky enough to have a ramp or triangle generator and an RF
signal generator that will do DC-level FM, you can feed the ramp or
triangle output into the siggen's FM modulation input and get a very
good approximation to a sweep generator. I do it with a ramp fed into my
HP 8640B's FM modulation in. Feed the stage output into the Y on your
scope and the ramp input into your scope's X, and you get to see (modulo
tweaking things so that the scope display, sweep rate, start and stop
freqs all are what you want) a really good idea of what the response
curves look like.

A dead-simple ramp generator is a constant-current generator (read LM117
or LM317 or LM318 with one resistor, if I recall correctly) feeding a
cap of the right value, a 555 to reset things periodically, and maybe a
few other components. The LM117/317/318 datasheet at national.com has
schematics for constant-current regs; I think I'll play this weekend.

--
Mike Andrews, W5EGO

Tired old sysadmin

Alignment Question on HQ 129X
 

"tchrme" wrote in message
...
A question for those with Hammarlund experience,
I have just restored my first HQ rcvr and the manual
says I need a
sweep generator and a scope to align the IF. On most of my
other rcvrs
(Hallicrafters), I just use a signal gen and a VTVM. Is
this really
necessary or can I just peak the IF's? Mike KF6KXG

The HQ 129X and its earlier versions use over coupled
transformers in at least one position. While these can be
just peaked the tuning will not be right although the set
will work. A sweep generator and scope will allow proper
tuning. The overall IF curve is supposed to be relatively
flat topped and have good skirts neither of which will be
obtained by simple peaking. I haven't looked at the tuning
instructions but it may be possible to determine the right
frequencies to peak the individual coils in the IF
transformers and use a very accurate source to peak them.
That's no trick now since the frequency counters in some
multimeters are quite accurate enough.
I also suggest that a good signal generator with known
frequencies will be helpful in adjusting the RF sections.
The frequency calibration of the main dial should be
reasonably accurate and RF tracking good. This was a deluxe
receiver in its day. However, it has only one RF stage so it
will have images on the higher bands. Hammarlund chose to
use three IF stages to obtain better selectivity and leave
the RF with a single stage. A combination of both two RF
stages and three IF stages is found in the Hammarlund
Super-Pro, perhaps the best communication receiver built
during its lifetime.


--
Richard Knoppow
Los Angeles
WB6KBL

Alignment Question on HQ 129X
 

On Thu, 9 Jul 2009 13:16:38 -0700, "Richard Knoppow"
wrote:


"tchrme" wrote in message
...
A question for those with Hammarlund experience,
I have just restored my first HQ rcvr and the manual
says I need a
sweep generator and a scope to align the IF. On most of my
other rcvrs
(Hallicrafters), I just use a signal gen and a VTVM. Is
this really
necessary or can I just peak the IF's? Mike KF6KXG

The HQ 129X and its earlier versions use over coupled
transformers in at least one position. While these can be
just peaked the tuning will not be right although the set
will work. A sweep generator and scope will allow proper
tuning. The overall IF curve is supposed to be relatively
flat topped and have good skirts neither of which will be
obtained by simple peaking. I haven't looked at the tuning
instructions but it may be possible to determine the right
frequencies to peak the individual coils in the IF
transformers and use a very accurate source to peak them.
That's no trick now since the frequency counters in some
multimeters are quite accurate enough.
I also suggest that a good signal generator with known
frequencies will be helpful in adjusting the RF sections.
The frequency calibration of the main dial should be
reasonably accurate and RF tracking good. This was a deluxe
receiver in its day. However, it has only one RF stage so it
will have images on the higher bands. Hammarlund chose to
use three IF stages to obtain better selectivity and leave
the RF with a single stage. A combination of both two RF
stages and three IF stages is found in the Hammarlund
Super-Pro, perhaps the best communication receiver built
during its lifetime.

I have an Hammarlund HQ-145 which in some ways is a lineal
decendent of the HQ 129X (which I also once had) and the
HQ-140 which was described at the time as a miniature tube version of
the 129. The manual I have for the 145 states that the sweep
generator and an O'scope are ideal for alignment, but lacking those
a VTVM and a signal generator will work as well if not "as well as."

I haven't tried either method with my HQ-145. I just did the peaking
thing when I had an HQ-129X some 40 years ago and it seemed to
work just fine though I had nothing to compare it with.

Jon W3JT

Alignment Question on HQ 129X
 

On Jul 9, 4:05*pm, Jon Teske wrote:
On Thu, 9 Jul 2009 13:16:38 -0700, "Richard Knoppow"





wrote:

"tchrme" wrote in message
....
A question for those with Hammarlund experience,
* *I have just restored my first HQ rcvr and the manual
says I need a
sweep generator and a scope to align the IF. On most of my
other rcvrs
(Hallicrafters), I just use a signal gen and a VTVM. Is
this really
necessary or can I just peak the IF's? Mike KF6KXG

* * The HQ 129X and its earlier versions use over coupled
transformers in at least one position. While these can be
just peaked the tuning will not be right although the set
will work. A sweep generator and scope will allow proper
tuning. The overall IF curve is supposed to be relatively
flat topped and have good skirts neither of which will be
obtained by simple peaking. I haven't looked at the tuning
instructions but it may be possible to determine the right
frequencies to peak the individual coils in the IF
transformers and use a very accurate source to peak them.
That's no trick now since the frequency counters in some
multimeters are quite accurate enough.
* * I also suggest that a good signal generator with known
frequencies will be helpful in adjusting the RF sections.
The frequency calibration of the main dial should be
reasonably accurate and RF tracking good. This was a deluxe
receiver in its day. However, it has only one RF stage so it
will have images on the higher bands. Hammarlund chose to
use three IF stages to obtain better selectivity and leave
the RF with a single stage. A combination of both two RF
stages and three IF stages is found in the Hammarlund
Super-Pro, perhaps the best communication receiver built
during its lifetime.

I have an Hammarlund HQ-145 which in some ways is a lineal
decendent of the HQ 129X (which I also once had) and the
HQ-140 which was described at the time as a miniature tube version of
the 129. *The manual I have for the 145 states that the sweep
generator and an O'scope are ideal for alignment, but lacking those
a VTVM and a signal generator will work as well if not "as well as."

I haven't tried either method with my HQ-145. *I just did the peaking
thing when I had an HQ-129X some 40 years ago and it seemed to
work just fine though I had nothing to compare it with.

Jon W3JT

Thank you to all who replied. I am going to mark the initial positions
so I have them for a reference, and then try the peaking method. Since
I changed all the caps and some resistors, it should improve things a
bit, although it works pretty well right now. The biggest problem is
dirty contacts on the top band of the bandswitch. I sprayed them once,
but will now clean them more thoroughly. 73 Mike KF6KXG

Alignment Question on HQ 129X
 

If stages are often peaked. For ham use, it should be acceptable. One
particular problem may be that am stations will not have full bandwidth, so
the audio may be restricted a bit. If you are careful, you can emulate the
sweep generator by setting the generaator above, on and below the if
frequency. The total bandwidth should be the desired wide bandwidth. Then,
adjust the transformers so that signal level is about the same on all three
frequencies.

A few years ago, I acquired a spectrum analyzer with tracking generator.
Now, alignment of any filters or if stages are so easy that I feel guilty.

I also recall using a BC-221 as a manual sweep generator.

the improtant thing is that you will come close with the old "peak each
stage" approach. Make sure you do not overload and follow the other
instructions. I have aligned more than one receiver by ear, when I had
nothing else. Generally, close is good enough.

Also, make sure you use the proper alignment tools. I have worked on a lot
of receivers butchered by improper alignment tools.

73, Colin K7FM

Alignment Question on HQ 129X
 

On Jul 10, 6:23*pm, "COLIN LAMB" wrote:
If stages are often peaked. *For ham use, it should be acceptable. *One
particular problem may be that am stations will not have full bandwidth, so
the audio may be restricted a bit. *If you are careful, you can emulate the
sweep generator by setting the generaator above, on and below the if
frequency. *The total bandwidth should be the desired wide bandwidth. *Then,
adjust the transformers so that signal level is about the same on all three
frequencies.

A few years ago, I acquired a spectrum analyzer with tracking generator.
Now, alignment of any filters or if stages are so easy that I feel guilty..

I also recall using a BC-221 as a manual sweep generator.

the improtant thing is that you will come close with the old "peak each
stage" approach. *Make sure you do not overload and follow the other
instructions. *I have aligned more than one receiver by ear, when I had
nothing else. *Generally, close is good enough.

Also, make sure you use the proper alignment tools. *I have worked on a lot
of receivers butchered by improper alignment tools.

73, *Colin *K7FM

Colin,
Thanks for the suggestions. I agree the the peaking method should be
okay. I will keep my eyes out of a used sweep gen and upcoming swaps.
I have a good set of alignment tools so I can align without causing
damage. Mike KF6KXG