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Installed an OA2.? I haver 150 volts at VFO on RX and Tx.? So this cant be the issue.

What could cause this Frequency offset?

https://shopgoodwill.com/item/196554053
--
Justin B.
KI5GKD

HAM techs

Attached are pictures of Hallicrafter rigs from 1940-1950. May have been
used on ships, land bases, recreationally or other. They are at an estate
where the spouse of the op wants all ham radio gear gone. I took a
Hammarlund HQ110A and HQ170 in pretty good cosmetic internal shape, but
until I replace the 2 cond powers cords with 3 conductor, I have no plans
of anything more than cleaning. The pictured gear is very heavy so it remains in NJ....MY QTH is 4 miles south of Nashua, NH.

The single pic is of a S36 or S27 Ultra High Frequency Communication Radio
Receiver...what lil I gathered from many searches yielded a 60lb recvr
capable of vhf at 28-143 or 36-165 or 125-240 and maybe 108-137 air or
88-108 fm. Very confusing, conflicting info found. So-so cosmetics, hinged top; front edge rust but no internal penetration.

The pic with 2 rigs is a S-76 on top at 46lbs with the right most large
microvolt/S-meter glass removed and the mechanicals of the meter/indicator are totally shot. Cosmetically pretty beat; bottom front case rust, but no internal penetration. Perhaps was capable of 538-34 mhz in its day.
The bottom rig is the HT-37 xmiter at 80 lbs and was capable of 100 watts
cw/ssb and 25 am on 10,14,20,40,80....Ok cosmetics....

The 3 hallicrafter rigs all have frayed 2 cond power cords and are pretty
dirty/dusty/grimy.....surprisingly all dial tuning/bedspread controls work smoothly as well as other pots, swts, toggles, etc....

Let know if I described them correctly and their specs correctly and In your honest opinion, any value, worth cleaning up? Feel free to pedal the pics around to others for opinions...
I may just make them available for sale/pickup as I have a Drake twins line, amp, Heaths and the Hammarlund's to attend to.

SO any takers with offers? PLEASE and TU! 73!

STAY SAFE AND STAY WELL
Respectfully,

Thomas K. Lanieri, NU2W
NJ Licensed EMT; PHTLS, AMLS, PHPEC
B.A.A. EMS Support
ARC N.E. BioMedical Services
ARC N.E. Disaster Health Services
DanaFarber-Am Cancer Society

I noticed that BOTH my radios have an OB2 108 volt gas regulator tube.? The schematic clearly shows a OA2 150 volt tube.? Was this a change or do both my rigs have the wrong tube installed?

C

Got the radio back in case and have noticed the frequency is different from rx to tx on LSB and USB.??

It's. 00 on RX and .97 on TX.? ?I cant think what would fx this behavior.? I have a freq counter on pin 11 on the socket. I can correct this with the RIT on.

What did I miss?



C

This issue is resolved.? I replaced all components. I used 1n5711 diodes. Two 470 resistors. Matched at 460.? Replaced the .1. Replaced rhe NPO 25pf trimmer.? Deep null now.

The other radio can null its carrier with factory components.? However I can get LSB on freq.? The exact same xtall in the other radio can. So now I must rebuild that curcuit.? ?Might be trimmer.? I have them now so I can start there.?

Ok. I got the Problem resolved. I am not sure what I did wrong Jim.? I Was able to peak T4 and run it down 80%.? Then Null the remaining carrier.

With Drive at 0 I get 20w out in tune mode on lower bands.? The drive control operates smooth and functions.? I am unsure where the 20 W is comming from. I understood that with drive at 0, there will be Zero output.? ?I am not sure if this is a problem or not.??

The next major hurdle is the L15 and L16 adjustments.? I used the 1k tone meathod to peak. Then went to 300 HZ and set by the book. The audio on SSB is extremely Thin sounding.? There is nothing below 400HZ.? ?

I went back over the speech amp.? I did replace the 2.7meg and 100K in the mic circuit. They were out of value. That got me more gain. But no low end frequency response?

It's not the mic. I tried three.? I can put the audio gen into the mic socket and the cut off is HARD at 400 and down.? I can pass Nothing more than 2.2k.? Anything more is gone.? The radio can't be used like this. I am unsure what to do.??

I guess I can go back and realign L15 and 16 so it does pass 300hz or at least try?? ?

Is there a better method to set L15 and L16?? I thought about using my Nano VNA to plot it. I have done this with Collins Filters.? What about pumping 1650 from my Generator into the input of L15 and viewing output on my VNA or TinySA???


C

C

OK, check the path from C135 to the function switch.
If the tube shield on the 12BY7A was lifted and a scope probe connected to it, a plethora of information could be obtained.? This is also used to precision neutralize the finals.

Regards Jim K9AXN

?

I thought I had this finished but went out to the shop, turned it on, and receiver dead!? After poking and probing it seemed like the 18.5 MHz oscillator was running at about 21.6 MHz.? I scrounged fleabay and couldn't find an 18.5 MHz crystal but did get some 18.463 MHz parts.? I replaced the crystal and although I couldn't get the osc adjustment to tune in at 20.15 MHZ it did tune in at around 20.06 MHz.? After this I was able to satisfactorily perform the rest of the adjustments and have the freq dead-on as far as signal input and dial reading.

My question is whether the oscillator being just a bit off frequency will cause me receive issues!? If so maybe I could tweak the value of C36 and/or C37 to dial in the frequency.? Or, maybe this would be a nice test for one of QRP Labs ProgRock2 if they are ever back in stock!

Any thoughts?? I'm hoping this slight freq difference is small enough to not make any difference.

73,
--
Justin B.
KI5GKD

Thank you Jim.? The xtals are not swapped.? They are correct and running at correct frequency.? Actually the LSB .540 instead of .550.? ? Close.

I am guessing I must have L15 and 16 off.? The carrier must be leaking though ?

C

?
Heil Sound has a replacement kit for the D -104 you can use either the HC-4 or HC-5 Element.
73 Tony WA4JQS


At 08:56 AM 4/18/2024 -0700, you wrote:

Good morning, C
It sounds like the carrier crystals are swapped.
The radio can be fully aligned without switching the HV on.??

This image shows the carrier peaks as they relate to the filter. Note that the carrier on the right is very close to the bandpass (Tune and CW), and the carrier on?the left is just outside.? The peak on the right will move out of the bandpass like the left in USB and LSB.?





Open?
The probe on the shield on the 12BY7A measures 13v to 19v. Use that to make adjustments and save the finals.??

I'm not at the computer much, family calls.

Kindest regards Jim K9AXN

Walt, Jim and others, I have run into a snag during the alignment. I must have made a mistake.

I followed Walts paper and the manual and aligned the Filter L15 and L16 That seemed to go smooth. ONE of them needed adjustment. The other was about right.

The issue is that I cannot peak T4. Or even set it to 80 %.? If I do, I have 500W on Tune mode and a massive carrier.? You cannot null this carrier out.? ?

If I back T4 off to just the point where LSB OSC stops running, then go a bit more for reliable startup, you CAN null the carrier out and the rig seems to work OK. The Null is nice and deep.?

The power in tune is up to 500W with drive control working.? Low power SSB is 550w.? High power is 1000w pep.??

The Carrier rocks are on freq.??

BOTH SR2000s behave this way.? This rules out a bad single component.? They behave Exactly the same. I suspect I have made a mistake somewhere.? Prior to the alignment I could peak T4, Set it down a bit on the soft slope side.? I can no longer do that.? Did I botch the L15 and L16 alignment???

What did I miss??

C

We all used the Kobitones 20 years ago. They are all long gone.? I have a personal stash of them and am running low.. I have lost five D104 elements in the last 5 or 6 years. I ran them on six different stations here.? They just up and die. Nothing happens. They just die.?

Lots of OM's purchased 10 and 20 of them, only to have them end up in a dump when they went SK.??

There is nothing on the market that works properly.? Installing an electret element in a D104 should be a felony offense.

C

FWIW, crystal microphones have not been made for many years. Old
ones should be avoided if you want a practical, working microphone. In
some cases ceramic versions were made with similar performance, these
have a much better chance of still working.
Rochell salt crystal elements for microphones and phonograph pickups
(also headphones and disc cutter heads) were introduced c.1933. The
original patents were owned by Brush Development company, who licensed
many others to manufacture them. Crystal elements have the virtue of
very high output and good quality sound at economical prices, so they
were very popular. However, they are very vulnerable to high
temperatures (much over 100F), moisture, mechanical shock (dropping or
scraping a pickup across a record), and where used as motors (headphones
and cutters) to mechanical shock from being over driven. The greatest
problems are exposure to high temperatures and entry of moisture. There
were several patented methods of protecting the elements from moisture
(Astatic called their Metalseal) but they develop leaks and the crystals
turn to mush (literally).
Crystal elements can not be tested with an ohm meter, they look
like capacitors and do not pass DC. If you measure any resistance the
element is probably dead.
Many of these mics are classic designs but should be seen as
collector's items and not usable.
The D-104 was the first crystal microphone sold commercially (I
think 1933). While a flat frequency response version was available early
on the rising response version became the more popular. The response is
exaggerated by operating it into too low an impedance, ideally, they
should work into an infinitely high impedance, however the response of
the D-104 is tailored for speech by means of resonances in the mechanism
and the large disc shape which results in additional rise due to
diffraction.
The elements can be replaced with others, which will preserve the
effect of the diffraction, but the internal resonances may not be the same.
The output level of a D-104 is one of the highest for any
non-amplified microphone. The high output for the mics and phono pickups
was high enough to often eliminate a stage of amplification, a great
economy in the vacuum tube days when amplification was expensive.

--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998

g'luck... most of the original elements have gone bad... a few still
linger.? Caveat Emptor Grasshopper...? An article in ELECTRIC RADIO some
time back showed the use of KOBITONE elements, which WORK SWELL.? I did
a D-104 and it actually sounds BETTER than the working ones I have.?
Sources tell me that the particular element specified in the article
isn't available, BUT... KOBITONE is verry much around and many other
elements will work.? MOUSER used to carry them, but that may no longer
be the case...? so do your own diggin'

Tom - W?EAJ

"waltcates" <cateswa@...> wrote
The 44 should make -65 to -70db unwanted sideband suppression. Inability to get a good reduction of the unwanted sideband points to audio distortion in the mic amp/modulator train or S3B switch failure.

Hi, Walt

The HT-44 manual (beginning of Section II, Northrop version) says:
Unwanted Sideband Rejection
50 DB or more at 1 KC. 30 DB or more, 500 to 2500 CPS.

Norgaard, in his article on the G.E. 'SSB, Jr.' claimed a worst case
rejection of 39dB, and an average of 45dB side band rejection over
a 225 Hz to 2750 Hz voice bandwidth, based on
the measured degree of error for the two audio phase shift circuits
he used. That's probably about as good as it gets,
using such a simple circuit.

73,
Ed Knobloch K4PF