|
Don - Crap!? I hadn't noticed I had fat-fingered that!? I can see the confusion, now...
73,
--
Justin B.
KI5GKD
|
?ref ? /g/HallicraftersRadios/message/28237
Justin:
Q ???why was the slug frozen [or seemingly so]??? A?? some guy drove it there.. to the end.. and gave up?
What is the drive –head ?shape ; slot, hex, cross?? And what kind or driver are you using? Soft enough not to put point pressures on it.. A =no I guess, or it was frozen very solid.? Possible to get it out ? and maybe use another?
are you sure the previous owner did not? muck-up the LO so that he was tuning on the image 910 kHz? away/
if the other IF transformer is tuned at 455 ,and you one set to 440 , 490? or 700 you will likely block everything from going thru the IF
but you do get signals, so the IF cant be too bad.??
perhaps you heard signals before fooling with the IF, but did not verify the frequencies? on the dial with the stations real frequencies.? possible you inherited? a rig? with the front end badly warped up and did not realize it??
...a few more pairs of pennies!
-- don??? va3drl
|
Justin From the first TS post… “BCB the closer I get to the top of the band the more off the scale is.”?? ? ===? Maybe ??alignment steps 2&3 were partly“reversed” “On band 3 I can copy 40M SSB but it shifted about 1 MHz!”? ?????maybe only 0.91???? just the amount of an image shift “To get into the 40M band I have to tune to a little over 8 MHZ” ????7.1 + 0.91? =8? ????same as above? ?of course ? ,_wonder about band 2 and ?4? -- don??? va3drl
|
Don? - The slug froze when I was tweaking it.? I had ran through the IF alignments several times so it wasn't a PO problem.? I was re-tweaking just than can as I read somewhere that the top of T5 needed to be tuned a bit off for the BFO to work properly, don't know if that's true, or not.? I was messing with that adjustment when the slug quit turning and I didn't have enough sense to quit cranking on it.
The radio seems to work fine, other than BFO, with the frozen slug so it must be fairly close so I may just put the old "bad" can back in and live with it.
73,
--
Justin B.
KI5GKD
|
Justin:
Your frequency shift can not be caused by an IF transformer. They do not
have the range to shift frequency by ~1MHz.
The likely culprit is a misaligned oscillator. You should be aligning
band 3 at: 11 MHz - C3, C26 and 5MHz - L2, T3.
The Allied R-100 has a similar alignment scheme using hex slug tuned
coils and compression trimmers.
From experience, the oscillator trimmers can be set to peak at 2
locations: one is the true frequency, the other is the image frequency.
The image is twice the IF: 2 x 455 kHz = 910 kHz (~1 MHz).
You need to go back to the high side set point, 11.0 MHz and readjust
C26 to the other peak
Then peak? C3. Then peak L2, T3 at 5MHz.
Repeat the set point adjustment because they interact with each other.
This holds true for band A, B and C.
Band D will likely find the image frequency 910 kHz on the low side.
You might want to bring your calibration points in to 5.0 and 10.0 MHz,
WWV is a great known frequency.
Another oddity with the R-100, All of the B, C and D band coils have two
locations at which you can peak the signal. Pick the stronger of the two.
Dick, K9FFK
|
Justin Questions on the S-120 IF alignment: Was the band spread tuning capacitor fully meshed or fully open during the IF alignment? Was the main tuning capacitor fully meshed or fully open during the IF alignment?
Are you confidant that the SG setting at 455kc is accurate? How did you monitor the IF alignment. by ear or by a meter connected to the speaker? What was the volume control setting? What was the BFO control setting? Did you reduce signal generator output as the IF alignment progressed to keep the tone just above the noise? What tool did you use to adjust the IFTs, L1, C1 and C24? Jim
Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Friday, December 8, 2023 at 10:41:54 PM CST, Justin Bowser - KI5GKD <justin.bowser@...> wrote:
Don? - The slug froze when I was tweaking it.? I had ran through the IF alignments several times so it wasn't a PO problem.? I was re-tweaking just than can as I read somewhere that the top of T5 needed to be tuned a bit off for the BFO to work properly, don't know if that's true, or not.? I was messing with that adjustment when the slug quit turning and I didn't have enough sense to quit cranking on it.
The radio seems to work fine, other than BFO, with the frozen slug so it must be fairly close so I may just put the old "bad" can back in and live with it.
73,
--
Justin B.
KI5GKD
|
can you take the slug from the crackly transformer and swap it into the frozen one, or they different construction?
toggle quoted message
Show quoted text
Don? - The slug froze when I was tweaking it.? I had ran through the IF alignments several times so it wasn't a PO problem.? I was re-tweaking just than can as I read somewhere that the top of T5 needed to be tuned a bit off for the BFO to work properly,
don't know if that's true, or not.? I was messing with that adjustment when the slug quit turning and I didn't have enough sense to quit cranking on it.
The radio seems to work fine, other than BFO, with the frozen slug so it must be fairly close so I may just put the old "bad" can back in and live with it.
73,
--
Justin B.
KI5GKD
|
Hi Dick, ?Justin and all tuned into and locked on the S-120? rf tuning I tend to agree with Dick’s comments on the S-120 , but dunno about the Allied, an a few details ? first ?remind ourselves of the strange 40 meter situation Justin found Re: ‘The likely culprit is a misaligned oscillator.”? [yes] ?????? Re: “You should be aligning ?band 3 at: 11 MHz - C3, C26 and 5MHz - L2, T3. “.? [yes? almost, but, I see T3 followed by L3] ?as in the bookbut very fuzzy looking, >>> small img copy…  <<end img Note in the schematic that the T’s are in the rf section and the L’s are in the osc section. ? if you do the alignment exactly as ?the book says/implies ,you do .. for the high end: ??[C3], rf 1st, then [C26],? the oscillator 2nd ??then for the low end:? ??[T3], rf 1st, then ?[L3], ?the oscillator 2nd ?? ? So they are suggesting to do the rf 1st, ?then the oscillator. If the radio? has been de-tuned very badly and you do the rf first, you could get trapped maximizing the image frequency, and never get out of the trap using the instructions. ? As Dick says the LO is almost certainly intended to be set at 455kc above the desired signal, so when the dial is on 7Mc, the LO should be 7.455? and ?not ?6.545 ?[osc ?below the dial] Back then few people had scopes and frequency counters, but I think Justin has a scope so just ?monitor near the osc coil to see check if ?it is above the dial, and if it is, I give up! ….But if ??if the radio is found trapped ?with osc ?below the dial, ?first set the dial to 11Mc? and adjust ?the ??[L3] LO coil so it is 11.455? , then? restart the alignment for band 3 ???? ? ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of K9FFK
Sent: Saturday, December 9, 2023 1:36 AM
To: [email protected]
Cc: justin.bowser@...
Subject: [HallicraftersRadios] Help Tweaking in New IF Can in S-120? Justin:
Your frequency shift can not be caused by an IF transformer. They do not
have the range to shift frequency by ~1MHz.
The likely culprit is a misaligned oscillator. You should be aligning
band 3 at: 11 MHz - C3, C26 and 5MHz - L2, T3.
The Allied R-100 has a similar alignment scheme using hex slug tuned
coils and compression trimmers.
From experience, the oscillator trimmers can be set to peak at 2
locations: one is the true frequency, the other is the image frequency.
The image is twice the IF: 2 x 455 kHz = 910 kHz (~1 MHz).
You need to go back to the high side set point, 11.0 MHz and readjust
C26 to the other peak
Then peak? C3. Then peak L2, T3 at 5MHz.
Repeat the set point adjustment because they interact with each other.
This holds true for band A, B and C.
Band D will likely find the image frequency 910 kHz on the low side.
You might want to bring your calibration points in to 5.0 and 10.0 MHz,
WWV is a great known frequency.
Another oddity with the R-100, All of the B, C and D band coils have two
locations at which you can peak the signal. Pick the stronger of the two.
Dick, K9FFK -- don??? va3drl
|
Don - My "method" differs from the book in that I tune the osc coil first then peak the antenna coil.? I have since swapped this odd-ball coil into the S-38C for testing and found about the same dial error so I will check the S-38C LO with scope tomorrow.? The coil actually worked better in the S-120 as I got good sensitivity and was able to "hear" the same SW stations as I did on the S-85 albeit at the wrong dial setting.? I've come to realize that I need the correct transformer...:-(
73,
--
Justin B.
KI5GKD
|
Jim - Bandspread was set on 100 and IF was aligned on band 1 @ 600 KHz.?
I'm fairly confident the SG was putting out the correct freq as I was monitoring it with my Leader freq counter.
DVM was hooked to speaker to monitor level.
Volume control was fairly low and BFO was turned off.
I used a plastic alignment wand to adjust the coils and a plastic tool with metal blade to adjust the trimmers.
73,
--
Justin B.
KI5GKD
|
Curious is you are using
the EIA Dummy Antenna when attempting to align the front end of
the S-120? Have not seen it mentioned to my knowledge.
73
Bob, W8RLC
On 12/9/2023 9:40 PM, Justin Bowser -
KI5GKD wrote:
toggle quoted message
Show quoted text
Jim - Bandspread was set on 100 and IF was aligned on band 1 @ 600
KHz.?
I'm fairly confident the SG was putting out the correct freq as I
was monitoring it with my Leader freq counter.
DVM was hooked to speaker to monitor level.
Volume control was fairly low and BFO was turned off.
I used a plastic alignment wand to adjust the coils and a plastic
tool with metal blade to adjust the trimmers.
73,
--
Justin B.
KI5GKD
|
Bob, no, only use that on the antenna and oscillator adjustments.
73,
--
Justin B.
KI5GKD
|
Thanks Justin,
Good, the antenna and
oscillator are the front end.
Best wishes on your
endeavor.
73
Bob
On 12/10/2023 12:18 AM, Justin Bowser -
KI5GKD wrote:
toggle quoted message
Show quoted text
Bob, no, only use that on the antenna and oscillator adjustments.
73,
--
Justin B.
KI5GKD
|
Oh, OK, learn something new every day hanging around here!
73,
--
Justin B.
KI5GKD
|
Justin Recommended in the hallicrafters manual is to set the receiver frequency to 1mc.? I would go a step further and short the plates of the oscillator section of the main tuning capacitor to kill the LO.? This will allow the IF to be aligned without any heterodyne signals from some local stations.? A metal paperclip should do the job without deforming the oscillator section rotor or stator plates.
The second recommendation is to set the volume control to maximum.? This sets the AVC or more appropriately AGC to allow for highest gain.? You should set the speaker volume by reducing the signal form the generator not the radio's volume control.? This technique will result in the best peak of the IFTs.
Not sure why the ferrite slug in the IF cracked but perhaps you weren't the only one who did an IF alignment on this receiver?? Metal should never come into contact with ferrite.? Ferrite is not very forgiving. Regards, Jim
Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Saturday, December 9, 2023 at 08:40:53 PM CST, Justin Bowser - KI5GKD <justin.bowser@...> wrote:
Jim - Bandspread was set on 100 and IF was aligned on band 1 @ 600 KHz.?
I'm fairly confident the SG was putting out the correct freq as I was monitoring it with my Leader freq counter.
DVM was hooked to speaker to monitor level.
Volume control was fairly low and BFO was turned off.
I used a plastic alignment wand to adjust the coils and a plastic tool with metal blade to adjust the trimmers.
73,
--
Justin B.
KI5GKD
|
It really doesn't matter, I use the dummy antenna for both IF and RF alignment.? I built the dummy antenna into a small aluminum project box with a coax cable on one end and two flying leads with mini alligator clips on the other.? This makes it convenient to use in either case.??
The dummy antenna has a series capacitor for DC blocking which is nice to have.? Any loss of signal at 455kc is not significant since you want minimum signal anyway to do a proper IF alignment. Regards, Jim
Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Saturday, December 9, 2023 at 11:18:35 PM CST, Justin Bowser - KI5GKD <justin.bowser@...> wrote:
Bob, no, only use that on the antenna and oscillator adjustments.
73,
--
Justin B.
KI5GKD
|
Dick, catching up some more… ?but rather academic
RE: “Band D will likely find the image frequency 910 kHz on the low side.” With the instructions, how would anyone ever know if any 455 IF radio on the 10 to 30Mc band has the LO above or below the dial as the variables would ??
likely allow you to be trapped ?either above or below the dial, until you can measure the real LO frequency. ?I have not tried this to it is not proven in Root’s labs! ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of K9FFK
Sent: Saturday, December 9, 2023 1:36 AM
To: [email protected]
Cc: justin.bowser@...
Subject: [HallicraftersRadios] Help Tweaking in New IF Can in S-120? Justin:
Your frequency shift can not be caused by an IF transformer. They do not
have the range to shift frequency by ~1MHz.
The likely culprit is a misaligned oscillator. You should be aligning
band 3 at: 11 MHz - C3, C26 and 5MHz - L2, T3.
The Allied R-100 has a similar alignment scheme using hex slug tuned
coils and compression trimmers.
From experience, the oscillator trimmers can be set to peak at 2
locations: one is the true frequency, the other is the image frequency.
The image is twice the IF: 2 x 455 kHz = 910 kHz (~1 MHz).
You need to go back to the high side set point, 11.0 MHz and readjust
C26 to the other peak
Then peak? C3. Then peak L2, T3 at 5MHz.
Repeat the set point adjustment because they interact with each other.
This holds true for band A, B and C.
Band D will likely find the image frequency 910 kHz on the low side.
You might want to bring your calibration points in to 5.0 and 10.0 MHz,
WWV is a great known frequency.
Another oddity with the R-100, All of the B, C and D band coils have two
locations at which you can peak the signal. Pick the stronger of the two.
Dick, K9FFK ? -- don??? va3drl
|
Don, Justin
You know by?
Sent from my iThing which often corrects my typing and what I say.?
toggle quoted message
Show quoted text
On Dec 10, 2023, at 2:41?PM, don Root <drootofallevil@...> wrote:
?
Dick, catching up some more… ?but rather academic
RE: “Band D will likely find the image frequency 910 kHz on the low side.”
With the instructions, how would anyone ever know if any 455 IF radio on the 10 to 30Mc band has the LO above or below the dial as the variables would ??
likely allow you to be
trapped ?either above or below the dial, until you can measure the real LO frequency. ?I have not tried this to it is not proven in Root’s labs!
?
?
Justin:
Your frequency shift can not be caused by an IF transformer. They do not
have the range to shift frequency by ~1MHz.
The likely culprit is a misaligned oscillator. You should be aligning
band 3 at: 11 MHz - C3, C26 and 5MHz - L2, T3.
The Allied R-100 has a similar alignment scheme using hex slug tuned
coils and compression trimmers.
From experience, the oscillator trimmers can be set to peak at 2
locations: one is the true frequency, the other is the image frequency.
The image is twice the IF: 2 x 455 kHz = 910 kHz (~1 MHz).
You need to go back to the high side set point, 11.0 MHz and readjust
C26 to the other peak
Then peak? C3. Then peak L2, T3 at 5MHz.
Repeat the set point adjustment because they interact with each other.
This holds true for band A, B and C.
Band D will likely find the image frequency 910 kHz on the low side.
You might want to bring your calibration points in to 5.0 and 10.0 MHz,
WWV is a great known frequency.
Another oddity with the R-100, All of the B, C and D band coils have two
locations at which you can peak the signal. Pick the stronger of the two.
Dick, K9FFK ?
--
don??? va3drl
|
Don, Justin and the group.
1. I fat fingered a coil ID. My Bad! L2 should
have been L3.
2. Don. To check for the image frequency, the
instructions for the Knight R-100 had you readjust the generator
to a frequency 910 kHz below the high end frequency at which the
receiver is tuned. If you heard the generator, you had the image
set. You needed to repeat the high end exercise and find the
other peak.
??? I like your method using the frequency
counter. No mistaking that frequency.
3. An additional caution was noted in the Knight
manual with regard to grossly misadjusted coils. There are two
locations (peaks) at which resonance can be achieved. The proper
positions of the slugs in the coils was given for every coil.
(This is not true for the IF cans.) If you had the wrong peak
for the oscillator, tracking was not accurate.
4. Dan has determined that the oscillator should
be set 455 kHz above the desired (rf) frequency for all 4 bands.
5. Make certain the bandspread is fully open.
Additional capacitance will impact your ability to set the high
end. Receiver tuning should be done only with the main tuning
capacitor with the bandspread at minimum capacitance.
73, Dick, K9FFK
On 12/10/2023 2:41 PM, don Root wrote:
Dick, catching up some more… ?but
rather academic
RE: “Band D will likely find the image frequency 910 kHz on
the low side.”
With the instructions, how would anyone
ever know if any 455 IF radio on the 10 to 30Mc band has the
LO above or below the dial as the variables would ??
likely
allow you to be trapped
?either above or below the dial, until you can measure
the real LO frequency. ?I have not tried this to it is not
proven in Root’s labs!
?
?
Justin:
Your frequency shift can not be caused by an IF transformer.
They do not
have the range to shift frequency by ~1MHz.
The likely culprit is a misaligned oscillator. You should be
aligning
band 3 at: 11 MHz - C3, C26 and 5MHz - L2, T3.
The Allied R-100 has a similar alignment scheme using hex slug
tuned
coils and compression trimmers.
From experience, the oscillator trimmers can be set to peak at
2
locations: one is the true frequency, the other is the image
frequency.
The image is twice the IF: 2 x 455 kHz = 910 kHz (~1 MHz).
You need to go back to the high side set point, 11.0 MHz and
readjust
C26 to the other peak
Then peak? C3. Then peak L2, T3 at 5MHz.
Repeat the set point adjustment because they interact with
each other.
This holds true for band A, B and C.
Band D will likely find the image frequency 910 kHz on the low
side.
You might want to bring your calibration points in to 5.0 and
10.0 MHz,
WWV is a great known frequency.
Another oddity with the R-100, All of the B, C and D band
coils have two
locations at which you can peak the signal. Pick the stronger
of the two.
Dick, K9FFK ?
--
don??? va3drl
--
73
K9FFK Dick
|
Here is a nice piece on the SX-120 and the BFO
Best donald
Justin:
Your frequency shift can not be caused by an IF transformer. They do not
have the range to shift frequency by ~1MHz.
The likely culprit is a misaligned oscillator. You should be aligning
band 3 at: 11 MHz - C3, C26 and 5MHz - L2, T3.
The Allied R-100 has a similar alignment scheme using hex slug tuned
coils and compression trimmers.
From experience, the oscillator trimmers can be set to peak at 2
locations: one is the true frequency, the other is the image frequency.
The image is twice the IF: 2 x 455 kHz = 910 kHz (~1 MHz).
You need to go back to the high side set point, 11.0 MHz and readjust
C26 to the other peak
Then peak? C3. Then peak L2, T3 at 5MHz.
Repeat the set point adjustment because they interact with each other.
This holds true for band A, B and C.
Band D will likely find the image frequency 910 kHz on the low side.
You might want to bring your calibration points in to 5.0 and 10.0 MHz,
WWV is a great known frequency.
Another oddity with the R-100, All of the B, C and D band coils have two
locations at which you can peak the signal. Pick the stronger of the two.
Dick, K9FFK
|
don Root
Jim Whartenby
Donald J