My planned fix for this is to add an analog filter between the
mic and the rig to roll off aggressively above 3 Khz.? Improving
it at RF level would involve far more work where cooking up an
active filter is easy and fun (for the twisted minds, anyway).
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 1:49 PM, W7WRX wrote:
toggle quoted message
Show quoted text
This makes sense.? A friend has the 32A, I have listed and
watched its signal for years on scope.? It's always been super
wide and always had some buckshot.? I assumed it was modified.
C
It does not make a material impact on the transmitted
bandwidth in my testing.? I certainly would be interested to
see if someone else has looked at the transmit bandwidth on
their units.? Maybe there is something wrong with my HT-32A.
Regarding CR2, that seems more of a leveling action and has
no sharpness by way of roll off at all.? And per 7-16 Crystal
Filter Alignment item 3, it says "transmitter output should
not drop BELOW 3dB at the extremes of the audio passband
(650-3Khz).? My claim is that there is no mechanism in the rig
that provides a meaningful roll off above 3 Khz beyond a small
number of dB per octave.
The measurements I published on the reflector May 10 2023 had
this data:
8.7K @ -12 dB from peak amplitude (yellow trace)
6.8K @ -12 dB from peak amplitude (green trace)
So yes, there is a roll off.? But from a crystal BPF
standpoint, the HT-32A I measured is really really wide by
comparison.? I would be very interested in someone else making
a similar measurement on their rig for a sanity check.?
--
73/jeff/ac0c
alpha-charlie-zero-charlie
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 1:23 PM, waltcates
wrote:
CR2 is the passband filter. Its adjustment is C121.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
?
That's true
Walt.? But if you sweep these filters, they don't provide
passband attenuation on the transmitted sideband.? They do a
fine job on the carrier and the opposite sideband, but don't
do anything for the occupied bandwidth of the transmitted
signal.
I actually could
not believe this was the case - and to that end, completely
disassembled the filter modules on a spare HT-32 I had to
check out what the SA was showing me.? I have plots &
photos of that exercise around here somewhere if someone is
interested.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 11:22 AM, waltcates wrote:
The 32 actually has 3 filters CR2, FL1 and FL2?
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
?
The HT-32 has
no BPF in the classic sense.? Just some L/C type providing
a pretty gentle roll off.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 10:48 AM, Rick W4XA wrote:
The Drake TR-4 came with 2.1 kHz filters.? I
replaced them in mine with the aftermarket Inrad 2.5kHz
filters.
Not only do I get much better reports on the air but the
receive fidelity is a LOT easier to listen to!
I get great audio reports with my HT-32B.? I think it's
got a 3kHz filter in it?
I couldn't find the filter specs in the SR-400 manual.? I
guess they really don't say what the BW? is. but it would
seem to be somewhere around 2.3-2.5 kHz based on the shift
in the carrier frequencies?? I guess the only way to know
for sure would be to "sweep" it.
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
|
Re: Sx100 question on 50.5 kc alignment
Use an attenuator (-10 or -20db) if the signal is too large. The emphasis is on peaking the signal to a maximum level, rather than adjusting to 1 volt PP. I'd use a banana to BNC adapter with a 50 ohm terminated coax to your clips.??
On Tuesday, April 2, 2024 at 10:45:45 AM PDT, Keith <kd4avp@...> wrote:
Drew I am coming straight out of the IG5282 into the IF. Using an alligator clip to tap at pin one on T1 and the other to chassis ground. 
|
This makes sense.? A friend has the 32A, I have listed and watched its signal for years on scope.? It's always been super wide and always had some buckshot.? I assumed it was modified.
C
toggle quoted message
Show quoted text
It does not make a material impact on the transmitted bandwidth in my testing.? I certainly would be interested to see if someone else has looked at the transmit bandwidth on their units.? Maybe there is something wrong with my HT-32A.
Regarding CR2, that seems more of a leveling action and has no sharpness by way of roll off at all.? And per 7-16 Crystal Filter Alignment item 3, it says "transmitter output should not drop BELOW 3dB at the extremes of the audio passband (650-3Khz).? My
claim is that there is no mechanism in the rig that provides a meaningful roll off above 3 Khz beyond a small number of dB per octave.
The measurements I published on the reflector May 10 2023 had this data:
8.7K @ -12 dB from peak amplitude (yellow trace)
6.8K @ -12 dB from peak amplitude (green trace)
So yes, there is a roll off.? But from a crystal BPF standpoint, the HT-32A I measured is really really wide by comparison.? I would be very interested in someone else making a similar measurement on their rig for a sanity check.?
--
73/jeff/ac0c
alpha-charlie-zero-charlie
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 1:23 PM, waltcates wrote:
CR2 is the passband filter. Its adjustment is C121.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
?
That's true Walt.? But if you sweep these filters, they don't provide passband attenuation on the transmitted sideband.? They do a fine job on the carrier and the opposite sideband, but don't do anything for the
occupied bandwidth of the transmitted signal.
I actually could not believe this was the case - and to that end, completely disassembled the filter modules on a spare HT-32 I had to check out what the SA was showing me.? I have plots & photos of that exercise
around here somewhere if someone is interested.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 11:22 AM, waltcates wrote:
The 32 actually has 3 filters CR2, FL1 and FL2?
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
?
The HT-32 has no BPF in the classic sense.? Just some L/C type providing a pretty gentle roll off.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 10:48 AM, Rick W4XA wrote:
The Drake TR-4 came with 2.1 kHz filters.? I replaced them in mine with the aftermarket Inrad 2.5kHz filters.
Not only do I get much better reports on the air but the receive fidelity is a LOT easier to listen to!
I get great audio reports with my HT-32B.? I think it's got a 3kHz filter in it?
I couldn't find the filter specs in the SR-400 manual.? I guess they really don't say what the BW? is. but it would seem to be somewhere around 2.3-2.5 kHz based on the shift in the carrier frequencies?? I guess the only way to know for sure would be to "sweep"
it.
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
|
It does not make a material impact on the transmitted bandwidth
in my testing.? I certainly would be interested to see if someone
else has looked at the transmit bandwidth on their units.? Maybe
there is something wrong with my HT-32A.
Regarding CR2, that seems more of a leveling action and has no
sharpness by way of roll off at all.? And per 7-16 Crystal Filter
Alignment item 3, it says "transmitter output should not drop
BELOW 3dB at the extremes of the audio passband (650-3Khz).? My
claim is that there is no mechanism in the rig that provides a
meaningful roll off above 3 Khz beyond a small number of dB per
octave.
The measurements I published on the reflector May 10 2023 had
this data:
8.7K @ -12 dB from peak amplitude (yellow trace)
6.8K @ -12 dB from peak amplitude (green trace)
So yes, there is a roll off.? But from a crystal BPF standpoint,
the HT-32A I measured is really really wide by comparison.? I
would be very interested in someone else making a similar
measurement on their rig for a sanity check.?
--
73/jeff/ac0c
alpha-charlie-zero-charlie
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 1:23 PM, waltcates wrote:
toggle quoted message
Show quoted text
CR2 is the passband filter. Its adjustment is C121.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
?
That's true Walt.?
But if you sweep these filters, they don't provide passband
attenuation on the transmitted sideband.? They do a fine job on
the carrier and the opposite sideband, but don't do anything for
the occupied bandwidth of the transmitted signal.
I actually could
not believe this was the case - and to that end, completely
disassembled the filter modules on a spare HT-32 I had to check
out what the SA was showing me.? I have plots & photos of
that exercise around here somewhere if someone is interested.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 11:22 AM, waltcates wrote:
The 32 actually has 3 filters CR2, FL1 and FL2?
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
?
The HT-32 has no
BPF in the classic sense.? Just some L/C type providing a
pretty gentle roll off.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 10:48 AM, Rick W4XA wrote:
The Drake TR-4 came with 2.1 kHz filters.? I
replaced them in mine with the aftermarket Inrad 2.5kHz
filters.
Not only do I get much better reports on the air but the
receive fidelity is a LOT easier to listen to!
I get great audio reports with my HT-32B.? I think it's got a
3kHz filter in it?
I couldn't find the filter specs in the SR-400 manual.? I
guess they really don't say what the BW? is. but it would seem
to be somewhere around 2.3-2.5 kHz based on the shift in the
carrier frequencies?? I guess the only way to know for sure
would be to "sweep" it.
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
|
CR2 is the passband filter. Its adjustment is C121.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
toggle quoted message
Show quoted text
?
That's true Walt.? But if you sweep these filters, they don't provide passband attenuation on the transmitted sideband.? They do a fine job on the carrier and the opposite sideband, but don't do anything for the
occupied bandwidth of the transmitted signal.
I actually could not believe this was the case - and to that end, completely disassembled the filter modules on a spare HT-32 I had to check out what the SA was showing me.? I have plots & photos of that exercise
around here somewhere if someone is interested.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 11:22 AM, waltcates wrote:
The 32 actually has 3 filters CR2, FL1 and FL2?
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
?
The HT-32 has no BPF in the classic sense.? Just some L/C type providing a pretty gentle roll off.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 10:48 AM, Rick W4XA wrote:
The Drake TR-4 came with 2.1 kHz filters.? I replaced them in mine with the aftermarket Inrad 2.5kHz filters.
Not only do I get much better reports on the air but the receive fidelity is a LOT easier to listen to!
I get great audio reports with my HT-32B.? I think it's got a 3kHz filter in it?
I couldn't find the filter specs in the SR-400 manual.? I guess they really don't say what the BW? is. but it would seem to be somewhere around 2.3-2.5 kHz based on the shift in the carrier frequencies?? I guess the only way to know for sure would be to "sweep"
it.
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
|
Re: Sx100 question on 50.5 kc alignment
This is the probe I am using 
|
Re: Sx100 question on 50.5 kc alignment
Drew I am coming straight out of the IG5282 into the IF. Using an alligator clip to tap at pin one on T1 and the other to chassis ground.
|
Re: Sx100 question on 50.5 kc alignment
I do have a RF probe. One that I made plus one that is a manufactured version.?
I am changing the connection on my VTVM from the 1/4 inch jack to a bnc this evening.
That will help also. The commercial probe has a bnc already and really good test ends for use in the radio.
My DIY version works in a pinch but prefer the bnc connection over the 1/4 phone jack.
|
That's true Walt.? But if you sweep these filters, they don't
provide passband attenuation on the transmitted sideband.? They do
a fine job on the carrier and the opposite sideband, but don't do
anything for the occupied bandwidth of the transmitted signal.
I actually could not believe this was the case - and to that end,
completely disassembled the filter modules on a spare HT-32 I had
to check out what the SA was showing me.? I have plots &
photos of that exercise around here somewhere if someone is
interested.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 11:22 AM, waltcates wrote:
toggle quoted message
Show quoted text
The 32 actually has 3 filters CR2, FL1 and FL2?
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
The HT-32 has no BPF in the classic sense.? Just some L/C
type providing a pretty gentle roll off.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 10:48 AM, Rick W4XA
wrote:
The Drake TR-4 came with 2.1 kHz
filters.? I replaced them in mine with the aftermarket Inrad
2.5kHz filters.
Not only do I get much better reports on the air but the
receive fidelity is a LOT easier to listen to!
I get great audio reports with my HT-32B.? I think it's got a
3kHz filter in it?
I couldn't find the filter specs in the SR-400 manual.? I
guess they really don't say what the BW? is. but it would seem
to be somewhere around 2.3-2.5 kHz based on the shift in the
carrier frequencies?? I guess the only way to know for sure
would be to "sweep" it.
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
|
The 32 actually has 3 filters CR2, FL1 and FL2?
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
toggle quoted message
Show quoted text
The HT-32 has no BPF in the classic sense.? Just some L/C type providing a pretty gentle roll off.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 10:48 AM, Rick W4XA wrote:
The Drake TR-4 came with 2.1 kHz filters.? I replaced them in mine with the aftermarket Inrad 2.5kHz filters.
Not only do I get much better reports on the air but the receive fidelity is a LOT easier to listen to!
I get great audio reports with my HT-32B.? I think it's got a 3kHz filter in it?
I couldn't find the filter specs in the SR-400 manual.? I guess they really don't say what the BW? is. but it would seem to be somewhere around 2.3-2.5 kHz based on the shift in the carrier frequencies?? I guess the only way to know for sure would be to "sweep"
it.
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
|
Re: SR2000 Cant Null carrier
Thanks Jim. I will check that.? I fail to see how this could make a trimmer cap not work.? There is a carrier on both side bands of about 2w.? I can kick the Carrier osc around and null the carrier which tells me that the Null circuit is not adjusting.
But I will start with the function switch and use the deoxit on the screws first!
C
toggle quoted message
Show quoted text
Hi Dave,
I'm fairly certain the capacitor is not the problem.? The rivets holding the function switch have loosened or oxidized from switching.? There is one black wire to ground that was to protect for this but is inadequate.? Drill one or both rivets out and wipe
a film of copper butter between the bracket plate and chassis and secure with a screw.? Voila the radio will become stable.
When restoring radios that use an aluminum chassis and riveted components, the following procedure will fix 95% of the strange behaviors.? Dab a bit of Deoxit 100 on each star washer between the chassis and socket or wherever you find one and using a screwdriver,
tap the star washer to reset the teeth.? For ALL screws, remove and dab a bit or copper butter and replace.? A PITA but that is a complex radio, and any ground loops will test your patience and satisfaction.?
Kindest regards Jim K9AXN? ? ??
|
Re: SR2000 Cant Null carrier
Hi Dave,
I'm fairly certain the capacitor is not the problem.? The rivets holding the function switch have loosened or oxidized from switching.? There is one black wire to ground that was to protect for this but is inadequate.? Drill one or both rivets out and wipe a film of copper butter between the bracket plate and chassis and secure with a screw.? Voila the radio will become stable.
When restoring radios that use an aluminum chassis and riveted components, the following procedure will fix 95% of the strange behaviors.? Dab a bit of Deoxit 100 on each star washer between the chassis and socket or wherever you find one and using a screwdriver, tap the star washer to reset the teeth.? For ALL screws, remove and dab a bit or copper butter and replace.? A PITA but that is a complex radio, and any ground loops will test your patience and satisfaction.?
Kindest regards Jim K9AXN? ? ??
|
The HT-32 has no BPF in the classic sense.? Just some L/C type
providing a pretty gentle roll off.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 10:48 AM, Rick W4XA wrote:
toggle quoted message
Show quoted text
The Drake TR-4 came with 2.1 kHz filters.? I replaced them in mine
with the aftermarket Inrad 2.5kHz filters.
Not only do I get much better reports on the air but the receive
fidelity is a LOT easier to listen to!
I get great audio reports with my HT-32B.? I think it's got a 3kHz
filter in it?
I couldn't find the filter specs in the SR-400 manual.? I guess
they really don't say what the BW? is. but it would seem to be
somewhere around 2.3-2.5 kHz based on the shift in the carrier
frequencies?? I guess the only way to know for sure would be to
"sweep" it.
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
|
The Drake TR-4 came with 2.1 kHz filters.? I replaced them in mine with the aftermarket Inrad 2.5kHz filters.
Not only do I get much better reports on the air but the receive fidelity is a LOT easier to listen to!
I get great audio reports with my HT-32B.? I think it's got a 3kHz filter in it?
I couldn't find the filter specs in the SR-400 manual.? I guess they really don't say what the BW? is. but it would seem to be somewhere around 2.3-2.5 kHz based on the shift in the carrier frequencies?? I guess the only way to know for sure would be to "sweep" it.
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
|
Re: Sx100 question on 50.5 kc alignment
Keith,
It seems to me you are going to need an RF probe on your VTVM to measure 1 volt RF. You can easily build your own single diode probe. Look on the internet for a simple circuit.
73
Scott
N6CIC
|
Re: SR2000 Cant Null carrier
The mount is insulated so rivets dont ground the cap..?
The cap is not adjusting the circuit.? They are known to fail.??
I put a drop of dexoit on it last night as a last resort. It did not fix it this morning.?
|
Re: Sx100 question on 50.5 kc alignment
toggle quoted message
Show quoted text
On Mon, Apr 1, 2024 at 7:07 PM, Keith <kd4avp@...> wrote: Ok that makes more sense to me now.
AGC was off.?
I will drop the output on the generator .
Will use my scope to get it just registering, then move it over to the T1 input point.?
This Heathkit is not as user friendly as I had hoped but should get me in the ballpark.?
I think learning to use what I have properly is my biggest challenge.
Will tackle it again later in the week.?
Thank you both for the guidance.?
I am learning a lot as I go thru this adventure.
|
Re: Sx100 question on 50.5 kc alignment
I'm getting close to doING the same on my SX-100. So I'm interested in knowing your outcome. What is the peak to peak measurement of your input signal and is it 50 ohm terminated? And, what about your probes (10:1 or not)? -Drew
On Mon, Apr 1, 2024 at 5:25 PM, Keith <kd4avp@...> wrote: Apparently I only thought my alignment was successful.
Think I either interpreted something wrong or there is something more going on.?
Inputting a 50.5kc signal at T1 on pin number 1 as directed in the manual.?
I am using a Heathkit IG 5282 signal generator adjusted as close to 50.5kc I can get.
Used my oscilloscope to get that on target.?
Pulled the 1 osc conversion tube as recommended.?
Using my VTVM connected at point B (R48, R49 & C81 all connect on a terminal strip at this point), was monitoring the DC voltage.
I was adjusting T3, T4, T5 & T6 (all 50.5 IFs) to maintain 1 volt reading on the VTVM.
I never got anywhere close to 1 volt DC.
It was actually closer to 10 and 12 vdc.
What am I missing here?
I did manage to get it down to 7 volts but it was not completely stable there. But I did expect it to vary a little bit.
In my mind, I must have been thinking it should only vary by 1 volt....not actually be 1 volt.
Leaning on you guys with a better understanding of what I may be seeing here.?
Thanks!
Keith
|
Re: Sx100 question on 50.5 kc alignment
Guess this old dog is not too old to keep learning. Definitely not what my work background has been. Just always had an interest in radios and hate to see these beautiful receivers just go to a junk pile. ? ?
toggle quoted message
Show quoted text
From: andrew griffith <agriffith@...>
Sent: Monday, April 1, 2024 10:23 PM
To: [email protected]; Keith <kd4avp@...>
Subject: Re: [HallicraftersRadios] Sx100 question on 50.5 kc alignment? You and me both, Keith -Drew ? On Mon, Apr 1, 2024 at 7:07 PM, Keith Ok that makes more sense to me now.
AGC was off.?
I will drop the output on the generator .
Will use my scope to get it just registering, then move it over to the T1 input point.?
This Heathkit is not as user friendly as I had hoped but should get me in the ballpark.?
I think learning to use what I have properly is my biggest challenge.
Will tackle it again later in the week.?
Thank you both for the guidance.?
I am learning a lot as I go thru this adventure.
|
The 150 filter is a little wider, a little better high frequency audio. It just sounds a little better.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
toggle quoted message
Show quoted text
My SR400 schematic appears to indicate 1650 and 1652.8 kHz crystals.? FL1 is a 1650 6-pole filter.
What is the advantage of changing? to the filter and frequencies from the SR150?
--
73/Rick
W4XA
__________________________________
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|
KN6WFM (Drew)
waltcates
Rick W7IMM