Re: SX-117 noise limiter behavior
Richard I am recommending penetrating oil to clean and lube switches and pots.? Kroil, Deoxit and the like are effective but are also expensive.? Just trying to point out that there are alternatives to name brand items which also do a decent job at a very reasonable price.
Perhaps we should share some cleaning tips on the reflector.? I am sure that there are many products that do a decent job and are less expensive.? I can recommend Bar Keeper's Friend for general metal cleaning, it works well for me.? For wood cabinets, waterless hand cleaner also does a decent job without harming the remining finish. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
The noise limiter in the SX117 is somewhat unusual. It is a diode
noise clipper, similar to the conventional limiters found in many
receivers, but works at IF frequency rather than audio. It is NOT a
noise blanker. The comments in the instructions are very similar to
those for a conventional limiter. In CW it works because there is no BFO
present at the point of clipping or limiting. The same for SSB. The
distortion on AM really traces to the same cause. In a conventional
series limiter the detected carrier sets the clipping point. In most
receivers its set at about the 100% modulation level but usually
produces some clipping below that. In conventional receivers the clipper
will be biased by the BFO. Since for CW or SSB the BFO level is usually
higher than the signal the clipping level is usually well above the
signal so the effectiveness of the limiter is, well, limited. Some
receivers use a shunt arrangement where there is a manual limiting
control. This can be set to produce more noise reduction on CW or SSB
but must be set for AM signals to minimize distortion.
Since the limiter is in the 50Khz IF, before the AVC it has somewhat
the advantage of a noise blanker of minimizing desensitizing by
preventing noise from influencing the AVC.
Why it isn't working? Guesswork, something is causing the diodes to
short the IF signal. Bad diode perhaps, there is really not much there.
Its hard to find on the schematic.
I generally use Deoxit for switches and Fader lube for pots, have
had long term good results. I have never tried Kroil for either and am
not certain Jim is recommending it.
On 6/8/2024 12:42 AM, Jim Whartenby via groups.io wrote: Floyd
You originally said: "Haven't dug into this yet, but wonder what other
SX-117 users see when turning on the Noise Limiter in? USB or LSB mode.
On my receiver, it's like disconnecting the antenna - an S9+20 signal
falls to S1."
If you had only read the SX-117 manual first you could have answered
your own question, see page 11, bottom of the second column.? Cutting to
the chase, the noise limiter is most useful in CW, somewhat useful in
SSB and causes distortion in AM.? Backing off of the RF gain control
will reduce some distortion.
You mentioned that the SX-117 had been repaired in the past.? If that
included replacing the HD6225 diodes then I would check to see if they
are now Germanium.? The HD6225 is a silicon diode from the dim past of
silicon diode availability.? I have not found a datasheet for it but I
would suggest using a high conductance, low reverse leakage, diode.? One
sub would be the FD333 which has 1/10 the leakage current of the
1N4148.? I am sure that there are others.? But the 1N4148 or the 1N914
would most likely be just as good.
As for the use of a spray to clean and lubricate switches and pots, I
found the info below at the Kroil site:
<>
*"What to Expect from a Penetrating Oil*
There are several benefits to choosing penetrating oil over other
products on the market. It offers lubrication, noise reduction, cleaning
power, and is corrosion resistant. Each brand will be slightly
different, but we want to share what to expect from most of the
traditional penetrating oils available today.
* *Penetration*?¨C Penetrating oils penetrate rust and corrosion in
threads, spaces, and small openings of frozen or seized metal parts
that might seem impossible to reach. Penetrating oil can work
quickly to help loosen items that you thought were a lost cause.
* *Reduction of Noise*?¨C If you¡¯re dealing with industrial equipment,
or a deafening suspension, penetrating oils are made to help. The
way the oil is created helps cut down on both friction and rust,
which is often responsible for creating these noises.
* *Lubrication*?¨C Penetrating oil contains lubricant, although the
actual amount depends on the brand and ingredient list. Sometimes
the lubrication is temporary, but it can also last for a long time
with the right components in the mix. The product can be used to
lubricate mechanical parts on various items. In addition, it helps
with loosening stuck parts, removing tight nuts and bolts, and
reducing friction.
* *Resistance to Corrosion*?¨C Penetrating oils are made to protect any
kind of metal surface from the issues related to corrosion. This is
huge since corrosion is a common enemy of metal used in the
construction of mechanical components. The formulation of the
penetrant works to displace moisture, which helps fight against rust
and other situations that create corrosion.
* *Cleaning Power*?¨C It¡¯s essential to look at the product information
to be sure, but many types of penetrating oil are made to be used
for cleaning. They are especially useful for removing grease,
adhesive, tar, and rust. The oil acts as a solvent which means that
the items it is placed on will start to soften. This makes it much
easier to remove what is left with a soft cloth or a wipe of some sort."
My go to spray is Dollar Store penetrating oil.? It is cheap and works
very well on switches and pots.? I have had no problems at all for the
last dozen years using this product.? Just as good as anything costing
10 times or more the new going price of $1.50 per can.? Like everything
else in life, moderation is key.
If your go to spray is WD-40 then I would agree that if one used
nothing, that would be far better then using
WD-40.? This junk turns to gum over a short period of time and makes
matters much worse for switches, pots and gears.
Regards,
Jim
Logic: Method used to arrive at the wrong conclusion, with confidence.
Murphy
On Friday, June 7, 2024 at 04:56:42 PM CDT, don Root
<drootofallevil@...> wrote:
So, guys, where is the formal non-partisan definition of..
"noise blanker"
"noise limiter"
Is there a defined difference between them ? and do the terms define? an
intent or a specific circuit?
Sorry to interfere but my poor education did not address this; at least
not that I remember.¡»å´Ç²Ô
*From:*[email protected]
[mailto:[email protected]] *On Behalf Of *Floyd - K8AC
*Sent:* Friday, June 7, 2024 5:06 PM
*To:* [email protected]
*Subject:* Re: [HallicraftersRadios] SX-117 noise limiter behavior
I had hoped that someone who has actually seen and used an SX-117 would
respond.? I've only been restoring receivers for 40 years or so, but
over that time I've learned that you can save a lot of time by
consulting with someone else who owns the same radio when observing an
odd behavior.? You might be surprised how many times "they all do that"
is the undesirable but true answer.? As I said, I have not dug into this
particular problem yet.? What I do know is that the SX-117 does not have
a "noise blanker" as seen in later or more sophisticated receivers like
the Drake R4C.? It is described as a noise limiter.? This particular
SX-117 has been completely restored with all new tubes and many
capacitors replaced, as well as a few out-of-tolerance resistors.
Spraying old switch sections with anything is a really bad idea.? All
switches in this unit have been carefully cleaned using De-Oxit and Q
tips and tooth picks to apply the cleaner in small amounts where needed. ,_
--
don??? va3drl
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: SX-117 noise limiter behavior
The noise limiter in the SX117 is somewhat unusual. It is a diode
noise clipper, similar to the conventional limiters found in many
receivers, but works at IF frequency rather than audio. It is NOT a
noise blanker. The comments in the instructions are very similar to
those for a conventional limiter. In CW it works because there is no BFO
present at the point of clipping or limiting. The same for SSB. The
distortion on AM really traces to the same cause. In a conventional
series limiter the detected carrier sets the clipping point. In most
receivers its set at about the 100% modulation level but usually
produces some clipping below that. In conventional receivers the clipper
will be biased by the BFO. Since for CW or SSB the BFO level is usually
higher than the signal the clipping level is usually well above the
signal so the effectiveness of the limiter is, well, limited. Some
receivers use a shunt arrangement where there is a manual limiting
control. This can be set to produce more noise reduction on CW or SSB
but must be set for AM signals to minimize distortion.
Since the limiter is in the 50Khz IF, before the AVC it has somewhat
the advantage of a noise blanker of minimizing desensitizing by
preventing noise from influencing the AVC.
Why it isn't working? Guesswork, something is causing the diodes to
short the IF signal. Bad diode perhaps, there is really not much there.
Its hard to find on the schematic.
I generally use Deoxit for switches and Fader lube for pots, have
had long term good results. I have never tried Kroil for either and am
not certain Jim is recommending it.
toggle quoted message
Show quoted text
On 6/8/2024 12:42 AM, Jim Whartenby via groups.io wrote: Floyd
You originally said: "Haven't dug into this yet, but wonder what other
SX-117 users see when turning on the Noise Limiter in? USB or LSB mode.
On my receiver, it's like disconnecting the antenna - an S9+20 signal
falls to S1."
If you had only read the SX-117 manual first you could have answered
your own question, see page 11, bottom of the second column.? Cutting to
the chase, the noise limiter is most useful in CW, somewhat useful in
SSB and causes distortion in AM.? Backing off of the RF gain control
will reduce some distortion.
You mentioned that the SX-117 had been repaired in the past.? If that
included replacing the HD6225 diodes then I would check to see if they
are now Germanium.? The HD6225 is a silicon diode from the dim past of
silicon diode availability.? I have not found a datasheet for it but I
would suggest using a high conductance, low reverse leakage, diode.? One
sub would be the FD333 which has 1/10 the leakage current of the
1N4148.? I am sure that there are others.? But the 1N4148 or the 1N914
would most likely be just as good.
As for the use of a spray to clean and lubricate switches and pots, I
found the info below at the Kroil site:
<>
*"What to Expect from a Penetrating Oil*
There are several benefits to choosing penetrating oil over other
products on the market. It offers lubrication, noise reduction, cleaning
power, and is corrosion resistant. Each brand will be slightly
different, but we want to share what to expect from most of the
traditional penetrating oils available today.
* *Penetration*?¨C Penetrating oils penetrate rust and corrosion in
threads, spaces, and small openings of frozen or seized metal parts
that might seem impossible to reach. Penetrating oil can work
quickly to help loosen items that you thought were a lost cause.
* *Reduction of Noise*?¨C If you¡¯re dealing with industrial equipment,
or a deafening suspension, penetrating oils are made to help. The
way the oil is created helps cut down on both friction and rust,
which is often responsible for creating these noises.
* *Lubrication*?¨C Penetrating oil contains lubricant, although the
actual amount depends on the brand and ingredient list. Sometimes
the lubrication is temporary, but it can also last for a long time
with the right components in the mix. The product can be used to
lubricate mechanical parts on various items. In addition, it helps
with loosening stuck parts, removing tight nuts and bolts, and
reducing friction.
* *Resistance to Corrosion*?¨C Penetrating oils are made to protect any
kind of metal surface from the issues related to corrosion. This is
huge since corrosion is a common enemy of metal used in the
construction of mechanical components. The formulation of the
penetrant works to displace moisture, which helps fight against rust
and other situations that create corrosion.
* *Cleaning Power*?¨C It¡¯s essential to look at the product information
to be sure, but many types of penetrating oil are made to be used
for cleaning. They are especially useful for removing grease,
adhesive, tar, and rust. The oil acts as a solvent which means that
the items it is placed on will start to soften. This makes it much
easier to remove what is left with a soft cloth or a wipe of some sort."
My go to spray is Dollar Store penetrating oil.? It is cheap and works
very well on switches and pots.? I have had no problems at all for the
last dozen years using this product.? Just as good as anything costing
10 times or more the new going price of $1.50 per can.? Like everything
else in life, moderation is key.
If your go to spray is WD-40 then I would agree that if one used
nothing, that would be far better then using
WD-40.? This junk turns to gum over a short period of time and makes
matters much worse for switches, pots and gears.
Regards,
Jim
Logic: Method used to arrive at the wrong conclusion, with confidence.
Murphy
On Friday, June 7, 2024 at 04:56:42 PM CDT, don Root
<drootofallevil@...> wrote:
So, guys, where is the formal non-partisan definition of..
"noise blanker"
"noise limiter"
Is there a defined difference between them ? and do the terms define? an
intent or a specific circuit?
Sorry to interfere but my poor education did not address this; at least
not that I remember.¡»å´Ç²Ô
*From:*[email protected]
[mailto:[email protected]] *On Behalf Of *Floyd - K8AC
*Sent:* Friday, June 7, 2024 5:06 PM
*To:* [email protected]
*Subject:* Re: [HallicraftersRadios] SX-117 noise limiter behavior
I had hoped that someone who has actually seen and used an SX-117 would
respond.? I've only been restoring receivers for 40 years or so, but
over that time I've learned that you can save a lot of time by
consulting with someone else who owns the same radio when observing an
odd behavior.? You might be surprised how many times "they all do that"
is the undesirable but true answer.? As I said, I have not dug into this
particular problem yet.? What I do know is that the SX-117 does not have
a "noise blanker" as seen in later or more sophisticated receivers like
the Drake R4C.? It is described as a noise limiter.? This particular
SX-117 has been completely restored with all new tubes and many
capacitors replaced, as well as a few out-of-tolerance resistors.
Spraying old switch sections with anything is a really bad idea.? All
switches in this unit have been carefully cleaned using De-Oxit and Q
tips and tooth picks to apply the cleaner in small amounts where needed. ,_
--
don??? va3drl
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: SX-117 noise limiter behavior
Floyd You originally said: "Haven't dug into this yet, but wonder what other SX-117 users see when turning on the Noise Limiter in? USB or LSB mode.? On my receiver, it's like disconnecting the antenna - an S9+20 signal falls to S1."
If you had only read the SX-117 manual first you could have answered your own question, see page 11, bottom of the second column.? Cutting to the chase, the noise limiter is most useful in CW, somewhat useful in SSB and causes distortion in AM.? Backing off of the RF gain control will reduce some distortion.
You mentioned that the SX-117 had been repaired in the past.? If that included replacing the HD6225 diodes then I would check to see if they are now Germanium.? The HD6225 is a silicon diode from the dim past of silicon diode availability.? I have not found a datasheet for it but I would suggest using a high conductance, low reverse leakage, diode.? One sub would be the FD333 which has 1/10 the leakage current of the 1N4148.? I am sure that there are others.? But the 1N4148 or the 1N914 would most likely be just as good.
As for the use of a spray to clean and lubricate switches and pots, I found the info below?at the Kroil site:?
"What to Expect from a Penetrating Oil
There are several benefits to choosing penetrating oil over other products on the market. It offers lubrication, noise reduction, cleaning power, and is corrosion resistant. Each brand will be slightly different, but we want to share what to expect from most of the traditional penetrating oils available today. - Penetration?¨C Penetrating oils penetrate rust and corrosion in threads, spaces, and small openings of frozen or seized metal parts that might seem impossible to reach. Penetrating oil can work quickly to help loosen items that you thought were a lost cause.
- Reduction of Noise?¨C If you¡¯re dealing with industrial equipment, or a deafening suspension, penetrating oils are made to help. The way the oil is created helps cut down on both friction and rust, which is often responsible for creating these noises.
- Lubrication?¨C Penetrating oil contains lubricant, although the actual amount depends on the brand and ingredient list. Sometimes the lubrication is temporary, but it can also last for a long time with the right components in the mix. The product can be used to lubricate mechanical parts on various items. In addition, it helps with loosening stuck parts, removing tight nuts and bolts, and reducing friction.
- Resistance to Corrosion?¨C Penetrating oils are made to protect any kind of metal surface from the issues related to corrosion. This is huge since corrosion is a common enemy of metal used in the construction of mechanical components. The formulation of the penetrant works to displace moisture, which helps fight against rust and other situations that create corrosion.
- Cleaning Power?¨C It¡¯s essential to look at the product information to be sure, but many types of penetrating oil are made to be used for cleaning. They are especially useful for removing grease, adhesive, tar, and rust. The oil acts as a solvent which means that the items it is placed on will start to soften. This makes it much easier to remove what is left with a soft cloth or a wipe of some sort."
My go to spray is Dollar Store penetrating oil.? It is cheap and works very well on switches and pots.? I have had no problems at all for the last dozen years using this product.? Just as good as anything costing 10 times or more the new going price of $1.50 per can.? Like everything else in life, moderation is key.
If your go to spray is WD-40 then I would agree that if one used nothing, that would be far better then using? WD-40.? This junk turns to gum over a short period of time and makes matters much worse for switches, pots and gears. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
So, guys, where is the formal non-partisan definition of.. "noise blanker" "noise limiter" Is there a defined difference between them ? and do the terms define? an intent or a specific circuit? Sorry to interfere but my poor education did not address this; at least not that I remember. ¡»å´Ç²Ô
From: [email protected] [mailto:[email protected]] On Behalf Of Floyd - K8AC
Sent: Friday, June 7, 2024 5:06 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] SX-117 noise limiter behavior ? I had hoped that someone who has actually seen and used an SX-117 would respond.? I've only been restoring receivers for 40 years or so, but over that time I've learned that you can save a lot of time by consulting with someone else who owns the same radio when observing an odd behavior.? You might be surprised how many times "they all do that" is the undesirable but true answer.? As I said, I have not dug into this particular problem yet.? What I do know is that the SX-117 does not have a "noise blanker" as seen in later or more sophisticated receivers like the Drake R4C.? It is described as a noise limiter.? This particular SX-117 has been completely restored with all new tubes and many capacitors replaced, as well as a few out-of-tolerance resistors.
Spraying old switch sections with anything is a really bad idea.? All switches in this unit have been carefully cleaned using De-Oxit and Q tips and tooth picks to apply the cleaner in small amounts where needed.?? ?,_
--
don??? va3drl
|
Re: SX-117 noise limiter behavior
A noise limiter (usually a diode or two) clips off audio above the strength that the desired audio wave reaches.? Some observers say it should be called a clipper, not a limiter.? Often the ¡°clipping off the peaks¡± threshold is adjustable.? Set the clipping threshold too high and the limiter is relatively ineffective.? Set too low and the audio peaks become clipped and distorted. ?Years ago, the ¡°Twin Noise Squelch¡± was popular with lots of us who operated ten meter and six meter AM mobile.? It provided both a squelch and a noise limiter in one easy-to-build circuit.? In SSB, the audio level is lots more varying, so James Lamb blankers are more effective.? In AM reception, the AVC level tends to hold the recovered (detected) AM audio envelope¡¯s peak values constant, which is valuable for both kinds of noise reduction, but particularly necessary for simple audio noise limiters.
Also ¨C noise limiters are among the group of noise reduction techniques that really only work well on impulse noise where the peak value is quite high compared to the average value (ignition noise).
Mike/
K5MGR
____________________________ ? Mike Langner
929 Alameda Road NW
Albuquerque, NM 87114-1901
(505) 898-3212 home/home office
(505) 238-8810 cell
mlangner@...
?
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Show quoted text
From: [email protected] <[email protected]> On Behalf Of Bob
Sent: Friday, June 7, 2024 4:32 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] SX-117 noise limiter behavior? A blanker normally reduces pulse type peaks such as spark plug type pulses. Someone else will need to describe a noise limiter. ? So, guys, where is the formal non-partisan definition of.. "noise blanker" "noise limiter" Is there a defined difference between them ? and do the terms define? an intent or a specific circuit? Sorry to interfere but my poor education did not address this; at least not that I remember. ¡»å´Ç²Ô ? I had hoped that someone who has actually seen and used an SX-117 would respond.? I've only been restoring receivers for 40 years or so, but over that time I've learned that you can save a lot of time by consulting with someone else who owns the same radio when observing an odd behavior.? You might be surprised how many times "they all do that" is the undesirable but true answer.? As I said, I have not dug into this particular problem yet.? What I do know is that the SX-117 does not have a "noise blanker" as seen in later or more sophisticated receivers like the Drake R4C.? It is described as a noise limiter.? This particular SX-117 has been completely restored with all new tubes and many capacitors replaced, as well as a few out-of-tolerance resistors.
Spraying old switch sections with anything is a really bad idea.? All switches in this unit have been carefully cleaned using De-Oxit and Q tips and tooth picks to apply the cleaner in small amounts where needed.?? ?,_
--
don??? va3drl
|
Re: SX-117 noise limiter behavior
A blanker normally reduces pulse type peaks such as spark plug type pulses. Someone else will need to describe a noise limiter. Bob W4JFA?
So, guys, where is the formal non-partisan definition of.. "noise blanker" "noise limiter" Is there a defined difference between them ? and do the terms define? an intent or a specific circuit? Sorry to interfere but my poor education did not address this; at least not that I remember. ¡»å´Ç²Ô ? I had hoped that someone who has actually seen and used an SX-117 would respond.? I've only been restoring receivers for 40 years or so, but over that time I've learned that you can save a lot of time by consulting with someone else who owns the same radio when observing an odd behavior.? You might be surprised how many times "they all do that" is the undesirable but true answer.? As I said, I have not dug into this particular problem yet.? What I do know is that the SX-117 does not have a "noise blanker" as seen in later or more sophisticated receivers like the Drake R4C.? It is described as a noise limiter.? This particular SX-117 has been completely restored with all new tubes and many capacitors replaced, as well as a few out-of-tolerance resistors.
Spraying old switch sections with anything is a really bad idea.? All switches in this unit have been carefully cleaned using De-Oxit and Q tips and tooth picks to apply the cleaner in small amounts where needed.?? ?,_
--
don??? va3drl
|
Re: SX-117 noise limiter behavior
So, guys, where is the formal non-partisan definition of.. "noise blanker" "noise limiter" Is there a defined difference between them ? and do the terms define? an intent or a specific circuit? Sorry to interfere but my poor education did not address this; at least not that I remember. ¡»å´Ç²Ô
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Floyd - K8AC
Sent: Friday, June 7, 2024 5:06 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] SX-117 noise limiter behavior? I had hoped that someone who has actually seen and used an SX-117 would respond.? I've only been restoring receivers for 40 years or so, but over that time I've learned that you can save a lot of time by consulting with someone else who owns the same radio when observing an odd behavior.? You might be surprised how many times "they all do that" is the undesirable but true answer.? As I said, I have not dug into this particular problem yet.? What I do know is that the SX-117 does not have a "noise blanker" as seen in later or more sophisticated receivers like the Drake R4C.? It is described as a noise limiter.? This particular SX-117 has been completely restored with all new tubes and many capacitors replaced, as well as a few out-of-tolerance resistors.
Spraying old switch sections with anything is a really bad idea.? All switches in this unit have been carefully cleaned using De-Oxit and Q tips and tooth picks to apply the cleaner in small amounts where needed.?? ?,_ -- don??? va3drl
|
Re: SX-117 noise limiter behavior
I had hoped that someone who has actually seen and used an SX-117 would respond.? I've only been restoring receivers for 40 years or so, but over that time I've learned that you can save a lot of time by consulting with someone else who owns the same radio when observing an odd behavior.? You might be surprised how many times "they all do that" is the undesirable but true answer.? As I said, I have not dug into this particular problem yet.? What I do know is that the SX-117 does not have a "noise blanker" as seen in later or more sophisticated receivers like the Drake R4C.? It is described as a noise limiter.? This particular SX-117 has been completely restored with all new tubes and many capacitors replaced, as well as a few out-of-tolerance resistors.
Spraying old switch sections with anything is a really bad idea.? All switches in this unit have been carefully cleaned using De-Oxit and Q tips and tooth picks to apply the cleaner in small amounts where needed.??
|
Wow. Awesome.? ?I tried that on mine but the plates where badly scorched.? Also, If you are not aware, You should run a wire from the rear section TOP terminal to the rear section bottom terminal.? Use teflon wire or HV wire if you have a piece.? Jim told me
this would prevent the terminal from being damaged on the one side of the cap.
C
toggle quoted message
Show quoted text
From: Walt Cates <cateswa@...>
Sent: Friday, June 7, 2024 11:31 AM
To: clark clarkturnertuning.com <clark@...>
Cc: HALLI IO GROUP <[email protected]>
Subject: SR-2000 load cap
?
I got lucky. Simple fix. When I got the load cap out, I could clearly?see the rotor was too far to the rear. I adjusted the end play screw and centered the rotor plates and all is fine. That is when I notice that the lock tight seal was only on the retainer
nut and did not cover the adjustment screw. I think I will drill a hole in the rear plate to allow access to that adjustment.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
|
I got lucky. Simple fix. When I got the load cap out, I could clearly?see the rotor was too far to the rear. I adjusted the end play screw and centered the rotor plates and all is fine. That is when I notice that the lock tight seal was only on the retainer
nut and did not cover the adjustment screw. I think I will drill a hole in the rear plate to allow access to that adjustment.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
|
Re: Parting out an SX-100
Contact me offline to arrange payment and shipping
THX
Yes I have those items Kevin
On Fri, Jun 7, 2024 at 11:40?AM trekkersteve via <trekkersteve= [email protected]> wrote: Donald,
Yes, these are the ones.
New to this process so is further communications handled here or offline??
If offline, I don't know how to reference your email address.
Steve?
|
Re: SX-117 noise limiter behavior
As far as I can see, there is a form of Noise Blanker implemented into the SX-117. Two silicon diodes, polarised by the signal from the last IF amp that de-sensitizes the input directly at the antenna connexion. Maybe the two diodes (CR1 and CR2) are busted¡. And that the antenna signal is shorted when the ¡°NL¡± is activated¡ Look at the schematic. ? 73, Jacques, VE2JFE in Montreal ? ? Clarify a little, do you mean a desired signal falls off that much
or background noise? If its a desired signal it sounds like the blanker
is blanking or blocking the signal all the time. A noise blanker is
supposed to cut or blank the signal path for short periods to eliminate
the effect of impulse noise, like ignition noise. Mostly to prevent it
from activating the AVC and desensitizing the receiver. Don't know how
its arranged in the SX-117 but it sounds like its blanking all the time.
toggle quoted message
Show quoted text
On 6/7/2024 9:02 AM, Floyd - K8AC wrote: Haven't dug into this yet, but wonder what other SX-117 users see when
turning on the Noise Limiter in? USB or LSB mode.? On my receiver, it's
like disconnecting the antenna - an S9+20 signal falls to S1.
73, Floyd - K8AC
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: SX-117 noise limiter behavior
Floyd Have the tubes been checked for conduction, leakage and shorts?? Are you planning to recap the radio or at least check some coupling and bypass caps for leakage?? Have you done a critical look to see if there are any signs of stress on components and the like?? Sprayed?all pots and switches with your your favorite contact cleaner? I would do all of the above before applying power, to any radio.? It will save a lot of time troubleshooting. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
Clarify a little, do you mean a desired signal falls off that much
or background noise? If its a desired signal it sounds like the blanker
is blanking or blocking the signal all the time. A noise blanker is
supposed to cut or blank the signal path for short periods to eliminate
the effect of impulse noise, like ignition noise. Mostly to prevent it
from activating the AVC and desensitizing the receiver. Don't know how
its arranged in the SX-117 but it sounds like its blanking all the time.
On 6/7/2024 9:02 AM, Floyd - K8AC wrote: Haven't dug into this yet, but wonder what other SX-117 users see when
turning on the Noise Limiter in? USB or LSB mode.? On my receiver, it's
like disconnecting the antenna - an S9+20 signal falls to S1.
73, Floyd - K8AC
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
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Re: SX-117 noise limiter behavior
Clarify a little, do you mean a desired signal falls off that much
or background noise? If its a desired signal it sounds like the blanker
is blanking or blocking the signal all the time. A noise blanker is
supposed to cut or blank the signal path for short periods to eliminate
the effect of impulse noise, like ignition noise. Mostly to prevent it
from activating the AVC and desensitizing the receiver. Don't know how
its arranged in the SX-117 but it sounds like its blanking all the time.
toggle quoted message
Show quoted text
On 6/7/2024 9:02 AM, Floyd - K8AC wrote: Haven't dug into this yet, but wonder what other SX-117 users see when
turning on the Noise Limiter in? USB or LSB mode.? On my receiver, it's
like disconnecting the antenna - an S9+20 signal falls to S1.
73, Floyd - K8AC
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
SX-117 noise limiter behavior
Haven't dug into this yet, but wonder what other SX-117 users see when turning on the Noise Limiter in? USB or LSB mode.? On my receiver, it's like disconnecting the antenna - an S9+20 signal falls to S1.
73, Floyd - K8AC
|
Re: Parting out an SX-100
Donald,
Yes, these are the ones.
New to this process so is further communications handled here or offline??
If offline, I don't know how to reference your email address.
Steve?
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Re: HT45 Loudenboomer working now with new power supply
Thanks for posting that article!? That stuff never changes with time does it!!
The original transformer is rated at 6750 (CT).....so with 12V the secondary should yield 675(RMS)? and Yes.....? The peak would be right up there too!. (With 12v RMS, the peak is about 17V)
I know there are many high voltage plate supplies that have placed the choke in the CT.? It actually is a pretty good way to reduce the total voltage on the choke.? Doesn't do much for the rectifier filament transformer though.
Don't forget to post pictures!
We love pictures!
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
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Re: Parting out an SX-100
Hi Donald,
I am interested in the S-meter, the S-meter control pot on the back of the chassis, along with the Response and Selectivity knobs. Let me know what you have available.
Regards
Kevin M - W2AQY
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Re: HT45 Loudenboomer working now with new power supply
Using the Duncan Amps power supply designer ( /g/duncanampspsud) I modeled the factory supply with 866As, with diodes, and with different bleeder and capacitor values. Long story short, everything other than design values increase transformer/choke current, HV, or both.? Took bottom cover off the RF deck and found: Rattling to be a small nut and washer that do not appear to be part of the amp; RF deck filament transformer good; 3-400Z heater continuity, Grid not shorted; Ig and Ip metering resistors are open(Ig resistor blown open :-); Meter works; Lots of dust, dirt, and cat(?) hair.? Hope to find some suitable 0.25 ohm resistors in the junk box. HP45: 10k resistor for the HP45 NE51 lamp is missing.? Hope the tube is not gassy. Use the ~10kV P to P transformer secondary with some current limiting to check for gas in the tube? Why not! What to do once working? Move RF deck fuse holder to HP45 chassis and use that hole for a HV connector to run HV+ with wire that's good for at least 3kV. Assemble TR relay(s) with 'PTT' keying circuit for tube bias as suggested in manual. 73, -bob ah7i
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They are not available.? They are reverse rotation.? ?I ordered five caps and no e really work directly.? I did find one that does work at tubes and more.com. however it's slightly smaller and will need a mounting plate made. The holes do not
line up. I can send that one to you if you are willing to adapt it Walt.??
C
I need the PA load capacitor for the SR-2000.
C156 3 section Halli. Part #048-000629.
I think someone else had the same need a short time ago. I cannot find the topic in the archives. Hope someone remembers the outcome or has a parts unit.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
|
I need the PA load capacitor for the SR-2000.
C156 3 section Halli. Part #048-000629.
I think someone else had the same need a short time ago. I cannot find the topic in the archives. Hope someone remembers the outcome or has a parts unit.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
|
Jim Whartenby
Mike Langner
Bob
don Root
Floyd - K8AC
waltcates
Donald J
Jacques_VE2JFE
Rick W7IMM
Bob ah7i