Re: HT-44/SX-117 CW transceive offset?
Couldn't agree more with "?instead of modifying a vintage setup that was never really intended to do that."Th
If you want to stay with vintage equipment. The Hallicreafters SR-150 is a transceiver with RIT built in and is comparable in performance to the 44/117. Any of the SR series from the three band SR 160 and 500 through the SR 2000 will give you that feture.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
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I suppose it would add extra steps in the process.....I guess I'm implying that the HT44/SX117 (or any separate transmitter/receiver combo)? wouldn't be my "go-to" set up for rapid "contest" like operation.?
?
I would probably opt for something a little more "Modern" instead of modifying a vintage setup that was never really intended to do that.??? Not saying it can't or even shouldn't be done!? Are there extra points during CW contests
for using vintage and separate T/R gear?
?
73/Rick
W7IMM
__________________________________
All posts are created using free and opensource? Linux
|
Re: HT-44/SX-117 CW transceive offset?
I suppose it would add extra steps in the process.....I guess I'm implying that the HT44/SX117 (or any separate transmitter/receiver combo)? wouldn't be my "go-to" set up for rapid "contest" like operation.?
?
I would probably opt for something a little more "Modern" instead of modifying a vintage setup that was never really intended to do that.??? Not saying it can't or even shouldn't be done!? Are there extra points during CW contests for using vintage and separate T/R gear?
?
73/Rick
W7IMM
__________________________________
All posts are created using free and opensource? Linux
|
Re: HT-44/SX-117 CW transceive offset?
Floyd,
I've operated old separates here in some contests and definitely
feel your pain.? The only set I have that works easily is the
Collins S line but even to get that behaving properly took some
modifications.? So my rule here now on contesting with old gear is
to run, and not do any S&P, with the separates.??
If I am needing to do S&P as well, then I will use something
like the TR4C or other era similar transceiver for the S&P
stuff as it's much easier to be QRG agile with it.? And I have the
pleasure of adding more heat to the shack while I'm at it.? :)?
Not really a specific solution to this issue but it does have the
attraction of getting contest Qs without having to do any rig
mods.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 11/23/2024 8:44 AM, Floyd - K8AC via
groups.io wrote:
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Show quoted text
On Fri, Nov 22, 2024 at 05:39 PM, waltcates wrote:
Yes. The entire SR series of transceivers has
receiver incremental tuning, RIT. Hallicrafters had the
original patten on the RIT concept and was the first?to go
into production with it.
Wow - everyone has missed the point entirely.? Guess there
aren't many folks using Hallicrafters gear in CW mode,
particularly in contests.? I will go into greater detail and
hope I don't offend anyone.??
?
Note: all of the following applies to the HT-44 with the rear
slide switch in XCVE (transceive) mode.? The goal here is: when
you tune in a CW station on the SX-117 (with the HT44 slide
switch in XCVE mode), you want the HT-44 to be tuned TO THE SAME
FREQUENCY AS THAT OF THE STATION YOU'RE HEARING.? That way, the
station you're calling will hear you at a reasonable pitch.?
But, when setting up the SX-117 and HT-44 for receive mode, you
adjust C1 for zero beat, putting the transmitter and receiver on
exactly the same frequency.? For SSB, that's exactly what you
want and it works perfectly.? But, for transceiving in CW mode,
you want the two to be offset by the frequency of the CW tone
you like to hear - say, 600 to 700 Hz.? On my HT-44, the range
of adjustment of C1 can provide an offset of around 200 Hz, not
enough.? Many early manufacturers of transceive capable gear got
this offset thing wrong - notably Collins.? If you wanted to
transceive in CW mode on the S Line, you ended up with an offset
of 1.5 Khz in some cases and that's simply not usable.? Drake
got this right in their 4 Line with a fixed offset of around 700
Hz.? In SSB mode, the offset is zero, but switching to CW
changes it to 700 Hz.??
?
So, what I'm after is being able to shift the frequency of
the HT-44 carrier oscillator by 600-700 Hz in an adjustable
fashion so that I can still put it back to 1650 Khz for SSB
operation.? Not something I'd often do, so a screwdriver
adjustment is entirely acceptable.? In the HT-44, the crystal
frequency is varied by adjusting C1, a capacitor in parallel
with the crystal.? You can also adjust the frequency of a
crystal oscillator using a capacitor in series with the
crystal.? A good way to do that in the HT-44 might be to use
varicap diodes.? But, pulling a crystal frequency has
limitations and in this case, I have no idea how far we could
actually pull the crystal frequency without some negative
effects.? Hence my original question: has anyone actually done
this and how did it work out?? ?Some academic papers I've read
on the subject of pulling a crystal frequency indicate that 50
ppm might be the limit, but it depends upon the crystal cut and
a lot of other factors.??
?
And, yes, an RIT function would satisfy my requirement but
that doesn't exist on the SX-117.? Fiddling with the BFO
frequency does NOT solve the problem and no need to explain that
here.? For now, I continue to use the SX-117/HT-44 for CW in the
NORM mode, having to switch the Operation switch to CAL and
turning the HT-44 VFO to the desired frequency.??
?
73, Floyd - K8AC
?
|
Re: For Sale: Hallicrafters SR-150, PM-150 Power Supply- Pick up Northern Illinois or will now Ship
Dave, ? ? ?Inside pics attached below. Sorry it took so long. Yesterday was a long day.
73,
Ron K9RH
Thanks Ron,? Could you pls open the lid and take a pic of the insides.?
73 Dave
Dave, ? ? ?See attached photos and videos.I will send pics of interior tomorrow. Mic is not included.
73,
Ron K9RH
On Thursday, November 21, 2024 at 05:42:53 PM CST, Dave Jordan via <wa3gin= [email protected]> wrote:
Do you any pictures inside and outside, front panel? ?
Thanks Dave Wa3gin?
Shipping at buyers expense is now available via The UPS Store
?
Downsizing. For Sale my Hallicrafters SR-150 Transceiver, PM-150-120. power supply and copy of manual downloaded from the internet. I purchased the SR-150 and power supply at a hamfest in Florida about three years ago and they are in excellent physical condition with some paint chips on their cabinets. They were both recapped by someone else previously. They have been used sparsely by me. I am downsizing my station in anticipation of moving to a smaller QTH. The SR-150 transmits and receives well. Some of the controls are a bit scratchy and could probably use a cleaning. Grabbing the cable between the radio and the power supply and twisting it will while the transceiver is powered up will occasionally blow the fuse in the power supply. This does not happen during normal operation. Although they are currently operational, they are nearly 62 years old and they are being sold as is with no warranty expressed or implied and no returns. The Price for everything is $325.00 picked up at my QTH in Highland Park, Illinois. (25 miles north of Chicago, 30 miles south of Wisconsin line.) The price for this equipment is far below what people are paying for units listed as "parts only-not operational" on eBay. Payment is by USPS Money Order only. Please do not contact me and make an offer below $325.00. Price is firm . SHIPPING. After I receive payment, ?I will take them to the local UPS store after you contact them and make arrangements and agree to pay them for shipping. I don’t have the proper boxes and materials to safely ship them. ?Please email with any questions. My email is good on QRZ.com.
Thank and 73,
Ron Harroff
K9RH
|
Re: HT-44/SX-117 CW transceive offset?
On Fri, Nov 22, 2024 at 05:39 PM, waltcates wrote:
Yes. The entire SR series of transceivers has receiver incremental tuning, RIT. Hallicrafters had the original patten on the RIT concept and was the first?to go into production with it.
Wow - everyone has missed the point entirely.? Guess there aren't many folks using Hallicrafters gear in CW mode, particularly in contests.? I will go into greater detail and hope I don't offend anyone.??
?
Note: all of the following applies to the HT-44 with the rear slide switch in XCVE (transceive) mode.? The goal here is: when you tune in a CW station on the SX-117 (with the HT44 slide switch in XCVE mode), you want the HT-44 to be tuned TO THE SAME FREQUENCY AS THAT OF THE STATION YOU'RE HEARING.? That way, the station you're calling will hear you at a reasonable pitch.? But, when setting up the SX-117 and HT-44 for receive mode, you adjust C1 for zero beat, putting the transmitter and receiver on exactly the same frequency.? For SSB, that's exactly what you want and it works perfectly.? But, for transceiving in CW mode, you want the two to be offset by the frequency of the CW tone you like to hear - say, 600 to 700 Hz.? On my HT-44, the range of adjustment of C1 can provide an offset of around 200 Hz, not enough.? Many early manufacturers of transceive capable gear got this offset thing wrong - notably Collins.? If you wanted to transceive in CW mode on the S Line, you ended up with an offset of 1.5 Khz in some cases and that's simply not usable.? Drake got this right in their 4 Line with a fixed offset of around 700 Hz.? In SSB mode, the offset is zero, but switching to CW changes it to 700 Hz.??
?
So, what I'm after is being able to shift the frequency of the HT-44 carrier oscillator by 600-700 Hz in an adjustable fashion so that I can still put it back to 1650 Khz for SSB operation.? Not something I'd often do, so a screwdriver adjustment is entirely acceptable.? In the HT-44, the crystal frequency is varied by adjusting C1, a capacitor in parallel with the crystal.? You can also adjust the frequency of a crystal oscillator using a capacitor in series with the crystal.? A good way to do that in the HT-44 might be to use varicap diodes.? But, pulling a crystal frequency has limitations and in this case, I have no idea how far we could actually pull the crystal frequency without some negative effects.? Hence my original question: has anyone actually done this and how did it work out?? ?Some academic papers I've read on the subject of pulling a crystal frequency indicate that 50 ppm might be the limit, but it depends upon the crystal cut and a lot of other factors.??
?
And, yes, an RIT function would satisfy my requirement but that doesn't exist on the SX-117.? Fiddling with the BFO frequency does NOT solve the problem and no need to explain that here.? For now, I continue to use the SX-117/HT-44 for CW in the NORM mode, having to switch the Operation switch to CAL and turning the HT-44 VFO to the desired frequency.??
?
73, Floyd - K8AC
?
|
Re: HT-44/SX-117 CW transceive offset?
On Fri, Nov 22, 2024 at 03:36 PM, Rick W7IMM wrote:
I'm not seeing much advantage in taking the time to do a modification like that when there's a knob called "VFO Selector" on the transmitter that does the job quite nicely .......(actually better)
Rick, I'm afraid that doesn't make a lot of sense to me.? When I'm operating in a CW contest in search-and-pounce mode, when I want to call a station I hear, I want to be able to hit the key immediately without turning any other knobs.? Turning the VFO Selector knob solves that how?
?
73, Floyd - K8AC
|
Re: HT-44/SX-117 CW transceive offset?
Yes. The entire SR series of transceivers has receiver incremental tuning, RIT. Hallicrafters had the original patten on the RIT concept and was the first?to go into production with it.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
toggle quoted message
Show quoted text
"Do
any tranceivers actually have a way
to
change the received CW tone without changing the receiver frequency?'
?
Sure
-? Many of the modern HF transceivers have a "CW tone/pitch" control that allows you to change the CW pitch without changing the Rx freq. I can't think of any of the vintage tube xcvrs that had that feature, but maybe someone knows of one. My TR4CW/RIT only
has a RIT control, which changes the Rx freq along with the CW tone.?
?
Bob
K3AC
In a message dated 11/22/2024 4:12:29 PM Eastern Standard Time, 1oldlens1@... writes:
?
Do any tranceivers actually have a way
to change the received CW tone without changing the receiver frequency?
|
Re: HT-44/SX-117 CW transceive offset?
My Swan 270B and 350B shift the oscillator between receive and transmit
so that you can transmit and receive on the same frequency but still
have nice receive audio tone frequency.
But tuning so that the transmit lands on the frequency of the other
station is not easy, at least for me, if you do it by ear. I've used
various methods, including zerobeating a guitar tuner with audio tone
output. This becomes important if the other station is using a narrow
CW filter.
73,
Maynard
W6PAP
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On 11/22/24 13:12, Richard Knoppow via groups.io wrote: It seems to me that having differential tuning for RX and TX serves
two purposes: one is to tune a received signal that is drifting
slightly, the other, and I think what is meant here, is to set the tone
of a received CW signal without changing the transmit frequency. This is
really a reason for having an adjustable BFO. The Receiver should really
be zeroed on the received frequency and the tone set via a variable BFO.
Standard practice with separate RX and TX. Where the BFO is fixed, as it
sometimes is in receivers designed mainly for SSB, it is necessary to
compromise the receiver tuning. Do any tranceivers actually have a way
to change the received CW tone without changing the receiver frequency?
I have only older Drake and Kenwood stuff intended mainly for SSB, none
is ideal for CW where my Drake separates work very well.
Separates sounds familier, does it refer to ladies underwear or bed
sheets? Can't remember.
On 11/22/2024 12:36 PM, Rick W7IMM via groups.io wrote:
Floyd,
I have the same twins (plus the HT45)
It would appear that using a varicap,? "switched-in" when selecting CW
would probably do the job.? It would require a little experimentation
though.....
I'm not seeing much advantage in taking the time to do a modification
like that when there's a knob called "VFO Selector" on the transmitter
that does the job quite nicely .......(actually better)
--
73/Rick
W7IMM
__________________________________
All posts are created using free and opensource? Linux
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: HT-44/SX-117 CW transceive offset?
"Do any tranceivers actually have a way
to change the received CW tone without changing the receiver frequency?'
?
Sure -? Many of the modern HF transceivers have a "CW tone/pitch" control that allows you to change the CW pitch without changing the Rx freq. I can't think of any of the vintage tube xcvrs that had that feature, but maybe someone knows of one. My TR4CW/RIT only has a RIT control, which changes the Rx freq along with the CW tone.?
?
Bob K3AC
In a message dated 11/22/2024 4:12:29 PM Eastern Standard Time, 1oldlens1@... writes:
?
Do any tranceivers actually have a way
to change the received CW tone without changing the receiver frequency?
|
|
|
Re: HT-44/SX-117 CW transceive offset?
It seems to me that having differential tuning for RX and TX serves
two purposes: one is to tune a received signal that is drifting
slightly, the other, and I think what is meant here, is to set the tone
of a received CW signal without changing the transmit frequency. This is
really a reason for having an adjustable BFO. The Receiver should really
be zeroed on the received frequency and the tone set via a variable BFO.
Standard practice with separate RX and TX. Where the BFO is fixed, as it
sometimes is in receivers designed mainly for SSB, it is necessary to
compromise the receiver tuning. Do any tranceivers actually have a way
to change the received CW tone without changing the receiver frequency?
I have only older Drake and Kenwood stuff intended mainly for SSB, none
is ideal for CW where my Drake separates work very well.
Separates sounds familier, does it refer to ladies underwear or bed
sheets? Can't remember.
toggle quoted message
Show quoted text
On 11/22/2024 12:36 PM, Rick W7IMM via groups.io wrote: Floyd,
I have the same twins (plus the HT45)
It would appear that using a varicap,? "switched-in" when selecting CW
would probably do the job.? It would require a little experimentation
though.....
I'm not seeing much advantage in taking the time to do a modification
like that when there's a knob called "VFO Selector" on the transmitter
that does the job quite nicely .......(actually better)
--
73/Rick
W7IMM
__________________________________
All posts are created using free and opensource? Linux
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: HT-44/SX-117 CW transceive offset?
Floyd,
?
I have the same twins (plus the HT45)
?
It would appear that using a varicap,? "switched-in" when selecting CW would probably do the job.? It would require a little experimentation though.....
?
I'm not seeing much advantage in taking the time to do a modification like that when there's a knob called "VFO Selector" on the transmitter that does the job quite nicely .......(actually better)
?
?
--
73/Rick
W7IMM
__________________________________
All posts are created using free and opensource? Linux
|
HT-44/SX-117 CW transceive offset?
I wonder if anyone has looked at a modification to the HT-44 to provide a CW mode offset in transceive?? I tried adjusting C1 in the HT-44 to get an offset in the area of 500-700 Hz, but could get it up to only about 200 Hz with minimum setting of C1.??
?
73, Floyd - K8AC
|
Re: For Sale: Hallicrafters SR-150, PM-150 Power Supply- Pick up Northern Illinois or will now Ship
Thanks Ron,? Could you pls open the lid and take a pic of the insides.?
73 Dave
Dave, ? ? ?See attached photos and videos.I will send pics of interior tomorrow. Mic is not included.
73,
Ron K9RH
On Thursday, November 21, 2024 at 05:42:53 PM CST, Dave Jordan via <wa3gin= [email protected]> wrote:
Do you any pictures inside and outside, front panel? ?
Thanks Dave Wa3gin?
Shipping at buyers expense is now available via The UPS Store
?
Downsizing. For Sale my Hallicrafters SR-150 Transceiver, PM-150-120. power supply and copy of manual downloaded from the internet. I purchased the SR-150 and power supply at a hamfest in Florida about three years ago and they are in excellent physical condition with some paint chips on their cabinets. They were both recapped by someone else previously. They have been used sparsely by me. I am downsizing my station in anticipation of moving to a smaller QTH. The SR-150 transmits and receives well. Some of the controls are a bit scratchy and could probably use a cleaning. Grabbing the cable between the radio and the power supply and twisting it will while the transceiver is powered up will occasionally blow the fuse in the power supply. This does not happen during normal operation. Although they are currently operational, they are nearly 62 years old and they are being sold as is with no warranty expressed or implied and no returns. The Price for everything is $325.00 picked up at my QTH in Highland Park, Illinois. (25 miles north of Chicago, 30 miles south of Wisconsin line.) The price for this equipment is far below what people are paying for units listed as "parts only-not operational" on eBay. Payment is by USPS Money Order only. Please do not contact me and make an offer below $325.00. Price is firm . SHIPPING. After I receive payment, ?I will take them to the local UPS store after you contact them and make arrangements and agree to pay them for shipping. I don’t have the proper boxes and materials to safely ship them. ?Please email with any questions. My email is good on QRZ.com.
Thank and 73,
Ron Harroff
K9RH
|
Re: For Sale: Hallicrafters SR-150, PM-150 Power Supply- Pick up Northern Illinois or will now Ship
Dave, ? ? ?See attached photos and videos.I will send pics of interior tomorrow. Mic is not included.
73,
Ron K9RH
Do you any pictures inside and outside, front panel? ?
Thanks Dave Wa3gin?
Shipping at buyers expense is now available via The UPS Store
?
Downsizing. For Sale my Hallicrafters SR-150 Transceiver, PM-150-120. power supply and copy of manual downloaded from the internet. I purchased the SR-150 and power supply at a hamfest in Florida about three years ago and they are in excellent physical condition with some paint chips on their cabinets. They were both recapped by someone else previously. They have been used sparsely by me. I am downsizing my station in anticipation of moving to a smaller QTH. The SR-150 transmits and receives well. Some of the controls are a bit scratchy and could probably use a cleaning. Grabbing the cable between the radio and the power supply and twisting it will while the transceiver is powered up will occasionally blow the fuse in the power supply. This does not happen during normal operation. Although they are currently operational, they are nearly 62 years old and they are being sold as is with no warranty expressed or implied and no returns. The Price for everything is $325.00 picked up at my QTH in Highland Park, Illinois. (25 miles north of Chicago, 30 miles south of Wisconsin line.) The price for this equipment is far below what people are paying for units listed as "parts only-not operational" on eBay. Payment is by USPS Money Order only. Please do not contact me and make an offer below $325.00. Price is firm . SHIPPING. After I receive payment, ?I will take them to the local UPS store after you contact them and make arrangements and agree to pay them for shipping. I don’t have the proper boxes and materials to safely ship them. ?Please email with any questions. My email is good on QRZ.com.
Thank and 73,
Ron Harroff
K9RH
|
Re: For Sale: Hallicrafters SR-150, PM-150 Power Supply- Pick up Northern Illinois or will now Ship
Hi Ron,
?
I'm still interested in the SR-150. ?Can you send me additional photos of the condition of the set-up? ?I'm good on QRZ and can also pick-up next week.
73,
Jim N9WW
|
Re: For Sale: Hallicrafters SR-150, PM-150 Power Supply- Pick up Northern Illinois or will now Ship
Do you any pictures inside and outside, front panel? ?
Thanks Dave Wa3gin?
Shipping at buyers expense is now available via The UPS Store
?
Downsizing. For Sale my Hallicrafters SR-150 Transceiver, PM-150-120. power supply and copy of manual downloaded from the internet. I purchased the SR-150 and power supply at a hamfest in Florida about three years ago and they are in excellent physical condition with some paint chips on their cabinets. They were both recapped by someone else previously. They have been used sparsely by me. I am downsizing my station in anticipation of moving to a smaller QTH. The SR-150 transmits and receives well. Some of the controls are a bit scratchy and could probably use a cleaning. Grabbing the cable between the radio and the power supply and twisting it will while the transceiver is powered up will occasionally blow the fuse in the power supply. This does not happen during normal operation. Although they are currently operational, they are nearly 62 years old and they are being sold as is with no warranty expressed or implied and no returns. The Price for everything is $325.00 picked up at my QTH in Highland Park, Illinois. (25 miles north of Chicago, 30 miles south of Wisconsin line.) The price for this equipment is far below what people are paying for units listed as "parts only-not operational" on eBay. Payment is by USPS Money Order only. Please do not contact me and make an offer below $325.00. Price is firm . SHIPPING. After I receive payment, ?I will take them to the local UPS store after you contact them and make arrangements and agree to pay them for shipping. I don’t have the proper boxes and materials to safely ship them. ?Please email with any questions. My email is good on QRZ.com.
Thank and 73,
Ron Harroff
K9RH
|
For Sale: Hallicrafters SR-150, PM-150 Power Supply- Pick up Northern Illinois or will now Ship
Shipping at buyers expense is now available via The UPS Store
?
Downsizing. For Sale my Hallicrafters SR-150 Transceiver, PM-150-120. power supply and copy of manual downloaded from the internet. I purchased the SR-150 and power supply at a hamfest in Florida about three years ago and they are in excellent physical condition with some paint chips on their cabinets. They were both recapped by someone else previously. They have been used sparsely by me. I am downsizing my station in anticipation of moving to a smaller QTH. The SR-150 transmits and receives well. Some of the controls are a bit scratchy and could probably use a cleaning. Grabbing the cable between the radio and the power supply and twisting it will while the transceiver is powered up will occasionally blow the fuse in the power supply. This does not happen during normal operation. Although they are currently operational, they are nearly 62 years old and they are being sold as is with no warranty expressed or implied and no returns. The Price for everything is $325.00 picked up at my QTH in Highland Park, Illinois. (25 miles north of Chicago, 30 miles south of Wisconsin line.) The price for this equipment is far below what people are paying for units listed as "parts only-not operational" on eBay. Payment is by USPS Money Order only. Please do not contact me and make an offer below $325.00. Price is firm . SHIPPING. After I receive payment, ?I will take them to the local UPS store after you contact them and make arrangements and agree to pay them for shipping. I don’t have the proper boxes and materials to safely ship them. ?Please email with any questions. My email is good on QRZ.com.
Thank and 73,
Ron Harroff
K9RH
|
Re: HT46 SX146 Slave Operation - CW Offset
Thanks for your suggestion Jeff. It made me think about this in a little different light and that's good. In the SX146 of course there is no front panel BFO knob. The two beat frequency oscillators 8998.7KHz and 9001.5KHz are set with trimmers inside the receiver and printed next to them it says "critical adjustments do not touch". That is important of course because in slaved operation they need to be set so that you are receiving and transmitting on the same freq.?
?
Your varactor idea is a good one. That could be configured as an outboard BFO knob (I wouldn't drill any holes in my precious SX146). A switch (or switch and relay) would take it out of the circuit when in SSB mode. In CW mode I would zero beat the station with the varactor switched out then switch it in and tune the BFO knob for the desired tone. I would just have to remember to have it switched out when operating SSB. Unfortunately the mode switch on the SX146 has CW and one of the SSB selections on the same position. If CW had it's own position on the rotary switch then it could be automatic.?
?
Maybe it is easier to just fix the transmitter and forget about slave operation with the RX VFO. The chirp could likely be fixed but the drift is a bear. It takes about 1.5 hours the transmitter frequency to settle down. The receiver however is stable after about 5 minutes.?
73 - Jerry - W0PWE
|
Re: Wanted: Schematic for S-38E
Richard. ??Re ?“they have the power switch on the ground side. Why? No idea.” Yes Richard, they all do. Here is my thought in pictures taken from the S38C.
? .. moves switch as many have suggested, more logical from AC and ground viewpoint, but what will happen to hum
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Richard Knoppow via groups.io
Sent: Tuesday, November 19, 2024 10:09 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] Wanted: Schematic for S-38E? Halicrafters seems to put the power switch in the hot side of the
AC or the + side of DC, seems fairly consistent going back to the
Echophone EC-1, however, see the schematics for the National SW-54, very
similar to the S-38B and the NC-33 and NC-46, these are more elaborate
AC/DC receivers than the Halicrafters sets, they have the power switch
on the ground side. Why? No idea.
On 11/19/2024 5:51 PM, don Root wrote: Dan, and all, One of your questions raised again an ongoing question
about where the switch is /usually is.? IN getting some education about
transformerless radios from way back, it seems that the switch is always
in the line running to B-minus, and this is well before the common tubes
in the S-38? series strings.
From small bits on the topic, it seems that it is because the switch is
then electrically very close to the detector heater which is also placed
next to B-minus; all this to reduce hum. ?We wonder if the switch? can
reasonably be moved?? Maybe somebody will test it and report.
--
don??? va3drl --
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998 -- don??? va3drl
|
waltcates
Rick W7IMM
Floyd - K8AC
don Root
Dave Jordan