Supercapacitors - Possible anti-surge device to protect filaments/ heaters
I have been reading about them for electric vehicles (boost and regen braking etc.) so I thought of using them to take the switch-on surge and divert the surge from the filaments.
You would need a high current silicon rectifier, but check that spec for surge current.
I have not put this through tests yet, to montoir the current profile over time to the filaments - just an idea at this stage.
They have a 2.7 volt rating, so 3 in series (8.1V) at 3F each gives you a very small 1F (one Farad) capacitor at 8.1V.?
I bought a 1F 16V electrolytic from a car audio (boom boom) shop for ?10 several years ago. ? I also put a 0.5 ohm resistor in series to limit the current. ? I thought it would stiffen my PS7, but the PS7 was plenty stiff enough.
Nigel Patterson
|
Using a Drake 2B receiver with a T4/T4X<any> transmitter, the
front panel
PASS BAND setting must be in the correct setting otherwise you won't
be
on the same Side Band as the station or ground you are wanting to
join.
The 2B manual discusses the PASS BAND setting on USB or LSB.
Tune in the station or group so they sound natural in the 2B
receiver.
Set the transmitter to SPOT and adjust the VFO so your voice sounds
natural in the 2B receiver as the distant station or group sounds.
Using CW, setting the PASS BAND is the same. Tune in the station and
adjust the PASS BAND (CW is typically in USB) so the tone is how you
want it. Turn on SPOT and adjust the transmitter so the SPOT signal
is
the same tone as the distant station. Do NOT adjust the receiver
so the distant station's tone drops to zero, no beat note in the
receiver's
speaker. Doing that will result in the distant station not hearing
you.
Zero Beat means exactly as it says, the receiver's tuning is
adjusted to
the point where the distant stations receive tone frequency
decreases
to zero, no beat note heard in the speaker. The typical CW beat note
receiver tuning is 700 to 800hz.
Always allow your transmitter and receiver to warm up for at least
30
minutes.
73
Mike W5RKL
On 5/21/25 5:47 AM, Paul Lukosius via
groups.io wrote:
toggle quoted message
Show quoted text
I used a 2-B with a T-4X in the 60s. Worked fine. Didn't
transceive, but back then spotting the transmitter in the
receiver was common.
?
73
Paul, N9PL
|
I used a 2-B with a T-4X in the 60s. Worked fine. Didn't transceive, but back then spotting the transmitter in the receiver was common.
?
73
Paul, N9PL
|
Re: The Drake 2B and its Frequency Spread Limitations
Opps.? Thank you, Gary.? I guess I need to open my eyes...
?
Richard
W2ONE
|
Re: The Drake 2B and its Frequency Spread Limitations
The link below is a W8JI article covering the affects of replacing
rectifier tubes with solid state diodes..
73
Mike W5RKL
On 5/20/25 10:25 PM, Jahman N5ASE via
groups.io wrote:
toggle quoted message
Show quoted text
Silicon diodes have different internal
resistances and voltage drops than rectifier vacuum tubes.
Before replacing the vacuum tubes I would first model
the power suppy to see how it would perform after the mod.
DUNCAN AMPS - PSUD2 PSU Modeling Software
QUOTE
PSU
Designer II is designed to help you with the design of
simple linear (unregulated) mains power supplies, as
often found in tube amplifiers.
UNQUOTE
73 de Andrew/N5ASE
I would not recommend replacing the
6X4 with silicon diodes. Leave the 6X4 in place.
Just what does one expect to accomplish by substituting
silicon diodes in place of the
6X4 rectifier tube? What harm to your 2B receiver have you
the owner found that
occurs by leaving the 6X4 tube in place?
The formula for calculating the crystal frequencies is found
on page 10 in the 2B manual.
A single crystal can provide 2 different frequency ranges.
This is explained in the 2B manual
on page 10.
I have two Drake 2B receivers. The calibrator is not as good
as one would expect it to be.
It's a little weak on some bands but stronger on other
bands. I found this to be true on
both on my 2B receiver. Both of my 2B receiver have the 2AC
plug in calibrators.
I recommend finding and adding the Drake 2AQ Multiplier. It
adds quite a bit of selectivity to the
2B receiver.
73
Mike W5RKL
On 5/20/25 7:09 PM, Steve Wedge, W1ES/4 via wrote:
My
first 1-A came with diodes replacing the 6X4,? At the
time, it was an easy mod that was popular at a time when
people wanted to replace tubes.? I removed the diodes
and bought a NOS 6X4 off eBay for about $4 + shipping.
If
not properly compensated, using solid state diodes in
place? of a tube can raise the voltage on the plate
supply.? In the case of the 1-A, Drake used lots of taps
to provide various voltages instead of just perhaps
using two different plate voltages like the R-4(any).?
The highest voltages were near 200V before I put the
tube back in.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a
banana.
Sent with
secure email.
On Tuesday, May 20th, 2025 at 6:32 PM, Richard W2ONE
via <cowboyhat@...>
wrote:
Hey Gary,
?
Here are some more pictures of my cabinet.? Yes,
a previous owner stuck a Heathkit 100 kc Calibrator
in place of the Drake 100 kc Calibrator.? A previous
owner also replaced the 6X4 tube with two diodes.? I
believe I read somewhere that this is a hack on the
2B, but I do not remember if the hack was an
improvement over the use of the 6X4 tube or as a
substitute if the tube cannot be located.? I would
appreciate any words of wisdom that anyone has on
these two situations (my Heathkit calibrator and the
diode replacement of the 6X4 tube).
?
Other pictures showing the crystals that have
been installed and the bottom of the chasis.
?
Richard
W2ONE
?
?
?
?
|
Re: The Drake 2B and its Frequency Spread Limitations
Richard,
The fuse is labeled right on the chassis, I see it in your photo!
?
0.6Amp (600ma) Slow Blow.
?
73,
Gary
WB6OGD
|
Re: The Drake 2B and its Frequency Spread Limitations
Richard's 2B already is running with diodes.
Long term reliability could possibly be a problem but I would just get it working for now.
?
73,
Gary
WB6OGD
|
Re: The Drake 2B and its Frequency Spread Limitations
OK - I have replaced the twin diodes with the proper 6X4 tube.? I am now able to finally pick up some code and some voice on the 80 meter band.? Now I need to do some work to improve my antenna.? I also checked the fuse.? But, the book does not tell me what size fuse I am supposed to have.? HA!? Anyone know the answer?
?
Richard
W2ONE
?
|
Stan,
While you could do it, you'd be giving up a lot.
An R-4x receiver doesn't cost that much more than the 2B.
?
The T-4Xx has a spot function, so it should be easy to sync the 2 and 4.
But you can't transceive.
?
73,
Gary
WB6OGD
|
Re: The Drake 2B and its Frequency Spread Limitations
Silicon diodes have different internal resistances and voltage drops than rectifier vacuum tubes.
Before replacing the vacuum tubes I would first model the power suppy to see how it would perform after the mod.
DUNCAN AMPS - PSUD2 PSU Modeling Software
QUOTE PSU Designer II is designed to help you with the design of simple linear (unregulated) mains power supplies, as often found in tube amplifiers. UNQUOTE
73 de Andrew/N5ASE
I would not recommend replacing the 6X4 with silicon diodes. Leave
the 6X4 in place.
Just what does one expect to accomplish by substituting silicon
diodes in place of the
6X4 rectifier tube? What harm to your 2B receiver have you the owner
found that
occurs by leaving the 6X4 tube in place?
The formula for calculating the crystal frequencies is found on page
10 in the 2B manual.
A single crystal can provide 2 different frequency ranges. This is
explained in the 2B manual
on page 10.
I have two Drake 2B receivers. The calibrator is not as good as one
would expect it to be.
It's a little weak on some bands but stronger on other bands. I
found this to be true on
both on my 2B receiver. Both of my 2B receiver have the 2AC plug in
calibrators.
I recommend finding and adding the Drake 2AQ Multiplier. It adds
quite a bit of selectivity to the
2B receiver.
73
Mike W5RKL
On 5/20/25 7:09 PM, Steve Wedge, W1ES/4
via wrote:
My
first 1-A came with diodes replacing the 6X4,? At the time, it
was an easy mod that was popular at a time when people wanted to
replace tubes.? I removed the diodes and bought a NOS 6X4 off
eBay for about $4 + shipping.
If
not properly compensated, using solid state diodes in place? of
a tube can raise the voltage on the plate supply.? In the case
of the 1-A, Drake used lots of taps to provide various voltages
instead of just perhaps using two different plate voltages like
the R-4(any).? The highest voltages were near 200V before I put
the tube back in.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Tuesday, May 20th, 2025 at 6:32
PM, Richard W2ONE via
<cowboyhat@...> wrote:
Hey Gary,
?
Here are some more pictures of my cabinet.? Yes, a
previous owner stuck a Heathkit 100 kc Calibrator in place
of the Drake 100 kc Calibrator.? A previous owner also
replaced the 6X4 tube with two diodes.? I believe I read
somewhere that this is a hack on the 2B, but I do not
remember if the hack was an improvement over the use of the
6X4 tube or as a substitute if the tube cannot be located.?
I would appreciate any words of wisdom that anyone has on
these two situations (my Heathkit calibrator and the diode
replacement of the 6X4 tube).
?
Other pictures showing the crystals that have been
installed and the bottom of the chasis.
?
Richard
W2ONE
?
?
?
?
|
Hi Ronnie,
?
I am interested in the 2-BQ if it is not too expensive (I do not know what they go for).? What do you want for it?
?
Richard
W2ONE
?
|
I have a 2-BQ surplus to my needs if anyone is interested
I can even send a video of it working
Ronnie
toggle quoted message
Show quoted text
On May 20, 2025, at 9:11?PM, Stan Gammons via groups.io <buttercup11421@...> wrote:
?With all of the talk about the 2-B, I wonder if any/many pair it with a
4 line transmitter? I can see where getting them synced could be a
problem. Sounds like putting the Stby/Rcv switch in Stby and connecting
the mute pins to the transmitter will mute the receiver during
transmit. My 2-B has the 2-AC, but I don't have a 2-AQ or 2-BQ. I'd
have to use the MS-4 for a speaker if I try to get the 2 and 4 line to
work together.
73
Stan
KM4HQE
|
With all of the talk about the 2-B, I wonder if any/many pair it with a
4 line transmitter?? I can see where getting them synced could be a
problem.? Sounds like putting the Stby/Rcv switch in Stby and connecting
the mute pins to the transmitter will mute the receiver during
transmit.? My 2-B has the 2-AC, but I don't have a 2-AQ or 2-BQ.? I'd
have to use the MS-4 for a speaker if I try to get the 2 and 4 line to
work together.
73
Stan
KM4HQE
|
Re: Drake C Line For Sale
Oh brother why do you tempt me
toggle quoted message
Show quoted text
Hello all,?
I am selling one of my Drake C Lines: R-4C, T-4XC, AC4, MS-4 and fresh cables.? All stock, very good condition,? and regularly on the air.? For the time being, pickup only in Arlington, VA.? $550.? tks, Burt W3IO
|
Re: The Drake 2B and its Frequency Spread Limitations
If nothing else, I'd be skittish about the leads sticking up with high voltage on them.
Barry - N4BUQ
From: "Steve Wedge, W1ES/4 via groups.io" <w1es@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Tuesday, May 20, 2025 7:09:08 PM
Subject: Re: [DRAKE-RADIO] The Drake 2B and its Frequency Spread Limitations
My first 1-A came with diodes replacing the 6X4,? At the time, it was an easy mod that was popular at a time when people wanted to replace tubes.? I removed the diodes and bought a NOS 6X4 off eBay for about $4 + shipping.
If not properly compensated, using solid state diodes in place? of a tube can raise the voltage on the plate supply.? In the case of the 1-A, Drake used lots of taps to provide various voltages instead of just perhaps using two different plate voltages like the R-4(any).? The highest voltages were near 200V before I put the tube back in.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Tuesday, May 20th, 2025 at 6:32 PM, Richard W2ONE via groups.io <cowboyhat@...> wrote:
Hey Gary,
?
Here are some more pictures of my cabinet.? Yes, a previous owner stuck a Heathkit 100 kc Calibrator in place of the Drake 100 kc Calibrator.? A previous owner also replaced the 6X4 tube with two diodes.? I believe I read somewhere that this is a hack on the 2B, but I do not remember if the hack was an improvement over the use of the 6X4 tube or as a substitute if the tube cannot be located.? I would appreciate any words of wisdom that anyone has on these two situations (my Heathkit calibrator and the diode replacement of the 6X4 tube).
?
Other pictures showing the crystals that have been installed and the bottom of the chasis.
?
Richard
W2ONE
?
?
?
?
|
Hello all,?
I am selling one of my Drake C Lines: R-4C, T-4XC with manual AC4, MS-4 and fresh cables.? All stock, very good condition,? and regularly on the air.? For the time being, pickup only in Arlington, VA.? $550.? tks, Burt W3IO
|
Re: The Drake 2B and its Frequency Spread Limitations
Sorry, I misspoke (happens a lot now that I¡¯m nearing 80 years old). The band switch does have a 80m position. It just didn¡¯t have a crystal slot. Now I know why.
It does have a rather factory (not Drake) addition to the main tuning knob and dial. I¡¯ll take a picture and pass it along.
Thanks for setting me straight.
Tom N5AMA
|
Re: The Drake 2B and its Frequency Spread Limitations
I would not recommend replacing the 6X4 with silicon diodes. Leave
the 6X4 in place.
Just what does one expect to accomplish by substituting silicon
diodes in place of the
6X4 rectifier tube? What harm to your 2B receiver have you the owner
found that
occurs by leaving the 6X4 tube in place?
The formula for calculating the crystal frequencies is found on page
10 in the 2B manual.
A single crystal can provide 2 different frequency ranges. This is
explained in the 2B manual
on page 10.
I have two Drake 2B receivers. The calibrator is not as good as one
would expect it to be.
It's a little weak on some bands but stronger on other bands. I
found this to be true on
both on my 2B receiver. Both of my 2B receiver have the 2AC plug in
calibrators.
I recommend finding and adding the Drake 2AQ Multiplier. It adds
quite a bit of selectivity to the
2B receiver.
73
Mike W5RKL
On 5/20/25 7:09 PM, Steve Wedge, W1ES/4
via groups.io wrote:
toggle quoted message
Show quoted text
My
first 1-A came with diodes replacing the 6X4,? At the time, it
was an easy mod that was popular at a time when people wanted to
replace tubes.? I removed the diodes and bought a NOS 6X4 off
eBay for about $4 + shipping.
If
not properly compensated, using solid state diodes in place? of
a tube can raise the voltage on the plate supply.? In the case
of the 1-A, Drake used lots of taps to provide various voltages
instead of just perhaps using two different plate voltages like
the R-4(any).? The highest voltages were near 200V before I put
the tube back in.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Tuesday, May 20th, 2025 at 6:32
PM, Richard W2ONE via groups.io
<cowboyhat@...> wrote:
Hey Gary,
?
Here are some more pictures of my cabinet.? Yes, a
previous owner stuck a Heathkit 100 kc Calibrator in place
of the Drake 100 kc Calibrator.? A previous owner also
replaced the 6X4 tube with two diodes.? I believe I read
somewhere that this is a hack on the 2B, but I do not
remember if the hack was an improvement over the use of the
6X4 tube or as a substitute if the tube cannot be located.?
I would appreciate any words of wisdom that anyone has on
these two situations (my Heathkit calibrator and the diode
replacement of the 6X4 tube).
?
Other pictures showing the crystals that have been
installed and the bottom of the chasis.
?
Richard
W2ONE
?
?
?
?
|
Re: RV-75 from Hamvention
Any caps that are branded CAPAR should be unconditionally replaced. The larger caps with more recognizable names should be OK. On Tue, 20 May 2025 21:03:07 -0400 "K8CCA via groups.io" <echapm4@...> wrote: Success! A few new caps and cleaning the grounds seems to have fixed it.
Very stable! I only did the caps on the top board as I didn't have the 10 &
100uf for the bottom board. I will pick some up tomorrow and this should be
back online. Thanks Evan for your thoughts on this thing!
73,
Eric
K8cca
On Tue, May 20, 2025, 3:56?PM K8CCA via groups.io <echapm4=
[email protected]> wrote:
Hey guys,
Picked up a nice looking Drake RV-75 vfo for my TR-7 last weekend. Hooked
it up last night and my main vfo was in the middle of the 20m band, but
when I switched on the remote vfo freq drop to around 13.9mhz and I am not
able to adjust it. I guess I got a hamfest special. Any hints on what to
look for? I have not even opened it up. Got a great deal on it however so I
hope I can fix it. I showed it to Evan, K9SQG when I ran into him there.
Thanks in advance,
Eric
K8cca
-- 73 -Jim NU0C
|
Re: RV-75 from Hamvention
Success! A few new caps and cleaning the grounds seems to have fixed it. Very stable! I only did the caps on the top board as I didn't have the 10 & 100uf for the bottom board. I will pick some up tomorrow and this should be back online. Thanks Evan for your thoughts on this thing!
73,? Eric? K8cca? 
Hey guys,
Picked up a nice looking Drake RV-75 vfo for my TR-7 last weekend. Hooked it up last night and my main vfo was in the middle of the 20m band, but when I switched on the remote vfo freq drop to around 13.9mhz and I am not able to adjust it. I guess I got a hamfest special. Any hints on what to look for? I have not even opened it up. Got a great deal on it however so I hope I can fix it. I showed it to Evan, K9SQG when I ran into him there.?
Thanks in advance,? Eric? K8cca?
|
Gary WB6OGD
Ronnie Hull - W5SUM
Burt W3IO
Jim Shorney