Okay - that appears to be the case.? I was seeing "yellow" but maybe it's just a slightly faded gold.? I knew yellow-yellow just didn't make sense but I think my brain just jumped to "yellow" because that's what it was expecting to see in the third position.
Thanks! Barry - N4BUQ
Instead of being yellow the colors should be gold.? That is a multiplier of .1 and a tolerance of 5 %.
That would put it correct at 2 ohms.
Ralph ku4pt
On Monday, May 19, 2025 at 10:36:36 AM EDT, n4buq <n4buq@...> wrote:
Since we started discussing meter shunt resistors in another thread, I took a look at those in my TR-4 and I'm a bit confused on the color codes.
R45 is designated as 2 ohms on the schematic.? The color bands on mine are red, black, yellow, yellow.? I think possibly one of those yellow bands indicates a 4% tolerance but not sure what the other yellow band means.? Ordinarily I would have seen that to as a 200k resistor but that's obviously not correct.
R13A in mine is a 27 ohms.? Measuring across R45 and R13A, I get about 2.2 ohms.? If R45 was initially 2 ohms, then 27 ohms across it would have dropped that to about 1.8 to 1.9 ohms.
I'm guessing that the 0.2 to 0.3 ohms is very negligible but can't help but wonder - especially with those rather odd color-codes on R45.? Probably better off to leave this one alone since I doubt the meter itself would be sensitive to such small changes, right?
Thanks,
Barry - N4BUQ
|
Instead of being yellow the colors should be gold.? That is a multiplier of .1 and a tolerance of 5 %.
That would put it correct at 2 ohms.
Ralph ku4pt
On Monday, May 19, 2025 at 10:36:36 AM EDT, n4buq <n4buq@...> wrote:
Since we started discussing meter shunt resistors in another thread, I took a look at those in my TR-4 and I'm a bit confused on the color codes.
R45 is designated as 2 ohms on the schematic.? The color bands on mine are red, black, yellow, yellow.? I think possibly one of those yellow bands indicates a 4% tolerance but not sure what the other yellow band means.? Ordinarily I would have seen that to as a 200k resistor but that's obviously not correct.
R13A in mine is a 27 ohms.? Measuring across R45 and R13A, I get about 2.2 ohms.? If R45 was initially 2 ohms, then 27 ohms across it would have dropped that to about 1.8 to 1.9 ohms.
I'm guessing that the 0.2 to 0.3 ohms is very negligible but can't help but wonder - especially with those rather odd color-codes on R45.? Probably better off to leave this one alone since I doubt the meter itself would be sensitive to such small changes, right?
Thanks,
Barry - N4BUQ
|
Since we started discussing meter shunt resistors in another thread, I took a look at those in my TR-4 and I'm a bit confused on the color codes.
R45 is designated as 2 ohms on the schematic. The color bands on mine are red, black, yellow, yellow. I think possibly one of those yellow bands indicates a 4% tolerance but not sure what the other yellow band means. Ordinarily I would have seen that to as a 200k resistor but that's obviously not correct.
R13A in mine is a 27 ohms. Measuring across R45 and R13A, I get about 2.2 ohms. If R45 was initially 2 ohms, then 27 ohms across it would have dropped that to about 1.8 to 1.9 ohms.
I'm guessing that the 0.2 to 0.3 ohms is very negligible but can't help but wonder - especially with those rather odd color-codes on R45. Probably better off to leave this one alone since I doubt the meter itself would be sensitive to such small changes, right?
Thanks,
Barry - N4BUQ
|
R111 was one of the very few exceptions in my TR-4.? It had doubled in resistance.? I really need to replace C145.? It isn't even getting warm but that's not necessarily going to be the case when it's leaking a little more than it should.
Barry - N4BUQ
From: "Mike W5RKL via groups.io" <mikew5rkl@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Monday, May 19, 2025 9:05:21 AM
Subject: Re: [DRAKE-RADIO] TR-4 - Soft Finals?
I had a similar problem with R111 (3.3K 1/2W) series resistor in my
TR3 that
overheated and burnt in half, lots of smoke. The cause of the
overheating of
R111 was C145B, 60ufd 250VDC capacitor in C145 can. It didn't show a
short
with an ohm meter but under voltage it shorted causing R111 to
overheat.
Not only did C145B short internally under voltage but the
capacitance value of
C145B had increased from 60ufd to "108ufd", an "80% increase" in
capacitance
value, C145B in my TR3 not only took out TR3's R111 but it also took
out R4 in
the AC3 power supply resulting in complete loss of +250VDC LV
supply.
If R192 in the TR4C is getting hot then it's quite possible C145A
20ufd can
capacitor is going bad. I agree, replace C145 can capacitor before
it takes
out R192 and quite possibly the AC power supply LV supply.
73
Mike W5RKL
On 5/19/25 8:21 AM, Steve Wedge, W1ES/4
via groups.io wrote:
If R192 in the TR-4C(any) appears heat stressed,
check the can cap. Replace R192 with the same value and wattage
¡ª it is a safety for the MV. If you still have the original can,
change it ASAP.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sun, May 18, 2025 at 22:56, VE7PS via groups.io <ve7ps@...> wrote:
Interesting topic about the aging resistors in
our 4-line gear.
Any time a rig comes into the shop ALL resistors get
visibly?checked, but some get more attention than
others.....
Here they are...
All PA screen and cathode resistors on the T-4X(any) and
TR-4(any), as we all know.
On the T4XC...R-81 and R91 in plate leads to V-9.? Both
are high value resistors which tend to go high with time,
reducing plate voltage.? If your audio drive seems low
check?these for sure. Also check Plate Voltage on V-9, and
if below spec, these resistors are likely the reason.? I
found plate voltage on one T-4XC I fixed for a friend years
ago at +69VDC on V-9, while spec is +95VDC.? R81 had?gone
way?high. Drakes aren't the only rigs I see this?happening
to.? K4OAH's "CD's" will help you locate the?resistors,
though that's just the start of the fun!? Frankly, ALL
resistors with values above?200K or so deserve a
resistance?check.? Doesn't seem to be as big an issue on the
B-line and?earlier?in this circuit as the circuits are
different and resistances are lower....cursory check though,
so keep that in mind.
Also on the T-4XC...R49 and R59 on the relay board.?
Often seen heat-stressed.
On the TR-4C series...R 192 and R-45 on the relay board.
On all TR-4(any) - R163 on the 200 VDC line to the S
meter.? ?It seems to act as a fuse and have found several
visibly?open!!!
I'm sure there are more, but this is a start.? I'm sure
there are others who can add to the list.
73
Peter
VE7PS
I have found that virtually all of the resistors
in my TR-4 have not aged out of tolerance which is a
little surprising.? ?I did, though, replace the three
15R cathode resistors.? I think one or two were over
20 ohms but I replaced them mainly because they were
no longer all the same value.
Since R13 is "selected", then I presume one can
read the bands and should be able to check whether
it's out of tolerance.? At least R45 is not
"selected".
Thanks for the tip!
Barry - N4BUQ (the other, other Barry)
Barry,
Something else to consider - Every
TR-n that I've worked on has had the plate
current meter resistors aged high.? The result
is that plate current measurement is not correct
which of course means that idle current is not
set correctly.? Seems to me that idle current is
the basic foundation for everything and if its
not right than there may be some odd things
happen.? There are two resistors.? One is a
standard value and the other is determined by
the Drake tech during final alignment before the
radio was shipped.
Also, I don't recall if you
mentioned checking it or not but the 68ohm and
15ohm resistors under the amp tubes are also
prone to aging high.? I always check and usually
replace those resistors and then measure the
resistors for the meter and replace if they have
drifted.? You can of course verify your idle
current by measuring resistance and voltage drop
across the three resistors under the amp tubes,
calculating the current draw, and adding up the
current draw for all three.
73,
Another Barry
KJ5GQM
On Sunday, May 18, 2025 at 05:23:44 PM
CDT, n4buq < n4buq@...>
wrote:
I tested all three tubes for gas
and none were bad in that respect.?
Interestingly, I decided to perform
the "LIFE TEST" where the filament
voltage is reduced (I think it goes
down to about 5.8V or maybe 5.9V for
a 6.3V filament).? While
transconductance drops by an
acceptable amount when that button
is pressed, the fall in value looked
a lot like what I see for plate
current when the key is down.
With all the tubes back in
place, I decided to monitor the
filament voltage.? I've been running
the rig between 110VAC and 115VAC
and that was giving me a
low-to-start-with filament voltage
of just under 6VAC.? With that,
key-down would cause that voltage to
drop to around 5.7VAC.? I then
bumped the autotransformer up to
closer to 120VAC which gave me very
close to 6.3VAC and, oddly enough,
on key-down, that voltage would drop
just a small amount - perhaps 0.1VAC
to 0.2VAC.? That seems a bit odd
that the sag was smaller but,
perhaps, the transformer is more
efficient at the input voltage
closer to 120VAC but that's just a
guess.
Also, with the input voltage
closer to 120VAC, I think I'm seeing
a good increase in plate current at
resonance.? I suppose that's
expected since the plate voltage
also climbs with that input voltage.
Thanks,
Barry - N4BUQ
From: "Barry" < n4buq@...>
To: "DRAKE-RADIO" < [email protected]>
Sent: Sunday, May 18, 2025
1:03:51 PM
Subject: Re: [DRAKE-RADIO]
TR-4 - Soft Finals?
Richard, Steve,
Thank you both for the
responses.? I wasn't sure if
"soft" was just a generic for
"weak" and, in general, maybe
that's true.
My three tubes do not
exhibit some of the more
obvious signs of excess gas
(e.g. white coating or a
"getter-like" spot but that's
not a very good indicator of
small gas amounts.? I'm going
to pull them again and run the
gas test as I didn't do that
when I was testing them.?
Maybe that will be revealing.
Thanks again,
Barry - N4BUQ
From: "Steve Wedge,
W1ES/4 via "
<w1es= [email protected]>
To: "DRAKE-RADIO"
< [email protected]>
Sent: Sunday, May
18, 2025 12:37:22 PM
Subject: Re:
[DRAKE-RADIO] TR-4 - Soft
Finals?
Yep, that sounds like
a textbook example.? Power
falls off first on the
higherbands as the gain
(transconductance)
decreases.? The electrons
are generated at the
heated cathode and
eventually, the cathode
material gets depleted.
I¡¯m starting to think
that my TR-4Cw RIT is
having similar issues,
though strangely, the
output only sags when on
the antenna and not on the
dummy load.? The tubes in
it are well-used.
Steve Wedge, W1ES
Time flies like an
arrow. Fruit flies
like a banana.
On Sat, May 17, 2025 at
10:46 PM, n4buq < n4buq@...>
wrote:
Can someone
please tell me what is
meant by the term "soft
finals"? I'm still having
problems getting proper
output from my TR-4 and,
for all I know, that might
be the problem. I've
tested them for
transconductance and all
three are very close to
the same value and,
furthermore, that value is
quite a bit above the
minimum for a good tube.
Aside from low output
(i.e. about 300 mA plate
current maximum into a
dummy load), I notice that
if I hold down the key for
a few seconds the plate
current tends to drop just
slightly and I think if I
were to continue holding
the key down, the current
would continue to slowly
decrease.
I measured the voltage
across each cathode
resistor and I notice the
same phenomenon: the
voltage climbs to about
1.6 VDC and then begins to
drop a bit. Like the
transconductance values,
each cathode resistor is
"matched" in value and
behavior to the other two
so I suppose that's one
good thing.
Am I seeing the result of
weak/soft tubes or is
something else going on
that would cause this?
Thanks,
Barry - N4BUQ
|
On 2025-05-19 07:05, Mike W5RKL via groups.io wrote: C145B, 60ufd 250VDC capacitor in C145 can. It didn't show a
short
with an ohm meter but under voltage it shorted *** That's why I check electrolytics with an old-fashioned capacitor checker. I have two - an old Heathkit with a magic eye tube, and a Sprague TO-6. That purchase was inspired by our own Steve Wedge. Either of these testers can perform leakage checks up to 600V or so. - Jerry, KF6VB Not only did C145B short internally under voltage but the capacitance
value of
C145B had increased from 60ufd to "108ufd", an "80% increase" in
capacitance
value, C145B in my TR3 not only took out TR3's R111 but it also took
out R4 in
the AC3 power supply resulting in complete loss of +250VDC LV supply.
If R192 in the TR4C is getting hot then it's quite possible C145A
20ufd can
capacitor is going bad. I agree, replace C145 can capacitor before it
takes
out R192 and quite possibly the AC power supply LV supply.
73
Mike W5RKL
On 5/19/25 8:21 AM, Steve Wedge, W1ES/4 via groups.io wrote:
If R192 in the TR-4C(any) appears heat stressed, check the can cap.
Replace R192 with the same value and wattage ¡ª it is a safety for
the MV. If you still have the original can, change it ASAP.
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail [1] for iOS
On Sun, May 18, 2025 at 22:56, VE7PS via groups.io
<ve7ps@... [2]> wrote:
Interesting topic about the aging resistors in our 4-line gear.
Any time a rig comes into the shop ALL resistors get visibly
checked, but some get more attention than others.....
Here they are...
All PA screen and cathode resistors on the T-4X(any) and TR-4(any),
as we all know.
On the T4XC...R-81 and R91 in plate leads to V-9. Both are high
value resistors which tend to go high with time, reducing plate
voltage. If your audio drive seems low check these for sure. Also
check Plate Voltage on V-9, and if below spec, these resistors are
likely the reason. I found plate voltage on one T-4XC I fixed for a
friend years ago at +69VDC on V-9, while spec is +95VDC. R81 had
gone way high. Drakes aren't the only rigs I see this happening to.
K4OAH's "CD's" will help you locate the resistors, though that's
just the start of the fun! Frankly, ALL resistors with values above
200K or so deserve a resistance check. Doesn't seem to be as big an
issue on the B-line and earlier in this circuit as the circuits are
different and resistances are lower....cursory check though, so keep
that in mind.
Also on the T-4XC...R49 and R59 on the relay board. Often seen
heat-stressed.
On the TR-4C series...R 192 and R-45 on the relay board.
On all TR-4(any) - R163 on the 200 VDC line to the S meter. It
seems to act as a fuse and have found several visibly open!!!
I'm sure there are more, but this is a start. I'm sure there are
others who can add to the list.
73
Peter
VE7PS
On Sun, May 18, 2025 at 6:49?PM n4buq via groups.io [3] <n4buq=
[email protected]> wrote:
I have found that virtually all of the resistors in my TR-4 have
not aged out of tolerance which is a little surprising. I did,
though, replace the three 15R cathode resistors. I think one or two
were over 20 ohms but I replaced them mainly because they were no
longer all the same value.
Since R13 is "selected", then I presume one can read the bands and
should be able to check whether it's out of tolerance. At least R45
is not "selected".
Thanks for the tip!
Barry - N4BUQ (the other, other Barry)
Barry,
Something else to consider - Every TR-n that I've worked on has had
the plate current meter resistors aged high. The result is that
plate current measurement is not correct which of course means that
idle current is not set correctly. Seems to me that idle current is
the basic foundation for everything and if its not right than there
may be some odd things happen. There are two resistors. One is a
standard value and the other is determined by the Drake tech during
final alignment before the radio was shipped.
Also, I don't recall if you mentioned checking it or not but the
68ohm and 15ohm resistors under the amp tubes are also prone to
aging high. I always check and usually replace those resistors and
then measure the resistors for the meter and replace if they have
drifted. You can of course verify your idle current by measuring
resistance and voltage drop across the three resistors under the amp
tubes, calculating the current draw, and adding up the current draw
for all three.
73,
Another Barry
KJ5GQM
On Sunday, May 18, 2025 at 05:23:44 PM CDT, n4buq <
n4buq@...> wrote:
I tested all three tubes for gas and none were bad in that respect.
Interestingly, I decided to perform the "LIFE TEST" where the
filament voltage is reduced (I think it goes down to about 5.8V or
maybe 5.9V for a 6.3V filament). While transconductance drops by an
acceptable amount when that button is pressed, the fall in value
looked a lot like what I see for plate current when the key is down.
With all the tubes back in place, I decided to monitor the filament
voltage. I've been running the rig between 110VAC and 115VAC and
that was giving me a low-to-start-with filament voltage of just
under 6VAC. With that, key-down would cause that voltage to drop to
around 5.7VAC. I then bumped the autotransformer up to closer to
120VAC which gave me very close to 6.3VAC and, oddly enough, on
key-down, that voltage would drop just a small amount - perhaps
0.1VAC to 0.2VAC. That seems a bit odd that the sag was smaller
but, perhaps, the transformer is more efficient at the input voltage
closer to 120VAC but that's just a guess.
Also, with the input voltage closer to 120VAC, I think I'm seeing a
good increase in plate current at resonance. I suppose that's
expected since the plate voltage also climbs with that input
voltage.
Thanks,
Barry - N4BUQ
-------------------------
FROM: "Barry" < n4buq@...>
TO: "DRAKE-RADIO" < [email protected]>
SENT: Sunday, May 18, 2025 1:03:51 PM
SUBJECT: Re: [DRAKE-RADIO] TR-4 - Soft Finals?
Richard, Steve,
Thank you both for the responses. I wasn't sure if "soft" was just
a generic for "weak" and, in general, maybe that's true.
My three tubes do not exhibit some of the more obvious signs of
excess gas (e.g. white coating or a "getter-like" spot but that's
not a very good indicator of small gas amounts. I'm going to pull
them again and run the gas test as I didn't do that when I was
testing them. Maybe that will be revealing.
Thanks again,
Barry - N4BUQ
-------------------------
FROM: "Steve Wedge, W1ES/4 via groups.io [3]" <w1es=
[email protected]>
TO: "DRAKE-RADIO" < [email protected]>
SENT: Sunday, May 18, 2025 12:37:22 PM
SUBJECT: Re: [DRAKE-RADIO] TR-4 - Soft Finals?
Yep, that sounds like a textbook example. Power falls off first on
the higherbands as the gain (transconductance) decreases. The
electrons are generated at the heated cathode and eventually, the
cathode material gets depleted.
I¡¯m starting to think that my TR-4Cw RIT is having similar
issues, though strangely, the output only sags when on the antenna
and not on the dummy load. The tubes in it are well-used.
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sat, May 17, 2025 at 10:46 PM, n4buq < n4buq@... [4]>
wrote: Can someone please tell me what is meant by the term "soft
finals"? I'm still having problems getting proper output from my
TR-4 and, for all I know, that might be the problem. I've tested
them for transconductance and all three are very close to the same
value and, furthermore, that value is quite a bit above the minimum
for a good tube.
Aside from low output (i.e. about 300 mA plate current maximum into
a dummy load), I notice that if I hold down the key for a few
seconds the plate current tends to drop just slightly and I think if
I were to continue holding the key down, the current would continue
to slowly decrease.
I measured the voltage across each cathode resistor and I notice the
same phenomenon: the voltage climbs to about 1.6 VDC and then begins
to drop a bit. Like the transconductance values, each cathode
resistor is "matched" in value and behavior to the other two so I
suppose that's one good thing.
Am I seeing the result of weak/soft tubes or is something else going
on that would cause this?
Thanks,
Barry - N4BUQ Links:
------
[1]
[2]
[3]
[4]
[5] /g/DRAKE-RADIO/message/84964
[6] /mt/113171093/243852
[7] /g/DRAKE-RADIO/post
[8] /g/DRAKE-RADIO/editsub/243852
[9] /g/DRAKE-RADIO/leave/12260778/243852/767576506/xyzzy
|
Re: Drake TR-22C question
Oh, my!
I have a stack of those radios, and I actually use them on the air. I prefer the TR22 over the ¡°33¡± for reasons I don¡¯t even know. I stuck a encoder in for the repeater and I¡¯m happy with how it works.
I, too, have several of the Kenwood rigs. I have the dead ni-cad packs, but for the life of me, can¡¯t locate replacements.
Mike, WB8VGE
SunLight Energy Systems
The Heathkit Shop
J e e p
o|||||||o?
A man with one clock knows what time it?is. A man with two clocks is never sure.
toggle quoted message
Show quoted text
On May 18, 2025, at 12:13 PM, Jim Shorney via < jimNU0C@...> wrote:
It was a popular modification. The built-in whip was prone to breakage and the BNC was the common fix. I have a T-22c, TR-33C, an coincidentally a Kenwood TR-2200A loaded with crystals and with an intact whip just followed me home from a 'fest for free. The 2200A has some improvements (including 12 channels) but is still essentially a TR-22C. Or maybe I should call it a TR-22D.... Still looking for a manual or copy for it. Yes, I know I can purchase one online, but the radio was free and it has been monkeyed with so I don't even know if it works yet.
|
I bought a whole stash of resistors at our recent Belton TX hamfest from a gentleman that was downsizing.? I've been pulling from that recently.? Previously I've used Mouser because they keep a great inventory of components and their shipping is lightning fast.? Not the cheapest option but they are efficient.? I try to keep a running list of stuff that I need for various projects and order it all at once since their shipping is basically a flat rate.? 1 resistor costs the same to ship as an order with 10 different items on it.
On Monday, May 19, 2025 at 06:04:10 AM CDT, George Cortez Jr via groups.io <ne2i@...> wrote:
Speaking of resistors, Where are you sourcing your resistors??
?
Thanks
?
George NE2I
|
I had a similar problem with R111 (3.3K 1/2W) series resistor in my
TR3 that
overheated and burnt in half, lots of smoke. The cause of the
overheating of
R111 was C145B, 60ufd 250VDC capacitor in C145 can. It didn't show a
short
with an ohm meter but under voltage it shorted causing R111 to
overheat.
Not only did C145B short internally under voltage but the
capacitance value of
C145B had increased from 60ufd to "108ufd", an "80% increase" in
capacitance
value, C145B in my TR3 not only took out TR3's R111 but it also took
out R4 in
the AC3 power supply resulting in complete loss of +250VDC LV
supply.
If R192 in the TR4C is getting hot then it's quite possible C145A
20ufd can
capacitor is going bad. I agree, replace C145 can capacitor before
it takes
out R192 and quite possibly the AC power supply LV supply.
73
Mike W5RKL
On 5/19/25 8:21 AM, Steve Wedge, W1ES/4
via groups.io wrote:
toggle quoted message
Show quoted text
If R192 in the TR-4C(any) appears heat stressed,
check the can cap. Replace R192 with the same value and wattage
¡ª it is a safety for the MV. If you still have the original can,
change it ASAP.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sun, May 18, 2025 at 22:56, VE7PS via groups.io <ve7ps@...> wrote:
Interesting topic about the aging resistors in
our 4-line gear.
Any time a rig comes into the shop ALL resistors get
visibly?checked, but some get more attention than
others.....
Here they are...
All PA screen and cathode resistors on the T-4X(any) and
TR-4(any), as we all know.
On the T4XC...R-81 and R91 in plate leads to V-9.? Both
are high value resistors which tend to go high with time,
reducing plate voltage.? If your audio drive seems low
check?these for sure. Also check Plate Voltage on V-9, and
if below spec, these resistors are likely the reason.? I
found plate voltage on one T-4XC I fixed for a friend years
ago at +69VDC on V-9, while spec is +95VDC.? R81 had?gone
way?high. Drakes aren't the only rigs I see this?happening
to.? K4OAH's "CD's" will help you locate the?resistors,
though that's just the start of the fun!? Frankly, ALL
resistors with values above?200K or so deserve a
resistance?check.? Doesn't seem to be as big an issue on the
B-line and?earlier?in this circuit as the circuits are
different and resistances are lower....cursory check though,
so keep that in mind.
Also on the T-4XC...R49 and R59 on the relay board.?
Often seen heat-stressed.
On the TR-4C series...R 192 and R-45 on the relay board.
On all TR-4(any) - R163 on the 200 VDC line to the S
meter.? ?It seems to act as a fuse and have found several
visibly?open!!!
I'm sure there are more, but this is a start.? I'm sure
there are others who can add to the list.
73
Peter
VE7PS
I have found that virtually all of the resistors
in my TR-4 have not aged out of tolerance which is a
little surprising.? ?I did, though, replace the three
15R cathode resistors.? I think one or two were over
20 ohms but I replaced them mainly because they were
no longer all the same value.
Since R13 is "selected", then I presume one can
read the bands and should be able to check whether
it's out of tolerance.? At least R45 is not
"selected".
Thanks for the tip!
Barry - N4BUQ (the other, other Barry)
Barry,
Something else to consider - Every
TR-n that I've worked on has had the plate
current meter resistors aged high.? The result
is that plate current measurement is not correct
which of course means that idle current is not
set correctly.? Seems to me that idle current is
the basic foundation for everything and if its
not right than there may be some odd things
happen.? There are two resistors.? One is a
standard value and the other is determined by
the Drake tech during final alignment before the
radio was shipped.
Also, I don't recall if you
mentioned checking it or not but the 68ohm and
15ohm resistors under the amp tubes are also
prone to aging high.? I always check and usually
replace those resistors and then measure the
resistors for the meter and replace if they have
drifted.? You can of course verify your idle
current by measuring resistance and voltage drop
across the three resistors under the amp tubes,
calculating the current draw, and adding up the
current draw for all three.
73,
Another Barry
KJ5GQM
On Sunday, May 18, 2025 at 05:23:44 PM
CDT, n4buq < n4buq@...>
wrote:
I tested all three tubes for gas
and none were bad in that respect.?
Interestingly, I decided to perform
the "LIFE TEST" where the filament
voltage is reduced (I think it goes
down to about 5.8V or maybe 5.9V for
a 6.3V filament).? While
transconductance drops by an
acceptable amount when that button
is pressed, the fall in value looked
a lot like what I see for plate
current when the key is down.
With all the tubes back in
place, I decided to monitor the
filament voltage.? I've been running
the rig between 110VAC and 115VAC
and that was giving me a
low-to-start-with filament voltage
of just under 6VAC.? With that,
key-down would cause that voltage to
drop to around 5.7VAC.? I then
bumped the autotransformer up to
closer to 120VAC which gave me very
close to 6.3VAC and, oddly enough,
on key-down, that voltage would drop
just a small amount - perhaps 0.1VAC
to 0.2VAC.? That seems a bit odd
that the sag was smaller but,
perhaps, the transformer is more
efficient at the input voltage
closer to 120VAC but that's just a
guess.
Also, with the input voltage
closer to 120VAC, I think I'm seeing
a good increase in plate current at
resonance.? I suppose that's
expected since the plate voltage
also climbs with that input voltage.
Thanks,
Barry - N4BUQ
From: "Barry" < n4buq@...>
To: "DRAKE-RADIO" < [email protected]>
Sent: Sunday, May 18, 2025
1:03:51 PM
Subject: Re: [DRAKE-RADIO]
TR-4 - Soft Finals?
Richard, Steve,
Thank you both for the
responses.? I wasn't sure if
"soft" was just a generic for
"weak" and, in general, maybe
that's true.
My three tubes do not
exhibit some of the more
obvious signs of excess gas
(e.g. white coating or a
"getter-like" spot but that's
not a very good indicator of
small gas amounts.? I'm going
to pull them again and run the
gas test as I didn't do that
when I was testing them.?
Maybe that will be revealing.
Thanks again,
Barry - N4BUQ
From: "Steve Wedge,
W1ES/4 via "
<w1es= [email protected]>
To: "DRAKE-RADIO"
< [email protected]>
Sent: Sunday, May
18, 2025 12:37:22 PM
Subject: Re:
[DRAKE-RADIO] TR-4 - Soft
Finals?
Yep, that sounds like
a textbook example.? Power
falls off first on the
higherbands as the gain
(transconductance)
decreases.? The electrons
are generated at the
heated cathode and
eventually, the cathode
material gets depleted.
I¡¯m starting to think
that my TR-4Cw RIT is
having similar issues,
though strangely, the
output only sags when on
the antenna and not on the
dummy load.? The tubes in
it are well-used.
Steve Wedge, W1ES
Time flies like an
arrow. Fruit flies
like a banana.
On Sat, May 17, 2025 at
10:46 PM, n4buq < n4buq@...>
wrote:
Can someone
please tell me what is
meant by the term "soft
finals"? I'm still having
problems getting proper
output from my TR-4 and,
for all I know, that might
be the problem. I've
tested them for
transconductance and all
three are very close to
the same value and,
furthermore, that value is
quite a bit above the
minimum for a good tube.
Aside from low output
(i.e. about 300 mA plate
current maximum into a
dummy load), I notice that
if I hold down the key for
a few seconds the plate
current tends to drop just
slightly and I think if I
were to continue holding
the key down, the current
would continue to slowly
decrease.
I measured the voltage
across each cathode
resistor and I notice the
same phenomenon: the
voltage climbs to about
1.6 VDC and then begins to
drop a bit. Like the
transconductance values,
each cathode resistor is
"matched" in value and
behavior to the other two
so I suppose that's one
good thing.
Am I seeing the result of
weak/soft tubes or is
something else going on
that would cause this?
Thanks,
Barry - N4BUQ
|
Re: The Drake 2B and its Frequency Spread Limitations
I agree, just look for an S-40, I see a lot of them on Craigslist.? I skip over them because they are not good ham
receivers (not like the 2B which is a great ham receiver but not so good of an SWL receiver).
?
73,
Gary
WB6OGD
?
|
Re: "I Never Should Have Gotten Rid Of......
Regarding the history of Heathkit, a video about the company's history can be 73, W4NPN
The library network is free¡my Mass. lib consortium is 38 public/municipal/memorial libraries¡. ? STAY SAFE AND STAY WELL! ? Respectfully,
Thomas K. Lanieri, NU2W NJ DOH Licensed EMT;? PHTLS, AMLS, PHPEC Millenium EMS ARC N.E. BioMedical Services ARC N.E. Disaster Cycle Services  ? 
? ? Joe, there are 6 of them listed on Bookfinder at the moment. It looks like you will have to pay a C-note to get a copy though. Dave
-- Frank Barnes
Chapel Hill, NC
Grid Square FM05
Cell 919.260.7955
|
My shack is converted from an ¡°extra¡± bedroom in the finished part of my cellar and my ¡°stockroom¡± is the large walk-in closet. Lots of room for parts. I have a mixture of older and new parts and I¡¯ll test the older ones before use.?
Before I got these bins back from my friend (long story) I had a 1/2W assortment that I bought on Amazon. Those are standard values but are 1% tolerance.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Mon, May 19, 2025 at 07:04, George Cortez Jr via groups.io < ne2i@...> wrote:
Speaking of resistors, Where are you sourcing your resistors??
?
Thanks
?
George NE2I
|
On Mon, May 19, 2025 at 06:11 AM, Steve Wedge, W1ES/4 wrote:
My mains can get to 126, so I set my variac to around 118. It doesn¡¯t hurt.
?
?
Ditto.? I use a Superior Electric "Variac" mounted under the operating desktop, within easy reach to make line voltage adjustments. ?Voltage is monitored with a Viz (formerly RCA) WV-120B line voltage monitor.
This setup is only used for boatanchor gear.? 110V for pre-WWII gear, 115V for gear made until about 1975, then 120V thereafter.? ? Additionally, a hospital-grade toroid isolation transformer with multiple receptacles follows the Variac device.? Photos attached.? Paul, W9AC
 
?
|
If R192 in the TR-4C(any) appears heat stressed, check the can cap. Replace R192 with the same value and wattage ¡ª it is a safety for the MV. If you still have the original can, change it ASAP.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sun, May 18, 2025 at 22:56, VE7PS via groups.io < ve7ps@...> wrote:
Interesting topic about the aging resistors in our 4-line gear.
Any time a rig comes into the shop ALL resistors get visibly?checked, but some get more attention than others.....
Here they are...
All PA screen and cathode resistors on the T-4X(any) and TR-4(any), as we all know.
On the T4XC...R-81 and R91 in plate leads to V-9.? Both are high value resistors which tend to go high with time, reducing plate voltage.? If your audio drive seems low check?these for sure. Also check Plate Voltage on V-9, and if below spec, these resistors are likely the reason.? I found plate voltage on one T-4XC I fixed for a friend years ago at +69VDC on V-9, while spec is +95VDC.? R81 had?gone way?high. Drakes aren't the only rigs I see this?happening to.? K4OAH's "CD's" will help you locate the?resistors, though that's just the start of the fun!? Frankly, ALL resistors with values above?200K or so deserve a resistance?check.? Doesn't seem to be as big an issue on the B-line and?earlier?in this circuit as the circuits are different and resistances are lower....cursory check though, so keep that in mind.
Also on the T-4XC...R49 and R59 on the relay board.? Often seen heat-stressed.
On the TR-4C series...R 192 and R-45 on the relay board.
On all TR-4(any) - R163 on the 200 VDC line to the S meter.? ?It seems to act as a fuse and have found several visibly?open!!!
I'm sure there are more, but this is a start.? I'm sure there are others who can add to the list.
73
Peter
VE7PS
I have found that virtually all of the resistors in my TR-4 have not aged out of tolerance which is a little surprising.? ?I did, though, replace the three 15R cathode resistors.? I think one or two were over 20 ohms but I replaced them mainly because they were no longer all the same value.
Since R13 is "selected", then I presume one can read the bands and should be able to check whether it's out of tolerance.? At least R45 is not "selected".
Thanks for the tip!
Barry - N4BUQ (the other, other Barry)
Barry,
Something else to consider - Every TR-n that I've worked on has had the plate current meter resistors aged high.? The result is that plate current measurement is not correct which of course means that idle current is not set correctly.? Seems to me that idle current is the basic foundation for everything and if its not right than there may be some odd things happen.? There are two resistors.? One is a standard value and the other is determined by the Drake tech during final alignment before the radio was shipped.
Also, I don't recall if you mentioned checking it or not but the 68ohm and 15ohm resistors under the amp tubes are also prone to aging high.? I always check and usually replace those resistors and then measure the resistors for the meter and replace if they have drifted.? You can of course verify your idle current by measuring resistance and voltage drop across the three resistors under the amp tubes, calculating the current draw, and adding up the current draw for all three.
73,
Another Barry
KJ5GQM
On Sunday, May 18, 2025 at 05:23:44 PM CDT, n4buq <
n4buq@...> wrote:
I tested all three tubes for gas and none were bad in that respect.? Interestingly, I decided to perform the "LIFE TEST" where the filament voltage is reduced (I think it goes down to about 5.8V or maybe 5.9V for a 6.3V filament).? While transconductance drops by an acceptable amount when that button is pressed, the fall in value looked a lot like what I see for plate current when the key is down.
With all the tubes back in place, I decided to monitor the filament voltage.? I've been running the rig between 110VAC and 115VAC and that was giving me a low-to-start-with filament voltage of just under 6VAC.? With that, key-down would cause that voltage to drop to around 5.7VAC.? I then bumped the autotransformer up to closer to 120VAC which gave me very close to 6.3VAC and, oddly enough, on key-down, that voltage would drop just a small amount - perhaps 0.1VAC to 0.2VAC.? That seems a bit odd that the sag was smaller but, perhaps, the transformer is more efficient at the input voltage closer to 120VAC but that's just a guess.
Also, with the input voltage closer to 120VAC, I think I'm seeing a good increase in plate current at resonance.? I suppose that's expected since the plate voltage also climbs with that input voltage.
Thanks,
Barry - N4BUQ
From: "Barry" <
n4buq@...>
To: "DRAKE-RADIO" <
[email protected]>
Sent: Sunday, May 18, 2025 1:03:51 PM
Subject: Re: [DRAKE-RADIO] TR-4 - Soft Finals?
Richard, Steve,
Thank you both for the responses.? I wasn't sure if "soft" was just a generic for "weak" and, in general, maybe that's true.
My three tubes do not exhibit some of the more obvious signs of excess gas (e.g. white coating or a "getter-like" spot but that's not a very good indicator of small gas amounts.? I'm going to pull them again and run the gas test as I didn't do that when I was testing them.? Maybe that will be revealing.
Thanks again,
Barry - N4BUQ
From: "Steve Wedge, W1ES/4 via
" <w1es=
[email protected]>
To: "DRAKE-RADIO" <
[email protected]>
Sent: Sunday, May 18, 2025 12:37:22 PM
Subject: Re: [DRAKE-RADIO] TR-4 - Soft Finals?
Yep, that sounds like a textbook example.? Power falls off first on the higherbands as the gain (transconductance) decreases.? The electrons are generated at the heated cathode and eventually, the cathode material gets depleted.
I¡¯m starting to think that my TR-4Cw RIT is having similar issues, though strangely, the output only sags when on the antenna and not on the dummy load.? The tubes in it are well-used.
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sat, May 17, 2025 at 10:46 PM, n4buq <
n4buq@...> wrote:
Can someone please tell me what is meant by the term "soft finals"? I'm still having problems getting proper output from my TR-4 and, for all I know, that might be the problem. I've tested them for transconductance and all three are very close to the same value and, furthermore, that value is quite a bit above the minimum for a good tube.
Aside from low output (i.e. about 300 mA plate current maximum into a dummy load), I notice that if I hold down the key for a few seconds the plate current tends to drop just slightly and I think if I were to continue holding the key down, the current would continue to slowly decrease.
I measured the voltage across each cathode resistor and I notice the same phenomenon: the voltage climbs to about 1.6 VDC and then begins to drop a bit. Like the transconductance values, each cathode resistor is "matched" in value and behavior to the other two so I suppose that's one good thing.
Am I seeing the result of weak/soft tubes or is something else going on that would cause this?
Thanks,
Barry - N4BUQ
|
Of course, there¡¯s nothing to prevent any of us from replacing the SAT resistor with a pot and then being able to directly calibrate the metering during an alignment. I¡¯ve not done this but it¡¯s certainly doable ¡ª I just don¡¯t think that amount of precision buys much.?
73,
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sun, May 18, 2025 at 21:49, n4buq < n4buq@...> wrote:
I have found that virtually all of the resistors in my TR-4 have not aged out of tolerance which is a little surprising.? ?I did, though, replace the three 15R cathode resistors.? I think one or two were over 20 ohms but I replaced them mainly because they were no longer all the same value.
Since R13 is "selected", then I presume one can read the bands and should be able to check whether it's out of tolerance.? At least R45 is not "selected".
Thanks for the tip!
Barry - N4BUQ (the other, other Barry)
Barry,
Something else to consider - Every TR-n that I've worked on has had the plate current meter resistors aged high.? The result is that plate current measurement is not correct which of course means that idle current is not set correctly.? Seems to me that idle current is the basic foundation for everything and if its not right than there may be some odd things happen.? There are two resistors.? One is a standard value and the other is determined by the Drake tech during final alignment before the radio was shipped.
Also, I don't recall if you mentioned checking it or not but the 68ohm and 15ohm resistors under the amp tubes are also prone to aging high.? I always check and usually replace those resistors and then measure the resistors for the meter and replace if they have drifted.? You can of course verify your idle current by measuring resistance and voltage drop across the three resistors under the amp tubes, calculating the current draw, and adding up the current draw for all three.
73,
Another Barry
KJ5GQM
On Sunday, May 18, 2025 at 05:23:44 PM CDT, n4buq <n4buq@...> wrote:
I tested all three tubes for gas and none were bad in that respect.? Interestingly, I decided to perform the "LIFE TEST" where the filament voltage is reduced (I think it goes down to about 5.8V or maybe 5.9V for a 6.3V filament).? While transconductance drops by an acceptable amount when that button is pressed, the fall in value looked a lot like what I see for plate current when the key is down.
With all the tubes back in place, I decided to monitor the filament voltage.? I've been running the rig between 110VAC and 115VAC and that was giving me a low-to-start-with filament voltage of just under 6VAC.? With that, key-down would cause that voltage to drop to around 5.7VAC.? I then bumped the autotransformer up to closer to 120VAC which gave me very close to 6.3VAC and, oddly enough, on key-down, that voltage would drop just a small amount - perhaps 0.1VAC to 0.2VAC.? That seems a bit odd that the sag was smaller but, perhaps, the transformer is more efficient at the input voltage closer to 120VAC but that's just a guess.
Also, with the input voltage closer to 120VAC, I think I'm seeing a good increase in plate current at resonance.? I suppose that's expected since the plate voltage also climbs with that input voltage.
Thanks,
Barry - N4BUQ
From: "Barry" <n4buq@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Sunday, May 18, 2025 1:03:51 PM
Subject: Re: [DRAKE-RADIO] TR-4 - Soft Finals?
Richard, Steve,
Thank you both for the responses.? I wasn't sure if "soft" was just a generic for "weak" and, in general, maybe that's true.
My three tubes do not exhibit some of the more obvious signs of excess gas (e.g. white coating or a "getter-like" spot but that's not a very good indicator of small gas amounts.? I'm going to pull them again and run the gas test as I didn't do that when I was testing them.? Maybe that will be revealing.
Thanks again,
Barry - N4BUQ
From: "Steve Wedge, W1ES/4 via groups.io" <w1es@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Sunday, May 18, 2025 12:37:22 PM
Subject: Re: [DRAKE-RADIO] TR-4 - Soft Finals?
Yep, that sounds like a textbook example. ?Power falls off first on the higherbands as the gain (transconductance) decreases. ?The electrons are generated at the heated cathode and eventually, the cathode material gets depleted.
I¡¯m starting to think that my TR-4Cw RIT is having similar issues, though strangely, the output only sags when on the antenna and not on the dummy load. ?The tubes in it are well-used.
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sat, May 17, 2025 at 10:46 PM, n4buq <
n4buq@...> wrote:
Can someone please tell me what is meant by the term "soft finals"? I'm still having problems getting proper output from my TR-4 and, for all I know, that might be the problem. I've tested them for transconductance and all three are very close to the same value and, furthermore, that value is quite a bit above the minimum for a good tube.
Aside from low output (i.e. about 300 mA plate current maximum into a dummy load), I notice that if I hold down the key for a few seconds the plate current tends to drop just slightly and I think if I were to continue holding the key down, the current would continue to slowly decrease.
I measured the voltage across each cathode resistor and I notice the same phenomenon: the voltage climbs to about 1.6 VDC and then begins to drop a bit. Like the transconductance values, each cathode resistor is "matched" in value and behavior to the other two so I suppose that's one good thing.
Am I seeing the result of weak/soft tubes or is something else going on that would cause this?
Thanks,
Barry - N4BUQ
|
My mains can get to 126, so I set my variac to around 118. It doesn¡¯t hurt. All modern equipment that aren¡¯t controlled by the C-4 runs on the mains directly.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sun, May 18, 2025 at 20:05, n4buq < n4buq@...> wrote:
Out mains typically runs 126VAC and that puts the HV well over 700VDC (I don't recall the exact value at the moment).? 6JB6s are rated at 770VDC plate voltage max so I think that's probably okay.
I bought a heavy-duty transformer with two 12VAC windings that, when in parallel, can give 8A that I want to use as a bucker.? In retrospect, that may not work as well as I'd hoped and I may need to look for a 6VAC version.? If the the rig is intended to run with the AC-4 at 120VAC, then perhaps that extra 6V may not matter too much and I can just leave the bucker out of the setup.? I was just looking at prolonging the life of the tubes as much as practical.
Thanks for the info.? I was thinking that 115 was probably the standard when these rigs were built but apparently that's not the case.
Barry - N4BUQ
From: "Steve Wedge, W1ES/4 via groups.io" <w1es@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Sunday, May 18, 2025 5:35:37 PM
Subject: Re: [DRAKE-RADIO] TR-4 - Soft Finals?
There is a common misconception that our Drake rigs were designed for 115VAC or even 110VAC.? They were designed for 120VAC nominal -- which, through all my years of testing and helping to design raw and linear power supplies, were given a tolerance of +/-5% (so, 114 - 126 VAC.? Of course many of those supplies would do just fine outside that tolerance band.? It also explains why you get 6.3VAC at the filaments at 120VAC.
When I started working as a tech in 1976, 120VAC had already been the standard.? Interestingly, the buss bars at out plant were sometimes labelled "120V/60CPS", so the changeover to 120 preceded the changeover from CPS to Hz.
We had the whole gamut in that Digital Equipment plant: 120/240 single-phase and 208/440 three-phase (IIRC).? Our equipment runs fine at 120VAC.? Yes, you can eke a little more tube life running the filaments slightly lower but our rigs were designed for 120 (it's in the manuals).
73,
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with
secure email.
On Sunday, May 18th, 2025 at 6:23 PM, n4buq <n4buq@...> wrote:
I tested all three tubes for gas and none were bad in that respect.? Interestingly, I decided to perform the "LIFE TEST" where the filament voltage is reduced (I think it goes down to about 5.8V or maybe 5.9V for a 6.3V filament).? While transconductance drops by an acceptable amount when that button is pressed, the fall in value looked a lot like what I see for plate current when the key is down.
With all the tubes back in place, I decided to monitor the filament voltage.? I've been running the rig between 110VAC and 115VAC and that was giving me a low-to-start-with filament voltage of just under 6VAC.? With that, key-down would cause that voltage to drop to around 5.7VAC.? I then bumped the autotransformer up to closer to 120VAC which gave me very close to 6.3VAC and, oddly enough, on key-down, that voltage would drop just a small amount - perhaps 0.1VAC to 0.2VAC.? That seems a bit odd that the sag was smaller but, perhaps, the transformer is more efficient at the input voltage closer to 120VAC but that's just a guess.
Also, with the input voltage closer to 120VAC, I think I'm seeing a good increase in plate current at resonance.? I suppose that's expected since the plate voltage also climbs with that input voltage.
Thanks,
Barry - N4BUQ
From: "Barry" <n4buq@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Sunday, May 18, 2025 1:03:51 PM
Subject: Re: [DRAKE-RADIO] TR-4 - Soft Finals?
Richard, Steve,
Thank you both for the responses.? I wasn't sure if "soft" was just a generic for "weak" and, in general, maybe that's true.
My three tubes do not exhibit some of the more obvious signs of excess gas (e.g. white coating or a "getter-like" spot but that's not a very good indicator of small gas amounts.? I'm going to pull them again and run the gas test as I didn't do that when I was testing them.? Maybe that will be revealing.
Thanks again,
Barry - N4BUQ
From: "Steve Wedge, W1ES/4 via groups.io" <w1es@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Sunday, May 18, 2025 12:37:22 PM
Subject: Re: [DRAKE-RADIO] TR-4 - Soft Finals?
Yep, that sounds like a textbook example. ?Power falls off first on the higherbands as the gain (transconductance) decreases. ?The electrons are generated at the heated cathode and eventually, the cathode material gets depleted.
I¡¯m starting to think that my TR-4Cw RIT is having similar issues, though strangely, the output only sags when on the antenna and not on the dummy load. ?The tubes in it are well-used.
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sat, May 17, 2025 at 10:46 PM, n4buq <
n4buq@...> wrote:
Can someone please tell me what is meant by the term "soft finals"? I'm still having problems getting proper output from my TR-4 and, for all I know, that might be the problem. I've tested them for transconductance and all three are very close to the same value and, furthermore, that value is quite a bit above the minimum for a good tube.
Aside from low output (i.e. about 300 mA plate current maximum into a dummy load), I notice that if I hold down the key for a few seconds the plate current tends to drop just slightly and I think if I were to continue holding the key down, the current would continue to slowly decrease.
I measured the voltage across each cathode resistor and I notice the same phenomenon: the voltage climbs to about 1.6 VDC and then begins to drop a bit. Like the transconductance values, each cathode resistor is "matched" in value and behavior to the other two so I suppose that's one good thing.
Am I seeing the result of weak/soft tubes or is something else going on that would cause this?
Thanks,
Barry - N4BUQ
|
Re: Thoughts on Dayton Hamfest
No Drake discussion forum like the old days.
|
Re: Hanvention tradition...broken
Another broken tradition¡ Whatever happened to the Drake forum they used to have on the schedule?
?
K7RAN
|
Speaking of resistors, Where are you sourcing your resistors??
?
Thanks
?
George NE2I
|
Re: The Drake 2B and its Frequency Spread Limitations
Crystals are costly and it may be challenging to find them for the bands you're interested in.? If you're more interested in listening to shortwave broadcast than listening to the ham bands, my suggestion is to buy a general coverage receiver.? There are a lot of them available.? Since you have fond memories of listening your Dad's Hallicrafters S-40B, why not pick up one of them and restore it?? The experience will be worth the money and effort.? My first exposure to SWL'ing as a youg boy came via my grandfather's Zenith Trans-Oceanic B600.? I spent countless hours listening to that TO with a pair of bakelite Baldwin cans on my little head.? I inherited that radio when he passed away in 1976, and I still have it.? The first SW radio that I owned was a Hallicrafters S-107 that was given to me by a neighbor when I was about 12 years old.? I have one of them, too, just for the nostalgia aspect.? I rarely listen to either of them, but I keep them both in working order.?
?
The Drake 2-B is a very capable ham-bands receiver.? It packs a lot of performance into a small package.? I own two of them at the moment.? Although they are capable of receiving most of them HF spectrum, they really weren't meant for it.?
|
Re: The Drake 2B and its Frequency Spread Limitations
Wikipedia has a good
list of the major bands for short wave broadcast stations. Note
that a number of broadcasters operate outside these ranges.
You don't have 10
(looks likes 12 band switch positions looking at the manual I
downloaded) positions that you can put any crystal into.? The
preselector, the RF amplifier which is the first stage of the
receiver, has 5 bands, A, B, C, D, and E.? The A tuning range is
covers from 3.5 to 5.0 MHz only ans is wired to the 80 and the A
switch positions. You could put a crystal in the A position to
cover the 60 meter SWL band, 4.75-4.995 MHz but not one for the
49 m band, 5.9 to 6.2 MHz.? The B range is from 4.6 to 13.5 MHz
and is wired to 40 and B. the C range is from 7.5 to 23.5 and is
wired to the C position only. The D range is from 8.4 to 25.5
and is on the D switch only. The E range is from 10.3 to 30 MHz
and is wired to the E position as well as 20, 15, and 10 meter
bands.? So the bands you choose to crystal for have to fit
within limited switch positions. Fortunately there is a large
overlap the the B, C, D and E ranges.? The ham band crystals can
be removed and replaced with SWL band crystals, matched to the
same preselector range. (assuming the receiver comes with the
factory standard ham band crystals)
If you are adapt with
electronics, I would also recommend the suggestion from Dave,
W7GZ to use one of the cheap Chinese synthesizer modules. You
can buy one for about the cost of a single crystal.? Drake made
a synthesizer, the FS-4, to replace crystals for their various
receivers tuning in 500 kHz bands, and there have been a few
articles for similar designs. Here's one such showing how it's
connected to the receiver.?
John???? KK6IL?? Former
SPR-4 owner
?
On 5/17/2025 6:23 PM, Richard W2ONE via
groups.io wrote:
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Hello everyone.? I am new here.? Let me know if I become too
much of a pain ...
?
I just received a Drake 2B from an eBay seller.? I will admit
to a lot of stupidity on my part and a lack of understanding
before I pushed the "Purchase now" button.? I purchased this
during an emotional stupor because I was looking for a GOOD old
tube SW receiver like my Dad used when I was in elementary
school in the 60s - a Hallicrafters S-40B.? Mom and Dad were
scrimping by with just barely enough money and my Dad picked-up
that Hallicrafters from a junk yard and got it working again.?
Even though Dad had to walk a mile to work and back because he
did not have a car, he gave some priority to buying that
Hallicrafters.? And we had a great time listening to stations
all over North and South America late into the night (usually
ending only when Mom came into the room with her hands on her
hips).? I remember the glow on the ceiling and the smell of
those hot tubes.? So, after reading a lot of reviews which all
kept focusing on the Drake 2B as THE radio to have, I pushed
that eBay button and have been waiting where my driveway meets
the street ever since.? It showed up yesterday and I unboxed it
and started reading the manual.? Boy, am I ever lost!? I am not
normally a stupid fellow and I can usually get my brain to
cooperate on new and even difficult concepts, but that manual
and me have decided to part company.? Surely, there is a better
source of information somewhere on how to work this radio!? I
have more questions than I believe this group will allow, but
let me start with this one:
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If I understand the manual correctly, and a little simple
math, if I purchase ten crystals and fill each of the ten slots,
that will give me a total band spread of frequencies of (let's
see: a 600 kHz spread per crystal, times ten crystals, equals
6,000 kHz of total frequencies) available on this radio.? Of the
frequencies usually collectively available on the LW, MW, and SW
bands on most of these old vintage radios (specifically, .5 to
30 MHz), this radio will not tune to the LW or MW groups and
will let me listen to only 6 MHz (6 MHz!) of the SW group.? Is
that REALLY true?? Surely a coveted radio with owners' comments
centering around "I will never give it up" to "I should not have
given it up" can do better than that!? Is this true, or will
someone here tell me where the secret button is that will allow
me to tune in the remainder of the HF field?? Really, I think I
goofed and bought a specialized radio that was never intended to
be in the hands of a "general receiver" fool.
?
Richard
W2ONE
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By the way, ever since I unboxed the radio and started
sighing heavily with each page turned in that manual, my wife
has started standing at the door with her hands on her hips...
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Gary WB6OGD
Paul Christensen
Randy K7RAN