Re: Henry 2K-3 TR switching
Guys, I ordered that board from Tom. Thank you for all the help etc. As far as the 7300 goes, I thought all that was adjustable in the menu??? Bob W4JFA
On Fri, Aug 2, 2024 at 12:38?PM Louis Parascondola via <Gudguyham= [email protected]> wrote:
Many amplifiers have a watch dog circuit that avoids the amp relays from being hot switched. Many amps will delay the closing of the relays until the PTT signal is present and no RF is at the input.? This is mostly prevalent when using CW.? The amp will clip the first bit of RF until there is none and then the relays close.? A 7300 or just about ANY solid state radio without RF delay control will hot switch an SB200,SB220,TL922, Drake etc etc unless the modern radio has an RF delay, the? amp will hot ?switch.? In? the case of the old open frame relay amps, the TR relay can be mechanically sequenced so that the contacts won¡¯t hot switch by insuring that the output contacts switch?before the amplifier is biased on with the bias switching contact of the relay. The 7300 isn¡¯t necessarily singled out on this regard.? Use a 20ms RF delay when using old amps with new radios.
On Friday, August 2, 2024, 11:42 AM, Alan - W5ARM <W5ARM.mail@...> wrote: On Fri, Aug 2, 2024 at 08:23 AM, Bill K3HZP wrote:
Sequencing is required for some rigs. The classic example is the ICOM 7300 which releases the amplifier key line before the RF goes to zero.? See QST review for IC7300.? In this case, sequencing is required on the release transition.??
? .... Bill K3HZP
I find that really hard to believe. That means that using a 7300 with ANY amplifier - even a modern tube or solid state amp - would allow the 7300 to hot-key (or hot "un-key") the amp? This would mean that, in reality, ALL amplifiers are effectively unusable (or subject to damage) if using a 7300, unless "sequencing" were employed.
?
I had (abut sold) a 7300. Never heard of such a thing...
?
I was unable to access the referenced QST article ("members only"), so please provide a quote or screen-shot of the appropriate article section to validate this claim.
?
--
73,
~Alan
|
Thanks Bill...but this is the same info you sent me some weeks ago. My question is: did you intend to attach a different 3rd file, rather than the bias schematic twice? Look at the attachments you sent...two of them are identical.
Thanks,
Robin Midgett K4IDC
On Fri, Aug 2, 2024 at 12:51?PM Bill Cotter, N4LG via <n4lg= [email protected]> wrote: Robin,
Here is a problem that may be similar to yours:
I had the shorted Q2 problem as well in my Centurion.
73 Bill N4LG
PS: Another problem is a wonky mode switch. I had to make a
modification to my Centurion logic to fix a "state" problem. See
attached.
|
Re: Henry 2K-3 TR switching
On Fri, Aug 2, 2024 at 11:37 AM, Louis Parascondola wrote:
Many amplifiers have a watch dog circuit that avoids the amp relays from being hot switched. Many amps will delay the closing of the relays until the PTT signal is present and no RF is at the input. ?This is mostly prevalent when using CW. ?The amp will clip the first bit of RF until there is none and then the relays close. ?A 7300 or just about ANY solid state radio without RF delay control will hot switch an SB200,SB220,TL922, Drake etc etc unless the modern radio has an RF delay, the? amp will hot ?switch. ?In?the case of the old open frame relay amps, the TR relay can be mechanically sequenced so that the contacts won¡¯t hot switch by insuring that the output contacts switch?before the amplifier is biased on with the bias switching contact of the relay. The 7300 isn¡¯t necessarily singled out on this regard. ?Use a 20ms RF delay when using old amps with new radios.
The 7300 does have TX RF output delay... an adjustable delay setting from (IIRC) 7ms (default) to ~30ms (In: MENU --> SET --> FUNCTION --> TX DELAY HF).? My Yaesu 101D also has an RF delay, although (interestingly) it is set through the CW function (break-in delay).? Not sure about Kenwood radios...
--
73,
~Alan
|
Robin,
Here is a problem that may be similar to yours:
,112624.0.html
I had the shorted Q2 problem as well in my Centurion.
73 Bill N4LG
PS: Another problem is a wonky mode switch. I had to make a modification to my Centurion logic to fix a "state" problem. See attached.
|
Re: Henry 2K-3 TR switching
Many amplifiers have a watch dog circuit that avoids the amp relays from being hot switched. Many amps will delay the closing of the relays until the PTT signal is present and no RF is at the input. ?This is mostly prevalent when using CW. ?The amp will clip the first bit of RF until there is none and then the relays close. ?A 7300 or just about ANY solid state radio without RF delay control will hot switch an SB200,SB220,TL922, Drake etc etc unless the modern radio has an RF delay, the? amp will hot ?switch. ?In? the case of the old open frame relay amps, the TR relay can be mechanically sequenced so that the contacts won¡¯t hot switch by insuring that the output contacts switch?before the amplifier is biased on with the bias switching contact of the relay. The 7300 isn¡¯t necessarily singled out on this regard. ?Use a 20ms RF delay when using old amps with new radios.
On Friday, August 2, 2024, 11:42 AM, Alan - W5ARM <W5ARM.mail@...> wrote: On Fri, Aug 2, 2024 at 08:23 AM, Bill K3HZP wrote:
Sequencing is required for some rigs. The classic example is the ICOM 7300 which releases the amplifier key line before the RF goes to zero.? See QST review for IC7300.? In this case, sequencing is required on the release transition.??
? .... Bill K3HZP
I find that really hard to believe. That means that using a 7300 with ANY amplifier - even a modern tube or solid state amp - would allow the 7300 to hot-key (or hot "un-key") the amp? This would mean that, in reality, ALL amplifiers are effectively unusable (or subject to damage) if using a 7300, unless "sequencing" were employed.
?
I had (abut sold) a 7300. Never heard of such a thing...
?
I was unable to access the referenced QST article ("members only"), so please provide a quote or screen-shot of the appropriate article section to validate this claim.
?
--
73,
~Alan
|
Re: Henry 2K-3 TR switching
On Fri, Aug 2, 2024 at 08:23 AM, Bill K3HZP wrote:
Sequencing is required for some rigs. The classic example is the ICOM 7300 which releases the amplifier key line before the RF goes to zero.? See QST review for IC7300.? In this case, sequencing is required on the release transition.??
? .... Bill K3HZP
I find that really hard to believe. That means that using a 7300 with ANY amplifier - even a modern tube or solid state amp - would allow the 7300 to hot-key (or hot "un-key") the amp? This would mean that, in reality, ALL amplifiers are effectively unusable (or subject to damage) if using a 7300, unless "sequencing" were employed.
?
I had (abut sold) a 7300. Never heard of such a thing...
?
I was unable to access the referenced QST article ("members only"), so please provide a quote or screen-shot of the appropriate article section to validate this claim.
?
--
73,
~Alan
|
Re: Henry 2K-3 TR switching
Sequencing is required for some rigs. The classic example is the ICOM 7300 which releases the amplifier key line before the RF goes to zero.? See QST review for IC7300.? In this case, sequencing is required on the release transition.??
? .... Bill K3HZP
|
Re: Henry 2K-3 TR switching
I agree. You never had any kind of sequencing with the old relay.
The new vacuum relays will be so much faster that you probably
won't need to bother with all that.
73, Alek VK6APK.
On 31/07/2024 11:37 pm, Bob wrote:
toggle quoted message
Show quoted text
Hello Jim, I was hoping you would respond. I've
read just about every amp article/post you've written the past
few years. Thank you.
I believe my 2K-3 OEM relay looks like this... Three
contacts.
You said in your last sentence... Simplify
it....just operate all 3 of em at once ( even if u don't
speed em up....and all 3 operate in 3 msecs) .? I
would be thrilled over that!
If so, that's what I had been thinking, basically, much
better than before/OEM. I didn't know if I was missing
something or not. Can it really be that simple?
Thanks again, Bob W4JFA
I just went through this with my 4 x Drake L4B's.?
I used 3 x new Gigavac GH1's.? ?You can buy em with either a
12 vdc coil or a 26.5 vdc coil.? ?Jennings version is called
an RJ1A. The kilovac version is called a HC-1.....and the
coils in all 3 x brands are field swappable to either a 12 /
26.5 / 115 vdc coil.? ?The Gigavac uses metric threads on
the big lockdown nut.
I used em for input / output / bias.? ?In my case, I used
the 12 vdc coil version.....and wired all 3 x coils in
series.? The oem drake fil xfmr also has a 22 vac winding on
it to run the oem 3PDT clunker TR relay.? Drake used a 1/2
wave rectifier, so the output was 31 vdc no load.? ?In my
case, I changed that to a FWD ( full wave doubler) to obtain
63 vdc no load.? ?A 175 ohm @ 25 watt metal finned dropping
resistor is used in series with the 3 x series coils. 36 vdc
used to operate the 3 x series 12 vdc coils.? 27 vdc is
dropped across the 175 ohm series drop resistor. Drop
resistor dissipates 3.9 watts on TX....and 0 watts on RX.?
IE: when T=0, the relay coils get hit with an initial over
voltage. (63/3 or 21 vdc per coil)....which will? speed em
up.? To speed em up even more, a 50uf @ 150 vdc lytic is
wired in parallel with the 175 ohm drop resistor.? This is
called a ...'RC hotshot' circuit. Jennings, Kilovac, Gigavac
all mention it's use.? ( Alpha used it on their older amps,
that used a vac relay.? Alpha used 36 vdc applied to the
26.5 vdc coil, and also a small lytic across the series drop
resistor).? With the small cap in parallel with the drop
resistor, it sustains the over voltage a hair longer.? The
concept works superb.? ?All 3 x vac relays in each drake amp
operate in slightly under 1 msec.?
80% of the total operate time is spent just building up the
magnetic field in the coil. (The XL of the coil impedes DC
current flow).? The over voltage? makes the current flow
faster.
The ONLY thing that needs to be sequenced is the RF output
from the xcvr itself.? You want to key the amp NOW,? but
delay RF from the xcvr by 1-2 msecs.? This gives the sped up
vac relays in the amp a head start.?
Modern xcvr's have an adjustable TX RF output delay...which
works on both CW + SSB.? ?My yaseu MK-V has an adjustable
0-30 msec delay, ( in 1 msec increments) to prevent hot
switching? the slow 3PDT mech relay in the older tube amps.
The drake 3PDT operates in 17 msecs.? ?The 3PDT in the
ameritron amps operates in 15 msecs.? ? The delay in the
MK-V was set at 20 msecs to ensure the oem drake relay got a
head start.? BUT the adjustable delay in the MK-V only works
on CW.? ?For SSB use, plan B.... which is to re-use the spst
tiny relay in the MK-V? (was used to key an amp)? to instead
GRND the TX inhibit lead in the MK-V.? ?UNTIL u grnd the TX
inhibit lead, you can key the amp, but zero RF coming out of
the xcvr.? ?To actually key the relays in the amp, I use an
opto isolator. The input of the opto is keyed? via the
'electronic TX grnd'? from the MK-V.? Input of opto only
draws a few ma.? ?You can get em with a 5-15-24 vdc input (
and each of those has a super wide operating range)..and the
output side is rated for either? 60 vdc @ 3 amps CCS...or
250 vdc @ 1 amp CCS.? 5 kv? isolation between input side and
output side.?
You can also use a 2nd opto to do the bias in the amp, which
works good.?
Ok, back to the henry 2K-3.? ?The small relay? xfmr in the
2K-3 is 8.5 vac on either side of the CT.? ?It's a FWCT
config.? Output is 8.5 vac x 1.414 = 12 vdc.? ?I would
reconfigure the small relay xfmr to a FWB..and use the
entire sec winding ( CT not used).? ?Then it becomes 17 vac
x 1.414 = 24 vdc no load.? ?Ok, then? wire the 3 x 12 vdc
vac relay coils in parallel.? ?Each 12 vdc coil is 80 ohms.?
?12 vdc / 26.67 ohms, ( 80/3 = 26.67 ohms)? ?= .450 amps.
The series drop resistor will be 26.67 ohms.? Diss in the
resistor will be (.45 x .45) x 26.67 ohms = 5.4 watts.?
?Each relay coil will diss? 1.8 watts.? Each coil has 150 ma
flowing through it.? Wire a 50 uf @? 100-150 vdc (axial
lead) lytic across the drop resistor.?
Depending on xcvr used, it has to handle? 24 vdc OCV (open
circuit voltage)? @ 450 ma under load.? You do NOT want to
use a slow mech relay in the xcvr to key the sped up vac
relays!? ?Hence the use of either an opto isolator or a fast
switch transistor.?
Ok, the 3 x relays will operate / rls in just a hair < 1
msec.? No hot switching.
I found a sidewall on the L4B, that would take all 3 x vac
relays.? ? A 9/16" hole is required.? ( A 5/8" will also
work).? ?The greenlee 1/2" -? 9/16"? - 5/8"? punches all use
a 1/4" draw stud....and hence require a 1/4" pilot hole.? I
used my roper whitney hand punch to punch the 3 x 1/4"?
pilot holes....bam, done.? Then the greenlee 9/16" punch
(die and cup, just tighten the wrench).?
You could use just 2 x vac relays...for input /
output.....and an opto for the cut off bias.? That would
save one vac relay.? ?You could maybe, use a super fast SPDT
tiny mech relay for the input side.? I wanted vac relay on
both the input and output, so the amp will handle 2 kw on
bypass mode.? ?I do that, since I string several drake amps
in series, one per band, or one at each end of 80m etc, or
any other combo.? A simple rotary switch in the key line of
the xcvr ensures only one amp can ever be keyed at one
time.? ? ?On the drake L4B, the only way to calibrate the
internal wattmeter is to take it apart to get to the
underside of chassis....and apply 1 kw cxr from a 2nd
amplifier ( with a bird 43)? to the drake amp...which of
course is powered down, and on bypass.? IE: it has to handle
a kw on bypass mode anyway.?
You could mount one vac relay near the input coax connector,
and a 2nd vac relay near the output side....or near the load
cap.? Then a short length of RG-400 between the NC contacts
of the input + output relay. ( aka..the 'bypass leg' ).? ?
All 3 of my vac relays are dead quiet.? ?The gigavac GH1 hi
-pot tests to 7.5 kv.?
The idea of using a 12 vdc coil came from the eng dept at
Kilovac, during a phone call I had with em years ago.? "IF u
are voltage limited, use the 12 vdc coil".?
There is also another method to obtain 28 vdc in ur henry
amp.? It uses a 10 vac fil xfmr ( with fils in series).?
?Tap off the 10 vac sec...and use a FWD ( doubler)? to
obtain 28.28 vdc.?
Without the speedup circuit, the vac relays typ operate in
2-3 msecs.? ?In the past, folks would use a semi complicated
sequencing mess...so the output relay would operate
1st.....like say 3 msec.? ?Then the input relay next, say 5
msecs...then the bias relay last....say 7 msecs.? When going
back to RX, the rls sequence was reversed, with bias relay
releasing 1st, then input relay, the output relay last.?
Simplify it....just operate all 3 of em at once ( even if u
don't speed em up....and all 3 operate in 3 msecs) .? The
only thing that has to be sequenced is to delay grnding the
handy dandy? TX inhibit lead in the xcvr.?
?
Sri? for the diatribe.?
Jim? VE7RF
|
Re: Henry 2K-3 TR switching
Howdy Bob,
?
Your second picture provided a better view... I think I figured it out.
?
The "big" 2-pole relay appears to have a micro-switch - or some sort of auxiliary contact -? attached to it (see your pic that I annotated).
?
The micro-switch (or aux contact) (I believe) is actuated by the big relay arm. The "big" relay contacts provide the RF switching (input & output), and the micro-switch/aux contacts provide the bias control via the purple and [barely visible] green wires, which bypass the bias resistor (R-27 on the schematic) located elsewhere.
?
In any case, it appears everything is right there on top, and it should be easy to modify it with a pair of vacuum relays, and a third high-speed relay for bias control.? You'll have to fabricate a little bracket to mount the relays on, and then replace the OEM "big" relay with your new bracket & relays, in the same location.
?
Also, just as an FYI, those Greenstone vacuum relays (from Henry Radio) are pretty compact (see pic below). A pair of them won't take up a whole-lot of room, and should easily fit in the old OEM relay location. I have a pair of them on-hand for a Heathkit HL-2100 project that is on the bench.
?
ON EDIT: FOR SOME REASON, MY TWO SMALL PICS ARE NOT COMING THROUGH... Oh well.
?
 ? ?
?
--
73,
~Alan
|
Re: Henry 2K-3 TR switching
pix came out fine.? There must be a 2nd relay for the bias cut off.? ?Only other method if a DPDT relay is used, is to use rf chokes on the input side of the DPDT relay, so do the cut off bias.?
U will have to delve into this more....and see exactly what they have done.? Once that is sorted out.....replacing with vac relays is straightforward.?
?
|
Re: Henry 2K-3 TR switching
Jim, OK I'll study that. Thank you. Attached is a picture of the relay on the top of the RF deck. I hope 2+ meg isn't too big of a file. Bob W4JFA
On the 2K-3 schematic,? RY3 is a 3PDT..... with input / output / and cutoff bias.?
If urs only is only a DPDT....there must be another relay in there for cut off bias.? And it only needs to be a SPST-NO relay.?
On the schematic, the NC contact is not used on the cut off bias.? It just shorts out the 10K @ 25 watt resistor on TX....leaving the CR7 bias diode in the circuit.?
The COM on any relay is the contact that actually physically moves.??
|
Re: Henry 2K-3 TR switching
On the 2K-3 schematic,? RY3 is a 3PDT..... with input / output / and cutoff bias.?
If urs only is only a DPDT....there must be another relay in there for cut off bias.? And it only needs to be a SPST-NO relay.?
On the schematic, the NC contact is not used on the cut off bias.? It just shorts out the 10K @ 25 watt resistor on TX....leaving the CR7 bias diode in the circuit.?
The COM on any relay is the contact that actually physically moves.??
|
Re: Henry 2K-3 TR switching
Thanks Jim. I'm in the research stage. Maybe I can get started September or so.?
Since I wrote the last email I took the top off of the RF deck. My relay up on top has two contacts, not three. Looking at the schematic that makes sense. Yep an antique, 1968. I use it every day.
I need to find the "happy medium" between cost and improving what it is now.
Not that it matters, this is a desk model. Power supply separate. Power supply will give u a hernia moving it around.
73, Bob W4JFA?
?Without the speed up, they will operate in 2-3 msecs.? The 3PDT clunker u have in there now will be 18-20 msecs at least.?
You could even leave the oem FWCT? 12 vdc supply in there.? ? Just toss the oem? clunker....and replace it with? 3 x vac relays, each with a 12 vdc coil...and wire all 3 x coils in parallel.? ? Then no drop resistor required.? ?Each coil will draw 1.8 watts? (5.4 watts in total)? ?on TX...and zero watts on RX.?
You will have to get creative on locating them,? but it's doable.? ? I still have the 2K-3 PDF manual saved.? ?I didn't realize this was an antique.?
?
The actual pickup / drop out voltage is a helluva lot less than the rated coil voltage.? The 6 msec they quote is for the actual pick up voltage.? When run at rated voltage, the actual operate time is 2 msecs on a GH1.?
If u need any help with this, lemme know.?
|
Re: Henry 2K-3 TR switching
?Without the speed up, they will operate in 2-3 msecs.? The 3PDT clunker u have in there now will be 18-20 msecs at least.?
You could even leave the oem FWCT? 12 vdc supply in there.? ? Just toss the oem? clunker....and replace it with? 3 x vac relays, each with a 12 vdc coil...and wire all 3 x coils in parallel.? ? Then no drop resistor required.? ?Each coil will draw 1.8 watts? (5.4 watts in total)? ?on TX...and zero watts on RX.?
You will have to get creative on locating them,? but it's doable.? ? I still have the 2K-3 PDF manual saved.? ?I didn't realize this was an antique.?
?
The actual pickup / drop out voltage is a helluva lot less than the rated coil voltage.? The 6 msec they quote is for the actual pick up voltage.? When run at rated voltage, the actual operate time is 2 msecs on a GH1.?
If u need any help with this, lemme know.?
|
Re: Henry 2K-3 TR switching
Hello Jim, I was hoping you would respond. I've read just about every amp article/post you've written the past few years. Thank you. I believe my 2K-3 OEM relay looks like this... Three contacts.
You said in your last sentence... Simplify it....just operate all 3 of em at once ( even if u don't speed em up....and all 3 operate in 3 msecs) .? I would be thrilled over that! If so, that's what I had been thinking, basically, much better than before/OEM. I didn't know if I was missing something or not. Can it really be that simple? Thanks again, Bob W4JFA
I just went through this with my 4 x Drake L4B's.?
I used 3 x new Gigavac GH1's.? ?You can buy em with either a 12 vdc coil or a 26.5 vdc coil.? ?Jennings version is called an RJ1A. The kilovac version is called a HC-1.....and the coils in all 3 x brands are field swappable to either a 12 / 26.5 / 115 vdc coil.? ?The Gigavac uses metric threads on the big lockdown nut.
I used em for input / output / bias.? ?In my case, I used the 12 vdc coil version.....and wired all 3 x coils in series.? The oem drake fil xfmr also has a 22 vac winding on it to run the oem 3PDT clunker TR relay.? Drake used a 1/2 wave rectifier, so the output was 31 vdc no load.? ?In my case, I changed that to a FWD ( full wave doubler) to obtain 63 vdc no load.? ?A 175 ohm @ 25 watt metal finned dropping resistor is used in series with the 3 x series coils. 36 vdc used to operate the 3 x series 12 vdc coils.? 27 vdc is dropped across the 175 ohm series drop resistor. Drop resistor dissipates 3.9 watts on TX....and 0 watts on RX.?
IE: when T=0, the relay coils get hit with an initial over voltage. (63/3 or 21 vdc per coil)....which will? speed em up.? To speed em up even more, a 50uf @ 150 vdc lytic is wired in parallel with the 175 ohm drop resistor.? This is called a ...'RC hotshot' circuit. Jennings, Kilovac, Gigavac all mention it's use.? ( Alpha used it on their older amps, that used a vac relay.? Alpha used 36 vdc applied to the 26.5 vdc coil, and also a small lytic across the series drop resistor).? With the small cap in parallel with the drop resistor, it sustains the over voltage a hair longer.? The concept works superb.? ?All 3 x vac relays in each drake amp operate in slightly under 1 msec.?
80% of the total operate time is spent just building up the magnetic field in the coil. (The XL of the coil impedes DC current flow).? The over voltage? makes the current flow faster.
The ONLY thing that needs to be sequenced is the RF output from the xcvr itself.? You want to key the amp NOW,? but delay RF from the xcvr by 1-2 msecs.? This gives the sped up vac relays in the amp a head start.?
Modern xcvr's have an adjustable TX RF output delay...which works on both CW + SSB.? ?My yaseu MK-V has an adjustable 0-30 msec delay, ( in 1 msec increments) to prevent hot switching? the slow 3PDT mech relay in the older tube amps. The drake 3PDT operates in 17 msecs.? ?The 3PDT in the ameritron amps operates in 15 msecs.? ? The delay in the MK-V was set at 20 msecs to ensure the oem drake relay got a head start.? BUT the adjustable delay in the MK-V only works on CW.? ?For SSB use, plan B.... which is to re-use the spst tiny relay in the MK-V? (was used to key an amp)? to instead GRND the TX inhibit lead in the MK-V.? ?UNTIL u grnd the TX inhibit lead, you can key the amp, but zero RF coming out of the xcvr.? ?To actually key the relays in the amp, I use an opto isolator. The input of the opto is keyed? via the 'electronic TX grnd'? from the MK-V.? Input of opto only draws a few ma.? ?You can get em with a 5-15-24 vdc input ( and each of those has a super wide operating range)..and the output side is rated for either? 60 vdc @ 3 amps CCS...or 250 vdc @ 1 amp CCS.? 5 kv? isolation between input side and output side.?
You can also use a 2nd opto to do the bias in the amp, which works good.?
Ok, back to the henry 2K-3.? ?The small relay? xfmr in the 2K-3 is 8.5 vac on either side of the CT.? ?It's a FWCT config.? Output is 8.5 vac x 1.414 = 12 vdc.? ?I would reconfigure the small relay xfmr to a FWB..and use the entire sec winding ( CT not used).? ?Then it becomes 17 vac x 1.414 = 24 vdc no load.? ?Ok, then? wire the 3 x 12 vdc vac relay coils in parallel.? ?Each 12 vdc coil is 80 ohms.? ?12 vdc / 26.67 ohms, ( 80/3 = 26.67 ohms)? ?= .450 amps.
The series drop resistor will be 26.67 ohms.? Diss in the resistor will be (.45 x .45) x 26.67 ohms = 5.4 watts.? ?Each relay coil will diss? 1.8 watts.? Each coil has 150 ma flowing through it.? Wire a 50 uf @? 100-150 vdc (axial lead) lytic across the drop resistor.?
Depending on xcvr used, it has to handle? 24 vdc OCV (open circuit voltage)? @ 450 ma under load.? You do NOT want to use a slow mech relay in the xcvr to key the sped up vac relays!? ?Hence the use of either an opto isolator or a fast switch transistor.?
Ok, the 3 x relays will operate / rls in just a hair < 1 msec.? No hot switching.
I found a sidewall on the L4B, that would take all 3 x vac relays.? ? A 9/16" hole is required.? ( A 5/8" will also work).? ?The greenlee 1/2" -? 9/16"? - 5/8"? punches all use a 1/4" draw stud....and hence require a 1/4" pilot hole.? I used my roper whitney hand punch to punch the 3 x 1/4"? pilot holes....bam, done.? Then the greenlee 9/16" punch (die and cup, just tighten the wrench).?
You could use just 2 x vac relays...for input / output.....and an opto for the cut off bias.? That would save one vac relay.? ?You could maybe, use a super fast SPDT tiny mech relay for the input side.? I wanted vac relay on both the input and output, so the amp will handle 2 kw on bypass mode.? ?I do that, since I string several drake amps in series, one per band, or one at each end of 80m etc, or any other combo.? A simple rotary switch in the key line of the xcvr ensures only one amp can ever be keyed at one time.? ? ?On the drake L4B, the only way to calibrate the internal wattmeter is to take it apart to get to the underside of chassis....and apply 1 kw cxr from a 2nd amplifier ( with a bird 43)? to the drake amp...which of course is powered down, and on bypass.? IE: it has to handle a kw on bypass mode anyway.?
You could mount one vac relay near the input coax connector, and a 2nd vac relay near the output side....or near the load cap.? Then a short length of RG-400 between the NC contacts of the input + output relay. ( aka..the 'bypass leg' ).? ?
All 3 of my vac relays are dead quiet.? ?The gigavac GH1 hi -pot tests to 7.5 kv.?
The idea of using a 12 vdc coil came from the eng dept at Kilovac, during a phone call I had with em years ago.? "IF u are voltage limited, use the 12 vdc coil".?
There is also another method to obtain 28 vdc in ur henry amp.? It uses a 10 vac fil xfmr ( with fils in series).? ?Tap off the 10 vac sec...and use a FWD ( doubler)? to obtain 28.28 vdc.?
Without the speedup circuit, the vac relays typ operate in 2-3 msecs.? ?In the past, folks would use a semi complicated sequencing mess...so the output relay would operate 1st.....like say 3 msec.? ?Then the input relay next, say 5 msecs...then the bias relay last....say 7 msecs.? When going back to RX, the rls sequence was reversed, with bias relay releasing 1st, then input relay, the output relay last.?
Simplify it....just operate all 3 of em at once ( even if u don't speed em up....and all 3 operate in 3 msecs) .? The only thing that has to be sequenced is to delay grnding the handy dandy? TX inhibit lead in the xcvr.?
?
Sri? for the diatribe.?
Jim? VE7RF
|
Re: Henry 2K-3 TR switching
I just went through this with my 4 x Drake L4B's.?
I used 3 x new Gigavac GH1's.? ?You can buy em with either a 12 vdc coil or a 26.5 vdc coil.? ?Jennings version is called an RJ1A. The kilovac version is called a HC-1.....and the coils in all 3 x brands are field swappable to either a 12 / 26.5 / 115 vdc coil.? ?The Gigavac uses metric threads on the big lockdown nut.
I used em for input / output / bias.? ?In my case, I used the 12 vdc coil version.....and wired all 3 x coils in series.? The oem drake fil xfmr also has a 22 vac winding on it to run the oem 3PDT clunker TR relay.? Drake used a 1/2 wave rectifier, so the output was 31 vdc no load.? ?In my case, I changed that to a FWD ( full wave doubler) to obtain 63 vdc no load.? ?A 175 ohm @ 25 watt metal finned dropping resistor is used in series with the 3 x series coils. 36 vdc used to operate the 3 x series 12 vdc coils.? 27 vdc is dropped across the 175 ohm series drop resistor. Drop resistor dissipates 3.9 watts on TX....and 0 watts on RX.?
IE: when T=0, the relay coils get hit with an initial over voltage. (63/3 or 21 vdc per coil)....which will? speed em up.? To speed em up even more, a 50uf @ 150 vdc lytic is wired in parallel with the 175 ohm drop resistor.? This is called a ...'RC hotshot' circuit. Jennings, Kilovac, Gigavac all mention it's use.? ( Alpha used it on their older amps, that used a vac relay.? Alpha used 36 vdc applied to the 26.5 vdc coil, and also a small lytic across the series drop resistor).? With the small cap in parallel with the drop resistor, it sustains the over voltage a hair longer.? The concept works superb.? ?All 3 x vac relays in each drake amp operate in slightly under 1 msec.?
80% of the total operate time is spent just building up the magnetic field in the coil. (The XL of the coil impedes DC current flow).? The over voltage? makes the current flow faster.
The ONLY thing that needs to be sequenced is the RF output from the xcvr itself.? You want to key the amp NOW,? but delay RF from the xcvr by 1-2 msecs.? This gives the sped up vac relays in the amp a head start.?
Modern xcvr's have an adjustable TX RF output delay...which works on both CW + SSB.? ?My yaseu MK-V has an adjustable 0-30 msec delay, ( in 1 msec increments) to prevent hot switching? the slow 3PDT mech relay in the older tube amps. The drake 3PDT operates in 17 msecs.? ?The 3PDT in the ameritron amps operates in 15 msecs.? ? The delay in the MK-V was set at 20 msecs to ensure the oem drake relay got a head start.? BUT the adjustable delay in the MK-V only works on CW.? ?For SSB use, plan B.... which is to re-use the spst tiny relay in the MK-V? (was used to key an amp)? to instead GRND the TX inhibit lead in the MK-V.? ?UNTIL u grnd the TX inhibit lead, you can key the amp, but zero RF coming out of the xcvr.? ?To actually key the relays in the amp, I use an opto isolator. The input of the opto is keyed? via the 'electronic TX grnd'? from the MK-V.? Input of opto only draws a few ma.? ?You can get em with a 5-15-24 vdc input ( and each of those has a super wide operating range)..and the output side is rated for either? 60 vdc @ 3 amps CCS...or 250 vdc @ 1 amp CCS.? 5 kv? isolation between input side and output side.?
You can also use a 2nd opto to do the bias in the amp, which works good.?
Ok, back to the henry 2K-3.? ?The small relay? xfmr in the 2K-3 is 8.5 vac on either side of the CT.? ?It's a FWCT config.? Output is 8.5 vac x 1.414 = 12 vdc.? ?I would reconfigure the small relay xfmr to a FWB..and use the entire sec winding ( CT not used).? ?Then it becomes 17 vac x 1.414 = 24 vdc no load.? ?Ok, then? wire the 3 x 12 vdc vac relay coils in parallel.? ?Each 12 vdc coil is 80 ohms.? ?12 vdc / 26.67 ohms, ( 80/3 = 26.67 ohms)? ?= .450 amps.
The series drop resistor will be 26.67 ohms.? Diss in the resistor will be (.45 x .45) x 26.67 ohms = 5.4 watts.? ?Each relay coil will diss? 1.8 watts.? Each coil has 150 ma flowing through it.? Wire a 50 uf @? 100-150 vdc (axial lead) lytic across the drop resistor.?
Depending on xcvr used, it has to handle? 24 vdc OCV (open circuit voltage)? @ 450 ma under load.? You do NOT want to use a slow mech relay in the xcvr to key the sped up vac relays!? ?Hence the use of either an opto isolator or a fast switch transistor.?
Ok, the 3 x relays will operate / rls in just a hair < 1 msec.? No hot switching.
I found a sidewall on the L4B, that would take all 3 x vac relays.? ? A 9/16" hole is required.? ( A 5/8" will also work).? ?The greenlee 1/2" -? 9/16"? - 5/8"? punches all use a 1/4" draw stud....and hence require a 1/4" pilot hole.? I used my roper whitney hand punch to punch the 3 x 1/4"? pilot holes....bam, done.? Then the greenlee 9/16" punch (die and cup, just tighten the wrench).?
You could use just 2 x vac relays...for input / output.....and an opto for the cut off bias.? That would save one vac relay.? ?You could maybe, use a super fast SPDT tiny mech relay for the input side.? I wanted vac relay on both the input and output, so the amp will handle 2 kw on bypass mode.? ?I do that, since I string several drake amps in series, one per band, or one at each end of 80m etc, or any other combo.? A simple rotary switch in the key line of the xcvr ensures only one amp can ever be keyed at one time.? ? ?On the drake L4B, the only way to calibrate the internal wattmeter is to take it apart to get to the underside of chassis....and apply 1 kw cxr from a 2nd amplifier ( with a bird 43)? to the drake amp...which of course is powered down, and on bypass.? IE: it has to handle a kw on bypass mode anyway.?
You could mount one vac relay near the input coax connector, and a 2nd vac relay near the output side....or near the load cap.? Then a short length of RG-400 between the NC contacts of the input + output relay. ( aka..the 'bypass leg' ).? ?
All 3 of my vac relays are dead quiet.? ?The gigavac GH1 hi -pot tests to 7.5 kv.?
The idea of using a 12 vdc coil came from the eng dept at Kilovac, during a phone call I had with em years ago.? "IF u are voltage limited, use the 12 vdc coil".?
There is also another method to obtain 28 vdc in ur henry amp.? It uses a 10 vac fil xfmr ( with fils in series).? ?Tap off the 10 vac sec...and use a FWD ( doubler)? to obtain 28.28 vdc.?
Without the speedup circuit, the vac relays typ operate in 2-3 msecs.? ?In the past, folks would use a semi complicated sequencing mess...so the output relay would operate 1st.....like say 3 msec.? ?Then the input relay next, say 5 msecs...then the bias relay last....say 7 msecs.? When going back to RX, the rls sequence was reversed, with bias relay releasing 1st, then input relay, the output relay last.?
Simplify it....just operate all 3 of em at once ( even if u don't speed em up....and all 3 operate in 3 msecs) .? The only thing that has to be sequenced is to delay grnding the handy dandy? TX inhibit lead in the xcvr.?
?
Sri? for the diatribe.?
Jim? VE7RF
|
Re: Henry 2K-3 TR switching
Hi Bob,
Good luck on your project.?
The relays must be sequenced so that the output relay is connected to the antenna before the amp input relay closes.? Likewise, the input relay must open before the output relay is removed from the antenna.? This assures that the amp is always connected to the antenna when there is possible RF at the input of the amp.
?? 73
Bill K3HZP
|
If I remember those meters were manufactured at a company near Cleveland. Maybe call them. I am not sure if I did or not, been a while. Mike
Too bad Ameritron/MFJ closed their doors! Thanks Mike ? Mod-U-Lator, Mike(y)/W3SLK ? ? ?
From: [email protected] [mailto:[email protected]] On Behalf Of mike repinski via groups.io
Sent: Tuesday, July 30, 2024 7:07 PM
To: [email protected]
Subject: Re: [ham-amplifiers] AL-80 Meter ? I needed one years ago and called Ameritron and they fixed me up with a new one. I remember having to change a resistor inside the meter. Good luck. Mike On Tuesday, July 30, 2024 at 07:04:04 PM EDT, Mike Sawyer via groups.io <w3slk@...> wrote: I¡¯m in need of a 0~1mA meter for an original AL-80, (ala Prime) amplifier. The one that is in there now has a bad set of ¡®innards¡¯. We can use the meter face from the original if I can find a same size one. TNX. ? Mod-U-Lator, Mike(y)/W3SLK ? ?
|
Too bad Ameritron/MFJ closed their doors! Thanks Mike ? Mod-U-Lator, Mike(y)/W3SLK ? ? ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of mike repinski via groups.io
Sent: Tuesday, July 30, 2024 7:07 PM
To: [email protected]
Subject: Re: [ham-amplifiers] AL-80 Meter? I needed one years ago and called Ameritron and they fixed me up with a new one. I remember having to change a resistor inside the meter. Good luck. Mike On Tuesday, July 30, 2024 at 07:04:04 PM EDT, Mike Sawyer via groups.io <w3slk@...> wrote: I¡¯m in need of a 0~1mA meter for an original AL-80, (ala Prime) amplifier. The one that is in there now has a bad set of ¡®innards¡¯. We can use the meter face from the original if I can find a same size one. TNX. ? Mod-U-Lator, Mike(y)/W3SLK ? ?
|
I needed one years ago and called Ameritron and they fixed me up with a new one. I remember having to change a resistor inside the meter. Good luck. Mike
I¡¯m in need of a 0~1mA meter for an original AL-80, (ala Prime) amplifier. The one that is in there now has a bad set of ¡®innards¡¯. We can use the meter face from the original if I can find a same size one. TNX. ? Mod-U-Lator, Mike(y)/W3SLK ? ?
|
Bob
Robin Midgett
Alan - W5ARM
Bill K3HZP
