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Re: Tuned input

 

开云体育

Correction in all uppers , darn I phone auto correct?


On what page of the manual does the book show alignment of the inductors . Ted Henry nor anyone ELSE ?I talked to at Henry radio had any clue, ?10 plus years ago . Also had no records of revisions ?they had done.?

I was rebuilding / fixing for re sale?

Ka1cde pat , was nice enough to let me come up to see his , to copy . As his was one of the last ones made , and was the most current version with all updates.?

Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 23, 2024, at 6:02 PM, Amp Guy Llc <kb1sel@...> wrote:

?On what page of the manual does the book show alignment of the inductors . Ted Henry nor anyone worse I talked to at Henry radio had any clue, ?10 plus years ago . Also had no records of revisions ?they had done.?

I was rebuilding / fixing for re sale?

Ka1cde pat , was nice enough to let me come up to see his , to copy . As his was one of the last ones made , and was the most current version with all updates.?

Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 23, 2024, at 12:21 PM, W7WRX <clark@...> wrote:

?
The board has a pass-through trace if no relays are selected.? RF in and OUT.? As you select a single relay, it pulls the contacts off the jump trace and places the inductor in series.? The caps go to ground. Simple.

I was just testing the board into the amp. I understand that it will be different once installed and that Unun mess is removed.

I read online that you should use the .01 coupling cap when making your bench settings.?

I tried this and found no difference on any band.? ?There is a page online where a man shows how the coupling cap effects it with graphs. I think he had something else going on.?

Its very hard to believe the -50 figure.? That seems out of the range of reality.? ?I have measured dozens and dozens of amps here and most are -29 to -32 DB range using a radio that is -45? The only two amps that are better are my 4cx10000D, which is showing -60DB down as good as the rig and my Collins 30S1 which shows in the -45 range.?

Remember, I was NOT using a Two-tone generator for my tests that I posted for the 8K. I was simply using a RTTY carrier with the Spec An loosely coupled.? ?

I was just trying to see if the board was in fact working on all bands and trying to see how much its going to lower harmonics as I tuned each band.

I also wanted to see if the inductors would heat with a 100W RTTY carrier through them. They dont.? They run cool and imagine how much air will be on the board near the tube socket.

Once I install the board, I can run a two-tone proper test and see how the overall amp performs.? It's dirty now. Real dirty.??

One thing I will circle back on is the adjustment of the LOAD side inductor in the 8k ultra.? ?Peter got me thinking.

The book shows how to align the big roller and the load side roller.? I was told by a man that worked for Henry on the 8k to adjust the load coil for max output.??

To do this you tune the amp on 20 meters,? Derail the chain and manually adjust the Load inductor for max output.? I did this with a tuning pulser and found 1000w!!! more output.? ?

I am now thinking of resetting it and testing the harmonics again to see if this throws off the network.??

Unfortunately, I was in the hospital over new year's and they found a herniated disk in my back, A growth on one disk and a problem in with my SI on left side.? I have been in massive pain and started physical therapy.? I don't think it's a good idea that I pull that RF deck right now. I am going to have to wait a bit and get a friend over here to help me yank it!?

C


From: [email protected] <[email protected]> on behalf of Jim VE7RF via groups.io <jim.thom@...>
Sent: Tuesday, January 23, 2024 7:25 AM
To: [email protected] <[email protected]>
Subject: Re: [ham-amplifiers] Tuned input
?

Clark, does the tuned input board have some sort of bypass mode ??? ? It would require one extra relay to pull that off.?
With relays wired correctly, only one relay is ever energized....(for whatever band it's on).? ?With no relays energized, the xcvr should see a wide open.? ?

?

If the output of the tuned input board is feeding that back to back un-un mess, that could easily screw things up.? You might want to at least temp bypass the 3 x un-uns and the relay that switches the back to back un-uns to the single un-un. Then retweak the Arco's.? If all is well, then remove the mess of un-uns + their relay.? Then feed the output of the tuned inputs....to the cathode..via the oem henry 4 x paralleled? .01uf coupling caps.?
A .01 uf coupling cap should not affect the tuning.? .01uf = 10,000 pf? =? 8.84 ohms of XL @ 1.8 mhz? = dick, non issue.? ?4 x .01uf caps in parallel = 40,000 pf =? 2.21 ohms of XC @ 1.8 mhz? = less than dick.?

Typ kw PI network on the output side is down 50 db for 2nd harmonic suppression.....and even more with a PI-L.? With the un-un mess bypassed / removed, you will probably see a big improvement.?

In the high gloss? Eimac catalog, they state IMD3 for the 3CX-3000A7? is -53dbc (-59db pep)...and that's at 5 kw pep out, using their 2 tone test.? ? It's one of the cleanest tubes in the entire catalog.?


Jim? ?VE7RF
Re: Tuned input

 

开云体育

On what page of the manual does the book show alignment of the inductors . Ted Henry nor anyone worse I talked to at Henry radio had any clue, ?10 plus years ago . Also had no records of revisions ?they had done.?

I was rebuilding / fixing for re sale?

Ka1cde pat , was nice enough to let me come up to see his , to copy . As his was one of the last ones made , and was the most current version with all updates.?

Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 23, 2024, at 12:21 PM, W7WRX <clark@...> wrote:

?
The board has a pass-through trace if no relays are selected.? RF in and OUT.? As you select a single relay, it pulls the contacts off the jump trace and places the inductor in series.? The caps go to ground. Simple.

I was just testing the board into the amp. I understand that it will be different once installed and that Unun mess is removed.

I read online that you should use the .01 coupling cap when making your bench settings.?

I tried this and found no difference on any band.? ?There is a page online where a man shows how the coupling cap effects it with graphs. I think he had something else going on.?

Its very hard to believe the -50 figure.? That seems out of the range of reality.? ?I have measured dozens and dozens of amps here and most are -29 to -32 DB range using a radio that is -45? The only two amps that are better are my 4cx10000D, which is showing -60DB down as good as the rig and my Collins 30S1 which shows in the -45 range.?

Remember, I was NOT using a Two-tone generator for my tests that I posted for the 8K. I was simply using a RTTY carrier with the Spec An loosely coupled.? ?

I was just trying to see if the board was in fact working on all bands and trying to see how much its going to lower harmonics as I tuned each band.

I also wanted to see if the inductors would heat with a 100W RTTY carrier through them. They dont.? They run cool and imagine how much air will be on the board near the tube socket.

Once I install the board, I can run a two-tone proper test and see how the overall amp performs.? It's dirty now. Real dirty.??

One thing I will circle back on is the adjustment of the LOAD side inductor in the 8k ultra.? ?Peter got me thinking.

The book shows how to align the big roller and the load side roller.? I was told by a man that worked for Henry on the 8k to adjust the load coil for max output.??

To do this you tune the amp on 20 meters,? Derail the chain and manually adjust the Load inductor for max output.? I did this with a tuning pulser and found 1000w!!! more output.? ?

I am now thinking of resetting it and testing the harmonics again to see if this throws off the network.??

Unfortunately, I was in the hospital over new year's and they found a herniated disk in my back, A growth on one disk and a problem in with my SI on left side.? I have been in massive pain and started physical therapy.? I don't think it's a good idea that I pull that RF deck right now. I am going to have to wait a bit and get a friend over here to help me yank it!?

C


From: [email protected] <[email protected]> on behalf of Jim VE7RF via groups.io <jim.thom@...>
Sent: Tuesday, January 23, 2024 7:25 AM
To: [email protected] <[email protected]>
Subject: Re: [ham-amplifiers] Tuned input
?

Clark, does the tuned input board have some sort of bypass mode ??? ? It would require one extra relay to pull that off.?
With relays wired correctly, only one relay is ever energized....(for whatever band it's on).? ?With no relays energized, the xcvr should see a wide open.? ?

?

If the output of the tuned input board is feeding that back to back un-un mess, that could easily screw things up.? You might want to at least temp bypass the 3 x un-uns and the relay that switches the back to back un-uns to the single un-un. Then retweak the Arco's.? If all is well, then remove the mess of un-uns + their relay.? Then feed the output of the tuned inputs....to the cathode..via the oem henry 4 x paralleled? .01uf coupling caps.?
A .01 uf coupling cap should not affect the tuning.? .01uf = 10,000 pf? =? 8.84 ohms of XL @ 1.8 mhz? = dick, non issue.? ?4 x .01uf caps in parallel = 40,000 pf =? 2.21 ohms of XC @ 1.8 mhz? = less than dick.?

Typ kw PI network on the output side is down 50 db for 2nd harmonic suppression.....and even more with a PI-L.? With the un-un mess bypassed / removed, you will probably see a big improvement.?

In the high gloss? Eimac catalog, they state IMD3 for the 3CX-3000A7? is -53dbc (-59db pep)...and that's at 5 kw pep out, using their 2 tone test.? ? It's one of the cleanest tubes in the entire catalog.?


Jim? ?VE7RF
Re: Tuned input

 

Any Ameritron AL-1200....on 40m, with 1.5 kw cxr, is -50 db down for the 2nd harmonic...... and the AL-1200/AL-1500 / AL-82 all use the same PI / PI-L network.

Those 3 x amps use a PI-L for 160 + 80m only...and a simple PI for 40-10m.? This is all per Tom Rauch.? He is correct.? BUT on the 8K, if you only drive it to 1 kw,? ur tank Q is all screwed up. Tank Q will increase..and on paper, the simple PI will have even more harmonic suppression.? Those german tube amps all claim -50 db 2nd? harmonic suppression..and they all use a simple PI network.?

?

Scott remembered, and mentioned to me on the phone.... abt the L coil having to be tweaked correctly, so it's in sync with the main tubing coil.? IE: correct ratios.?

I usually don't mess with the PI-L config.? I ran it through software, and with a simple PI network on the output side, if the coil is a bit high (+ both caps a bit low) the Q drops a bit.? And vice versa...(less coil, more C).? Not a huge deal.? ?I like to run the Q on the low side, since it results in less? tuning when qsy'ing.? ?Also less current in the coil and also bandswitch / roller contacts.

?

On a PI-L, whole different ballgame. Yikes.? If the tubing coil is a bit off, the caps are? then tweaked.... BUT you have the 2nd 'L' coil to contend with.? IF the 2nd coil is not tweaked correctly (for a given C1-main coil- C2 set of values), then all hell breaks loose.? So yes, temp? disconnecting the chain drive for the L coil, then tweaking it manually for max PO...then reconnecting the chain will result in more PO, and better harmonic suppression...... depending on whether the L coil had too much, or too little coil dialed in.?

?

Watch out.? ?I think the procedure had to be done on 10m.? If the L coil is slightly outa whack on 10m, you will notice right away.?
Re: Tuned input

 

开云体育

The board has a pass-through trace if no relays are selected.? RF in and OUT.? As you select a single relay, it pulls the contacts off the jump trace and places the inductor in series.? The caps go to ground. Simple.

I was just testing the board into the amp. I understand that it will be different once installed and that Unun mess is removed.

I read online that you should use the .01 coupling cap when making your bench settings.?

I tried this and found no difference on any band.? ?There is a page online where a man shows how the coupling cap effects it with graphs. I think he had something else going on.?

Its very hard to believe the -50 figure.? That seems out of the range of reality.? ?I have measured dozens and dozens of amps here and most are -29 to -32 DB range using a radio that is -45? The only two amps that are better are my 4cx10000D, which is showing -60DB down as good as the rig and my Collins 30S1 which shows in the -45 range.?

Remember, I was NOT using a Two-tone generator for my tests that I posted for the 8K. I was simply using a RTTY carrier with the Spec An loosely coupled.? ?

I was just trying to see if the board was in fact working on all bands and trying to see how much its going to lower harmonics as I tuned each band.

I also wanted to see if the inductors would heat with a 100W RTTY carrier through them. They dont.? They run cool and imagine how much air will be on the board near the tube socket.

Once I install the board, I can run a two-tone proper test and see how the overall amp performs.? It's dirty now. Real dirty.??

One thing I will circle back on is the adjustment of the LOAD side inductor in the 8k ultra.? ?Peter got me thinking.

The book shows how to align the big roller and the load side roller.? I was told by a man that worked for Henry on the 8k to adjust the load coil for max output.??

To do this you tune the amp on 20 meters,? Derail the chain and manually adjust the Load inductor for max output.? I did this with a tuning pulser and found 1000w!!! more output.? ?

I am now thinking of resetting it and testing the harmonics again to see if this throws off the network.??

Unfortunately, I was in the hospital over new year's and they found a herniated disk in my back, A growth on one disk and a problem in with my SI on left side.? I have been in massive pain and started physical therapy.? I don't think it's a good idea that I pull that RF deck right now. I am going to have to wait a bit and get a friend over here to help me yank it!?

C


From: [email protected] <[email protected]> on behalf of Jim VE7RF via groups.io <jim.thom@...>
Sent: Tuesday, January 23, 2024 7:25 AM
To: [email protected] <[email protected]>
Subject: Re: [ham-amplifiers] Tuned input
?

Clark, does the tuned input board have some sort of bypass mode ??? ? It would require one extra relay to pull that off.?
With relays wired correctly, only one relay is ever energized....(for whatever band it's on).? ?With no relays energized, the xcvr should see a wide open.? ?

?

If the output of the tuned input board is feeding that back to back un-un mess, that could easily screw things up.? You might want to at least temp bypass the 3 x un-uns and the relay that switches the back to back un-uns to the single un-un. Then retweak the Arco's.? If all is well, then remove the mess of un-uns + their relay.? Then feed the output of the tuned inputs....to the cathode..via the oem henry 4 x paralleled? .01uf coupling caps.?
A .01 uf coupling cap should not affect the tuning.? .01uf = 10,000 pf? =? 8.84 ohms of XL @ 1.8 mhz? = dick, non issue.? ?4 x .01uf caps in parallel = 40,000 pf =? 2.21 ohms of XC @ 1.8 mhz? = less than dick.?

Typ kw PI network on the output side is down 50 db for 2nd harmonic suppression.....and even more with a PI-L.? With the un-un mess bypassed / removed, you will probably see a big improvement.?

In the high gloss? Eimac catalog, they state IMD3 for the 3CX-3000A7? is -53dbc (-59db pep)...and that's at 5 kw pep out, using their 2 tone test.? ? It's one of the cleanest tubes in the entire catalog.?


Jim? ?VE7RF
Re: Tuned input

 

Clark, does the tuned input board have some sort of bypass mode ??? ? It would require one extra relay to pull that off.?
With relays wired correctly, only one relay is ever energized....(for whatever band it's on).? ?With no relays energized, the xcvr should see a wide open.? ?

?

If the output of the tuned input board is feeding that back to back un-un mess, that could easily screw things up.? You might want to at least temp bypass the 3 x un-uns and the relay that switches the back to back un-uns to the single un-un. Then retweak the Arco's.? If all is well, then remove the mess of un-uns + their relay.? Then feed the output of the tuned inputs....to the cathode..via the oem henry 4 x paralleled? .01uf coupling caps.?
A .01 uf coupling cap should not affect the tuning.? .01uf = 10,000 pf? =? 8.84 ohms of XL @ 1.8 mhz? = dick, non issue.? ?4 x .01uf caps in parallel = 40,000 pf =? 2.21 ohms of XC @ 1.8 mhz? = less than dick.?

Typ kw PI network on the output side is down 50 db for 2nd harmonic suppression.....and even more with a PI-L.? With the un-un mess bypassed / removed, you will probably see a big improvement.?

In the high gloss? Eimac catalog, they state IMD3 for the 3CX-3000A7? is -53dbc (-59db pep)...and that's at 5 kw pep out, using their 2 tone test.? ? It's one of the cleanest tubes in the entire catalog.?


Jim? ?VE7RF
Re: LK 5xx Variable Cap Plates with pix attached

 

Just buy the cap from the ameritron AL-80B / AL-572.? It's a drop in replacement. On the original thread u started, scott showed the u tube video and the simple mod to get it to work..... by cutting off the fiberglass / delrin white shaft, and using a brass shaft coupler.... then a piece of 1/4" steel shaft ou through the front panel...done.? ?Those caps are dirt cheap, new.? Model 282-2112-1?

?

?

BTW, the tune cap from the ameritron AL-1500 / AL-1200 / AL-82 is way too long.
Re: LK 5xx Variable Cap Plates with pix attached

 

开云体育

Ask for rob then ask for this

282-2112-1



Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 22, 2024, at 1:58 PM, Amp Guy Llc <kb1sel@...> wrote:

?Too long?

Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 22, 2024, at 1:53 PM, Rich k0zx <k0zx.co@...> wrote:

?

[Edited Message Follows]

could you pass me a link to that page, mike... i'm on??with no results. Also tried there 2023 catalog and 204-2112

Re: LK 5xx Variable Cap Plates with pix attached

 

开云体育

Too long?

Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 22, 2024, at 1:53 PM, Rich k0zx <k0zx.co@...> wrote:

?

[Edited Message Follows]

could you pass me a link to that page, mike... i'm on??with no results. Also tried there 2023 catalog and 204-2112

Re: LK 5xx Variable Cap Plates with pix attached

 

ok, tnx joe
Re: LK 5xx Variable Cap Plates with pix attached

 

开云体育

Sorry. they must have changed part numbers again. I just searched for that part number and it is no good already.

Happy hunting!

Joe WB9SBD


A Contest 40 Years in The Making!

MAIDENHEAD MAYHEM
On 1/22/2024 12:51 PM, Joe wrote:

?The ameritron? tune cap from the? AL-1500/1200/82? amp.??? Rated for 4.5 kv? and is ameritron part # 204-2570.
It's a 190 pf cap....with real low min C, like < 20 pf.

Joe WB9SBD
On 1/22/2024 12:46 PM, Rich k0zx wrote:
which caps were you referring to Joe?


Re: LK 5xx Variable Cap Plates with pix attached

 

开云体育

?The ameritron? tune cap from the? AL-1500/1200/82? amp.??? Rated for 4.5 kv? and is ameritron part # 204-2570.
It's a 190 pf cap....with real low min C, like < 20 pf.

Joe WB9SBD
On 1/22/2024 12:46 PM, Rich k0zx wrote:

which caps were you referring to Joe?

Re: LK 5xx Variable Cap Plates with pix attached

 
Edited

could you pass me a link to that page, mike... i'm on??with no results. Also tried there 2023 catalog and 204-2112
Re: LK 5xx Variable Cap Plates with pix attached

 

which caps were you referring to Joe?
Re: LK 5xx Variable Cap Plates with pix attached

 

Tnx Peter, i'll check that out!
rich
Re: LK 5xx Variable Cap Plates with pix attached

 

开云体育

The Caps are Great! Especially for the price! But unless you know the exact part number, finding them is near impossible.

I went through the same issue a few years ago.

Once found and ordered. in less than a week it was in the amp.

Joe WB9SBD


A Contest 40 Years in The Making!

MAIDENHEAD MAYHEM
On 1/22/2024 11:38 AM, Amp Guy Llc wrote:

Spec in one pic , current part number in the second pic?

Same value as what you need?


image0.jpegimage1.png

Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 22, 2024, at 12:31 PM, Amp Guy Llc <kb1sel@...> wrote:

?
<image0.png>


Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 22, 2024, at 12:07 PM, Rich k0zx <k0zx.co@...> wrote:

?Not seeing anything at Ameritron that matches this thing, needing 75-250pf 3.5kv min

Re: LK 5xx Variable Cap Plates with pix attached

 

开云体育

Spec in one pic , current part number in the second pic?

Same value as what you need?


image0.jpegimage1.png

Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 22, 2024, at 12:31 PM, Amp Guy Llc <kb1sel@...> wrote:

?
<image0.png>


Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 22, 2024, at 12:07 PM, Rich k0zx <k0zx.co@...> wrote:

?Not seeing anything at Ameritron that matches this thing, needing 75-250pf 3.5kv min

Re: Tuned input

 

开云体育

I cant imagine what could be wrong.? I went through it front to back and made sure its all timed correctly.? I think it must be a measurement error.? I need to try to confirm that today.?

Side note. I am not using a two tone. I have a generator but did not use it for this test. I just transmitted an RTTY carrier, Varied tuning, loading and drive power at about 1 KW out into a bird dummy load.

I cant find any IMD data for the 3cx3000A7. The data sheets do not seem to be as in depth as other Eimac tubes for some reason.? ?I am really surprised you suggested its a clean tube. It has a reputation of being really bad on IMD and that seems to be what I am seeing here.?

The amp is rated at 32DB in manual but it does not say how they measured that. Two tone or carrier.??

From: [email protected] <[email protected]> on behalf of Peter Voelpel via groups.io <dj7ww@...>
Sent: Monday, January 22, 2024 10:25 AM
To: [email protected] <[email protected]>
Subject: Re: [ham-amplifiers] Tuned input
?

?

There might be something wrong.with the output tuning.

At DR1A we use (d) 7? modified Henry 3000D amplifiers without tuned input.

No problem at all with harmonics with just stub filters on the antennas and standard Pi not Pi-L.

DR1A is a Multi/Multi station.

The 3CX3000A 7 is a very clean tube.

?

73

Peter

?

?

?

?

-----Original-Nachricht-----

Betreff: Re: [ham-amplifiers] Tuned input

Datum: 2024-01-22T16:02:22+0100

Von: "W7WRX" <clark@...>

An: "[email protected]" <[email protected]>

?

?

?

The board is now complete.
?
I went through and tuned the board for 50 ohms.? Actually, my Cantenna has been beaten badly over the years and is more like 60 ohms.?
?
I then added a 40 PF cap across the tube side of the board to simulate the tube. That through off 10, 15,20 and 40 big time.? I had to go back and retune those bands.
?
80 and 160 are not effected by the tube PF.
?
I then added a .01 coupling cap and saw no difference.? I read an article showing the .01 will change it slightly. I did not see this on bench.
?
I then hooked the board to the 8K using coax.? ?
?
10M now 1.2 to 1 from 3 to 1.
15M flat from 2 to 1
20M flat from 2.5 to 1
40M Flat from 1.8 to 1
80M flat from 2 to 1
160M Flat from 1.5 to 1
?
So the matching DOES WORK.
?
I then switched the board ON and OFF while testing harmonics on the Spec AN.? The 8K is a very dirty amplifier.? Even if I use an ICOM 7800 which shows the second harmonic way down in the noise Like 50 to 60 down At low drive levels or an FT2000D in Class A mode. The harmonics are only 10 to 20 DB down on most bands.
?
With the board I noticed I can actually tune the second harmonic live and further reduce it by 10 DB.? This makes the match very slightly higher at 1.1 to 1.2.
?
With the board most bands are 30 to 40 DB down now.? So this is a HUGE improvement.
?
I do notice something very odd on 20 and 40 meters with the 8K. It shows the SECOND harmonic STRONGER than the primary.? This is with the board off. With it on, the problem is fixed and the second is 30 to 40 db down.
?
How is it possible that the second harmonic be 5 DB stronger than the primary???? Is this a measurement error?
?
Keep in mind, this is with COAX and the henry UNUN input mess is still in line!? So all this will change when that is removed, I am sure.
?
Just wanted to check board operation.
?
IT WORKS!! ?
?
C
?
?
?
?
?
?
?
?
From: [email protected] <[email protected]> on behalf of Jim VE7RF via groups.io <jim.thom@...>
Sent: Saturday, January 20, 2024 5:19 PM
To: [email protected] <[email protected]>
Subject: Re: [ham-amplifiers] Tuned input
?
On Sat, Jan 20, 2024 at 07:47 PM, W7WRX wrote:
The RF flows into the center common pins in and out.? The coils are across the common pins when keyed.? These relays are labeled DPDT but the common pins are tied together!!!!!!!!!!!!!!!!!!!!!? ??

I checked the NO and NC operation and it passed. I did not think to check ACROSS the two center poles to each other!

I got the new relays from mouser. I have 10, 15, 20 and 40 working now!? ?The cut off is very sharp. On 40, at 8MHZ its brick wall steep cut off.? Flat in the band.

I am going to work on 80 and 160 today.
## excellent. Once all done....and installed, the trick will be trying to adjust each band, with drive applied.? ?Document it really good.? It will? come in handy? for 8k and 3k owners.?
?

Re: LK 5xx Variable Cap Plates with pix attached

 

开云体育

image0.png

Amp guy llc
Amprepairguy.com
YouTube Amp repair guy
203-892-4119

On Jan 22, 2024, at 12:07 PM, Rich k0zx <k0zx.co@...> wrote:

?Not seeing anything at Ameritron that matches this thing, needing 75-250pf 3.5kv min

Re: LK 5xx Variable Cap Plates with pix attached

 

开云体育

Might be a Johnson capacitor.

?

?

73

Peter

?

?

?

-----Original-Nachricht-----

Betreff: [ham-amplifiers] LK 5xx Variable Cap Plates with pix attached

Datum: 2024-01-22T17:51:25+0100

Von: "Rich k0zx" <k0zx.co@...>

An: "[email protected]" <[email protected]>

?

?

?

Repost added pix:
Rebuilding another LK cap here and another Plate Tuning cap with nasty pits and therefore....arcing. Any info to secure those rotor and stator plates appreciated.
Rich k0zx
?
Re: Tuned input

 

开云体育

?

There might be something wrong.with the output tuning.

At DR1A we use (d) 7? modified Henry 3000D amplifiers without tuned input.

No problem at all with harmonics with just stub filters on the antennas and standard Pi not Pi-L.

DR1A is a Multi/Multi station.

The 3CX3000A 7 is a very clean tube.

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73

Peter

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-----Original-Nachricht-----

Betreff: Re: [ham-amplifiers] Tuned input

Datum: 2024-01-22T16:02:22+0100

Von: "W7WRX" <clark@...>

An: "[email protected]" <[email protected]>

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The board is now complete.
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I went through and tuned the board for 50 ohms.? Actually, my Cantenna has been beaten badly over the years and is more like 60 ohms.?
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I then added a 40 PF cap across the tube side of the board to simulate the tube. That through off 10, 15,20 and 40 big time.? I had to go back and retune those bands.
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80 and 160 are not effected by the tube PF.
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I then added a .01 coupling cap and saw no difference.? I read an article showing the .01 will change it slightly. I did not see this on bench.
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I then hooked the board to the 8K using coax.? ?
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10M now 1.2 to 1 from 3 to 1.
15M flat from 2 to 1
20M flat from 2.5 to 1
40M Flat from 1.8 to 1
80M flat from 2 to 1
160M Flat from 1.5 to 1
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So the matching DOES WORK.
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I then switched the board ON and OFF while testing harmonics on the Spec AN.? The 8K is a very dirty amplifier.? Even if I use an ICOM 7800 which shows the second harmonic way down in the noise Like 50 to 60 down At low drive levels or an FT2000D in Class A mode. The harmonics are only 10 to 20 DB down on most bands.
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With the board I noticed I can actually tune the second harmonic live and further reduce it by 10 DB.? This makes the match very slightly higher at 1.1 to 1.2.
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With the board most bands are 30 to 40 DB down now.? So this is a HUGE improvement.
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I do notice something very odd on 20 and 40 meters with the 8K. It shows the SECOND harmonic STRONGER than the primary.? This is with the board off. With it on, the problem is fixed and the second is 30 to 40 db down.
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How is it possible that the second harmonic be 5 DB stronger than the primary???? Is this a measurement error?
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Keep in mind, this is with COAX and the henry UNUN input mess is still in line!? So all this will change when that is removed, I am sure.
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Just wanted to check board operation.
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IT WORKS!! ?
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C
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From: [email protected] <[email protected]> on behalf of Jim VE7RF via groups.io <jim.thom@...>
Sent: Saturday, January 20, 2024 5:19 PM
To: [email protected] <[email protected]>
Subject: Re: [ham-amplifiers] Tuned input
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On Sat, Jan 20, 2024 at 07:47 PM, W7WRX wrote:
The RF flows into the center common pins in and out.? The coils are across the common pins when keyed.? These relays are labeled DPDT but the common pins are tied together!!!!!!!!!!!!!!!!!!!!!? ??

I checked the NO and NC operation and it passed. I did not think to check ACROSS the two center poles to each other!

I got the new relays from mouser. I have 10, 15, 20 and 40 working now!? ?The cut off is very sharp. On 40, at 8MHZ its brick wall steep cut off.? Flat in the band.

I am going to work on 80 and 160 today.
## excellent. Once all done....and installed, the trick will be trying to adjust each band, with drive applied.? ?Document it really good.? It will? come in handy? for 8k and 3k owners.?
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