I get back tonight. ?Ill have some simple tests cooked up to get to the bottom of this.?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
toggle quoted message
Show quoted text
On Mar 17, 2025, at 10:28?AM, D Solt via groups.io <davesolt@...> wrote:
? So, I am still tracking down the 20W amp oscillation, and making progress.? I have C24 in the amp, although it makes no difference to the oscillation in the high bands.? I also have the onboard attenuator in the PA.? Bypassing the BPF and the LPF made no difference to the oscillation.? Ferrites, RF chokes, and additional bypassing right on the center tap of the output transformer made no difference.
The oscillation goes away when I take the output of the LPF directly to the dummy load bypassing the SWR circuit and the Transmitt Receive Switch.? I wonder if I have something wired up wrong in the transformer or the switch.
Thanks again for all of your help.
dave Sounds like the inpuu connection to the PA is high impedance (like something is not connected on the boads in front of the PA).. ?you migjt take the BpF put of the circuit temporarily.? Just jumper across it on the LPF board pr remove ?the LPF too just temporarily. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it:
email:??bill@... ? ?Thanks Jerry and Bill. I¡¯ll get back to this on Monday. 3 dB pad on input of PA reduces oscillation, 6 dB pad stops the oscillation? dave ?Remove the bpf and see what happens. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it:
email:??bill@... ? ?Yes, I agree. The amp is solid. Previously , I swept the amps and got solid performance. And, when I disconnect the drive to the amp the oscillation stops. It is being caused by something in the T41 interacting with the amp dave ?Something is wrong.? The amp will NOT oscillate by itself. ??
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it:
email:??bill@... ?
|
So, I am still tracking down the 20W amp oscillation, and making progress.? I have C24 in the amp, although it makes no difference to the oscillation in the high bands.? I also have the onboard attenuator in the PA.? Bypassing the BPF and the LPF made no difference to the oscillation.? Ferrites, RF chokes, and additional bypassing right on the center tap of the output transformer made no difference.
The oscillation goes away when I take the output of the LPF directly to the dummy load bypassing the SWR circuit and the Transmitt Receive Switch.? I wonder if I have something wired up wrong in the transformer or the switch.
Thanks again for all of your help.
dave
Sounds like the inpuu connection to the PA is high impedance (like something is not connected on the boads in front of the PA).. ?you migjt take the BpF put of the circuit temporarily.? Just jumper across it on the LPF board pr remove ?the LPF too just temporarily. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it:
email:??bill@... ? ?Thanks Jerry and Bill. I¡¯ll get back to this on Monday. 3 dB pad on input of PA reduces oscillation, 6 dB pad stops the oscillation? dave ?Remove the bpf and see what happens. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it:
email:??bill@... ? ?Yes, I agree. The amp is solid. Previously , I swept the amps and got solid performance. And, when I disconnect the drive to the amp the oscillation stops. It is being caused by something in the T41 interacting with the amp dave ?Something is wrong.? The amp will NOT oscillate by itself. ??
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it:
email:??bill@... ?
|
I will be home tomorrow evening late and will have a closer look. ?It is not likely that it is the PA itself. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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Show quoted text
On Mar 16, 2025, at 8:47?PM, glenn percy via groups.io <vk3pe@...> wrote:
? A picture of the PA might help.??
I wonder if he fitted C24 ???? Have no idea if this would stop oscillation but worth a check.
?
glenn
vk3pe
|
A picture of the PA might help.??
I wonder if he fitted C24 ???? Have no idea if this would stop oscillation but worth a check.
?
glenn
vk3pe
|
Sorry no glasses reply this AM
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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Show quoted text
On Mar 15, 2025, at 8:12?AM, K9HZ <bill@...> wrote:
? Sounds like the inpuu connection to the PA is high impedance (like something is not connected on the boads in front of the PA).. ?you migjt take the BpF put of the circuit temporarily. ?Just jumper across it on the LPF board pr remove ?the LPF too just temporarily. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ? On Mar 15, 2025, at 3:10?AM, D Solt via groups.io <davesolt@...> wrote:
? Thanks Jerry and Bill. I¡¯ll get back to this on Monday. 3 dB pad on input of PA reduces oscillation, 6 dB pad stops the oscillation? dave On Mar 15, 2025, at 1:34?AM, K9HZ via groups.io <bill@...> wrote:
? Remove the bpf and see what happens. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ? On Mar 14, 2025, at 6:29?PM, D Solt via groups.io <davesolt@...> wrote:
? Yes, I agree. The amp is solid. Previously , I swept the amps and got solid performance. And, when I disconnect the drive to the amp the oscillation stops. It is being caused by something in the T41 interacting with the amp dave On Mar 14, 2025, at 7:05?PM, K9HZ via groups.io <bill@...> wrote:
? Something is wrong. ?The amp will NOT oscillate by itself. ??
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ? On Mar 14, 2025, at 2:13?PM, D Solt via groups.io <davesolt@...> wrote:
? Yes it is on a DL
On Mar 14, 2025, at 4:58?PM, jerry-KF6VB via groups.io <jerry@...> wrote:
|
Sounds like the inpuu connection to the PA is high impedance (like something is not connected on the boads in front of the PA).. ?you migjt take the BpF put of the circuit temporarily. ?Just jumper across it on the LPF board pr remove ?the LPF too just temporarily. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
toggle quoted message
Show quoted text
On Mar 15, 2025, at 3:10?AM, D Solt via groups.io <davesolt@...> wrote:
? Thanks Jerry and Bill. I¡¯ll get back to this on Monday. 3 dB pad on input of PA reduces oscillation, 6 dB pad stops the oscillation? dave On Mar 15, 2025, at 1:34?AM, K9HZ via groups.io <bill@...> wrote:
? Remove the bpf and see what happens. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ? On Mar 14, 2025, at 6:29?PM, D Solt via groups.io <davesolt@...> wrote:
? Yes, I agree. The amp is solid. Previously , I swept the amps and got solid performance. And, when I disconnect the drive to the amp the oscillation stops. It is being caused by something in the T41 interacting with the amp dave On Mar 14, 2025, at 7:05?PM, K9HZ via groups.io <bill@...> wrote:
? Something is wrong. ?The amp will NOT oscillate by itself. ??
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ? On Mar 14, 2025, at 2:13?PM, D Solt via groups.io <davesolt@...> wrote:
? Yes it is on a DL
On Mar 14, 2025, at 4:58?PM, jerry-KF6VB via groups.io <jerry@...> wrote:
|
On 2025-03-15 03:09, D Solt via groups.io wrote: Thanks Jerry and Bill. I¡¯ll get back to this on Monday. 3 dB pad on
input of PA reduces oscillation, 6 dB pad stops the oscillation *** Does your RF board have the built-in xmit attenuator? If so, will 6dB there stop the oscillation? I would look for RF on - the power lead and also the control lead - that enables the PA. It might be that a ferrite on the power lead could cure the problem without further fuss. - Jerry, KF6VB dave
On Mar 15, 2025, at 1:34?AM, K9HZ via groups.io
<bill@...> wrote: ?Remove the bpf and see what happens.
DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton, Illinois
Owner ¨C Operator
Villa Grand Piton - J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com
email: bill@...
On Mar 14, 2025, at 6:29?PM, D Solt via groups.io
<davesolt@...> wrote: ?Yes, I agree. The amp is solid. Previously , I swept the amps and
got solid performance. And, when I disconnect the drive to the amp
the oscillation stops. It is being caused by something in the T41
interacting with the amp
dave
On Mar 14, 2025, at 7:05?PM, K9HZ via groups.io
<bill@...> wrote:
?Something is wrong. The amp will NOT oscillate by itself.
DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton, Illinois
Owner ¨C Operator
Villa Grand Piton - J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com
email: bill@...
On Mar 14, 2025, at 2:13?PM, D Solt via groups.io
<davesolt@...> wrote:
?Yes it is on a DL
On Mar 14, 2025, at 4:58?PM, jerry-KF6VB via groups.io
<jerry@...> wrote:
?Do you have it on a dummy load?
- jerry
On 2025-03-14 13:54, D Solt via groups.io wrote:
It is the K9HZ 20W amp
On Fri, Mar 14, 2025 at 4:53?PM jerry-KF6VB via groups.io [1]
<jerry@...> wrote:
Is it a K9HZ final? Or the one with the IRF510s?
- Jerry, KF6VB
On 2025-03-14 13:52, D Solt via groups.io [1] wrote:
I got the second T41 v12 with SW ver66.4 with amplifier operating
today. Both are acting the same, oscillations around 40MHz at
several
watts when PTT is engaged. With the oscillation, I was still able
to
do the TX IQ null. I am stumped. I don't have a very accurate way
to
measure power yet; using a 50MHz TBS1052B tek scope and an HP363
kit.
dave, n3ds
Links:
------
[1] /g/AmateurRadioBuilders/message/6170
[2] /mt/111686473/243852
[3] /g/AmateurRadioBuilders/post
[4] /g/AmateurRadioBuilders/editsub/243852
[5] /g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
Links:
------
[1]
[2] /g/AmateurRadioBuilders/message/6172
[3] /mt/111686473/243852
[4] /g/AmateurRadioBuilders/post
[5] /g/AmateurRadioBuilders/editsub/243852
[6]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
Links:
------
[1] /g/AmateurRadioBuilders/message/6181
[2] /mt/111686473/243852
[3] /g/AmateurRadioBuilders/post
[4] /g/AmateurRadioBuilders/editsub/243852
[5]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
|
Thanks Jerry and Bill. I¡¯ll get back to this on Monday. 3 dB pad on input of PA reduces oscillation, 6 dB pad stops the oscillation? dave
toggle quoted message
Show quoted text
On Mar 15, 2025, at 1:34?AM, K9HZ via groups.io <bill@...> wrote:
? Remove the bpf and see what happens. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ? On Mar 14, 2025, at 6:29?PM, D Solt via groups.io <davesolt@...> wrote:
? Yes, I agree. The amp is solid. Previously , I swept the amps and got solid performance. And, when I disconnect the drive to the amp the oscillation stops. It is being caused by something in the T41 interacting with the amp dave On Mar 14, 2025, at 7:05?PM, K9HZ via groups.io <bill@...> wrote:
? Something is wrong. ?The amp will NOT oscillate by itself. ??
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ? On Mar 14, 2025, at 2:13?PM, D Solt via groups.io <davesolt@...> wrote:
? Yes it is on a DL
On Mar 14, 2025, at 4:58?PM, jerry-KF6VB via groups.io <jerry@...> wrote:
|
Remove the bpf and see what happens. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
toggle quoted message
Show quoted text
On Mar 14, 2025, at 6:29?PM, D Solt via groups.io <davesolt@...> wrote:
? Yes, I agree. The amp is solid. Previously , I swept the amps and got solid performance. And, when I disconnect the drive to the amp the oscillation stops. It is being caused by something in the T41 interacting with the amp dave On Mar 14, 2025, at 7:05?PM, K9HZ via groups.io <bill@...> wrote:
? Something is wrong. ?The amp will NOT oscillate by itself. ??
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ? On Mar 14, 2025, at 2:13?PM, D Solt via groups.io <davesolt@...> wrote:
? Yes it is on a DL
On Mar 14, 2025, at 4:58?PM, jerry-KF6VB via groups.io <jerry@...> wrote:
|
I wonder if it will oscillate if you stick an attenuator pad between the
BPF and the amp?
- Jerry, KF6VB
toggle quoted message
Show quoted text
On 2025-03-14 18:29, D Solt via groups.io wrote: Yes, I agree. The amp is solid. Previously , I swept the amps and got
solid performance. And, when I disconnect the drive to the amp the
oscillation stops. It is being caused by something in the T41
interacting with the amp
dave
On Mar 14, 2025, at 7:05?PM, K9HZ via groups.io
<bill@...> wrote: ?Something is wrong. The amp will NOT oscillate by itself.
DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton, Illinois
Owner ¨C Operator
Villa Grand Piton - J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com
email: bill@...
On Mar 14, 2025, at 2:13?PM, D Solt via groups.io
<davesolt@...> wrote: ?Yes it is on a DL
On Mar 14, 2025, at 4:58?PM, jerry-KF6VB via groups.io
<jerry@...> wrote:
?Do you have it on a dummy load?
- jerry
On 2025-03-14 13:54, D Solt via groups.io wrote:
It is the K9HZ 20W amp
On Fri, Mar 14, 2025 at 4:53?PM jerry-KF6VB via groups.io [1]
<jerry@...> wrote:
Is it a K9HZ final? Or the one with the IRF510s?
- Jerry, KF6VB
On 2025-03-14 13:52, D Solt via groups.io [1] wrote:
I got the second T41 v12 with SW ver66.4 with amplifier operating
today. Both are acting the same, oscillations around 40MHz at
several
watts when PTT is engaged. With the oscillation, I was still able
to
do the TX IQ null. I am stumped. I don't have a very accurate way
to
measure power yet; using a 50MHz TBS1052B tek scope and an HP363
kit.
dave, n3ds
Links:
------
[1] /g/AmateurRadioBuilders/message/6170
[2] /mt/111686473/243852
[3] /g/AmateurRadioBuilders/post
[4] /g/AmateurRadioBuilders/editsub/243852
[5] /g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
Links:
------
[1]
[2] /g/AmateurRadioBuilders/message/6172
[3] /mt/111686473/243852
[4] /g/AmateurRadioBuilders/post
[5] /g/AmateurRadioBuilders/editsub/243852
[6]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
Links:
------
[1] /g/AmateurRadioBuilders/message/6177
[2] /mt/111686473/243852
[3] /g/AmateurRadioBuilders/post
[4] /g/AmateurRadioBuilders/editsub/243852
[5]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
|
On 2025-03-14 14:13, D Solt via groups.io wrote: Yes it is on a DL *** I did get oscillation from my system a few weeks ago. I had installed an End Fed Half Wave antenna. It only happened with my big linear. A big fat common mode choke fixed it. - Jerry, KF6VB
On Mar 14, 2025, at 4:58?PM, jerry-KF6VB via groups.io
<jerry@...> wrote: ?Do you have it on a dummy load?
- jerry
On 2025-03-14 13:54, D Solt via groups.io wrote:
It is the K9HZ 20W amp
On Fri, Mar 14, 2025 at 4:53?PM jerry-KF6VB via groups.io [1]
<jerry@...> wrote:
Is it a K9HZ final? Or the one with the IRF510s?
- Jerry, KF6VB
On 2025-03-14 13:52, D Solt via groups.io [1] wrote:
I got the second T41 v12 with SW ver66.4 with amplifier operating
today. Both are acting the same, oscillations around 40MHz at
several
watts when PTT is engaged. With the oscillation, I was still able
to
do the TX IQ null. I am stumped. I don't have a very accurate way
to
measure power yet; using a 50MHz TBS1052B tek scope and an HP363
kit.
dave, n3ds
Links:
------
[1] /g/AmateurRadioBuilders/message/6170
[2] /mt/111686473/243852
[3] /g/AmateurRadioBuilders/post
[4] /g/AmateurRadioBuilders/editsub/243852
[5] /g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
Links:
------
[1]
[2] /g/AmateurRadioBuilders/message/6172
[3] /mt/111686473/243852
[4] /g/AmateurRadioBuilders/post
[5] /g/AmateurRadioBuilders/editsub/243852
[6]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
Links:
------
[1] /g/AmateurRadioBuilders/message/6174
[2] /mt/111686473/243852
[3] /g/AmateurRadioBuilders/post
[4] /g/AmateurRadioBuilders/editsub/243852
[5]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
|
Yes, I agree. The amp is solid. Previously , I swept the amps and got solid performance. And, when I disconnect the drive to the amp the oscillation stops. It is being caused by something in the T41 interacting with the amp dave
toggle quoted message
Show quoted text
On Mar 14, 2025, at 7:05?PM, K9HZ via groups.io <bill@...> wrote:
? Something is wrong. ?The amp will NOT oscillate by itself. ??
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ? On Mar 14, 2025, at 2:13?PM, D Solt via groups.io <davesolt@...> wrote:
? Yes it is on a DL
On Mar 14, 2025, at 4:58?PM, jerry-KF6VB via groups.io <jerry@...> wrote:
|
On 2025-03-14 16:05, K9HZ wrote: Something is wrong. The amp will NOT oscillate by itself. *** I have to agree with Bill. I built two of them, and neither of them showed any instability. I would try improving the bypassing on the power traces. Scope them to see if there's RF on them. - Jerry, KF6VB
|
Something is wrong. ?The amp will NOT oscillate by itself. ??
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
toggle quoted message
Show quoted text
On Mar 14, 2025, at 2:13?PM, D Solt via groups.io <davesolt@...> wrote:
? Yes it is on a DL
On Mar 14, 2025, at 4:58?PM, jerry-KF6VB via groups.io <jerry@...> wrote:
|
|
|
|
|
|
|
|
|
I got the second T41 v12 with SW ver66.4 with amplifier operating today.? Both are acting the same, oscillations around 40MHz at several watts when PTT is engaged.? With the oscillation, I was still able to do the TX IQ null.? I am stumped.? I don't have a very accurate way to measure power yet; using a 50MHz TBS1052B tek scope and an HP363 kit.
dave, n3ds
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I have been setting TX IQ Calibration parameters.? Everything aligns well on the lower bands.? When I engage PTT on 12m, 10m, and 6m in the TX IQ Cal menu, the amp oscillates around 40MHz and draws >2amps.? It I disconnect the input to the amp, it does not oscillate.? When I put a 6db pad between the LPF-Control and the amp it does not oscillate.? It does oscillate if I drop the 6dB pad to 3dB, but only draws 700ma.? Bias current is 250ma per side.? Maybe the correct filters are not being switched in and there is some weird reactance on the input of the amp.? Any suggestions?
dave, n3ds
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K9HZ