Ok sorry＃? I apologize for the email shouting. ??Just got back from my colonoscopy and still feeling crappy from the anesthesia and lack of sleep (up at 5:30 AM to start the colon-blow process). ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ?
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From: [email protected] <[email protected]> On Behalf Of D Solt via groups.io
Sent: Friday, March 21, 2025 7:12 PM
To: [email protected]
Subject: Re: [AmateurRadioBuilders] 20 W Amp Oscillates? I meant this only as a test to show where the feedback entry point is
On Mar 21, 2025, at 6:01?PM, K9HZ via groups.io <bill@...> wrote:
? DON＊T DO THAT!?? It REMOVES THE BPF FROM THE RX CHANNEL!!! ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? Try removing C18 on the LPF-Control or grounding the receive pins on the TR switch.? I think the feedback is getting in through U1 & U8.? Maybe the control logic is not correct. ? No this is a software problem because others are having it too.? Did you recently upgrade? ? Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ?
On Mar 21, 2025, at 3:10?PM, jerry-KF6VB <jerry@...> wrote:
?No progress on my oscillation problem. I figured maybe it was external
feedback from the
LPF to the BPF. So I tried moving the BPF farther away from the
LPF...no difference. Then I
disconnected the BPF entirely & replaced it with an SMA barrel...no
difference.
I noticed that a few of my SMA connectors were fraying where the cable
joined the crimp.
Peeled off a bit of insulation and soldered them to the crimp ferrule.
No difference.
- Jerry, KF6VB
|
See my comment on another thread for something to try:?
?
|
I meant this only as a test to show where the feedback entry point is dave
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On Mar 21, 2025, at 6:01?PM, K9HZ via groups.io <bill@...> wrote:
? DON＊T DO THAT!?? It REMOVES THE BPF FROM THE RX CHANNEL!!! ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? Try removing C18 on the LPF-Control or grounding the receive pins on the TR switch.? I think the feedback is getting in through U1 & U8.? Maybe the control logic is not correct. ? No this is a software problem because others are having it too.? Did you recently upgrade? ? Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ?
On Mar 21, 2025, at 3:10?PM, jerry-KF6VB <jerry@...> wrote:
?No progress on my oscillation problem. I figured maybe it was external
feedback from the
LPF to the BPF. So I tried moving the BPF farther away from the
LPF...no difference. Then I
disconnected the BPF entirely & replaced it with an SMA barrel...no
difference.
I noticed that a few of my SMA connectors were fraying where the cable
joined the crimp.
Peeled off a bit of insulation and soldered them to the crimp ferrule.
No difference.
- Jerry, KF6VB
|
DON＊T DO THAT!?? It REMOVES THE BPF FROM THE RX CHANNEL!!! ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ?
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From: [email protected] <[email protected]> On Behalf Of D Solt via groups.io
Sent: Friday, March 21, 2025 3:30 PM
To: [email protected]
Subject: Re: [AmateurRadioBuilders] 20 W Amp Oscillates? Try removing C18 on the LPF-Control or grounding the receive pins on the TR switch.? I think the feedback is getting in through U1 & U8.? Maybe the control logic is not correct. ? No this is a software problem because others are having it too.? Did you recently upgrade? ? Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ?
On Mar 21, 2025, at 3:10?PM, jerry-KF6VB <jerry@...> wrote:
?No progress on my oscillation problem. I figured maybe it was external
feedback from the
LPF to the BPF. So I tried moving the BPF farther away from the
LPF...no difference. Then I
disconnected the BPF entirely & replaced it with an SMA barrel...no
difference.
I noticed that a few of my SMA connectors were fraying where the cable
joined the crimp.
Peeled off a bit of insulation and soldered them to the crimp ferrule.
No difference.
- Jerry, KF6VB
|
C18 needs to be there or the BPF is NOT in the RX path＃ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ?
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From: [email protected] <[email protected]> On Behalf Of D Solt via groups.io
Sent: Friday, March 21, 2025 3:04 PM
To: [email protected]
Subject: Re: [AmateurRadioBuilders] 20 W Amp Oscillates? I have narrowed the amplifier oscillation to feedback getting through the Tx/Rx solid state switch area.? If I remove C18, the oscillations go away.?? ? ※The cap across the primary of T2 on my PA is for gain shaping.§ ? I＊ve never tried that＃ you should publish your results because when I ran just the first stage, the gain is very flat＃ almost to 70 Mhz. That transformer (T2) only decouples the stages＃ same impedance. ? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? The cap across the primary of T2 on my PA is for gain shaping. The oscillation continues with the BPF and the LPF out of the circuit.? I notice that additional grounding on the TR switch lowered the amplitude of the oscillation (2amps to 1amp).? I brought more ground up through J17.2 pins 4 and 5, (after I removed U18).? Still oscillates, but lower amplitude I tried some low pass filtering on the receive line down to the LPF-Control board.? That reduces the oscillation, but doesn't eliminate it. ? Ok you have a lot of good equipment to solve this. ? Yeah it would not hurt to try shorting over the relay on the daughter board. ? I would also try removing the BPF board and just use a jumper to reduce the number of things in line.? I would expect an oscillatory behavior if one of the TR switches either on the BPF or on the LPF was not switching correctly (so feeding back in TX).? Those things are really small and just a tiny drop of solder could cause it. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? I have a TinySA, NanoVNA, 50MHz scope, DVM's, Taidacent Pwr Mtr, KiwiSDR, audio generators, assorted dummy loads, attenuators, and couplers. I used the NanoVNA to sweep the 20 wt Power Amp (I built 2 of them last year) and they were very flat and stable from 3-50 MHz at 12VDC and ~1.5ADC and ~5 wt output. I have put 22 AWG wire over all the TR switch RF output tracks.? I have soldered the TR Switch into the circuit to rule out connector issues.? The amplifier works great with the home built TR switch bypass perf board (from 3-54MHz).? It oscillates with the TR switch installed on the 12, 10, and 6 meter bands at roughly 33MHz and drawing about 2ADC when the PTT is engaged.? In CW mode it has the desired frequency and the rogue 33 MHz. Tomorrow, I'll get the NanoVNA and sweep the TR Switch circuit from J23 (FROM LPF) on the LPF-Cntl board to ANT1 with the PTT engaged.? Maybe that will give me a clue. I have 2 TR Switch boards - both exhibit this behavior.? The relays are working fine at 21MHz, so don't think they are the problem.? Thanks for your help. ? First off＃ what sort of test equipment do you have Dave? ? Just stuff like DVMs or do you have something like a VNA or a Spectrum Analyzer? And possibly a signal generator or another radio you can test this PA on? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? 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 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ? ? On Mar 17, 2025, at 10:28?AM, D Solt via <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. ? 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 每 K9ZC Staunton, Illinois ? Owner 每 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? ?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 每 K9ZC Staunton, Illinois ? Owner 每 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 ?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 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ?
|
Re: [SoftwareControlledHamRadio] Tx-Rx logic on LPF-Control
First, R8-R11 should NOT BE POPULATED under I2C control.? ?U15 pins GPA0 and GPA1 should ALTERNATE STATE.? NOTHING should be plugged into J1 unless it LISTENS ONLY. ???U3 and U7 appear to be working correctly＃ ? I think something happened the software and I need to have Oliver look into this because its happening to everyone and just after the last version of the software was released. Sorry just finished a colonoscopy so a little out of it＃ ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ?
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From: [email protected] <[email protected]> On Behalf Of D Solt via groups.io
Sent: Friday, March 21, 2025 2:56 PM
To: [email protected]
Subject: [SoftwareControlledHamRadio] Tx-Rx logic on LPF-Control? In my efforts to track a PA oscillation problem I noticed that in the SSB mode, the receive solid state switches (U1 & U8 on the LPF-Cntl) do not change state when the PTT is engaged but the transmit SSS's (U3 & U7) do change state.? I'm using ver 66.4.? In the CW mode, all 4 SSS's change state on key down.? I would expect all the switches to change state in CW and SSB so that the BPF is used in Tx and Rx.? Am I understanding this correctly?
|
On 2025-03-21 13:25, K9HZ wrote: No this is a software problem because others are having it too. Did
you recently upgrade? *** Hi Bill, I upgrade constantly. Have to, because I'm working on the software. I have lots of versions on my server. I'll downgrade and see if that fixes it. - Jerry
DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ
Owner - Operator
Big Signal Ranch 每 K9ZC
Staunton, Illinois
Owner 每 Operator
Villa Grand Piton - J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com
email: bill@...
On Mar 21, 2025, at 3:10?PM, jerry-KF6VB <jerry@...> wrote: ?No progress on my oscillation problem. I figured maybe it was
external
feedback from the
LPF to the BPF. So I tried moving the BPF farther away from the
LPF...no difference. Then I
disconnected the BPF entirely & replaced it with an SMA barrel...no
difference.
I noticed that a few of my SMA connectors were fraying where the
cable
joined the crimp.
Peeled off a bit of insulation and soldered them to the crimp
ferrule.
No difference.
- Jerry, KF6VB
Links:
------
[1] /g/AmateurRadioBuilders/message/6229
[2] /mt/111686473/243852
[3] /g/AmateurRadioBuilders/post
[4] /g/AmateurRadioBuilders/editsub/243852
[5]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
|
Jerry, Try removing C18 on the LPF-Control or grounding the receive pins on the TR switch.? I think the feedback is getting in through U1 & U8.? Maybe the control logic is not correct. dave
No this is a software problem because others are having it too.? Did you recently upgrade?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it:
email:??bill@... ? On Mar 21, 2025, at 3:10?PM, jerry-KF6VB <jerry@...> wrote:
?No progress on my oscillation problem. I figured maybe it was external
feedback from the
LPF to the BPF. So I tried moving the BPF farther away from the
LPF...no difference. Then I
disconnected the BPF entirely & replaced it with an SMA barrel...no
difference.
I noticed that a few of my SMA connectors were fraying where the cable
joined the crimp.
Peeled off a bit of insulation and soldered them to the crimp ferrule.
No difference.
- Jerry, KF6VB
|
I think this is a software issue. ?I need to consult with Oliver. ?Several people magically started having oscillation problems at the same time where this was never an issue. ? Almost like something is getting actuated that should not be. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 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 21, 2025, at 3:04?PM, D Solt via groups.io <davesolt@...> wrote:
? I have narrowed the amplifier oscillation to feedback getting through the Tx/Rx solid state switch area.? If I remove C18, the oscillations go away.?? ※The cap across the primary of T2 on my PA is for gain shaping.§ ? I＊ve never tried that＃ you should publish your results because when I ran just the first stage, the gain is very flat＃ almost to 70 Mhz. That transformer (T2) only decouples the stages＃ same impedance. ? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? The cap across the primary of T2 on my PA is for gain shaping. The oscillation continues with the BPF and the LPF out of the circuit.? I notice that additional grounding on the TR switch lowered the amplitude of the oscillation (2amps to 1amp).? I brought more ground up through J17.2 pins 4 and 5, (after I removed U18).? Still oscillates, but lower amplitude I tried some low pass filtering on the receive line down to the LPF-Control board.? That reduces the oscillation, but doesn't eliminate it. ? Ok you have a lot of good equipment to solve this. ? Yeah it would not hurt to try shorting over the relay on the daughter board. ? I would also try removing the BPF board and just use a jumper to reduce the number of things in line.? I would expect an oscillatory behavior if one of the TR switches either on the BPF or on the LPF was not switching correctly (so feeding back in TX).? Those things are really small and just a tiny drop of solder could cause it. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? I have a TinySA, NanoVNA, 50MHz scope, DVM's, Taidacent Pwr Mtr, KiwiSDR, audio generators, assorted dummy loads, attenuators, and couplers. I used the NanoVNA to sweep the 20 wt Power Amp (I built 2 of them last year) and they were very flat and stable from 3-50 MHz at 12VDC and ~1.5ADC and ~5 wt output. I have put 22 AWG wire over all the TR switch RF output tracks.? I have soldered the TR Switch into the circuit to rule out connector issues.? The amplifier works great with the home built TR switch bypass perf board (from 3-54MHz).? It oscillates with the TR switch installed on the 12, 10, and 6 meter bands at roughly 33MHz and drawing about 2ADC when the PTT is engaged.? In CW mode it has the desired frequency and the rogue 33 MHz. Tomorrow, I'll get the NanoVNA and sweep the TR Switch circuit from J23 (FROM LPF) on the LPF-Cntl board to ANT1 with the PTT engaged.? Maybe that will give me a clue. I have 2 TR Switch boards - both exhibit this behavior.? The relays are working fine at 21MHz, so don't think they are the problem.? Thanks for your help. ? First off＃ what sort of test equipment do you have Dave? ? Just stuff like DVMs or do you have something like a VNA or a Spectrum Analyzer? And possibly a signal generator or another radio you can test this PA on? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? 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 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ? ? On Mar 17, 2025, at 10:28?AM, D Solt via <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. ? 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 每 K9ZC Staunton, Illinois ? Owner 每 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? ?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 每 K9ZC Staunton, Illinois ? Owner 每 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 ?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 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ?
|
No this is a software problem because others are having it too. ?Did you recently upgrade?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 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 21, 2025, at 3:10?PM, jerry-KF6VB <jerry@...> wrote:
?No progress on my oscillation problem. I figured maybe it was external
feedback from the
LPF to the BPF. So I tried moving the BPF farther away from the
LPF...no difference. Then I
disconnected the BPF entirely & replaced it with an SMA barrel...no
difference.
I noticed that a few of my SMA connectors were fraying where the cable
joined the crimp.
Peeled off a bit of insulation and soldered them to the crimp ferrule.
No difference.
- Jerry, KF6VB
|
No progress on my oscillation problem. I figured maybe it was external
feedback from the
LPF to the BPF. So I tried moving the BPF farther away from the
LPF...no difference. Then I
disconnected the BPF entirely & replaced it with an SMA barrel...no
difference.
I noticed that a few of my SMA connectors were fraying where the cable
joined the crimp.
Peeled off a bit of insulation and soldered them to the crimp ferrule.
No difference.
- Jerry, KF6VB
|
I have narrowed the amplifier oscillation to feedback getting through the Tx/Rx solid state switch area.? If I remove C18, the oscillations go away.??
※The cap across the primary of T2 on my PA is for gain shaping.§ ? I＊ve never tried that＃ you should publish your results because when I ran just the first stage, the gain is very flat＃ almost to 70 Mhz. That transformer (T2) only decouples the stages＃ same impedance. ? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? The cap across the primary of T2 on my PA is for gain shaping. The oscillation continues with the BPF and the LPF out of the circuit.? I notice that additional grounding on the TR switch lowered the amplitude of the oscillation (2amps to 1amp).? I brought more ground up through J17.2 pins 4 and 5, (after I removed U18).? Still oscillates, but lower amplitude I tried some low pass filtering on the receive line down to the LPF-Control board.? That reduces the oscillation, but doesn't eliminate it. ? Ok you have a lot of good equipment to solve this. ? Yeah it would not hurt to try shorting over the relay on the daughter board. ? I would also try removing the BPF board and just use a jumper to reduce the number of things in line.? I would expect an oscillatory behavior if one of the TR switches either on the BPF or on the LPF was not switching correctly (so feeding back in TX).? Those things are really small and just a tiny drop of solder could cause it. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? I have a TinySA, NanoVNA, 50MHz scope, DVM's, Taidacent Pwr Mtr, KiwiSDR, audio generators, assorted dummy loads, attenuators, and couplers. I used the NanoVNA to sweep the 20 wt Power Amp (I built 2 of them last year) and they were very flat and stable from 3-50 MHz at 12VDC and ~1.5ADC and ~5 wt output. I have put 22 AWG wire over all the TR switch RF output tracks.? I have soldered the TR Switch into the circuit to rule out connector issues.? The amplifier works great with the home built TR switch bypass perf board (from 3-54MHz).? It oscillates with the TR switch installed on the 12, 10, and 6 meter bands at roughly 33MHz and drawing about 2ADC when the PTT is engaged.? In CW mode it has the desired frequency and the rogue 33 MHz. Tomorrow, I'll get the NanoVNA and sweep the TR Switch circuit from J23 (FROM LPF) on the LPF-Cntl board to ANT1 with the PTT engaged.? Maybe that will give me a clue. I have 2 TR Switch boards - both exhibit this behavior.? The relays are working fine at 21MHz, so don't think they are the problem.? Thanks for your help. ? First off＃ what sort of test equipment do you have Dave? ? Just stuff like DVMs or do you have something like a VNA or a Spectrum Analyzer? And possibly a signal generator or another radio you can test this PA on? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? ? 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 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ? ? On Mar 17, 2025, at 10:28?AM, D Solt via <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. ? 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 每 K9ZC Staunton, Illinois ? Owner 每 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? ?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 每 K9ZC Staunton, Illinois ? Owner 每 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 ?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 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ?
|
Re: Rob Sherwood rankings??
Got it! Thanks!
Jack, W8TEE
On Thursday, March 20, 2025 at 04:31:22 PM EDT, K9HZ <bill@...> wrote:
Just sent the list to you privately＃ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ?
From: [email protected] <[email protected]> On Behalf Of Jack, W8TEE via groups.io
Sent: Thursday, March 20, 2025 3:19 PM
To: [email protected]
Subject: Re: [AmateurRadioBuilders] Rob Sherwood rankings?? ? Nope, not using private mode. On Thursday, March 20, 2025 at 04:12:04 PM EDT, Doug W via groups.io <dougwilner@...> wrote: On Thu, Mar 20, 2025 at 03:05 PM, Jack, W8TEE wrote: I tried that, no luck.
------------------------------------- any chance you are browsing in private mode?? as far as I can tell you will always get the insecure warning trying to load an http address in private now.? if that doesn't do it hopefully someone else jumps in I'm about at the edge of my limited firefox knowledge.
--
Jack, W8TEE
-- Jack, W8TEE
|
Re: Rob Sherwood rankings??
Hi Gibby:
I tried the setting that turns off the HTTPS requirement, still no go.
Jack, W8TEE
On Thursday, March 20, 2025 at 07:08:59 PM EDT, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote:
I think it has to do with whether or not your browser will accept older pages that are not HTTPS available.?
On Mar 20, 2025, at 16:05, Jack, W8TEE via groups.io <jjpurdum@...> wrote:
?
I tried that, no luck.
Jack, W8TEE
On Thursday, March 20, 2025 at 04:00:21 PM EDT, Doug W via groups.io <dougwilner@...> wrote:
On Thu, Mar 20, 2025 at 02:47 PM, Jack, W8TEE wrote:
It did an update two days ago and my guess is something got reset.
----------------------------------------------------------------------
check tools/settings/privacy&security look for https-only mode toward the bottom.? if you change to "don't enable https-only mode" it should load. ? if that works you can either leave it that way if you are comfortable with the potential security issues or add sherwood as an exception with the "manage exceptions" button
?
?
-- Jack, W8TEE
<inline.0.part>
--
Jack, W8TEE
|
Re: Rob Sherwood rankings??
I think it has to do with whether or not your browser will accept older pages that are not HTTPS available.?
toggle quoted message
Show quoted text
On Mar 20, 2025, at 16:05, Jack, W8TEE via groups.io <jjpurdum@...> wrote:
?
I tried that, no luck.
Jack, W8TEE
On Thursday, March 20, 2025 at 04:00:21 PM EDT, Doug W via groups.io <dougwilner@...> wrote:
On Thu, Mar 20, 2025 at 02:47 PM, Jack, W8TEE wrote:
It did an update two days ago and my guess is something got reset.
----------------------------------------------------------------------
check tools/settings/privacy&security look for https-only mode toward the bottom.? if you change to "don't enable https-only mode" it should load. ? if that works you can either leave it that way if you are comfortable with the potential security issues or add sherwood as an exception with the "manage exceptions" button
?
?
-- Jack, W8TEE
<inline.0.part>
|
Re: T41 high frequency weirdness
On 2025-03-20 13:33, K9HZ wrote: Yeah but＃ what＊s different? Did you:
* Play with wires
* Move equipment
* Change microphones
* Etc. ?
Well, I did recently... Wire up an EHFW antenna. And a coax switch. The coax switch switches between my existing trap vertical, the EFHW, and the dummy load. The EFHW has a dedicated MFJ998RT remote autotuner. The vertical has a second dedicated autotuner. Each autotuner has its own bias T which is past the coax switch. The setup is: T41->Bigger Linear->LP100->Coax Switch -> bias-T -> Trap Vertical -> bias-T -> common-mode-choke -> EFHW HOWEVER, the fault is manifesting itself with the coax switch switched to the dummy load. Also, I tried bypassing everything and connecting the T41 direct to the dummy load - no difference. - Jerry, KF6VB DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch 每 K9ZC
Staunton, Illinois
Owner 每 Operator
Villa Grand Piton 每 J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com [2]
Moderator: North American QRO Group at Groups.IO.
Moderator: Amateur Radio Builders Group at Groups.IO.
email: bill@...
FROM: [email protected] <[email protected]>
ON BEHALF OF jerry-KF6VB
SENT: Thursday, March 20, 2025 3:30 PM
TO: [email protected]
CC: K9HZ <bill@...>
SUBJECT: Re: [AmateurRadioBuilders] T41 high frequency weirdness
On 2025-03-20 12:19, K9HZ wrote:
What has changed? *** Nothing!!!!!!!!!!!!!! That I know of. Well, obviously SOMETHING
has
changed, because it didn't use to do that.
- Jerry
DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch 每 K9ZC
Staunton, Illinois
Owner 每 Operator
Villa Grand Piton 每 J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com [1] [1]
Moderator: North American QRO Group at Groups.IO.
Moderator: Amateur Radio Builders Group at Groups.IO.
email: bill@...
FROM: [email protected]
<[email protected]>
ON BEHALF OF jerry-KF6VB
SENT: Thursday, March 20, 2025 2:09 PM
TO: AmateurRadioBuilders <[email protected]>
SUBJECT: [AmateurRadioBuilders] T41 high frequency weirdness
My T41 has started doing something weird on 15M and 10M. On 10M,
when
I
hit the mike button, I immediately get 6W out on my
Telepost 100LP - without talking into the mike!
I piped the output from the dummy load ( actually, a Bird 500W 30dB
attenuator ) into my Rigol SA. Signal at 28.350MHz looks reasonably
normal - carrier about 30dB down from voice peaks.
HOWEVER, when I increased the span, I found a giant spur at
33.305883
MHz. About 15dB taller than the proper output signal ( at 28.350MHz
).
If I go to 24.9MHz and transmit, the same sort of spur appears - at
32.305883 MHz.
If I go to 21.2MHz & transmit, the spur is at 27.9195 MHz. (
Telepost
says 2.7W )
If I go to 18.096MHz - no spur.
14.2MHz and below - no spur.
At a wide span, it looks like a nice clean peak. But if I crank down
on
it, it starts to get messy.
This is a latest-greatest V12, with the K9Hz BPF, LPF, and PA.
I connected the output of the RF board directly to the SA - no
constant
spur. Plenty of harmonics with no BPF or LPF though.
I can only conclude that the PA is oscillating:(.
As to why it doesn't oscillate on lower bands....some interaction
between the PA and the BPF & LPF?
- Jerry, KF6VB
Links:
------
[1]
[2] /g/AmateurRadioBuilders/message/6210
[3] /mt/111814954/243852
[4] /g/AmateurRadioBuilders/post
[5] /g/AmateurRadioBuilders/editsub/243852
[6]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
Links:
------
[1]
[2]
[3] /g/AmateurRadioBuilders/message/6221
[4] /mt/111814954/243852
[5] /g/AmateurRadioBuilders/post
[6] /g/AmateurRadioBuilders/editsub/243852
[7]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
|
Re: Rob Sherwood rankings??
I had an ad-blocker plugin working on Firefox, and it killed several
websites - including
the one for ordering pizza!
- Jerry, KF6VB
toggle quoted message
Show quoted text
On 2025-03-20 12:47, Jack, W8TEE via groups.io wrote: It doesn't work for me. I even turned off the Secure Site only setting
and it still won't load. However, I closed FIrefox and loaded Opera
and it worked fine. Can anyone who knows Firefox tell me what got
reset? It did an update two days ago and my guess is something got
reset.
Jack, W8TEE
On Thursday, March 20, 2025 at 03:34:18 PM EDT, K9HZ
<bill@...> wrote:
Works for me,,,
DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch 每 K9ZC
Staunton, Illinois
Owner 每 Operator
Villa Grand Piton 每 J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com [1]
Moderator: North American QRO Group at Groups.IO.
Moderator: Amateur Radio Builders Group at Groups.IO.
email: bill@...
FROM: [email protected] <[email protected]>
ON BEHALF OF Jack, W8TEE via groups.io
SENT: Thursday, March 20, 2025 2:25 PM
TO: [email protected]
SUBJECT: Re: [AmateurRadioBuilders] Rob Sherwood rankings??
I get a _Secure Connection Failed_ error message. I never used to get
this.
Jack, W8TEE
On Thursday, March 20, 2025 at 03:18:03 PM EDT, K9HZ
<bill@...> wrote:
Receiver Test Data [2] This?
DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch 每 K9ZC
Staunton, Illinois
Owner 每 Operator
Villa Grand Piton 每 J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com [1]
Moderator: North American QRO Group at Groups.IO.
Moderator: Amateur Radio Builders Group at Groups.IO.
email: bill@...
FROM: [email protected] <[email protected]>
ON BEHALF OF Jack, W8TEE via groups.io
SENT: Thursday, March 20, 2025 2:07 PM
TO: SoftwareControlledHamRadio <[email protected]>;
AmateurRadioBuilders <[email protected]>
SUBJECT: [AmateurRadioBuilders] Rob Sherwood rankings??
All:
I can't seem to find Rob's transceiver ranking list. Anyone have a URL
that works?
Jack, W8TEE
--
Jack, W8TEE
--
Jack, W8TEE
--
Jack, W8TEE
Links:
------
[1]
[2]
[3] /g/AmateurRadioBuilders/message/6213
[4] /mt/111814916/243852
[5] /g/AmateurRadioBuilders/post
[6] /g/AmateurRadioBuilders/editsub/243852
[7]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
|
Re: T41 high frequency weirdness
Yeah but＃ what＊s different?? Did you: - Play with wires
- Move equipment
- Change microphones
- Etc.?? ?
? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of jerry-KF6VB
Sent: Thursday, March 20, 2025 3:30 PM
To: [email protected]
Cc: K9HZ <bill@...>
Subject: Re: [AmateurRadioBuilders] T41 high frequency weirdness? On 2025-03-20 12:19, K9HZ wrote: What has changed?
*** Nothing!!!!!!!!!!!!!! That I know of. Well, obviously SOMETHING
has
changed, because it didn't use to do that.
- Jerry
DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch 每 K9ZC
Staunton, Illinois
Owner 每 Operator
Villa Grand Piton 每 J68HZ
Soufriere, St. Lucia W.I.
Rent it: [1]
Moderator: North American QRO Group at Groups.IO.
Moderator: Amateur Radio Builders Group at Groups.IO.
email: bill@...
FROM: [email protected] <[email protected]>
ON BEHALF OF jerry-KF6VB
SENT: Thursday, March 20, 2025 2:09 PM
TO: AmateurRadioBuilders <[email protected]>
SUBJECT: [AmateurRadioBuilders] T41 high frequency weirdness
My T41 has started doing something weird on 15M and 10M. On 10M, when
I
hit the mike button, I immediately get 6W out on my
Telepost 100LP - without talking into the mike!
I piped the output from the dummy load ( actually, a Bird 500W 30dB
attenuator ) into my Rigol SA. Signal at 28.350MHz looks reasonably
normal - carrier about 30dB down from voice peaks.
HOWEVER, when I increased the span, I found a giant spur at 33.305883
MHz. About 15dB taller than the proper output signal ( at 28.350MHz ).
If I go to 24.9MHz and transmit, the same sort of spur appears - at
32.305883 MHz.
If I go to 21.2MHz & transmit, the spur is at 27.9195 MHz. ( Telepost
says 2.7W )
If I go to 18.096MHz - no spur.
14.2MHz and below - no spur.
At a wide span, it looks like a nice clean peak. But if I crank down
on
it, it starts to get messy.
This is a latest-greatest V12, with the K9Hz BPF, LPF, and PA.
I connected the output of the RF board directly to the SA - no
constant
spur. Plenty of harmonics with no BPF or LPF though.
I can only conclude that the PA is oscillating:(.
As to why it doesn't oscillate on lower bands....some interaction
between the PA and the BPF & LPF?
- Jerry, KF6VB
Links:
------
[1]
[2] /g/AmateurRadioBuilders/message/6210
[3] /mt/111814954/243852
[4] /g/AmateurRadioBuilders/post
[5] /g/AmateurRadioBuilders/editsub/243852
[6]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
|
Re: Rob Sherwood rankings??
Just sent the list to you privately＃ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch 每 K9ZC Staunton, Illinois ? Owner 每 Operator Villa Grand Piton 每 J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of Jack, W8TEE via groups.io
Sent: Thursday, March 20, 2025 3:19 PM
To: [email protected]
Subject: Re: [AmateurRadioBuilders] Rob Sherwood rankings??? Nope, not using private mode. On Thursday, March 20, 2025 at 04:12:04 PM EDT, Doug W via groups.io <dougwilner@...> wrote: On Thu, Mar 20, 2025 at 03:05 PM, Jack, W8TEE wrote: I tried that, no luck.
------------------------------------- any chance you are browsing in private mode?? as far as I can tell you will always get the insecure warning trying to load an http address in private now.? if that doesn't do it hopefully someone else jumps in I'm about at the edge of my limited firefox knowledge.
--
Jack, W8TEE
|
Re: T41 high frequency weirdness
I Have something very similar happening.? It appears to be feedback getting into the receiver circuit.? One easy test is to ground the receiver pins on the TR Switch.? On my T41, that stopped the oscillation.? A good test is to take both the BPF and the LPF out of the circuit to isolate where the problem is.? For more info on what I have tried see Bill and my posts from the last few days. dave, n3ds
My T41 has started doing something weird on 15M and 10M. On 10M, when I
hit the mike button, I immediately get 6W out on my
Telepost 100LP - without talking into the mike!
I piped the output from the dummy load ( actually, a Bird 500W 30dB
attenuator ) into my Rigol SA. Signal at 28.350MHz looks reasonably
normal - carrier about 30dB down from voice peaks.
HOWEVER, when I increased the span, I found a giant spur at 33.305883
MHz. About 15dB taller than the proper output signal ( at 28.350MHz ).
If I go to 24.9MHz and transmit, the same sort of spur appears - at
32.305883 MHz.
If I go to 21.2MHz & transmit, the spur is at 27.9195 MHz. ( Telepost
says 2.7W )
If I go to 18.096MHz - no spur.
14.2MHz and below - no spur.
At a wide span, it looks like a nice clean peak. But if I crank down on
it, it starts to get messy.
This is a latest-greatest V12, with the K9Hz BPF, LPF, and PA.
I connected the output of the RF board directly to the SA - no constant
spur. Plenty of harmonics with no BPF or LPF though.
I can only conclude that the PA is oscillating:(.
As to why it doesn't oscillate on lower bands....some interaction
between the PA and the BPF & LPF?
- Jerry, KF6VB
|
K9HZ
Jack, W8TEE