No issues. ?It went out to others capable of building it and commenting. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Mar 30, 2025, at 1:40?PM, Albert Peter via groups.io <albertfpeter@...> wrote:
?
Bill, I have not had time to get to it: working on the book, update helping my grandson study for his pilot exam, etc. As soon as I can i will try it out.
Al
I sent out five of those new display driver boards about a week ago and only saw posted that Terrance got his working as was able to use a 3-foot long display cable without display-T41 errors/lockups. ?Anyone else built it yet? ?I know i didnt
publish an assembly manual before i headed out of the country but the thing is pretty simple and i did send out a note re how to make it work on 5v or 3.3v. ?
Anyone else? ? I think its a winner but would like to know so i can get parts and boards ordered to send these out before Hamvention
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
?
Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois
?
Owner – Operator
Villa Grand Piton - J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com
email:??bill@...
?
|
Bill, I have not had time to get to it: working on the book, update helping my grandson study for his pilot exam, etc. As soon as I can i will try it out.
Al
toggle quoted message
Show quoted text
I sent out five of those new display driver boards about a week ago and only saw posted that Terrance got his working as was able to use a 3-foot long display cable without display-T41 errors/lockups. ?Anyone else built it yet? ?I know i didnt
publish an assembly manual before i headed out of the country but the thing is pretty simple and i did send out a note re how to make it work on 5v or 3.3v. ?
Anyone else? ? I think its a winner but would like to know so i can get parts and boards ordered to send these out before Hamvention
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
?
Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois
?
Owner – Operator
Villa Grand Piton - J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com
email:??bill@...
?
|
I sent out five of those new display driver boards about a week ago and only saw posted that Terrance got his working as was able to use a 3-foot long display cable without display-T41 errors/lockups. ?Anyone else built it yet? ?I know i didnt publish an assembly manual before i headed out of the country but the thing is pretty simple and i did send out a note re how to make it work on 5v or 3.3v. ?
Anyone else? ? I think its a winner but would like to know so i can get parts and boards ordered to send these out before Hamvention
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
|
Small latching relays for RF switching
I have for my AT kot but nothing else. ? Didn't make sense for the cost of the relays. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
Begin forwarded message:
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From: "Mark Frost via groups.io" <mark.frost@...> Date: March 28, 2025 at 12:38:22?AM AST To: [email protected]Subject: [AmateurRadioBuilders] Small latching relays for RF switchingReply-To: [email protected]
? Has anyone know of further experiments done along the lines of this, but with smaller relays suitable for portable/QRP applications?
I see the IM43 relays being used in the (tr)uSDX
Axicom D2n relays have been swapped into the uBitX.
Stock uBitX uses VRS2H, which is hard to find.
Browsing the digikey catalog there are several other series of small latching relays that I don't see any reference to (in ham related gear, at least). Has anyone played with the alternatives? Anyone have data?
73, Mark AC9VC
|
Small latching relays for RF switching
Has anyone know of further experiments done along the lines of this, but with smaller relays suitable for portable/QRP applications?
I see the IM43 relays being used in the (tr)uSDX
Axicom D2n relays have been swapped into the uBitX.
Stock uBitX uses VRS2H, which is hard to find.
Browsing the digikey catalog there are several other series of small latching relays that I don't see any reference to (in ham related gear, at least). Has anyone played with the alternatives? Anyone have data?
73, Mark AC9VC
|
I have no knowledge of caps across C2 and what that may do…. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Mar 20, 2025, at 12:20?PM, D Solt via groups.io <davesolt@...> wrote:
? 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.
dave 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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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 – K9ZC Staunton, Illinois ? Owner – 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 – K9ZC Staunton, Illinois ? Owner – 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 – K9ZC Staunton, Illinois ? Owner – 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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ?
|
Re: [SoftwareControlledHamRadio] boards and kits and stuff
Thanks Doug. ?I always try to be responsive bit sometimes i get helped by the comm software… and not in a good way. ?
Yeah please contact me on the 4th and ill get whatever you need togethet and shipped out. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Mar 27, 2025, at 9:54?AM, Doug W via groups.io <dougwilner@...> wrote:
? On Thu, Mar 27, 2025 at 07:10 AM, K9HZ wrote:
For some reason, groups locked me off the platform and started bouncing emails. ?I hope i got that resolved. ?
--------------------------------------------------------------------
?
I was wondering if something like that happened? I emailed you last week wanting to order a new RF board.? I forwarded a groups email to your wjschmidt email.? I just figured you were busy and I didn't want to pester you.? I'll try again directly when you get back.? Thanks again for all your time and work on this project.? I'll keep an ear toward the windwards for you this weekend.
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Re: [SoftwareControlledHamRadio] boards and kits and stuff
On Thu, Mar 27, 2025 at 07:10 AM, K9HZ wrote:
For some reason, groups locked me off the platform and started bouncing emails. ?I hope i got that resolved. ?
--------------------------------------------------------------------
?
I was wondering if something like that happened? I emailed you last week wanting to order a new RF board.? I forwarded a groups email to your wjschmidt email.? I just figured you were busy and I didn't want to pester you.? I'll try again directly when you get back.? Thanks again for all your time and work on this project.? I'll keep an ear toward the windwards for you this weekend.
|
Re: [SoftwareControlledHamRadio] boards and kits and stuff
Ok. ?I am currently at my contest station in the Caribbean (J62K) getting ready for WPX with some youngsters early in their contesting careers. ?Ill ne back home on April 4th and ill get your order out the same day. ?Contact me directly. ?
For some reason, groups locked me off the platform and started bouncing emails. ?I hope i got that resolved. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Mar 26, 2025, at 12:15?PM, Tom Schulte via groups.io <tomschulte9@...> wrote:
? Bill.?
? ?
Would like 4 encoder boards. Let me know cost and will pay through pay pal.
?
?
Tom?
AB9EK
|
Re: Combiner calculation spreadsheet
Sorry to show my ignorance, I am not too sure what you mean by combiner, is it to feed different antennas in an array or some kind of diplexer to use one coax for several antennas on several bands ??
?
73,
?
Yannig - F4IUJ
|
Combiner calculation spreadsheet
? Attached is my spreadsheet for building combiners in your garage.? ?You input the frequency, and that fixes the length of the wave guide.? Then select the diameter of the inner conductor and that fixes the diameter of the outer container such that it is the correct impedance for the transform.? Note that since square conduit only comes in specific inner dimensional sizes… but inner tubes come in 1/64” increments… you must adjust the inner diameter in 1/64” increments to find an outer diameter tube that is actually dimensionally produced.? It won’t matter if there are a few thousands difference between theoretical and produced dimensions (changes the transform by a few tenths of an ohm).? Also watch carefully the difference between the inside and outside diameters (last two columns) to make sure there is enough clearance for the power you want to run (1/4” needed for 1kW).? Larger inner gives larger distance.? You then buy the predicted square tube, put the coax connectors exactly 1” from the ends (and in the exact middle if it’s a half-wave design), solder in the center conductor, close the ends, and you have your combiner.? Easy-peasy. ? Yeah I know, this is a bit anal, but it’s so cheap to actually make these things it’s worth the effort over charged prices. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator – North American QRO Group at Groups.IO. ? email:? bill@... ? ?
|
On 2025-03-21 17:21, K9HZ wrote: 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).
*** For me the worst part is the gallon of crap they make you drink. - Jerry, KF6VB DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois
Owner – Operator
Villa Grand Piton – 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 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
dave
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 – K9ZC
Staunton, Illinois
Owner – Operator
Villa Grand Piton – 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 D Solt via groups.io
SENT: Friday, March 21, 2025 3:30 PM
TO: [email protected]
SUBJECT: Re: [AmateurRadioBuilders] 20 W Amp Oscillates
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
On Fri, Mar 21, 2025 at 4:25?PM K9HZ via groups.io [2]
<bill@...> wrote:
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 – K9ZC
Staunton, Illinois
Owner – Operator
Villa Grand Piton - J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com [3]
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]
[2]
[3]
[4] /g/AmateurRadioBuilders/message/6238
[5] /mt/111686473/243852
[6] /g/AmateurRadioBuilders/post
[7] /g/AmateurRadioBuilders/editsub/243852
[8]
/g/AmateurRadioBuilders/leave/11522011/243852/920863695/xyzzy
|
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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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 – K9ZC Staunton, Illinois ? Owner – 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
toggle quoted message
Show quoted text
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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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 – K9ZC Staunton, Illinois ? Owner – 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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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 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 – K9ZC Staunton, Illinois ? Owner – 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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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 – K9ZC Staunton, Illinois ? Owner – 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 – K9ZC Staunton, Illinois ? Owner – 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 – K9ZC Staunton, Illinois ? Owner – 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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ?
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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 – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – 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?
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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 – K9ZC
Staunton, Illinois
Owner – 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:
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[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
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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 – K9ZC Staunton, Illinois ? Owner – 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
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K9HZ