On Wed, Apr 2, 2025 at 07:48 AM, K9HZ wrote:
Dr. Bill
Playing with compensation caps around 180-220 flattens out from 3-30Mhz I can't seem to get much gain past 35-40Mhz
Still playing not that interested in 6M qrp? so not a big deal.
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Just curious on how Paul got his so flat out to 50Mhz.
Tim?
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Re: TX sidebands reversed
That was an instant fix!
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Thanks Rick.
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Roger G8JWT
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Re: TX sidebands reversed
Roger. Try a 180 deg flip of the 3 pin connector going from the audio top hat to the teensy 3 pin connector.? Worked on V11 should also work on V12. No guarantees but easy to try. Rick, KN4AIE ? ?
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From: [email protected] <[email protected]> On Behalf Of bty84827531 via groups.io
Sent: Thursday, April 3, 2025 9:54 AM
To: [email protected]
Subject: [SoftwareControlledHamRadio] TX sidebands reversed? I'm in the middle of doing the TX calibration using 66.9. On receive the radio works with the indicated sideband just fine, but when I switch to transmit the sideband is reversed. In other words when the screen says I'm on LSB the radio transmits on USB. This only affects transmit. The receiver works correctly as shown on the screen.
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I'm in the middle of doing the TX calibration using 66.9.
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On receive the radio works with the indicated sideband just fine, but when I switch to transmit the sideband is reversed. In other words when the screen says I'm on LSB the radio transmits on USB. This only affects transmit. The receiver works correctly as shown on the screen.
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Any ideas anyone?
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Roger G8JWT
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Re: T41 Transmit Calibration V12
Thanks Oliver. On to SSB Cal tomorrow. Almost done! dave
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On Apr 2, 2025, at 4:42?PM, Oliver KI3P via groups.io <oliver@...> wrote:
? That's right Dave -- you null the lower image if you're in a USB band, and vice versa
-------- Original Message -------- On 4/2/25 2:38 PM, D Solt via groups.io wrote: When doing the TX IQ calibration of the higher bands that use USB, do you null the lower image?
dave, n3ds
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Re: T41 T41EEE.9 Firmware Release
Very nice, Greg!
Jack, W8TEE
On Wednesday, April 2, 2025 at 08:32:00 PM EDT, Greg KF5N via groups.io <greg.electricity@...> wrote:
Demo of the new AGC in T41EEE.9:
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Compressor2 is part of the Open Audio Library.? Bob's Tiny Ten Transceiver uses it in the audio data path.
This seemed to be a natural replacement for the code inherited from the SDR Convolution receiver.
I tried it, and WOW it works great!
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The Open Audio Library:
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Compressor2 is also used in the transmitter path along with the CESSB module.? Good stuff!
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73 Greg KF5N
-- Jack, W8TEE
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Re: T41 T41EEE.9 Firmware Release
Demo of the new AGC in T41EEE.9:
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Compressor2 is part of the Open Audio Library.? Bob's Tiny Ten Transceiver uses it in the audio data path.
This seemed to be a natural replacement for the code inherited from the SDR Convolution receiver.
I tried it, and WOW it works great!
?
The Open Audio Library:
?
Compressor2 is also used in the transmitter path along with the CESSB module.? Good stuff!
?
--
73 Greg KF5N
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Hi Oliver, you're generally right, but missing one important detail.? The harmonic copies coming out of the QSE circuitry will mix with the fundamental in the power amplifier
and produce intermodulation products (adjacent channel splatter) right along side the fundamental.? At that point, that junk can't be filtered out.? The LPF won't help.
The math of the problem kind of catches you off guard.? The harmonic energy is offset from exact harmonics, due to the modulator.? I was able to simulate this.? We were all surprised when we saw this phenomenon
in the early days of the T41.
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So a bandpass (or lowpass) between QSE output and PA input keeps that energy out of the PA and there is no opportunity for generation of those adjacent channel intermodulation products.
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73 Greg KF5N
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Yeah exactly right¡ everyone is use to having a BPF in transmit to clean up the signal before transmitting¡. ? But what many SDRs are missing is a preselector¡ a band filter mechanism in receive that only allows the band you are listening through (Hence two BPFs for dual receive¡ because you could be on different bands).? And because SDRs (and particularly this SRD that can operate from about 400kc up to almost 150 mhz), receiving a very loud signal pretty much anywhere in its receive range can desensitize the front end/ mixer to the point that you hear nothing!? We fixed that with the BPF in the T41 operating in Receive too¡. ? So when at Field Day operating with friends on different bands¡ you won¡¯t see any interference in the receiver from them. ? That¡¯s the reason we used a 5 pole filter¡the skirts are very sharp so all the trash outside of the TX and RX frequency is greatly attenuated. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C 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 Oliver KI3P via groups.io
Sent: Wednesday, April 2, 2025 4:09 PM
To: [email protected]
Subject: Re: [SoftwareControlledHamRadio] Ver066_9_3_22_25? Bill can comment further, but the BPF should be in the signal path in both RX and TX mode.? In TX mode it cleans up the signal before it goes to the PA. This means that higher-order harmonics of the signal produced by the exciter -- copies of the signal at multiples of the transmit signal -- are filtered out and not amplified by the PA. These would be removed by the LPF anyway before they could hit the antenna, but removing them before the PA helps with signal quality because the PA isn't having to amplify signals at multiple bands simultaneously. In RX mode the BPF keeps the other bands away from the input to the mixer. If you didn't have the BPF in place you would expect to get a higher noise level in the audio at best, and distortion from strong signals in other bands at worst. On Wednesday, April 2nd, 2025 at 3:54 PM, epif18 via groups.io <epif18@...> wrote:
Well, I did some more troubleshooting and this is what I found: I stuck some troubleshooting code at the beginning (first line) of loop().? Draw a line on the display.? Well, looked like setup never exited.? Stuck that code in various places in .ino and eventually found that swrSetup() was hanging up.? I have the SWR_AD7991 installed but not the transformer (shorted RF In to RFOut). I commented #define V12_LPF_SWR_AD7991 out.? Then I commented out swrSetup() and 66.9 ran! Looks like it's not in the latest code on github (KI3P/SDTVer066-9) that was updated 2 weeks ago. I've shut down my radio and brought it back up and all is good. Still a little noisy on 40M but 20M seems to be working great. While I'm at it, when should the BPF_TX and _RX be in or out?? I attached a test cable to the LPF ACC Control connector and those signals are different moving from 66.4 to 66.9.? In 66.4, BPF_RX was out in SSB mode and in when in CW mode.? In 66.9, it appears that BPF_RX is "in" in both modes.?
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Bill can comment further, but the BPF should be in the signal path in both RX and TX mode.?
In TX mode it cleans up the signal before it goes to the PA. This means that higher-order harmonics of the signal produced by the exciter -- copies of the signal at multiples of the transmit signal -- are filtered out and not amplified by the PA. These would be removed by the LPF anyway before they could hit the antenna, but removing them before the PA helps with signal quality because the PA isn't having to amplify signals at multiple bands simultaneously.
In RX mode the BPF keeps the other bands away from the input to the mixer. If you didn't have the BPF in place you would expect to get a higher noise level in the audio at best, and distortion from strong signals in other bands at worst.
On Wednesday, April 2nd, 2025 at 3:54 PM, epif18 via groups.io <epif18@...> wrote:
Well, I did some more troubleshooting and this is what I found:
I stuck some troubleshooting code at the beginning (first line) of loop().? Draw a line on the display.? Well, looked like setup never exited.? Stuck that code in various places in .ino and eventually found that swrSetup() was hanging up.? I have the SWR_AD7991 installed but not the transformer (shorted RF In to RFOut). I commented #define V12_LPF_SWR_AD7991 out.? Then I commented out swrSetup() and 66.9 ran!
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Looks like it's not in the latest code on github (KI3P/SDTVer066-9) that was updated 2 weeks ago. ?
I've shut down my radio and brought it back up and all is good.
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Still a little noisy on 40M but 20M seems to be working great.
?
While I'm at it, when should the BPF_TX and _RX be in or out?? I attached a test cable to the LPF ACC Control connector and those signals are different moving from 66.4 to 66.9.? In 66.4, BPF_RX was out in SSB mode and in when in CW mode.? In 66.9, it appears that BPF_RX is "in" in both modes.?
Thanks
Mark KU3O
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Re: T41 Transmit Calibration V12
That's right Dave -- you null the lower image if you're in a USB band, and vice versa
-------- Original Message -------- On 4/2/25 2:38 PM, D Solt via groups.io wrote: When doing the TX IQ calibration of the higher bands that use USB, do you null the lower image?
dave, n3ds
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Well, I did some more troubleshooting and this is what I found:
I stuck some troubleshooting code at the beginning (first line) of loop().? Draw a line on the display.? Well, looked like setup never exited.? Stuck that code in various places in .ino and eventually found that swrSetup() was hanging up.? I have the SWR_AD7991 installed but not the transformer (shorted RF In to RFOut). I commented #define V12_LPF_SWR_AD7991 out.? Then I commented out swrSetup() and 66.9 ran!
?
Looks like it's not in the latest code on github (KI3P/SDTVer066-9) that was updated 2 weeks ago. ?
I've shut down my radio and brought it back up and all is good.
?
Still a little noisy on 40M but 20M seems to be working great.
?
While I'm at it, when should the BPF_TX and _RX be in or out?? I attached a test cable to the LPF ACC Control connector and those signals are different moving from 66.4 to 66.9.? In 66.4, BPF_RX was out in SSB mode and in when in CW mode.? In 66.9, it appears that BPF_RX is "in" in both modes.?
Thanks
Mark KU3O
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Re: Oscillations on high bands
Yeah you can short C14 and C16 but C15 needs to be a 0.1uf¡?? I¡¯ll fix that on the Carrier board for the PIN DIODE TR switch¡ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C 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: Wednesday, April 2, 2025 1:28 PM
To: [email protected]
Subject: Re: [SoftwareControlledHamRadio] Oscillations on high bands? I solved my oscillation problem.? I did not populate the 1.8MHz HPF.? I placed shorts across the capacitors forgetting that the MASWSS0179TR RF Switch needs DC blocks.? I now have >65 dB isolation across the frequency range. I am running version 66.9.
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Re: T41 Transmit Calibration V12
When doing the TX IQ calibration of the higher bands that use USB, do you null the lower image?
dave, n3ds
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Re: Oscillations on high bands
I solved my oscillation problem.? I did not populate the 1.8MHz HPF.? I placed shorts across the capacitors forgetting that the MASWSS0179TR RF Switch needs DC blocks.? I now have >65 dB isolation across the frequency range.
I am running version 66.9.
dave, n3ds
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You have the compensation cap in place on the primary of T3? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C 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 Tim via groups.io
Sent: Monday, March 31, 2025 2:06 PM
To: [email protected]
Subject: [SoftwareControlledHamRadio] More testing on PA? I have Dr. Bills PA and a similar (same finals) from 60dbm shop. Both on 13V same 0dB sweep from SA. I attached the 60dBm Schematic for reference. Here is Dr. Bills with 0dB in
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Tnx Henning
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SA was not overdriven, I did the 60dBM plot first and did not want to change anything.
The low bands were 12W so exceeded scale. SA had a lot of headroom left, I had 40dB attenuator in line from PA to SA.
You were quick to? see that shows you know your instrumentation well.
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Tim W4YN?
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Although I didn't know Mike well he took the time one day to spend several hours on AnyDesk probing my Mac trying to resolve an issue with how WSJT-X interfaced with my Icom IC-7851. Mike was a fellow veteran and we spoke about our experiences while we worked. He shared his medical issues with me and I understood his concerns about his future but that didn't stop him from helping folks almost right up until the time he became a Silent Key. Most of us will never know how much he did for the hobby with his work mostly in the background. Thanks Mike and RIP.
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VR,
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Dino KL0S
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Re: boards and kits and stuff
Did you find it?
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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On Mar 30, 2025, at 8:46?PM, Glenn via groups.io <glennp@...> wrote:
? Bill Is there a. Link to sch etc for this little board.? I don't have any issues with my build and a 6inch cable but then again, not checked the? higher bands. Glenn?
'72 ISUZU BELLETT SPORT Sent from my Samsung Galaxy S21 FE Smartphone.
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jjpurdum
K9HZ