Re: T41 Transmitting (noise in ssb)
Ok, I floated the ground to QSE. I used a 3 pin dupont on a short TRS 1/8 and did not connect the shield to the center pin, although the shield runs the length of the wire, just hangs at the 3 pin connection that Line out R, L comes off the Teensy audio board.?
And now the audio spurs are gone. The ratty audio that tracks with mic gain remains, but the 60, 156, etc on either side of the carrier are now not there.?
That leads credence to my theory that there was a ground loop.?
Im going to try minimal mic gain and an external mic preamp to see if that helps the audio.?
Larry
KB3CUF
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The designated quiet zone near by sugar grove naval radio station maybe. ?And that anechoic chamber i built in the garage once. ?
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 Sep 5, 2023, at 7:05 PM, Albert Peter <albertfpeter@...> wrote:
?I know that Greg, however, I wanted to show the 0.25uV signal in a realistic display. By the way do you know any location where a signal that low won't be buried in the environmental noise?
Al
AC8GY
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Who wants that?
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 Sep 5, 2023, at 7:43 PM, Dave W6OQ via groups.io <david.hostetler@...> wrote:
?"By the way do you know any location where a signal that low won't be buried in the environmental noise?"
How about an inefficient antenna?
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"By the way do you know any location where a signal that low won't be buried in the environmental noise?"
How about an inefficient antenna?
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A receiver located on the far side of the Moon?
--
73 Greg KF5N
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I know that Greg, however, I wanted to show the 0.25uV signal in a realistic display. By the way do you know any location where a signal that low won't be buried in the environmental noise?
Al
AC8GY
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Here is a micro SD card extender that works great to put the SD card somewhere else besides int the Teensy!
? I used this one last time (V011) but don¡¯t recommend it because it¡¯s hard to mount:
? ? ? 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 K9HZ Sent: Wednesday, August 30, 2023 9:10 AM To: [email protected]Subject: Re: [SoftwareControlledHamRadio] 4SQRP T41 kit ? Oh! ?Ill post a link to the remote SD card dongle i found on amazon¡ thanks for the reminder. ? ? Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ?
On Aug 30, 2023, at 8:56 AM, jjpurdum via groups.io <jjpurdum@...> wrote:
? I am assembling the 4SQRP version of the T41. Yesterday, Al and I connect my PS, main board, encoders, and switch matrix to a cannibalized T41. After Al isolated a cold solder joint on the Main board, the radio came to life. It is taking me much longer than expected because I am adding narrative and photos to the assembly manual as I go. I hope to finish the receiver board today. BTW, the small (1.25") dedicated CPU fan is so quiet you cannot hear it. But the fan pushed such a small volume of air, you need to old it to your cheek to feel which way to aim the fan. By hot gluing a mini magnet (e.g., Amazon B0B3WMVHPL) on the base of the fan and one on the PCB, you can easily rotate the fan if you put it in wrong. Also, you can swing it out of the way, which gives you easier access to the micro SD card. Just make sure you orient them so they attract, not repel.
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Re: T41 Transmitting (noise in ssb)
Not exactly the right impedance, but would be useful to make a point...
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: www.VillaGrandPiton.com
Moderator: North American QRO Group at Groups.IO.
Moderator: Amateur Radio Builders Group at Groups.IO.
email: bill@...
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-----Original Message----- From: [email protected] < [email protected]> On Behalf Of jerry-KF6VB Sent: Tuesday, September 5, 2023 11:25 AM To: [email protected]Cc: Larry Acklin <acklin@...> Subject: Re: [SoftwareControlledHamRadio] T41 Transmitting (noise in ssb) On 2023-09-05 09:16, Larry Acklin wrote: I¡¯m trying a different scheme for connecting, need 1/8 TRS jacks which
should arrive today.
Basically different ground schemes and/or floating one end. *** I wonder if audio transformers could help? I have a box of postage-stamp size 600-600 ohm transformers here... - Jerry, KF6VB
Larry
KB3CUF
On Tue, Sep 5, 2023 at 11:45 AM K9HZ <bill@...> wrote:
Audio? Same to the RF board.
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: 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 Greg KF5N
SENT: Tuesday, September 5, 2023 6:52 AM
TO: [email protected]
SUBJECT: Re: [SoftwareControlledHamRadio] T41 Transmitting (noise in
ssb)
I've wondered what will happen with a direct connection from the
Audio Hat to the QSE.
--
73 Greg KF5N
Links:
------
[1]
[2] /g/SoftwareControlledHamRadio/message/24107
[3] /mt/101160969/243852
[4] /g/SoftwareControlledHamRadio/post
[5] /g/SoftwareControlledHamRadio/editsub/243852
[6]
/g/SoftwareControlledHamRadio/leave/10484476/243852/1
943518115/xyzzy
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Re: T41 Transmitting (noise in ssb)
Ok good! ? ? 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 Larry Acklin Sent: Tuesday, September 5, 2023 11:16 AM To: [email protected]Subject: Re: [SoftwareControlledHamRadio] T41 Transmitting (noise in ssb) ? I¡¯m trying a different scheme for connecting, need 1/8 TRS jacks which should arrive today.? Basically different ground schemes and/or floating one end.? ? On Tue, Sep 5, 2023 at 11:45 AM K9HZ <bill@...> wrote: Audio?? Same to the RF board. ? ? 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@... ? ? ? I've wondered what will happen with a direct connection from the Audio Hat to the QSE.
--
73 Greg KF5N
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Re: T41 Transmitting (noise in ssb)
On 2023-09-05 09:16, Larry Acklin wrote: I¡¯m trying a different scheme for connecting, need 1/8 TRS jacks
which should arrive today.
Basically different ground schemes and/or floating one end. *** I wonder if audio transformers could help? I have a box of postage-stamp size 600-600 ohm transformers here... - Jerry, KF6VB Larry
KB3CUF
On Tue, Sep 5, 2023 at 11:45 AM K9HZ <bill@...> wrote:
Audio? Same to the RF board.
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: 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 Greg KF5N
SENT: Tuesday, September 5, 2023 6:52 AM
TO: [email protected]
SUBJECT: Re: [SoftwareControlledHamRadio] T41 Transmitting (noise in
ssb)
I've wondered what will happen with a direct connection from the
Audio Hat to the QSE.
--
73 Greg KF5N Links:
------
[1]
[2] /g/SoftwareControlledHamRadio/message/24107
[3] /mt/101160969/243852
[4] /g/SoftwareControlledHamRadio/post
[5] /g/SoftwareControlledHamRadio/editsub/243852
[6]
/g/SoftwareControlledHamRadio/leave/10484476/243852/1943518115/xyzzy
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Re: T41 Transmitting (noise in ssb)
I¡¯m trying a different scheme for connecting, need 1/8 TRS jacks which should arrive today.?
Basically different ground schemes and/or floating one end.?
Larry KB3CUF?
On Tue, Sep 5, 2023 at 11:45 AM K9HZ < bill@...> wrote: Audio?? Same to the RF board. ? ? 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@... ? ? ? I've wondered what will happen with a direct connection from the Audio Hat to the QSE.
--
73 Greg KF5N
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Yep the insertion losses will disappear with the Minicircuits devices. ? Yeah-buddy!? This is looking like one hot receiver now!? Wait until the other groups hear of this! ? ? 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 Albert Peter Sent: Tuesday, September 5, 2023 7:29 AM To: [email protected]Subject: Re: [SoftwareControlledHamRadio] T41 V12 Boards ? I have done a bit more testing of the V12.2 boards, specifically on the receive side.?
First i attempted to characterize the sensitivity of the V12.2 unit. The first plot is a 10KHz wide spectrum of the audio output with 2.5uV input on the 40M band. Input was from a Siglent SDG 2122x signal generator through a 60dB 50ohm attenuator, yielding 2.5uV at the input to the T41. This is shown for reference. The next plot is the same presentation, but with 0.25uV input. As I mentioned on the last post on this topic, my testing environment is not particularly low noise, however the 1KHz tone thorough the T41 speaker was quite audible and well above the noise. The next figure is a screen shot of the T41 with the 0.25uV input. The T41 readout shows approximately S1 on the meter and an input value of -121dBm, consistent with 0.25 uV input. Note the lack of any indication of noise on the T41 spectrum display.?
Al AC8GY
Spectrum 2.5uV input.
!0KHz spectrum 0.25u V
Screen shot 0.25uV
Finally,
The last plot shows the T41 response to a 50uV input from 3.5MHz to 100MHz, with and w/o the PL filters. There is some insertion loss through the current LP filters at 40 and 80M. The lower sensitivity at each end of the spectrum is probably because of the toroid input transformer.? I will try a Minicircuits transformer next.
T41 frequency response 3.5 to 100MHz
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Re: T41 Transmitting (noise in ssb)
Audio?? Same to the RF board. ? ? 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 Greg KF5N Sent: Tuesday, September 5, 2023 6:52 AM To: [email protected]Subject: Re: [SoftwareControlledHamRadio] T41 Transmitting (noise in ssb) ? I've wondered what will happen with a direct connection from the Audio Hat to the QSE.
--
73 Greg KF5N
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Re: A competitor ... ... ... or an ally?
Not really a competitor as it is nowhere as powerful and way more smaller...
Nevertheless, it could become an ally if some bright spark were to implement the Scamp protocol on the T41 !
73,
Yannig - F4IUJ
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Hi Al, you can see the noise floor if you boost the "pixel above axis" feature.? Use button 12 and the adjustment encoder.? The offset is saved for each band.
--
73 Greg KF5N
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Re: T41 Transmitting (noise in ssb)
I've wondered what will happen with a direct connection from the Audio Hat to the QSE.
--
73 Greg KF5N
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Re: T41 Transmitting (noise in ssb)
Another data point.?
The mic gain directly affects the ¡°hum¡± interference. Even without a microphone plugged in, keying PTT in SSB mode can vary from clean -40 gain, to noisy at -10, with the interference as well. I¡¯m suspecting a ground loop.?
The schematic shows mic gnd on the teensy audio board tied to the sleeve (common) on both the mic and SQE jacks, but they have grounds to the Vdd ground plane as well, and the QSE schematic explicitly shows the input I/Q jack sleeve tied to ground.?
The Codec chip on the Teensy is presented with the recommended grounding being a star topology, with a single point near the Teensy to tie back to audio ground. The mic gnd seems the logical point.?
Larry
KB3CUF
?
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A competitor ... ... ... or an ally?
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Best now to start at the output and trace it back to the main board. ?I have a funny feeling about this problem. ?Like a bad part. ?
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 Sep 3, 2023, at 2:22 PM, jerry-KF6VB <jerry@...> wrote:
? On 2023-09-03 10:57, Larry Acklin wrote:https://www.learningelectronics.net/circuits/voice-bandwidth-filter_17.html
Little more work but proven.
*** Looks like the actual high pass filter is a pair of 39nF capacitors, a 10Kresistor and a 20K resistor. ?The op-amps are just unity-gain buffers. ?I tried hooking the cable from the QSE audio input to my scope...saw nothing.Interestingly, with the QSE input unconnected, I get a lot MORE NOISE when I hittransmit. ?The noise goes down to almost nothing if I short out the ends of the cable.If I unplug and plug the QSE audio cable, the noise goes up and down. ?Much more withthe cable unplugged. ?I think the noise is being created inside the QSE. ???????????????- Jerry
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K9HZ