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Re: Transmitting noise

 

¿ªÔÆÌåÓý

That¡¯s not bad¡­ there is some low-level noise on the signal at about 400 hz and I wonder what that is?

?

?

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@...

?

?

From: [email protected] <[email protected]> On Behalf Of Oliver KI3P via groups.io
Sent: Saturday, April 5, 2025 9:44 AM
To: [email protected]
Subject: Re: [SoftwareControlledHamRadio] Transmitting noise

?

?

The frequency calibration of my HackRF One is a little bit off, but here's what the audio sounds like from my radio (see attached WAV file). I haven't done anything to try to improve the mic.

On Saturday, April 5th, 2025 at 10:32 AM, Oliver KI3P via groups.io <oliver@...> wrote:

If I connect a broadband power meter to the output of my radio I measure the following:

?

State

Power [dBm]

Calculated RMS Voltage [V]

Measurement configuration

PTT not pressed

-47

9.99E-04

No attenuation

PTT pressed, no sound

4

0.35

Added 40 dB of attenuation

PTT pressed, speaking

40

22.4

Added 60 dB of attenuation

?

So I get roughly similar numbers.

?

If I connect an oscilloscope across a 50 Ohm load connected to the antenna output I see the following waveform when I start PTT with no mic connected, SSB mode at 14.1 MHz. I don't see a signal that exponentially decays in 5 ms.

?

Untitled screenshot.png

?

If I press the PTT while whistling loudly, the waveform looks like this (note the change in vertical scale from 5 to 20V per division):

?

?

?

On Friday, April 4th, 2025 at 4:12 PM, D Solt via groups.io <davesolt@...> wrote:

I am getting about 50mv noise out of the 20W amp in SSB with PTT engaged; no mic plugged in.? I'm running version 66.9 and am all calibrated.? Additionally, when PTT is engaged there is a burst of signal (about500mv) that exponentially decays in 5ms.? The audio sounds pretty rough on my other radio, but wonder if that is because of such close proximity.? Amplitude is affected by MIC GAIN.? Any thoughts?

dave, n3ds

?

?


FW: [SoftwareControlledHamRadio] boards and kits and stuff

 

¿ªÔÆÌåÓý

John¡­ This is good work.?

?

I just ordered the parts for the Display Driver kits after I got good reports from 4 of the 5 kits I sent out for people to try.? The parts for the remainder of the Drivers should be here by Tuesday.? I¡¯ll send you one when the parts get here.

?

My goal is to generate a PCB type box to put over the display to keep the RFI down to a minimum.? If you can help me design those boxes for the % and 7 inch displays, I¡¯ll have some made and send you a couple to try out.? As you know, his makes a HUGE difference in the usable floor and weak signal reception/ sensitivity of the receiver.

?

Also interested in any help from the readers of this to get this right the first time.

?

?

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@...

?

?

From: [email protected] <[email protected]> On Behalf Of John V Lundberg via groups.io
Sent: Wednesday, March 19, 2025 1:52 PM
To: [email protected]
Subject: Re: [SoftwareControlledHamRadio] boards and kits and stuff

?

I am interested in getting a 3.3 V board to see if it will further improve the receive noise on 6M by reducing radiation from the cable between the Main and Display boards. I have an AI6YM chassis with V12 Main, RF, and Front Panel boards. I use a 5" display in a shielded enclosure which greatly improved the RX noise floor on 80M through 10M (see the attachment).

John W2TX


Re: SDTVer66.9 results

 

¿ªÔÆÌåÓý

What is coming out of the QSE after the BPF?? The PA will amplify pretty much everything from 1-150 MHz (at different gains).? If the input is not clean, the output won¡¯t be that clean.

?

?

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@...

?

?

From: [email protected] <[email protected]> On Behalf Of Robert Luken W3RDL via groups.io
Sent: Tuesday, March 25, 2025 4:51 PM
To: [email protected]
Subject: Re: [SoftwareControlledHamRadio] SDTVer66.9 results

?

Bill, I don't have any oscillations, but then I don't have a LPF or PA built yet. I lost over a week trying to get back to where I could compile a running version.?

I attached the spectrum of the 10m & 6m outputs from the RF board. The output on 6m is down significantly.

On 3/24/2025 12:08 AM, K9HZ via groups.io wrote:

Any oscillations on 10M or 6M?

?

?

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@...

?

?

From: [email protected] <[email protected]> On Behalf Of Robert Luken W3RDL via groups.io
Sent: Sunday, March 23, 2025 10:51 PM
To: [email protected]
Subject: [SoftwareControlledHamRadio] SDTVer66.9 results

?

After totally scrubbing and rebuilding the IDE and libraries, I can compile and run everything again. However Ver66.4 and 66.9 only run at 600MHz if TCXO is defined. They both freeze if compiled with 528MHz.

The Receive I&Q Cal worked quite well, except the button assignments don't agree with the directions.

Compiled with: Faster with LTO, 600 MHz, Dual Serial

SDTVer66.4
Memory Usage on Teensy 4.1:
? FLASH: code:308228, data:132408, headers:8892?? free for files:7676936
?? RAM1: variables:194528, code:284488, padding:10424?? free for local variables:34848
?? RAM2: variables:483744? free for malloc/new:40544

SDTVer66.9
Memory Usage on Teensy 4.1:
? FLASH: code:312196, data:132408, headers:9020?? free for files:7672840
?? RAM1: variables:194784, code:288584, padding:6328?? free for local variables:34592
?? RAM2: variables:483744? free for malloc/new:40544

--


73 Animated graphic flashing 73 in Morse code.

Bob W3RDL

?

Virus-free.

--

73 Animated graphic flashing 73 in Morse code.

Bob W3RDL


Re: RA8875 display problems with T4.x - a visual study

 

¿ªÔÆÌåÓý

The noise floor for the current V12 radio is better than -100 db as measured without the driver chip¡­ My V11 with the buffer chip is nominally -78 db.? That is ok for a test platform (toy level) but intolerable for a modern radio¡­ The new display driver board does not change that -100 db figure because it was designed specifically to buffer SPI signals (in that frequency range with softer on-off switching).

?

?

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@...

?

?

From: [email protected] <[email protected]> On Behalf Of Terrance Robertson, KN6ZDE via groups.io
Sent: Tuesday, March 25, 2025 4:08 PM
To: [email protected]
Subject: Re: [SoftwareControlledHamRadio] RA8875 display problems with T4.x - a visual study

?

On Tue, Mar 25, 2025 at 01:19 PM, K9HZ wrote:

but the noise from the SPI buffer chip brought the noise level in the receiver up to an intolerable level

I've been happy with my 4SQRP T41, but I don't have much experience with this.? What's considered an "intolerable" noise level for that radio?

?

Currently, my partially built v12 has a receiver noise floor 48 dB above my 4SQRP unit.? I have enough experience to know something is wrong with my v12 build.


Re: RA8875 display problems with T4.x - a visual study

 

¿ªÔÆÌåÓý

Have you got a block diagram of this/ signal flows.? Its something to contemplate vs. a FPGA and a Teensy.? I¡¯m formulating my next steps and want to get the next step absolutely perfect.

?

?

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@...

?

?

From: [email protected] <[email protected]> On Behalf Of Mark J Culross
Sent: Tuesday, March 25, 2025 3:01 PM
To: [email protected]
Subject: Re: [SoftwareControlledHamRadio] RA8875 display problems with T4.x - a visual study

?

Greg et al:

?

The TMPS previously had noise induced in the audio chain by the display interface when everything was managed by a single Teensy (touching the screen & changing onscreen objects caused a high-pitched whine in the audio...the audio was also interrupted/delayed by the same actions).? That's the primary reason why I split the functionality across two Teensy processors, as well as spreading/reducing the RAM consumption & spreading/reducing the processor load.? Now that the audio & display are on separate Teensy processors, there is absolutely no detectable noise in the generated audio stream & everything executes in real time, so problem(s) solved.

?

Mark J Culross

KD5RXT

?

?

On Tue, Mar 25, 2025 at 1:14 PM, Greg KF5N via groups.io

Mark's application may be tolerant of digital noise and the buffer part may be relevant only towards fixing the display robustness.? In other words he may not need to work a lot on EMI issues.

?

--

73 Greg KF5N


Re: Ver066_9_3_22_25

 

¿ªÔÆÌåÓý

May be a bad cable or on the wrong cable (remember¡­ there is WINE, WIRE1, and WIRE2¡­. Three channels for the I2C comms so you gotta be on the right cable.? See the development document on the github about the I2C assignments).

?

?

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@...

?

?

From: [email protected] <[email protected]> On Behalf Of epif18 via groups.io
Sent: Tuesday, March 25, 2025 10:15 AM
To: [email protected]
Subject: [SoftwareControlledHamRadio] Ver066_9_3_22_25

?

Hey yall',

I was running Ver66.9 and it seemed to address some of the issues I was having.? Calibrated FREQ and REC I/Q.? All good through several shutdowns and startups. Shut my radio down and brought it back up and now there is no spectrum, waterfall, audio.? Keypad and encoders don't work.? BIT passes.? For a while the SWR 7991 wasn't being picked up (failed), resoldered it and it still failed.? Then, on one restart, it magically passed. ?I reformatted the SD card, no luck. ?Re-extracted the .zip, recompiled and reloaded, no luck.? Weird! Thought MAIN may have failed, but I loaded Ver66.4 and that worked.?

Has anyone seen this?? SWR 7991 commented out.? RF 23017 is at 0x22, not 0x27.

Argh!

Thanks

Mark


Re: Transmitting noise

 

Thanks Oliver.? I'll redo the tests next week.
dave

On Sat, Apr 5, 2025 at 10:32?AM Oliver KI3P via <oliver=[email protected]> wrote:
If I connect a broadband power meter to the output of my radio I measure the following:

State Power [dBm] Calculated RMS Voltage [V] Measurement configuration
PTT not pressed -47 9.99E-04 No attenuation
PTT pressed, no sound 4 0.35 Added 40 dB of attenuation
PTT pressed, speaking 40 22.4 Added 60 dB of attenuation

So I get roughly similar numbers.

If I connect an oscilloscope across a 50 Ohm load connected to the antenna output I see the following waveform when I start PTT with no mic connected, SSB mode at 14.1 MHz. I don't see a signal that exponentially decays in 5 ms.

Untitled screenshot.png

If I press the PTT while whistling loudly, the waveform looks like this (note the change in vertical scale from 5 to 20V per division):

Untitled screenshot.png


On Friday, April 4th, 2025 at 4:12 PM, D Solt via <davesolt=[email protected]> wrote:
I am getting about 50mv noise out of the 20W amp in SSB with PTT engaged; no mic plugged in.? I'm running version 66.9 and am all calibrated.? Additionally, when PTT is engaged there is a burst of signal (about500mv) that exponentially decays in 5ms.? The audio sounds pretty rough on my other radio, but wonder if that is because of such close proximity.? Amplitude is affected by MIC GAIN.? Any thoughts?
dave, n3ds


Re: Transmitting noise

 


The frequency calibration of my HackRF One is a little bit off, but here's what the audio sounds like from my radio (see attached WAV file). I haven't done anything to try to improve the mic.
On Saturday, April 5th, 2025 at 10:32 AM, Oliver KI3P via groups.io <oliver@...> wrote:

If I connect a broadband power meter to the output of my radio I measure the following:

State Power [dBm] Calculated RMS Voltage [V] Measurement configuration
PTT not pressed -47 9.99E-04 No attenuation
PTT pressed, no sound 4 0.35 Added 40 dB of attenuation
PTT pressed, speaking 40 22.4 Added 60 dB of attenuation

So I get roughly similar numbers.

If I connect an oscilloscope across a 50 Ohm load connected to the antenna output I see the following waveform when I start PTT with no mic connected, SSB mode at 14.1 MHz. I don't see a signal that exponentially decays in 5 ms.

Untitled screenshot.png

If I press the PTT while whistling loudly, the waveform looks like this (note the change in vertical scale from 5 to 20V per division):

Untitled screenshot.png


On Friday, April 4th, 2025 at 4:12 PM, D Solt via groups.io <davesolt@...> wrote:
I am getting about 50mv noise out of the 20W amp in SSB with PTT engaged; no mic plugged in.? I'm running version 66.9 and am all calibrated.? Additionally, when PTT is engaged there is a burst of signal (about500mv) that exponentially decays in 5ms.? The audio sounds pretty rough on my other radio, but wonder if that is because of such close proximity.? Amplitude is affected by MIC GAIN.? Any thoughts?
dave, n3ds



Re: Transmitting noise

 

If I connect a broadband power meter to the output of my radio I measure the following:

State Power [dBm] Calculated RMS Voltage [V] Measurement configuration
PTT not pressed -47 9.99E-04 No attenuation
PTT pressed, no sound 4 0.35 Added 40 dB of attenuation
PTT pressed, speaking 40 22.4 Added 60 dB of attenuation

So I get roughly similar numbers.

If I connect an oscilloscope across a 50 Ohm load connected to the antenna output I see the following waveform when I start PTT with no mic connected, SSB mode at 14.1 MHz. I don't see a signal that exponentially decays in 5 ms.

Untitled screenshot.png

If I press the PTT while whistling loudly, the waveform looks like this (note the change in vertical scale from 5 to 20V per division):

Untitled screenshot.png


On Friday, April 4th, 2025 at 4:12 PM, D Solt via groups.io <davesolt@...> wrote:

I am getting about 50mv noise out of the 20W amp in SSB with PTT engaged; no mic plugged in.? I'm running version 66.9 and am all calibrated.? Additionally, when PTT is engaged there is a burst of signal (about500mv) that exponentially decays in 5ms.? The audio sounds pretty rough on my other radio, but wonder if that is because of such close proximity.? Amplitude is affected by MIC GAIN.? Any thoughts?
dave, n3ds


Reminder

 

¿ªÔÆÌåÓý

Just a reminder that I will ALWAYS send out an invoice for boards and kits you order from me.? Wait for the invoice.? NEVER send me money without an invoice because it messes up my accounting system and you will just get that money refunded.

?

?

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@...

?

?


Re: [AmateurRadioBuilders] Back in the Saddle

 

¿ªÔÆÌåÓý

The only think that has changed on this list is the RF board¡­ and that change was just to remove the divider circuit for the low-frequency operation that can now be done in software.? The previous board can be used by just not building out the divider circuits.? They are otherwise identical and no need to rush out and get the new boards.

?

?

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@...

?

?

From: [email protected] <[email protected]> On Behalf Of John Owens K1JO via groups.io
Sent: Saturday, April 5, 2025 8:10 AM
To: [email protected]
Subject: Re: [AmateurRadioBuilders] Back in the Saddle

?

Thanks Bill, I appreciate any advice.
I'm just wondering about getting the updated RF boards and any other new boards or kits that you have. Currently, I have 4 sets of the following:
LPF Filter 100W 11 Band 2024-02-03
LPF Control 100W 11 Band 2024-02-14

2 - BPF 2024-04-20 V012.6
2- RF 2024-04-08 V12.06
Front Panel K9HZ (After G0ORX0) V012.6 11/15/23
Switch Matrix K9HZ (After G0ORX0) V012.5 09/27/23
2nd Receiver Adapter X12.6 04/14/24
Teensy HAT Adapter V12.6 11/22/23

4 - Encoder Boards 3428224 AP11
TR Switch Carrier 2024/01/14
Tiny 85V with socket
20W PA Kit V2.01


Re: More testing on PA

 

¿ªÔÆÌåÓý

I have four of the PA kits built here and I get a gain fluctuation of +0.2/-0.8 from 1-54 Mhz inclusive after a little tuning of the capacitor across the T3 primary.? You might check to make sure you got the right numbers of turns on T1, T2, and T3¡­ More than one person has had trouble with that.

?

?

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@...

?

?

From: [email protected] <[email protected]> On Behalf Of Tim via groups.io
Sent: Thursday, April 3, 2025 7:46 PM
To: [email protected]
Subject: Re: [SoftwareControlledHamRadio] More testing on PA

?

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.

?

Just curious on how Paul got his so flat out to 50Mhz.

Tim?

?

?


Re: Updated (and final) Version of T41 book

 

Thanks, Todd...it's appreciated!

Jack, W8TEE

On Saturday, April 5, 2025 at 06:20:17 AM EDT, Todd W2TEF via groups.io <w2tef@...> wrote:


Thank you, Jack and Al, for this labor of love! This has been a monumental contribution to Amateur Radio!

73 de Todd W2TEF






--
Jack, W8TEE


Re: Updated (and final) Version of T41 book

 

Thank you, Jack and Al, for this labor of love! This has been a monumental contribution to Amateur Radio!

73 de Todd W2TEF


Transmitting noise

 

I am getting about 50mv noise out of the 20W amp in SSB with PTT engaged; no mic plugged in.? I'm running version 66.9 and am all calibrated.? Additionally, when PTT is engaged there is a burst of signal (about500mv) that exponentially decays in 5ms.? The audio sounds pretty rough on my other radio, but wonder if that is because of such close proximity.? Amplitude is affected by MIC GAIN.? Any thoughts?
dave, n3ds


Re: [AmateurRadioBuilders] Updated (and final) Version of T41 book

 

¿ªÔÆÌåÓý

Our booth at Hamvention is inside this year¡­ 4111 in building 4. ?You can buy the lasted and greatest T41 boards and kits along with everything else I sell there. ?Plus we will be advertising the contest station for rent. ??

My wife was tired of being out in the rain and the smell of the porto-pottys in the outfield. ?


Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton - J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com


email:??bill@...

?


On Apr 4, 2025, at 12:33?PM, Albert Peter via groups.io <albertfpeter@...> wrote:

?
Robert and everyone attending the Hamvention:
I will probably be at K9HZ's booth in one of the buildings on Friday and Saturday. I will have some signed T41 books available at that time. Get there early, since I will only have a limited number of books.
(Jack probably will not be there at Hamvention.)

Bill Schmidt will also has T41 V12 board set available .
Hope to see you there.
Al Peter
AC8GY

From: [email protected] <[email protected]> on behalf of Robert Luken W3RDL via groups.io <now.w3rdl@...>
Sent: Friday, April 4, 2025 12:18 PM
To: [email protected] <[email protected]>
Subject: Re: [AmateurRadioBuilders] Updated (and final) Version of T41 book
?

Jack, is there a way to get an autographed copy of Version 4, since I can't make it to the FDIM conference?

On 4/4/2025 10:53 AM, Jack, W8TEE via groups.io wrote:

All:

Al and I have just updated the 3rd edition T41 book. We moved the calibration info from Appendix C to its own chapter (20). The expanded instructions and new software make T41 calibration much easier. We have also updated the narrative in numerous places and have concentrated discussions on the V12.6 release where those changes are important.

Some of you are asking yourself: Do I need to buy this update. Truthfully, if you already own the 3rd edition, we would say no. Most of the important changes are discussed on the web site and photos and schematics are available there, too.

On the other hand, this is the last change we will be making to this book. Al and I have been at this for almost 7 years now and we're getting a little burned out. For that reason, we are turning this site over to Oliver King, KI3P, and Dr. Bill Schmidt, K9HZ. Al and I will continue to be active relative to the T41, but will leave the details to Oliver and Bill.

If you do want the final version of the book, its new cover looks like this:

The book is actually available now, but the Amazon ad will not reflect the new cover for about 10 more days. (If you order now, it will be the new version.) If you are attending the FDIM conference this May (coincides with Dayton Hamvention and the conference hotel is about 10 miles away), Al and I will be selling autographed copies on Thursday night (May 15th) at the conference hotel starting around 8PM. We have reduced the price of the autographed copies from $12,500 to $40...which is a deal and less than the Amazon price! If you have a previous copy of the book, bring it along and we will be happy to sign it.

This has been a fun project and we want to thanks the hundreds of people have contributed to its improvement over time. We hope that continues long after Al and I are gone.


72,

Jack Purdum, W8TEE

Al Peter, AC8GY



--
Jack, W8TEE
--

73 73cw.gif

Bob W3RDL


Virus-free.


Updated (and final) Version of T41 book

 

All:

Al and I have just updated the 3rd edition T41 book. We moved the calibration info from Appendix C to its own chapter (20). The expanded instructions and new software make T41 calibration much easier. We have also updated the narrative in numerous places and have concentrated discussions on the V12.6 release where those changes are important.

Some of you are asking yourself: Do I need to buy this update. Truthfully, if you already own the 3rd edition, we would say no. Most of the important changes are discussed on the web site and photos and schematics are available there, too.

On the other hand, this is the last change we will be making to this book. Al and I have been at this for almost 7 years now and we're getting a little burned out. For that reason, we are turning this site over to Oliver King, KI3P, and Dr. Bill Schmidt, K9HZ. Al and I will continue to be active relative to the T41, but will leave the details to Oliver and Bill.

If you do want the final version of the book, its new cover looks like this:

Inline image
The book is actually available now, but the Amazon ad will not reflect the new cover for about 10 more days. (If you order now, it will be the new version.) If you are attending the FDIM conference this May (coincides with Dayton Hamvention and the conference hotel is about 10 miles away), Al and I will be selling autographed copies on Thursday night (May 15th) at the conference hotel starting around 8PM. We have reduced the price of the autographed copies from $12,500 to $40...which is a deal and less than the Amazon price! If you have a previous copy of the book, bring it along and we will be happy to sign it.

This has been a fun project and we want to thanks the hundreds of people have contributed to its improvement over time. We hope that continues long after Al and I are gone.


72,

Jack Purdum, W8TEE

Al Peter, AC8GY



--
Jack, W8TEE


Re: Where can I purchase V12 pc boards for the T41-EP SDT?

 

¿ªÔÆÌåÓý

That would be me. ? Ill be home late tonight. ?Tell me what you are looking for exactly. ?


Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton - J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com


email:??bill@...

?


On Apr 4, 2025, at 9:55?AM, rkherod via groups.io <rkherod@...> wrote:

?
I am interested in purchasing the latest V12 blank pc boards for the T41-EP SDT.? Can anyone point me in the right direction to purchase these?
?
Thanks?


Where can I purchase V12 pc boards for the T41-EP SDT?

 

I am interested in purchasing the latest V12 blank pc boards for the T41-EP SDT.? Can anyone point me in the right direction to purchase these?
?
Thanks?


Re: More testing on PA

 

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.
?
Just curious on how Paul got his so flat out to 50Mhz.
Tim?
?
?