Bill, ? The switching function could be managed by an add-on function to a common S11 (mag + phase) complex impedance analyzer.? What’s missing from portable S11 analyzers is a built-in “TLW” matching function.? Once the R+X value is known, TLW computes the exact L/C value combination in several tuner choices (e.g., CLC T, low-pass L, high-pass L and Pi). ?So, taking the S11 analyzer one step further, it would be possible to design a digital output that either switches L/C components, or allows for servo indexing. ? Paul, W9AC ?
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Hi Bill,
That would be an excellent project to build given the assumed faster tuning speed and your estimated low cost. It would prove very popular I am sure.
Glenn
vk3pe
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Rather interesting….. K3BO ? Sent from for Windows ?
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From: N2MSSent: Wednesday, November 8, 2023 7:48 PM To: [email protected]Subject: Re: [AmateurRadioBuilders] Tuner interests ? Bill,
I'll be looking forward to see the design...
Mike N2MS On 11/08/2023 7:42 PM EST K9HZ <bill@...> wrote:
Most of the commercial antenna tuners for hams (MFJ, Elecraft, LDG, etc.) are built with fixed components (fixed caps and coils) in a series L parallel C (either side of the L to ground)… and an SWR bridge is part of the thing that reads power and SWR. Then tuner… when requested… starts at the beginning (typically with no coil and no capacitor) and starts trying all of the combinations to get to a low SWR. If all you measure is SWR that’s all the information you have… find a minimum SWR… and there is no relationship between the solution and the minimum SWR other than… since you are using the “L network” type of tuner… a smith chart would tell you that there is only one solution… so guess away. There can be something like 256*256 different guesses to get to a solution, and NO a prior guess does not give you any information on what the next guess should be. Typically these bridges can just be transformers and diodes to generate a voltage that is logarithmically related to SWR. Some more advanced ones will use two AD8307 devices (Log amps) instead of the diodes… and they can work pretty well… but the tuning is still slow.
But there is a better way. The Intelligent antenna tuners work differently… they actually measure phase and magnitude of load transmission… So why is this so important. Well (and this is all in Sabins book…) if you know where the load is on a smith chart… then you know EXACTLY what you need (what transform) to do to get to 50 ohms real and minimize the non-real parts. Right? So if you measured the REAL part (magnitude different than 50 ohms) at 100 ohms… and the non-real parts at -300j… you instantly know to add inductance to bring the 100 0hms to 50 ohms… and then add capacitance to move the -300j to zero (and you can see this on the smith chart). WOW! Smart. So how do you measure MAG and Phase? Well……. there’s this part… AD8302… It’s in your LP-100A watt meter. It generates Mag and Phase info from a bridge (look at your LP-100A schematic). ALL OF THE MILITARY tuners do this The 601 and the Harris that you have all do this (granted doesn’t use a AD8302 to do it, but rather a different type of bridge).
So I have designed and prototyped the tuner for a very nice small 100W tuner that is generic to work with any radio. It uses an Arduino as smarts to do the tuning and a bunch of small latching relays to keep the power consumption low for QRP radios. It works using the stupid method of tuning above but I want to switch to a smarter tuning algorithm using the phase and mag. That’s why I want to completely understand the coupler design… so I can get the thing right for the AD8302. This little tuner of mine costs about $35 to build.
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
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I talked to Goody, K3NG about this to add to his little mini tuner.? He was interested. ? The Harris RF-601 military works this very same way… but it’s all done analog (all op-amp stuff). ? ? 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 N2MS Sent: Wednesday, November 8, 2023 6:48 PM To: [email protected]Subject: Re: [AmateurRadioBuilders] Tuner interests ? Bill,
I'll be looking forward to see the design...
Mike N2MS On 11/08/2023 7:42 PM EST K9HZ <bill@...> wrote:
Most of the commercial antenna tuners for hams (MFJ, Elecraft, LDG, etc.) are built with fixed components (fixed caps and coils) in a series L parallel C (either side of the L to ground)… and an SWR bridge is part of the thing that reads power and SWR. Then tuner… when requested… starts at the beginning (typically with no coil and no capacitor) and starts trying all of the combinations to get to a low SWR. If all you measure is SWR that’s all the information you have… find a minimum SWR… and there is no relationship between the solution and the minimum SWR other than… since you are using the “L network” type of tuner… a smith chart would tell you that there is only one solution… so guess away. There can be something like 256*256 different guesses to get to a solution, and NO a prior guess does not give you any information on what the next guess should be. Typically these bridges can just be transformers and diodes to generate a voltage that is logarithmically related to SWR. Some more advanced ones will use two AD8307 devices (Log amps) instead of the diodes… and they can work pretty well… but the tuning is still slow.
But there is a better way. The Intelligent antenna tuners work differently… they actually measure phase and magnitude of load transmission… So why is this so important. Well (and this is all in Sabins book…) if you know where the load is on a smith chart… then you know EXACTLY what you need (what transform) to do to get to 50 ohms real and minimize the non-real parts. Right? So if you measured the REAL part (magnitude different than 50 ohms) at 100 ohms… and the non-real parts at -300j… you instantly know to add inductance to bring the 100 0hms to 50 ohms… and then add capacitance to move the -300j to zero (and you can see this on the smith chart). WOW! Smart. So how do you measure MAG and Phase? Well…….. there’s this part… AD8302… It’s in your LP-100A watt meter. It generates Mag and Phase info from a bridge (look at your LP-100A schematic). ALL OF THE MILITARY tuners do this The 601 and the Harris that you have all do this (granted doesn’t use a AD8302 to do it, but rather a different type of bridge).
So I have designed and prototyped the tuner for a very nice small 100W tuner that is generic to work with any radio. It uses an Arduino as smarts to do the tuning and a bunch of small latching relays to keep the power consumption low for QRP radios. It works using the stupid method of tuning above but I want to switch to a smarter tuning algorithm using the phase and mag. That’s why I want to completely understand the coupler design… so I can get the thing right for the AD8302. This little tuner of mine costs about $35 to build.
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
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Bill,
I'll be looking forward to see the design...
Mike N2MS
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On 11/08/2023 7:42 PM EST K9HZ <bill@...> wrote:
Most of the commercial antenna tuners for hams (MFJ, Elecraft, LDG, etc.) are built with fixed components (fixed caps and coils) in a series L parallel C (either side of the L to ground)… and an SWR bridge is part of the thing that reads power and SWR. Then tuner… when requested… starts at the beginning (typically with no coil and no capacitor) and starts trying all of the combinations to get to a low SWR. If all you measure is SWR that’s all the information you have… find a minimum SWR… and there is no relationship between the solution and the minimum SWR other than… since you are using the “L network” type of tuner… a smith chart would tell you that there is only one solution… so guess away. There can be something like 256*256 different guesses to get to a solution, and NO a prior guess does not give you any information on what the next guess should be. Typically these bridges can just be transformers and diodes to generate a voltage that is logarithmically related to SWR. Some more advanced ones will use two AD8307 devices (Log amps) instead of the diodes… and they can work pretty well… but the tuning is still slow.
But there is a better way. The Intelligent antenna tuners work differently… they actually measure phase and magnitude of load transmission… So why is this so important. Well (and this is all in Sabins book…) if you know where the load is on a smith chart… then you know EXACTLY what you need (what transform) to do to get to 50 ohms real and minimize the non-real parts. Right? So if you measured the REAL part (magnitude different than 50 ohms) at 100 ohms… and the non-real parts at -300j… you instantly know to add inductance to bring the 100 0hms to 50 ohms… and then add capacitance to move the -300j to zero (and you can see this on the smith chart). WOW! Smart. So how do you measure MAG and Phase? Well…….. there’s this part… AD8302… It’s in your LP-100A watt meter. It generates Mag and Phase info from a bridge (look at your LP-100A schematic). ALL OF THE MILITARY tuners do this The 601 and the Harris that you have all do this (granted doesn’t use a AD8302 to do it, but rather a different type of bridge).
So I have designed and prototyped the tuner for a very nice small 100W tuner that is generic to work with any radio. It uses an Arduino as smarts to do the tuning and a bunch of small latching relays to keep the power consumption low for QRP radios. It works using the stupid method of tuning above but I want to switch to a smarter tuning algorithm using the phase and mag. That’s why I want to completely understand the coupler design… so I can get the thing right for the AD8302. This little tuner of mine costs about $35 to build.
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
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Most of the commercial antenna tuners for hams (MFJ, Elecraft, LDG, etc.) are built with fixed components (fixed caps and coils) in a series L parallel C (either side of the L to ground)… and an SWR bridge is part of the thing that reads power and SWR.? Then tuner… when requested… starts at the beginning (typically with no coil and no capacitor) and starts trying all of the combinations to get to a low SWR.? If all you measure is SWR that’s all the information you have… find a minimum SWR… and there is no relationship between the solution and the minimum SWR other than… since you are using the “L network” type of tuner… a smith chart would tell you that there is only one solution… so guess away.? There can be something like 256*256 different guesses to get to a solution, and NO a prior guess does not give you any information on what the next guess should be.? Typically these bridges can just be transformers and diodes to generate a voltage that is logarithmically related to SWR.? Some more advanced ones will use two AD8307 devices (Log amps) instead of the diodes… and they can work pretty well… but the tuning is still slow. ? But there is a better way.? The Intelligent antenna tuners work differently… they actually measure phase and magnitude of load transmission…? So why is this so important.? Well (and this is all in Sabins book…) if you know where the load is on a smith chart… then you know EXACTLY what you need (what transform) to do to get to 50 ohms real and minimize the non-real parts. ?Right?? So if you measured the REAL part (magnitude different than 50 ohms) at 100 ohms… and the non-real parts at -300j… you instantly know to add inductance to bring the 100 0hms to 50 ohms… and then add capacitance to move the -300j to zero (and you can see this on the smith chart).? WOW! Smart.? So how do you measure MAG and Phase?? Well……..? there’s this part… AD8302… It’s in your LP-100A watt meter.? It generates Mag and Phase info from a bridge (look at your LP-100A schematic).? ALL OF THE MILITARY tuners do this? The 601 and the Harris that you have all do this (granted doesn’t use a AD8302 to do it, but rather a different type of bridge). ? So I have designed and prototyped the tuner for a very nice small 100W tuner that is generic to work with any radio.? It uses an Arduino as smarts to do the tuning and a bunch of small latching relays to keep the power consumption low for QRP radios.? It works using the stupid method of tuning above but I want to switch to a smarter tuning algorithm using the phase and mag.? That’s why I want to completely understand the coupler design… so I can get the thing right for the AD8302.? This little tuner of mine costs about $35 to build. ? ? 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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Re: FW: [Elecraft] HI CUR warning on K3
Well I bet you guys have more experience than we do, but Alachua County ARES(R) has been using a 270-foot off center fed dipole on multiple bands for several years with up to 600 watts.? ? We also use them on summer Field Day.? ? ?
In order to reduce common?mode currents, we do these things: a)? use a CURRENT BALUN instead of a voltage balun.? ? ?We build our own 4:1 Guannella?type current baluns. b)? Add a 1:1 current choke type balun near the transmitter.? ? We hand construct THOSE also.
(Yes, I know, these are more properly called UN-UNs, but we all know what we re talking about).??
Using these techniques we are very?successful with both voice and digital techniques for several years.? ? Hope that helps!
Gordon KX4Z
On Wed, Nov 8, 2023 at 2:59?PM K9HZ < bill@...> wrote: I could not have put this better but was afraid to say it because sooooo
many people have these silly antennas.
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@...
-----Original Message-----
From: elecraft-bounces@... <elecraft-bounces@...> On
Behalf Of Jim Brown
Sent: Wednesday, November 8, 2023 1:55 PM
To: elecraft@...
Subject: Re: [Elecraft] HI CUR warning on K3
On 11/8/2023 8:21 AM, Pete Smith N4ZR wrote:
I've fairly well established that the problem is not at the antenna,
but arising somewhere in the grounding/RFI protection in my station,
since it occurs only on one band and (more importantly) because it
stopped totally after I re-tightened all the connections in my
grounding system yesterday That can certainly be a major cause of problems with RF in the shack.
The Carolina Windom incorporates a line isolator 22 feet down from the
feedpoint, but technical questions have been raised about exactly what
you describe, and I'm not technical enough either to question the
analysis or to experimentally measure the common mode current on the
feedline.
ALL off-center-fed antennas are a train wreck for RF in the shack, and for
blowing "line isolators" and chokes. This is because their strong imbalance
puts huge common mode current on the feedline. They are a very bad idea,
especially if running high power. Anything done to try to "fix" them is
putting lipstick on a pig.
73, Jim K9YC
______________________________________________________________
Elecraft mailing list
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Help:
Post: mailto:Elecraft@...
This list hosted by:
Please help support this email list: Message
delivered to bill@...
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FW: [Elecraft] HI CUR warning on K3
I could not have put this better but was afraid to say it because sooooo
many people have these silly antennas.
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
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: elecraft-bounces@... <elecraft-bounces@...> On Behalf Of Jim Brown Sent: Wednesday, November 8, 2023 1:55 PM To: elecraft@... Subject: Re: [Elecraft] HI CUR warning on K3 On 11/8/2023 8:21 AM, Pete Smith N4ZR wrote: I've fairly well established that the problem is not at the antenna,
but arising somewhere in the grounding/RFI protection in my station,
since it occurs only on one band and (more importantly) because it
stopped totally after I re-tightened all the connections in my
grounding system yesterday That can certainly be a major cause of problems with RF in the shack.
The Carolina Windom incorporates a line isolator 22 feet down from the
feedpoint, but technical questions have been raised about exactly what
you describe, and I'm not technical enough either to question the
analysis or to experimentally measure the common mode current on the
feedline.
ALL off-center-fed antennas are a train wreck for RF in the shack, and for blowing "line isolators" and chokes. This is because their strong imbalance puts huge common mode current on the feedline. They are a very bad idea, especially if running high power. Anything done to try to "fix" them is putting lipstick on a pig. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: Help: Post: mailto:Elecraft@... This list hosted by: Please help support this email list: Message delivered to bill@...
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File /K9HZ I2C 64 dB Digital RF Attenuator Module/Using a PE4312 to replace a PE4302.pdf uploaded
#file-notice
The following files and folders have been uploaded to the Files area of the [email protected] group.
By: K9HZ <bill@...>
Description:
What to keep in mind if you use PE4312 attenuator chips in place of PE4302 chips.
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Re: Digital RF Attenuator - PE4302 and PE4312
I uploaded a file that contains this advice… ? ? 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 Rod Gatehouse Sent: Saturday, October 21, 2023 9:54 AM To: [email protected]Subject: [AmateurRadioBuilders] Digital RF Attenuator - PE4302 and PE4312 ? Bill,
I use the PE4312 to control the TX Drive in my 2022 SDR Transceiver. The implementation was per the , including the 10K resistors in the C16 and Data lines: "A 10 kΩ resistor on the inputs to pin 1 and 3 (see
Figure 26) will eliminate package resonance between the RF input pin and the two digital inputs." I operate the PE4312 in direct parallel programming mode similar to your 64-dB RF Attenuator Board. The performance was erratic and I couldn't always achieve maximum attenuation.
In the course of researching this problem, I came across . The application note is titled "Replacing PE4302 with PE4312" and includes the following statements: - The Peregrine PE4312 is a pin-compatible upgraded version of the PE4302 with higher linearity, improved attenuation accuracy and faster switching speed. Although it was designed to be pin-for-pin compatible with PE4302 there are some subtle differences that should be considered when using PE4312 as a direct replacement.
- The PE4302 application circuit contained two resistors in the C16 and DATA lines....The PE4312 does not need resistors on the C16 or the DATA line and it is preferable to remove them or reduce the values so the logic threshold levels are met.
The second point above from the Application Note is in direct contradiction with the PE4312 Datasheet. Replacing the 10K Ohm resistors with 100 Ohm resistors solved my problem.
The need for the 10K Ohm resistors with the PE4312 was touched on briefly in an older thread, however, it appears leaving them in with the PE4312 may lead to erratic behavior. Anyone substituting PE4312 for PE4302 in your
64-dB RF Attenuator Board should be aware of this.
73,
Rod, AD5GH
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I will release more on this project this coming week… ? ? 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 John Eickwort via groups.io Sent: Friday, November 3, 2023 9:18 AM To: [email protected]Subject: [AmateurRadioBuilders] 100W PA ? Hi all, havent seen any talk lately. Just wondering how it was going with the 100watt amp kit/testing?
? Regards
?73, ?John ?KE2AMP
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Re: [SoftwareControlledHamRadio] T41 Who needs Version 12 ?
I’m replying to the note attached below (attached for context)… ? Here’s where I am with respect to the T41 Project.? I just returned to the USA (last night after midnight) after two weeks at my contest station J68HZ in the Caribbean after participating in CQWW SSB last weekend.? A lot went on and I won’t take up space here for it, but I will say that it was the first time we broke 10-million points. ? As for the T41 project… I have been working with Al on refining the final set of V012 boards.? So far I have completed the “MAIN” board except for finishing the prototyping of the start-up/shut-down circuit that should be completed this weekend.? As a note here, I have added some functions that Al and I talked about that are “build as you need”. ?For example, this shut-down circuit.. it you build it, you get a cool orderly shutdown of the radio, running a shutdown routine in the Teensy before the power to the radio goes off.? If you don’t care about this, don’t build it and the original T41 circuit (no extra parts) works just fine.? I should have this board completed by Monday. ? The new RF board is still being worked.? I have a laundry list of updates from the beta board to complete.? The CW circuit is still being worked, and I added attenuators to the input to the receive signal and to the transmit signal for “proper” power control (using the D/A to do this is problematic).? I also added pads for a TXCO, switches for auto calibration, and am currently working to add a cheap pre-scalar to give full RX/TX capability from about 250Kc to 100Mhz.? Again, build what you want.? The base case works from 80M-6M. ?I’ll spend all of next week on this to finish it up. ? I have the 20W module kits and boards back in stock now so that can ship immediately. ? The 100 watt module is completed and I have some proto boards available.? HOWEVER, There is one upgrade I’m thinking about before I release it…? I can do on-board bias control from various modes for sub class-C through class-A operation basis the mode the radio is selected.? I may make this an option (build it as you need it) but have not settled on that yet… would love input from the community on this topic.? However, I’ve had one of the prototype modules sitting here transmitting for three weeks at 52MHz into a dummy load and its barely warm.? ? Front panel boards (using the mux chips rather than the voltage ladder) are here and in stock.? Encoder boards are in stock too. ? Al was working on a BPF and I need to circle back to see where he is.? I also have a full range BPF (to cover the full range capabilities of the radio) schematic done, working on board layout.? ? All other boards not mentioned are in production. ? Hope this helps.? Send me private emails with specific comments or requests. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZF ? 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 Peter McCracken EI3JCB Sent: Friday, November 3, 2023 8:02 AM To: [email protected]Subject: Re: [SoftwareControlledHamRadio] T41 Who needs Version 12 ? ? Hi Jack / Bill, Do we have a more solid understanding of when the v12 boards will be available, are we looking at 1 week, 1 month or possibly longer ? ?
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Ah, very nice - I hope I manage to have a QSO with you then ;-)
73 de HB9HEI
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Thanks for the update Bill.?
Good luck in contest.?
73, John KE2AMP
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Just posted
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 Nov 3, 2023, at 10:18 AM, John Eickwort via groups.io <jgike@...> wrote:
?Hi all, havent seen any talk lately. Just wondering how it was going with the 100watt amp kit/testing?
? Regards
?73, ?John ?KE2AMP
|
No i have an alternative life as a contester and to that end have been at my contest station J68HZ in the Caribbean for a couple of weeks getting it in shape for CQWW. ?Ill give an update when i get home soon. ?
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 Nov 3, 2023, at 10:31 AM, Lou, KI5FTY <lscalpati@...> wrote:
? interested also in the progress of the control board for the amplifiers. Hi all, havent seen any talk lately. Just wondering how it was going with the 100watt amp kit/testing?
? Regards
?73, ?John ?KE2AMP
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interested also in the progress of the control board for the amplifiers.
Hi all, havent seen any talk lately. Just wondering how it was going with the 100watt amp kit/testing?
? Regards
?73, ?John ?KE2AMP
|
Hi all, havent seen any talk lately. Just wondering how it was going with the 100watt amp kit/testing?
? Regards
?73, ?John ?KE2AMP
|
Digital RF Attenuator - PE4302 and PE4312
Bill, I use the PE4312 to control the TX Drive in my 2022 SDR Transceiver. The implementation was per the , including the 10K resistors in the C16 and Data lines: "A 10 kΩ resistor on the inputs to pin 1 and 3 (see Figure 26) will eliminate package resonance between the RF input pin and the two digital inputs." I operate the PE4312 in direct parallel programming mode similar to your 64-dB RF Attenuator Board. The performance was erratic and I couldn't always achieve maximum attenuation. In the course of researching this problem, I came across . The application note is titled " Replacing PE4302 with PE4312" and includes the following statements:
- The Peregrine PE4312 is a pin-compatible upgraded version of the PE4302 with higher linearity, improved attenuation accuracy and faster switching speed. Although it was designed to be pin-for-pin compatible with PE4302 there are some subtle differences that should be considered when using PE4312 as a direct replacement.
- The PE4302 application circuit contained two resistors in the C16 and DATA lines....The PE4312 does not need resistors on the C16 or the DATA line and it is preferable to remove them or reduce the values so the logic threshold levels are met.
The second point above from the Application Note is in direct contradiction with the PE4312 Datasheet. Replacing the 10K Ohm resistors with 100 Ohm resistors solved my problem. The need for the 10K Ohm resistors with the PE4312 was touched on briefly in an older thread, however, it appears leaving them in with the PE4312 may lead to erratic behavior. Anyone substituting PE4312 for PE4302 in your 64-dB RF Attenuator Board should be aware of this. 73, Rod, AD5GH
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Re: uBITX not T-41: Inversion of t/r signal
Ya das is richtig! ? ? 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 Siegfried Jackstien Sent: Thursday, October 19, 2023 3:07 PM To: [email protected]Subject: Re: [AmateurRadioBuilders] uBITX not T-41: Inversion of t/r signal ? nope .. the trigger from the rig (positive 3 to 12v) is the power supply in this case never seen an "open collector" output?? (any ptt circuit pulling to ground does this) dg9bfc sigi Am 19.10.2023 um 21:43 schrieb jean-marie via groups.io: I think there is an error in the drawing . No powersupply Here is what I’m using in the T41.? It’s good to 250V and 2amps. ? 
? ? 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@... ? ? ? On Thu, Oct 19, 2023 at 09:25 AM, Mark Hatch wrote: The last item on my hardware TODO list is to provide a remote signal to trigger an amp or a RF switch. The signal that I need to expose is the T/R signal. The problem is that it goes positive on TX and grounds on RX. Sort of the opposite of what external devices expect.
Hi Mark,
Here is an inverting switch that I use on my TeensyMaestro project to key my rig.? This assumes keying a positive line by bringing it to ground.? This can be just about any NPN switching transistor.? I used a 2N3904 because I had some on hand.? Because this is inverting, it might work for you as-is.? If the polarity (HIGH vs LOW) is incorrect, you can use another GPIO pin (if you have a free one available) that is set the opposite of the existing RX/TX pin.???A better choice than my switching transistor would be an opto-isolator.? I believe it would be set up in a very similar way.
If you are out of GPIO pins, you could stack another transistor ahead of this one to invert the signal.? You would need a + V (3.5 or 5) through a current limiting resistor to the collector of the other transistor.
Any of you engineers see a flaw in what I am telling Mark?
73, Len, KD0RC ?
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Paul Christensen
K9HZ