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Re: Conductive Paint
Good stuff!? Thanks On Tue, Feb 11, 2025 at 9:09?AM chris corcoran via <imnotanumber6=[email protected]> wrote:
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Re: Conductive Paint
开云体育Well, that’s 4 hours of my life I won’t get back. ? Rohde & Schwarz hade doing an online seminar ref EMC DEMC 2025 , obviously to sell their equipment, but normally some gems hidden.
? 3 things that come to mind from presentation: ?
I think links top the presentations will be available from the 13th from above url, don’t quote me…
? He referenced an expensive (well to me, ?80ish) ?book Henry Otts Book “Electromagnetic Compatibility Engineering” is a great resource for enclosure design ? BUT, 2009 pdf version can be found ? ? Pages 238 onwards, p270 mentions slot antennas. Also mentions meters/displays on p287, a bit extreme for us amateurs? ? ?
? ? hopefully helpful to someone….. ? ? From: [email protected] <[email protected]>
On Behalf Of K9HZ
Sent: 08 February 2025 15:46 To: [email protected] Subject: Re: [AmateurRadioBuilders] Conductive Paint ? I’m sure we should care about the EMI from the display too.??? Tell you what… You work on the EMR and I’ll finish getting the data line noise from propagating back into the radio… ? ? 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: [SoftwareControlledHamRadio] Rob Sherwood Presentation Slides on Amateur Radio Transceiver Performance
开云体育Could be that John Melton worked on some of that… ? ? 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@... ? ? From: [email protected] <[email protected]> On Behalf Of Gary via groups.io
Sent: Monday, February 10, 2025 3:11 PM To: [email protected] Subject: Re: [AmateurRadioBuilders] [SoftwareControlledHamRadio] Rob Sherwood Presentation Slides on Amateur Radio Transceiver Performance ? Jerry, The Thetis software for the Hermes Lite, ANAN and radioberry radios has adaptive predistortion and you can examine the source files to see how it works. Thise radios have the capability of operating full duplex so they use the receiver to listen to a sample of the transmitter output and down convert it to baseband where the predistortion is calculated and applied to the baseband transmitter before upconversion. Gary W9TD |
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Re: [SoftwareControlledHamRadio] Rob Sherwood Presentation Slides on Amateur Radio Transceiver Performance
开云体育The new attenuator/ 20W dummy load I made can be used as just a 40db tap on the RF line for feedback for something like this (besides the radio calibration).? I don’t think it’s that difficult to design a filter that notches out the salient part of the RF spectrum and add the inverse of the garbage back to the signal at the correct amplitude and phase to cancel the garbage out.? I’ve worked on problems like this before… if I get time to do it… I’ll have a look. ? ? 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@... ? ? From: [email protected] <[email protected]> On Behalf Of jerry-KF6VB
Sent: Monday, February 10, 2025 2:25 PM To: [email protected] Cc: [email protected] Subject: Re: [AmateurRadioBuilders] [SoftwareControlledHamRadio] Rob Sherwood Presentation Slides on Amateur Radio Transceiver Performance ? On 2025-02-10 11:34, K9HZ wrote:
*** NO thanks. A 100W transmitter the size of a Heathkit Apache? |
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Re: [SoftwareControlledHamRadio] Rob Sherwood Presentation Slides on Amateur Radio Transceiver Performance
Jerry,
The Thetis software for the Hermes Lite, ANAN and radioberry radios has adaptive predistortion and you can examine the source files to see how it works. Thise radios have the capability of operating full duplex so they use the receiver to listen to a sample of the transmitter output and down convert it to baseband where the predistortion is calculated and applied to the baseband transmitter before upconversion.
Gary
W9TD |
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Re: [SoftwareControlledHamRadio] Rob Sherwood Presentation Slides on Amateur Radio Transceiver Performance
开云体育For those who are interested…. Here is a tutorial on Class-A operation of transistor amplifiers:? ? ? ? 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@... ? ? From: [email protected] <[email protected]> On Behalf Of K9HZ
Sent: Monday, February 10, 2025 1:34 PM To: [email protected]; [email protected] Subject: Re: [AmateurRadioBuilders] [SoftwareControlledHamRadio] Rob Sherwood Presentation Slides on Amateur Radio Transceiver Performance ? A couple comments on Rob’s talks… there are plenty more of them in addition to these. ? Rob has done a wonderful job of evaluating radio transceivers… I’ve been to his house/ lab and he has the perfect location for his evaluations.? He will always give you an honest evaluation answer but never recommend a radio.? He does have some peculiar operating habits, like all of us, that causes him to identify waterfalls and knobs that he likes… that might not be your cup of tea.? In the past 5+ years Rob has been on an SSB IMD tirade, pushing predistortion accommodations with the top commercial radio manufacturers.? It’s all good stuff but he tends to extend that to the builder and hobbyist level at times that doesn’t always resonate with some of us.? In any case, he does tout using class-A final RF amplifiers in the transmit stages of radios because they, by shear design, will generate less IMD. ? If any of you want to join the “Class-A” club, my 20W and 100W amplifiers will operate in Class-A operation.? The amps have plenty of head-room in terms of dissipation to perform this task, but at a reduced power and efficiency.? My original PA designs contained hardware to adjust the bias to perform this, but I was worried that people would try to keep the PA at the 20W level while in this pseudo class-A operation at about 28% efficiency.? Now will this be of use with the T41… hmmm that is left to the reader. ? I will publish instructions on how to put the 20W PA in class-A operation by readjusting the bias.? Have fun with this but also have a extra set of transistors laying around!? Expect about 5 watts out for a safe level of performance. ? ? 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@... ? ? From: [email protected] <[email protected]> On Behalf Of Greg KF5N via groups.io ? The slides are here: ? -- 73 Greg KF5N |
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Re: [SoftwareControlledHamRadio] Rob Sherwood Presentation Slides on Amateur Radio Transceiver Performance
开云体育A couple comments on Rob’s talks… there are plenty more of them in addition to these. ? Rob has done a wonderful job of evaluating radio transceivers… I’ve been to his house/ lab and he has the perfect location for his evaluations.? He will always give you an honest evaluation answer but never recommend a radio.? He does have some peculiar operating habits, like all of us, that causes him to identify waterfalls and knobs that he likes… that might not be your cup of tea.? In the past 5+ years Rob has been on an SSB IMD tirade, pushing predistortion accommodations with the top commercial radio manufacturers.? It’s all good stuff but he tends to extend that to the builder and hobbyist level at times that doesn’t always resonate with some of us.? In any case, he does tout using class-A final RF amplifiers in the transmit stages of radios because they, by shear design, will generate less IMD. ? If any of you want to join the “Class-A” club, my 20W and 100W amplifiers will operate in Class-A operation.? The amps have plenty of head-room in terms of dissipation to perform this task, but at a reduced power and efficiency.? My original PA designs contained hardware to adjust the bias to perform this, but I was worried that people would try to keep the PA at the 20W level while in this pseudo class-A operation at about 28% efficiency.? Now will this be of use with the T41… hmmm that is left to the reader. ? I will publish instructions on how to put the 20W PA in class-A operation by readjusting the bias.? Have fun with this but also have a extra set of transistors laying around!? Expect about 5 watts out for a safe level of performance. ? ? 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@... ? ? From: [email protected] <[email protected]> On Behalf Of Greg KF5N via groups.io
Sent: Monday, February 10, 2025 8:15 AM To: [email protected] Subject: [SoftwareControlledHamRadio] Rob Sherwood Presentation Slides on Amateur Radio Transceiver Performance ? The slides are here: ? -- 73 Greg KF5N |
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Display Board evaluation help
开云体育I have a couple of the 3.3V ONLY display boards prebuilt and I want a couple of volunteers to test them out.? They have to be: 1) people with working radios, and 2) have displays that misbehave (meaning if you move them around, elongate the cable, etc… the processor locks up). ? I don’t really have the problem so its hard for me to fully evaluate if the display driver boards completely solve this issue. ? ? 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: V12 RF Board
开云体育Yes I have a couple hundred of the off-set boards.? They are $0.50 plus shipping and can ship in a regular first class envelope for a couple of stamps. ? ? 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@... ? ? From: [email protected] <[email protected]> On Behalf Of Tim via groups.io
Sent: Monday, February 10, 2025 8:43 AM To: [email protected] Subject: Re: [AmateurRadioBuilders] V12 RF Board ? Display freezes buttons and encoders stop working. Do you have some extra Audio Hat extender boards? I would like a few. Tim W4YN |
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Re: V12 RF Board
开云体育Hey Tim… when you say it shuts down… what do you mean?? The signal stops or the power goes off? ? ? 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@... ? ? From: [email protected] <[email protected]> On Behalf Of Tim via groups.io
Sent: Sunday, February 9, 2025 1:15 PM To: [email protected] Subject: Re: [AmateurRadioBuilders] V12 RF Board ? My bad I had left off Jumpers 18 and 19. I can now rx fine, but only for short period then it shuts down. Not up long enough to do RX calibration.? Tim W4YN |
K9HZ
Gary