|
Re: For you designer builders...
¿ªÔÆÌåÓýHave you ever used one from aliexpress?? Interested to hear if they actually work¡ because they sell those replacements for less than what I can buy just the chips for. ? ? 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 glenn percy via groups.io
Sent: Monday, February 17, 2025 7:41 PM To: [email protected] Subject: Re: [AmateurRadioBuilders] For you designer builders... ? They pop up on Aliexpress at about US$4 |
|
Re: For you designer builders...
¿ªÔÆÌåÓýKind-of, yes! ? ? 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 Bennett via groups.io
Sent: Monday, February 17, 2025 11:40 AM To: [email protected] Subject: Re: [AmateurRadioBuilders] For you designer builders... ? A great thing about the LT3045 is that you can parallel them for higher current and even lower noise (with careful PCB layout). John Bennett AE0AM |
|
Re: For you designer builders...
¿ªÔÆÌåÓýYep.? I can get then for the same price here but I must order them for future delivery¡? Yeah.? Make some small boards and¡ Fanny and Bob are both in the house! ? ? 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 mk3msm via groups.io
Sent: Monday, February 17, 2025 10:51 AM To: [email protected] Subject: Re: [AmateurRadioBuilders] For you designer builders... ? and in 1K lots they cost $3.37 each On 17/02/2025 16:28, John Bennett via groups.io wrote:
? |
|
Re: For you designer builders...
¿ªÔÆÌåÓýYep that¡¯s the ticket!? I had in the back of my brain designing a board identical to that little guy¡ that would simply replace the regulator and there it is!? ? I think I could do it for less than half that cost though¡? If time permits, I¡¯ll give making it a try.? It certainly would be a major improvement for us radio guys that use A/D and D/A converters in our radios! ? ? 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 Bennett via groups.io
Sent: Monday, February 17, 2025 10:28 AM To: [email protected] Subject: Re: [AmateurRadioBuilders] For you designer builders... ? Great idea - a French DIY audio company offers these for sale (not cheap): ? ? John Bennett AE0AM ? ? |
|
Re: FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
¿ªÔÆÌåÓýYeah.? That¡¯s where the ¡°DUH¡± came from¡ ? ? 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 Gordon Gibby KX4Z via groups.io
Sent: Friday, February 14, 2025 7:29 PM To: [email protected] Subject: Re: [AmateurRadioBuilders] FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress ? Easy to sacrifice gain to get negative feedback (and better linearity) when power isn't an issue and there is excess gain available (e.g. low power stages) ? Much more expensive and risky to add high power gain stage after high power gain stage trying to keep them at "low power" -- I don't know for sure but I worry that the phase shift at parasitic frequencies could become an issue and cause instability (would have to go back to 50 years ago to review all that....) ? The available power amplification devices we have just aren't perfectly LINEAR, and we usually don't have huge gain around to throw away in that stage.....so tough to deal with.? ? I'm guessing it is easier if we run the corrections to an ealier?stage some how that doesn't risk oscillation.? ?Certainly not an expert here.? ? But if the output becomes cleaner and we didn't have to spend a bazillion $$$, that's a good thing, right? ? Gordon KX4Z ? ? ? On Fri, Feb 14, 2025 at 7:16?PM K9HZ via <bill=[email protected]> wrote:
|
|
Re: For you designer builders...
¿ªÔÆÌåÓýI think that depends on the circumstances but yes the low noise parts make a much bigger difference. ? ? 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 glenn percy via groups.io
Sent: Sunday, February 16, 2025 7:03 PM To: [email protected] Subject: Re: [AmateurRadioBuilders] For you designer builders... ? Hi Bill Not sure how true this is but apparently LM317 style regulators are better than the LM7805's.?? Not as good as a dedicated low noise part though for sure. ? glenn vk3ep ? |
|
T41 BPF results
These are great, Oliver. If it's okay with you, could you send me the hi-rez versions of the graphs? Al and I would like to include them in the book. BTW, I tweaked the toroids in the LPF board to match their table values. As it turns out, they are very close as is. I fiddled with the turn spacing on a few, but did not have to add or subtract turns for any toroid. I've attached the table. Below is the first band in the table to illustrate what the file contains: Band Inductor Type (Core) ????Turns ???? Wire Length 160M ???? L3 ????????????T68-2 (Red) ????????30 ????????????25.00¡± ????????????? L14 ????????????T68-2 (Red) ?????? 28 ????????????23.50¡± ????????????? L25 ????????????T68-2 (Red) ????????30 ????????????25.00 The wire length is taken from the Kits and Parts table () but I changed the wire length to account for the #20 gauge wire that is suggested if you plan to use Bill's 100W PA. (The K&P table is for #26 gauge wire and the 20W PA.) I also added about an inch to each length so you have enough for generous pigtails. Alas, the Crochet Hook Method for winding cores doesn't lend itself to the heavier gauge and small core diameter. Just take your time and you'll be fine. I will also be posting the table to the SCHR site. Jack, W8TEE
On Sunday, February 16, 2025 at 02:23:34 PM EST, Oliver KI3P via groups.io <oliver@...> wrote:
?
I wound another V12 bandpass filter board to replace the prototype board in my radio. I'm pretty happy with the performance. Here are some plots showing the measured transmission curves for all the channels.
?
?
?
I measured and tweaked the inductance for every core and ended up with values that often differ from the recommended values. You can find a fill write up with all the details of the core windings and a comparison of each filter to the ELSIE simulation on my blog here:
?
Cheers,
Oliver KI3P
-- Jack, W8TEE |
|
Re: CAT Transmit
All: The final version of the code is about to be released by Al and I and we are turning it over to Oliver to care for it in the future. There are coding style differences that some people will disagree with, and that's fine. Jerry has be active in working with the code and prefers another style. What follows is my response to some of the questions he raised. ============= It is kinda a matter of choice and style. As to finding function prototypes, I have tried to maintain those alphabetically in the SDT.h header file. I've done the same for globals. The problem is that more than one person is editing the code and header file(s). Also, you landed on one of my pet peeves: the confusion between the terms "define" and "declare". They are not the same terms. You said: A class definition doesn't assign storage. That is incorrect. From the 2nd edition of the K&R C book, page 210: ??? Declarations specify the interpretation given to each identifier; they do not necessarily reserve storage associated with the identifier. Declarations that reserve storage are called definitions. The first sentence above means that a declaration creates an attribute list for each variable and stores it in the symbol table. Because declarations do not allocate storage for the variable, that attribute list will NOT contain an entry that specifies where in memory to find that variable. This memory location is called the lvalue of a variable. (What a variable contains is called the rvalue. The terms lvalue and rvalue are likely hangovers from assembly language programming for location (lvalue) and register (rvalue) concepts.) It is only after a definition of the variable that it has an lvalue that can be added to the attribute list found in the symbol table. If anyone still thinks they are the same, then have them explain the need for the C extern keyword. The extern keyword was created specifically because of the need to use a variable in one file when it is defined in another file. The data declaration in one file: ??? extern int myVariable; says to the compiler: "I know this variable is not defined in this file, but you can assume it's an int variable named myVariable and it is defined elsewhere in the program." Think of the compiler generating the code for the variable but instead of suppling the variable's lvalue, it leaves "????" in the generated code where the lvalue should be. Then, in the Arduino environment, in the INO file we find the definition of myVariable: ??? int myVariable; which is the program statement that defines the variable myVariable. This definition allocates storage and allows the compiler to fill in the lvalue for this variable in the symbol table. Now, after the compiler finishes, the linker comes along looking at the generated code from the compiler and sees the ???? marker in the object file, looks in the symbol table for ???? in the symbol table, and substitutes that variable's lvalue for the ???? marker. When it's done with that, the linker continues to stitch in the code from the libraries and any other extern declarations to generate the final program code. Using the terms define and declare as if they are the same concepts is wrong, but most programmers fail to make the distinction. Indeed, even Microsoft's documentation treats the two terms the same. Programming is confusing enough without confusing the terms that are integral to it. Jack, W8TEE ?
On Saturday, February 15, 2025 at 10:59:24 AM EST, jerry <jerry@...> wrote:
? I'm not a fan of this coding approach where class methods are defined > in a header file...I just don't like to see executable code in a > header file. Nor do I like the idea of each cpp file having it's own > header file. I just seems like clutter to me. On the other side, I > think this was written by Paul and I have the utmost respect for his > code. Kinda a rock/hard-place for me. > > Jack, W8TEE I OTOH like the idea of a matching header file for each .cpp file.? Having everything in SDT.h seems.... like clutter.? Lots of scanning up & down in that huge file.? How to find the prototypes to call stuff in CAT.cpp?? Easy, they're in CAT.h.? No scanning up & down. Aesthetically, that giant SDT.h file gives me a similar feeling to seeing a few zillion global variables. You and Al architected the T41 as a collection of small modules with well defined functions and interfaces that can be dropped in & out.? I feel that the software should be the same way.? A .cpp file/.h file pair with well defined interfaces that can be dropped in & out.? So - for example - if I want a CW keyer in another project, I can grab cw_keyer.cpp and cw_keyer.h, and I pretty much have it.? Yeah, I'll have to tweak them for another architecture, but I won't have to go scanning through some giant file to find the bits that correspond. I do agree on the concept of not having anything whatsoever executable inside an include file.? Or rather - not having anything that assigns storage. A class definition doesn't assign storage.? But it still looks messy. ? I did use the USB output on another project.? It worked fine.? It should work here too.? Time to get to work. ? ? ? ? ? ? ? ? - Jerry -- Jack, W8TEE |
|
Re: FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress
It's different for every different amp design... needs to be tested, BUT IN GENERAL you want enough headroom so that you never reach saturation of the devices... that means PTP power divided by four.
toggle quoted message
Show quoted text
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@... -----Original Message-----
From: jerry <jerry@...> Sent: Friday, February 14, 2025 9:09 PM To: [email protected] Cc: K9HZ <bill@...> Subject: Re: [AmateurRadioBuilders] FW: [FlexRadioSmartSDR] Adaptive Predistortion Progress On 2025-02-14 16:16, K9HZ wrote: More mumbling about APP¡ operating the amp at less than 25% of its*** Does it have to be 1/4? How much improvement would 1/2 of available output give you? I recently saw a new LDMOS device that's rated for 2.5kW CW output. I think it runs off 75V. I was thinking that at 1.5kW output, it might be pretty clean. Or would IMD due to near flat-topping be replaced with IMD due to crossover distortion? - Jerry, KF6VB |
K9HZ
JP McGinley
Jack, W8TEE