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How to get Files from the old qrp-tech group
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Hi everyone, I mentioned that I was working on a solution for getting files from the old qrp-tech group, and I am glad to report that I was able to make progress so that anyone can have access to them. The owner of the original qrp-tech group has re-enabled registration for new users. If you are unable to view the files, simply register to become a member of the group, and your registration will allow you to see the files. They are located at: /g/qrp-tech/files Please add any new files to this group and go to the old group for pre-existing files. Is it a little bit of a hoop to jump through? Yes. Does it keep satisfy everyone's needs? I hope so. -- Ryan Flowers W7RLF https://miscdotgeek.com
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Group Introduction: If you're going to post on the group, reply here!
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Hello everyone, Thank you for joining this group! I am new to being an admin of a groups.io group, but not to groups in general. If you see something that needs to be changed, feel free to comment about it. I'm flexible! This isn't my group, it's your group. My goal is to keep the old qpr-tech group alive under this new name, and I hope that all 2500+ on the old group will join this one, but I know that's not realistic. If you all could put the word out that the group has moved, it'll help keep this going. Despite those saying that "homebrew is dying" and the like, groups like this prove that it's alive and well. let's keep it that way! Because of the way 开云体育 is set up, I can either moderate peoples first post, or I can set it so that so that people have to be approved to join the group. qrp-tech was set to the former, and so I've set this group the same. Your first post will have to be moderated, but I'll approve it as soon as possible. I'm never far from a browser and it's easy to do. Thank you and 73! -- Ryan Flowers W7RLF https://miscdotgeek.com
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Looking through my library, this is the earliest example of using PCB pads glued to a board for construction. Is it the earliest you have seen? September 1979 QST (back when there were construction articles) "Quick and Easy Circuit Boards for the Beginner" by Doug DeMaw, W1FB <sk>. Page 30-34 of the "QRP Classics" book by the ARRL dated 1990. FYI -- chuck adams, aa7fo QRP WAS 17m started Apr 2, 2025 WAS-17 QRP --> TX,FL,SC,GA,OK,AR,KS,AL,AZ,MN PA,CA,CO,WI,NE,ID,IL,NC DXCC W,VE,JA,PY
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Tayda Electronics and parts, heatsinks, Octopus
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Hey, I was thinking of getting some parts from Tayda Electronics. I think they have a warehouse also in the US but not sure if all the parts I need are there. I think some of you have gotten those D882 transistors before and had good luck with them? https://www.taydaelectronics.com/2sd882-transistor-npn-30v-3a-to-126-2sd882l-p-t60-k.html US $ 0.14 each. And get some heat sinks for the D882 transistors above but also those 2SC5706 I got from kits and parts. But not sure about the packaging of either of those. So, not sure what heat sinks where work for either of them. Some trimmer capacitors too. I think Steve buys his from there and they work for him. Question - good place to get NG0 / CG0 good quality capacitors for VFO and filters right now? Sure, I got a value boxes of capacitors off Amazon and I checked them and they seem to be in range of their stated tolerance. But when it comes to a VFO and filters, I think better quality capacitors are needed. 73 Daniel KK4MRN
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A few weeks ago, I started building a 2N2/20 from a kit and ran into a problem with what appears to be a lack of gain somewhere in the receiver. I couldn't figure out where the problem lay. As a result, I thought that if I scratch-built a 2N2/20 using the same schematic as the Norcal kit version, I'd have a working unit with which to make measurements and comparisons. I've been wanting to scratch-build a 2N2 rig for years now anyway, so this was a good opportunity. I wasn't going to post anything until it was completely finished and fully operational, but I'm running into a small snag, so thought I'd share my progress so far and share the info, in case anyone can shed some light. The picture shows the state of the build as of 2 days ago. Everything seems to be working normally, based on simple tests touching wire antennas to the inputs of the various stages, and listening to the sounds from the speaker. The only abnormality is a slight instability in the IF amp stage immediately following the main 4-pole crystal filter. I have circled this stage in the second picture and also in the schematic. It manifests itself as a scratchy noise in the speaker. When I bring a finger in close proximity to the toroidal transformer T11, or either the 100 ohm resistor R36 or 01.?F coupling capacitor C46 that feed the input of the MPSH10 transistor, the noise stops, but the gain of the receiver strip is not affected. It just kills what sounds like some kind of parasitic oscillation. I replaced the 0.1?F cap C46, suspecting a noisy component, but that wasn't it. I may end up rebuilding the stage. We'll see. Anyway, the debugging process is engaging, and it gives me something to do when I get up in the morning. In other news, I've had the pleasure of two very brief QSO's with Chuck on 17M in the last few days. QSB was working against us, but I'm happy with brief exchanges anyway. Chuck and I are only about 600 miles apart, so it's not too challenging a haul for a couple of QRP'ers. Dave AA7EE Dave AA7EE
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Did get two chances to work Dave, AA7EE, on 17m. He called me once and I called him once. Time of day when you are 599 and 15secs later you are gone. Nil. Nada. Zilch. Thanks Dave. Attached is the audio amp board about ready to go. Not as neat as Daves work, but it is sure fun to build. I had to start this project his morning and I'll have it done by sunset. Using the same size board, but sheared into 3 parts, I'll build the other three sections. Then the plan is to attach them to the back of this board, thus coming up with what may be the smallest form factor or all. I'm not in the same league as Dave, AA7EE, and Jim, K8IQY, but I do enjoy working the technique. I recommend it for anyone who has a small project to learn with. Just do it. The Manhattan Madness continues. FYI -- chuck adams, aa7fo QRP WAS 17m started Apr 2, 2025 WAS-17 QRP --> TX,FL,SC,GA,OK,AR,KS,AL,AZ,MN PA,CA,CO,WI,NE,ID,IL,NC DXCC W,VE,JA,PY
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Help aligning VFO (Ozark Patrol regen)
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Hi Ross, On mine, the Low band tunes 3.90-5.24 MHz; High band tunes 5.46-- ~19 MHz, as you note at least the High band is very wide tuning. Your scheme would probably work but I predict it will take a lot of experimentation to achieve it. Good luck and please let us know how it all turns out. 73, Steve AA7U
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The end of inexpensive printed circuit boards and parts
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As some of you may be aware, the president has eliminated the de-minimis tariff exemption for China and Hong Kong. Under the executive order, packages coming through the international postal network will either be subject to a fee of 30 percent of the value of the goods, or $25, rising to $50 in June. Whichever is greater. This means the duty will be $25.00 for packages from these countries from May 2, 2025 and $50.00 from June 2, 2025 Onwards. Relevant news article: https://www.nytimes.com/2025/04/03/business/trump-de-minimis-china-shipments.html This means no more inexpensive printed circuit boards from Chinese manufacturers such as JLCPCB and PCBWAY and no more inexpensive parts from LCSC or Aliexpress. The only way we'll get inexpensive circuit board fabrication in the future is if some US-based circuit board manufacturer decides that the hobby market is big enough to service. Of course JLCPCB et. al could open a plant in another country, but that would be a risky proposition. The de-minimis tariff exemption could be eliminated from other countries in the future. So if you have any PCB designs ready or parts needs to submit it would be prudent to submit them soon to take advantage of the low costs before the de-minimis tariff ends. You also should make sure that your design ships out before the middle of April so that it doesn't get held in customs for duty payment. If this de-minimis exemption isn't relaxed by the president, then guess I'm going to have to find something else to occupy my time for the near term as these increases are going to make homebrewing using fabricated PCB's too expensive. Steve WA6ZFT
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For those of you wanting to do Manhattan construction. You want to plan ahead as much as possible. And not spend a lot of time being an artist. I found that if I use a membership card for a gated community that has the lanyard hole already in it, it works to easily place and draw pads on paper with a pen or pencil. Possibly use an expired credit card and use the hole punch and make the hole sizes you need. Punch through the magnetic strip and card numbers for security. And I just draw a from pad to pad with a centered space with the part number, i.e. R1, and I don't have to spend a lot of time drawing outlines for resistors, caps, etc. Does not have to be to scale and you adjust as you build. dit dit -- chuck adams, aa7fo QRP WAS 17m started Apr 2, 2025 WAS-17 QRP --> TX,FL,SC,GA,OK,AR,KS,AL,AZ,MN PA,CA,CO,WI,NE DXCC W,VE,JA,PY
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Encyclopedia of Electronics Vols 1-6
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Gang, Probably, most of you know about the Graf series of books titled "Encyclopedia of Electronics" with volumes 1 through 6. Just about anything you are looking for may be in there. Crystal oscillators to sirens. Amplifiers of all types and the list goes on. All six volumes are on archive.org and are downloadable. If you are looking for something to do, then you should consider spending the next three or four months reading these in your spare time. You wont have any spare time when you start. Been there. Done that. Or read them in place on the web. FYI chuck, aa7fo
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LTSpice vs ngspice vs DeepSeek vs ChatGPT
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It's a different environment today for simulation. I can't run LTSpice on my ARM based Orange Pi 5 Plus like I can on the 32 processor Intel. But I can run ngspice for circuit analysis just fine. But, for grins, I asked DeepSeek to give me the tuning range for the values KD1JV was using for the ADC-40 receiver BPF in the front end. That's reason for the order for trimmers. Was getting different values than the BOM (which is changing daily and the reason I don't like doing one until the project is complete). So, the point, no more cranking up simulation and for getting the slide rule out for some things. Just type in a simple question and out comes the analysis and the values. Try this on the AI of your choice. Given L=12 micro Henry. What is the resonant frequencies for C=30pF and 5pF? For DeepSeek I'm impressed. It shows each step. Kids in the engineering and the sciences don't have to do homework anymore. Didn't try the others. Also, I use the turns calculator for toroids on KitsAndParts.com and compared with DeepSeek and results were slightly different, but good enough for starting assembly. FYI -- chuck adams, aa7fo WAS started Apr 2, 2025 at 5W. WAS-17 QRP --> TX,FL,SC,GA,OK,AR,KS,AL,AZ,PA,MN
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Jim, Thanks, I've used them before. When do we start getting hit with the tariff charges? Can I get an order in soon enough? I went ahead and ordered the Honbay trimmers, as I get them today and I can get the ADC-40 project back on track. So, let me take one for the team and I'll run an analysis and report back to the group at large, if they don't mind. I got KS yesterday around 0000UTC, so I'm willing to get on your frequency of 18.080MHz (the same one I start out on almost every day :-) ) today and we'll try to hook up. I'm up to nine states in 4 days with my one element beam at 4m. I've hit Japan twice in the last two days grey line. Hoping for KL7 and KH6 at the same time. Funny story. I had fired up the rig and heard N6TR/7 (the most famous contest op in the world IMHO) Tree working VT. So OR and VT to get in 15 sec. (*&(*)(*#$ My patented AA7FO Bencher paddle failed to operate. Pic attached. It has been sitting on the shelf for decades. I had run paper between the silver plated contacts. But, the ground is connected through the four pointy contacts and dust/corrosion/rust... had made a high enough resistor to not trigger the keyer. Got the N3ZN paddle and by that time they were gone. I'll be running my old QCX+ from QRP-Labs and I have a QCX-mini to build when I can get the ADC-40 project off the workbench. Did you know the QCX-mini has sold over 16K units. They are used a lot for POTA and SOTA ops as far as the YouTube videos seem to show. I got AZ yesterday with a ham 2km away in the same gated community. Didn't know I had any one on HF in the same complex. Funny. See you this afternoon buddy, -- chuck adams, aa7fo WAS-17 QRP --> TX,FL,SC,GA,OK,AR,KS,AL,AZ
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Trimmer Capacitor Kits on Amazon.com
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Choices are Honbay or Acxico. Any preference or experiences with either or both? -- chuck adams, aa7fo WAS-17 QRP --> TX,FL,SC,GA,OK,AR,KS,AL,AZ
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This is a new one for me. I copied a couple of old sources for ft testers but some of them just vanished from the hard drive. One was a real nice PNP/NPN with a VFO and meters. 1960s. You could test common base or common emitter max oscillator use. Alpha Test or something. An old VHF manual had this in it. Was trying to squeeze it into an altoids tin but moving interrupted that build. I wonder where it is.... At the time, I was looking for a small variable cap 1 to 100pf. Just may go with a multipole mini rotary..... There is this one from techlib https://techlib.com/newprojects.htm Ft tester and included is an LTspice file. This could be automated with a micro, 5351, a couple of diodes, and a display. Maybe add the DC beta test, and the BVcbo, BVceo, BVebo and .... mission creep. The test is done at about 10 mA. The CAL and OUT points would typically connect to a scope, preferably through coax terminated with 50 ohms at the scope, but 50 ohm resistors and scope probes should work, too. Other measurement devices will also work. The user plugs in the transistor and adjusts the frequency of the signal generator (set near 10 dBm out or lower) until the signals at CAL and OUT are equal in amplitude. F is 20 times that frequency ND6T made a simple tester from an absorption wave meter from a hamfest. http://www.nd6t.com I have only text, the images didn't come through
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Help aligning VFO
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I am building an Ozark Patrol regen. The stock tuning range is very large and I would like to limit it. By default, there is a SPDT switch that adds a parallel capacitance for a second range. My goal is to align the two ranges with the 20 and 40 m bands. Math shows that I need two fixed capacitors (one in series with the tuning, one in parallel with that) for each band. My thought is to replace the SPDT with a DPDT. I would build the circuit for 20 m and the switch poles would select in the appropriate differences to each fixed capacitor. Does this seem reasonable? Is this how it's done?
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Solder expring
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In the post earlier today about tariffs there was mentioned the pricing of solder. I have had good luck with picking up mostly full rolls of solder at garage sales or when the shop at work has to dispose of it because it "expires". I am sure many of you are familiar with similar industrial practices that adhere to strict shelf life requirements. I have used and or tested many of these rolls of solder, and they often work just fine. So the question is: Does it really expire, or more precisely, go bad? And yes, I am certainly familiar with the rosin vs acid core varieties and the leaded vs lead free. I do pay attention to that fact when picking up said items at garage sales. Sometimes I do want the acid core solder because I use it in the garage for different things. -Albert KI4ORI
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Worked a critter yesterday and he said he was sending a QSL card to confirm QSO. Went looking for online source/printer and not having any luck since we lost W4MPY. Any ideas? tnx -- chuck adams, aa7fo WAS-17 QRP --> TX,FL,SC,GA
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When PCB's are too expensive, and you're out of copper boards.
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https://www.hanssummers.com/101/1011.html -- Ryan Flowers - W7RLF https://MiscDotGeek.com W7RLF Prototyping Boards MiscDotGeek YouTube Channel
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1. Screenshot... New Manhattan layout diagram for an AA7FO Noise Generator /w values 2. 1698.jpg How I mount a transistor with 3 legs on pads. Compact. IMHO. 3. 0614.jpg Note diode and resistor lower right have leads soldered to ground plane. 4. 0617.jpg This is what I do when I have multiple leads going to a pad. I wait until I have all leads in place and then solder. Saves expensive solder. On the layout diagram. The dark circles are pads with leads soldered to them. The leads with multiple circles drawn represent the lead is soldered to the ground plane. The resistors are mounted in vertical position. And 1037.jpg shows what parts mounted end up look like, even though this is with a Muppet board that K7QO used to make for me. I have not shown in the layout the specific details on attaching the 9V battery. I used the snap on critter that I got in quantity from ebay. For the output I solder the ground lug to the ground plane and it serves to give a good solid support to the BNC connector. Think outside the box for your own. FYI. Just wanted to clarify for the new Manhattan builders for now and in the future. Download the photos so you don't have to go looking for them. I hope 1037.jpg looks OK. It did with one viewer, but enlarged for view with thunderbird for some reason. -- chuck adams, aa7fo WAS-17 QRP --> TX,FL,SC,GA
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For some things that I test on a receiver, I find the following to be of great use around the lab. It uses the fact that a zener diode will generate a lot of random noise. Let's not nit the pink vs gaussian vs exponential vs white vs .... types of noise. 1. Use it at the build of each stage in a receiver, if you start with the audio amp first as in the series of videos I'm doing. 2. Use it after a build or even for working rigs to test the IF filter. Requires an audio analysis computer program that shows a spectrum plot. I'm currently looking for an ARM based SBC program since most non-free software binaries run only on Intel/AMD base computers. Open source would be great. 3. Irritate the neighbors. Attached: 0084.jpg original prototype using on two stages on PCB done toner transfer Screenshot... showing Manhattan layout drawn by C program I wrote I will come back and change the call sign. :-) Schematic lost in the dark caves of large SSDs and to be recreated at some later date. But you can reverse engineer the layout to a schematic. You've been there and done that many times before. BOM: R1,R3,R5 1.2K 1/4W resistors (not too critical) R7 680ohms 1/4W resistor (drives the final stage harder) C1,C2,C3,C4 10nF mono or disc caps (.01uF if you prefer labeled 104) D1 6.8V 1/2W zener diode Q1,Q2,Q3 2N2222, 2N3904 or 2N4401 NPN transistors (just about anything) The part values are not critical. You can use what you have in the parts depot in the closet and it's more fun to experiment. I think I got everything. Exercise for the student(s). This critter will be used pretty soon in the ongoing videos and there after many times. FYI -- chuck adams, aa7fo WAS-17 QRP --> TX,FL,SC,GA
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Sat 8:39am
Sat 8:39am