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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

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 Groups.io 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

I know there has been lots of discussions abut crystal pulling but I am looking for more frequency agility. Has anyone used these DDS synthesizers in their projects: https://www.ebay.com/itm/116497346876 I was looking for a lowered powered unit using an AD9834 but could not find any AD9834 modules with the controls and readout. These AD9850 modules are all over eBay and Aliexpress. Can any recommend a buyer? This buyer has other nifty modules I may be interested in. 73 Mike N2MS

Yesterday, I got out an old 20m 1W xcvr along with the unbuilt 10m version. I found my old LDG ATU, which was unmarked anywhere on the enclosure. Took off the cover to find out it is an LDG QRP Autotuner Version 2.0 1996. Uses non-latching relays, so it's going to be replaced. LDG did not have a manual, so if you have one, I'd appreciate it. Tuned the red vertical to 1.00:1 and called a POTA station in NE. Got a 439 RST. I'll take it as band wasn't in the best of shape. It is only 1W. Remember, these POTA guys and gals are looking for any Q they can get and you can be down in the noise level and they hear you. Any replacement recommendations? Doesn't have to automatic, but it'd be nice, since my plan is to go back and forth between 17 and 20m for the rest of the year. For use with only the vertical at this time. Any luck with the Chinese QRP ATU under $100? Last post (I and you hope) for a few days. QRPMe pads to arrive on Monday, so the work begins. I think I'm just going to turn off the computer. <click> -- 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,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9

I have crystals coming from Mouser on Friday to complete all frequencies I will ever need for any project. There was 30% added for 'estimated tariff'. I've got two sets of PCBWay boards stuck in customs for 'unexpected delays'. I paid $11.64 for 10 boards but an additional $8.00 was added for 'VAT' charges to cover the tariffs. This is a stupid waste of money and time. So, those of you doing the SST Manhattan construction, if you are in a rush just follow AA7EEs web page. I can't start until I get the QRPMe pads from Rex. I got all the toroids I'll ever need from Mike, KU4QO, at KitsAndParts.com yesterday. Thanks Mike. I sacrificed a 10m 1W unbuilt kit yesterday to build up the VXO using a MPSH10 BJT to reduce phase noise to test out. I have 10 boards at the port to replace it and do some more projects. Along with the AA7FO-G3UUR boards. Hopefully I'll see them PDQ. Here are the current ranges between the two VXO circuits (single crystal and no mods): SST [40m] 7.030-7.040MHz 11.046MHz VXO 1W [40m] 7.020-7.039MHz 23.040MHz VXO SST [20m] 14.056-14.061MHz 8.064MHz VXO 1W [20m] 14.040-14.055MHz 18.000MHz VXO and some more tests to be done upon construction Manhattan style or done in the next few days while watching the mailbox. :-) I plan on the BJT VXO for fun. I'll also do the dual crystal extension of the range and the 10pF addition that Diz, W8DIZ<sk>, did in the original design of his VXO. I have another test to do for HC-49/U vs HC-49/S form factors. It's a lot of work, but well worth the time and effort. IMHO. My plan is to do only the 20m version and then try for WAS working only POTA stations. For fun and the challenge. Sorry for the length and the BS. ciao, -- 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,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9

If I did it, do I get to name it? :-) I went to Aliexpress and ebay and looked up available crystal frequencies for off the shelf values. I cheated and added one more frequency from the 1W values (22.040MHz) as a double check for 40m. I wound up with 49 values, shown here so you can cut and paste or use as you see fit. Even add values that you find. I did not go to Digikey or Mouser as I did not want to spend hours on this. Spent less than 30mins, so you get what you pay for. 1.843 2.000 2.457 3.276 3.579 4.000 4.096 4.433 4.500 4.897 4.915 5.000 5.529 6.000 6.745 7.200 7.372 8.000 8.192 9.380 9.815 10.000 10.245 11.059 12.000 12.288 13.560 14.318 14.745 15.000 16.000 16.934 18.000 18.432 20.000 21.477 22.118 24.000 24.576 25.000 26.000 27.000 30.000 32.000 32.780 33.868 36.000 40.000 23.040 Wrote a quick little ditty in C and here is what I get. FYI and hope it helps. I only did 40m to 10m for the first pass, including the WAR bands. ham freq crystal crystal 10.103 4.897 15.000 10.118 12.000 22.118 14.105 7.372 21.477 14.118 8.000 22.118 21.040 2.000 23.040 21.085 4.915 26.000 21.103 4.897 26.000 21.197 1.843 23.040 28.157 1.843 30.000 28.280 4.500 32.780 7.040 16.000 23.040 7.059 4.000 11.059 7.066 16.934 24.000 -- 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,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9

Found the following on the internet for those interested in such stuff for the SST project. FYI and shown without any attempt at organization. The following shows quantitative results using two crystals in parallel for a few crystal freqs. <http://g4oep.epizy.com/pulling/pulling.htm?i=1> Note the higher the VXO frequency and the range. NB6M article from NorCal QRP Club site. <http://www.norcalqrp.org/nb6mvxo.htm> For those that want instant gratification, here are a few videos. Interesting YouTube video showing 10.111MHz crystals for 30m <https://tinyurl.com/2cj2btsx> <https://vk3ye.com/technical/vxo.htm> links to more videos from VK3YE. I haven't the time right now to scrape YouTube from end to end in a search. FYI and hope you find something you can use. -- 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,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9

Gang, Has anyone created a excel spreadsheet where one can experiment by either plugging in given crystal frequencies for the VXO and IF per Band or a table of popular crystal frequencies? Just curious. I will keep my fingers crossed! :) Alan/N8WQ

1. It's the WARC bands. Typo on my part. I'll send back my UIL typing championship trophy. Now you know why my postings are so long. :-) 2. I restricted the band search to the CW bands. There is the possibility that some combos generate digital and voice band frequencies. tnx es 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,ID,IL,NC,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9

Perhaps some one on the list has one excess to their needs. My email address is Ki6ds1[@]gmail.com Remove the brackets to email. Thanks, Doug

Forgot. Note, in the SST, Wayne went with molded inductors. When NorCal did this (and Doug can verify) I'll bet that molded inductors were much cheaper than toroids. They do heat up as a side note. I reserve the right to go with toroids to get the optimum range. In the 1W and 5W, Diz went with toroids. He had the world supply of them. Look at the inventory at KitsAndParts.com that Mike has on hand. I just placed a significant order for ones that I need and want to use. The rigs used toroid inductors because you can wind to the optimal inductance value you need for maximum tuning range you can get out of the crystal critters. Less heating with larger surface area for heat dissipation using largest wire you can wind and get the turns you need. OK. I carry on too much. I know. -- 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,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9

Been on 17m for 6.5 weeks now and you can see my results thus far in the signature block. Using a QRP-Labs QCX-mini at 4.2W with a one element beam (sounds better than a dual hamstick dipole) at 4m. Night before last was the most fun. Was about 10:45pm local. Saw that a ZL2 was calling CQ and spotted in UT. Fired up the rig and I could just barely hear him in the noise level. So, called and he came back to me with a 339, but it counts. Both A- and K-indices were relatively high, but adventure is just doing it. Thought I'd switch for the next 6.5 weeks to the red Chinese vertical that was discussed a month or so ago. Here is a mod that I HIGHLY recommend. Go to HomeDepot for 3 M10 lock washers. You find them the hardware section in a bag of 3 for a little over $2. Or, you might have them in your hardware can/jar for loose stuff. Put one between the whip and the red critter (center conductor connected). Put the other two between the radial lug and the red module and the radial lug and the spike. Previously I wondered if I hadn't loosened the spike and radial contact in twisting the spike into the ground and I find that the lock washers reduce the chance of doing it again. Not completely, but most likely if you take care in the field or yard. Report in 1.5 months. On the side. I dare you guys with your 40m and/or 20m SSTs to work a contact during this weekend CQ WW WPX contest. Sunday afternoon is a better chance when they have worked everybody else. I can't but I'm shooting for next year. -- 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,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9

This is not an easy answer. It is mathematically, but there are some variances between manufacturers and quality control. Let me explain. The series resonant frequency of the crystal is determined by L_1 and C_1, the motional parameters due to the physics. In a VXO, we are interested in just how far we can "pull" the frequency of operation, say delta_f. We can approximate this value by the formula: (Colpitts oscillator is typical) delta_f ~= 0.5*(L_ext/L_1 - C_1/C_ext). L_1 and C_1 we can't do anything about. It comes with the crystal as it is manufactured. In both the SST and 1W transceivers, look at the schematics. What do you see in series with the crystal. Yep. An inductor, let's call that L_ext and a variable cap C_ext. L_ext is fixed. As you vary C_ext, you shift the frequency. At first you say, well heck let's make L_ext large and C_ext large. Several things happen. You can't shift far (L is fixed) and L_ext swamps the capacitance change. A bad side effect is that the oscillator stability goes to heck in a hand basket. This leads up the answer for the question. I have to take the different frequencies, different varactor diodes, different molded inductors and transistors (2N3904, 2N4401, or even a JFET) and see what gives the greatest range for each band, greatest output and if that is good at the output of the mixer, least drift, .... You see the problem, but I have the fixture set up on a Manhattan layout. As soon as I get the crystals off the boat, I will do the experiments and report to the group. In the meantime, maybe some of the group can also give their results from previous builds and lab work. Look at the frequency range of the specs of every rig that uses a VXO. This may help you see just how much you can in tunable range of the VXO. Get out the G3UUR and measure the L and C values. R_1 of the crystal is also at play in the range of frequency pull you can get and a large R_1 will get you drift due to heating. Since we are getting these things from China, there may be a spec sheet that gives some ranges, but crystal axis cutting and accuracy causes some variance between batches. That's why you buy crystals in bulk. They come from the same batch and setup and you are more likely to get a close match more easily. We used to see a date code, but with the HC-49/S, there is no room and the new crystals rarely show a batch code like transistors. BTW, the HC-49/S and the HC-49/U should have almost the same L_1 and C_1 values. Go to K8IQYs home page and go to the crystal page values he has measured. <https://www.k8iqy.com/miscellaneous/XtalParms/xtal_parameters.htm> L_m and C_m are the L_1 and C_1 variables used in the formula. You will see both sets of variables spread across the Internet. L_m and C_m are the ones used by the industry. I'll make up a table and put it on the web for my results to add to the body of knowledge to be found on crystals. Maybe W7ZOI has some values also on the web. If the circuit capacitance across the crystal matches the C_o value, then the circuit should resonant at the frequency marked on the crystal in parallel mode. This is just the tip of the iceberg..... 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,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9

<https://archive.org/details/introductory.electronic.devices.and.circuits.6th-robert.t.paynter/page/763/mode/2up> Most Colpitts designs I see hams use have the capacitor divider network with two equal values. It's just fine. In the SST, Wayne chose to keep C19 and C20 fixed and equal for all bands. In the 1W and 5W transceivers, Diz chose to have some values of C15 and C16 to be different on some bands and the same on others. I am assuming that he did significant experimentation on the values. Also note, C_x in the 1W schematic between the crystal and the inductor. Diz found this to sometimes extend the tuning range and sometimes it caused the circuit to fail to oscillate. Again, my plan is to try this scheme out on the SST to see if there are any possible gains. That's the end of this series of posts. I hope. The book above is a good one for some detailed electronics. -- 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,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9

Gang, For those that haven't stocked up over the years on crystal deals or renewing their stock like I am, here is a list for you to go through at your time of choice. If you are interested, I'd recommend you do so rapidly as the climate is a changing. See the 4.032 and 10.000 vendor and what I got before things changed. Presented here to save you time that I spent on searching the web and I just got the tip of the iceberg. Share if you have better deals. ------------------------ <https://www.ebay.com/itm/393816488432> o about $0.64 per critter for 10 with free S&H o I've ordered here and was happy and you get them quick. <https://www.ebay.com/itm/166477846005> o I got my 4.032 and 10.000MHz here when it was free shipping! But, the $50 S&H is ridiculous now. He did it after the trade wars started. List of vendors I've ordered from and some are on the boat as we speak. I'll come back with reports when I receive them, but I show them here as a current status in case the vendor later decides to change things for the worse. This list is for the small gamblers among us. I went out on the limb on this one. I'm not responsible for being the village idiot. <https://www.aliexpress.us/item/3256807441959330.html> 14.318MHz <https://www.aliexpress.us/item/3256806107320730.html> 15 freq options <https://www.aliexpress.us/item/3256806684489012.html> 10 freq options <https://www.aliexpress.us/item/3256805353383825.html> a bunch! <https://www.aliexpress.us/item/2251801854466699.html> options And while I'm wasting your time, take a look at how much quartz is being manufactured. Quartz crystals are used in more places than you think about. Enjoy. I know that I do for this one. Things start at 3:00 or so on the factory floor. <https://www.youtube.com/watch?v=lzHqhNoyx2o> -- 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,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9

Is there an easy way to test smd soic8 packaged sa612 chips? Doug

QRP Power: See <https://qrpguys.com/12w-dummy-load-power-meter> manual for how it is done with a dummy load. Unfortunately QRPGuys are shut down for a month due to traveling on vacation. The power formula on the PCB is very very easy to derive and easy to compute on your phone calculator. $20 is pretty cheap for thing IMHO. I'd like them to change the pin out to allow a two pin Arduino cable to be used with the center pin on the board going to ground. Makes it easier for me, and I like easy. AA7FO Web Page: Because of the security notice threat that was coming up on my old web page, I have moved it. <https://www.qsl.net/aa7fo> Note that I have revived some of my legacy writings on Manhattan construction, 1W and 5W building guides for those of you still hoarding the unbuilt kits in secret storage locations. The money I save I'll donate to qsl.net to keep them going. Not a friend of money for nothing and chicks for free, as the song goes. I'm trying to get time to get back to writing, but its more fun to build and operate. I'll let you know how my combo of 10.000MHz(VXO) and 4.032MHz(IF) work out. I'll measure the MDS with the old S1-S9 generator from NorCal and report back first thing. You still have yours? Battery check. AA7FO YouTube Status: Lost use of my video camera after 20 years of faithful service, so if you are a vlogger, let me know offline (I'm sure this group isn't interested in how to do it) what a good deal is. Too many options on amazon.com. Want one with macro capability for the closeups of boards etc. Manhattan Build: Awaiting QRPMe pads to get the SST build going. FYI. If you look at the crystals needed, some are very hard to find. But, look at the 1W frequencies in the retired kits on kitsandparts.com for easy frequency combos to find on ebay and aliexpress for less than a quarter a piece in quantities of 10 with free shipping. Search the isles for what you need. 40m is the tough combo. Experimental Venture: Someone in this group can open source a technique for using the cheap Si5351 module to replace the VXO and allow us to use any on hand crystals for the IF we want with the usual caveats on birdies. May already be available from unknown source previously written up. FYI 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,ID,IL,NC,NY,WV MA,OH,OR,RI,MT,WY,WA,MI DXCC W,VE,JA,PY,ZL,TX9