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Hi Charlie, the wspr zl2ctm re78jr 20 encoded symbols shown on the screen demo of genwspr.exe don't match the low or high power symbols in your code on your web site. I generated a symbol table using jtencode in the arduino ide for zl2ctm re78 10 and that matched the LowPWR_WSPR_DATA array in your code.

Out of focus circuit

I didn't see the main volume control on your schematic. From the photos I can see a cable with either 2 or 3 wires leading to a pot. What value pot did you use ? Did you use all 3 terminals on that pot ? Thanks.

This spiel covers a heat tabbed SMD mosfet that is a contender to replace the BS 170 in a lot of PP circuits and may indeed serve as cheap subs for the expensive LD mosfets ,VHF rated, which you used. They are likely hard to find on Ebay but are a part that can be found on Mouser and Digikey. The Tab on these is voltage hot so the copper pads have to be kept isolated when in service. -The PA mod accommodates two FDT86256 Mosfets and provides some heatsink PCB space with footprints matching the motherboard BS170 for easy installation. The FDT86256 offers several advantages over the BS170. The most notable advantage is its higher breakdown voltage (Vds), which stands at an impressive 150V, in contrast to the BS170's 60V. Another significant benefit of the FDT86256 is its ability to handle higher power levels, with a rating of 10 watts, compared to the BS170's 800 milliwatts. However, it's worth noting a drawback of the FDT86256 when compared to the BS170, and that's its higher input capacitance (Ciss), which measures 55 picofarads (pf). This higher capacitance can potentially impact its performance at higher frequencies. However, in a Class D configuration, it performs comparably to a pair of BS170s. Typically, the Ciss capacitance of a BS170 is around 24pf. When used in parallel pairs, the total capacitance reaches 48pf, which is not significantly different from that of a single FDT86256. This encouraged me to consider the FDT86256 as a replacement for a BS170 pair. End of snip . TEF (Relates to use of this Mos device in an RF PPull circuit. ). TheFDT is of the order of $1.50 US each from the normal supply houses like MOuser (and the high courier bill that goes with it).

I would love to build an AM Air band receiver around an Arduino and the Si5351, but i just don't understand the analogue part of the receiver. Something like the Signal Corp R-532 or 535.

Great

A quick note about the resistor at TIP31C B-C. If you do a bootstrap by splitting that resistor into two in series and feeding the mid point from your amplifier's output, you can get a better positive swing. I like the design. I would have used TIP35 and TIP36 for my output but only because I have some.

Hi Charlie, have you, or ever thought of building an updated version of the Tucker Tin ssb transmitter with commonly available parts? Anyway, keep up the excellent work! Best regards, Lance ZL3LAD.

Blabla blabla blabla !!!!!!!!!!!

As always you explain things excellently and make it look very easy and simple.

*MUCHOS CIRCUITOS,ESQUEMAS,PLANOS,Y EXPLICACIONES,PERO EN 30 MINUTOS DE VIDEO,NO FUISTE CAPAZ DE HACERNOS ESCUCHAR COMO FUNCIONA?????* *INEPTO!!!!*

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Excelente !!!!LW8DNV

Charlie, can you explain the volume control shown on your breadboard, it's not shown on the schematic or video?

If you just wanted to listen to the station up the road you could have just done it with a few transistors and an AF amplifier 😅 Nup not good enough says Charlie... but I won't worry about an AGC hahaha, might as well set up an AGC now anyway 😂

Wow, this is amazing. As someone previously said, this is something i have been looking for. Awesome job Sir.

I built this just today. Works great! Very interested to follow along with this series. Thanks Charlie.

Hi Charlie! The only suggestion I would have, is to try different semis. While the 510 is used in many RF applications, I’ve heard some people having better efficiencies with RF transistors. In fact, some great results were had (even over MOSFETS) by using RF bipolars such as recovered CB final transistors such as a 2N1969. This (to me) would seem more likely to be the area whereby the efficiency would most likely be compromised. The only argument against that is, if-so, one would think you’d see the inefficiency manifest as heating in the device. Anyway, even though you may have to ‘buck-up’ the input driver, I’d still give the RF bipolar a try. Thanks very much for your excellent explanations, analysis and demonstration. 73… 😊

I do love the engineers view on design, we will calculate what value we need then just pick a close preferred value. before PC's we would work out the affects of tolerances on the components, taking the min and max values to calculate what the tolerance spread would do in production and writing the test specification around it. PC's and lt-spice made that a much easer job. 🙂

Hello, which machine is the mixer from?

Good result and circuit board :)

Missed watching Charlie....took a break from things for some life stuff.....kicking off my resurgence into radio this weekend at Hamvention! Hopefully i will add many things to my junk box for future trials into the homebrew world.

Really enjoyed the run through ..It sounded good too...Keep it up Charlie!

How did you decide on the inductance of the coil in the collector load? Why is a coil beter than a resonance tank or maybe a simple resistor? Also, I think your attempt to match the impedance of the filter is incorrect - if the input filter impedance is 910 ohm, this should be the output impedance of the common emitter amplifier stage. Since for CE config it's the collector load, your collector resistor should be ~910 ohm or equivalent. Shunting with a resistor makes it worse, since now you have 910 ohm in parallel with ~25uH of the coil which is roughly 1600 ohm at 10.7MHz.

I love the world according to Charlie! Brilliant job as always. I'm certainly going to play around with an infinite impedance detector and maybe even a Franklin oscillator (if I can prize the Si5351 from my hands!). So good to have you back on UA-cam. 73, Nick M0NTV

Great video, as always!

a masterpiece of discrete component design. if it isn't, i don't know what is.

Thanks for the update..enjoyed learning as always 73s

Really nice Charlie. It sounds great. I like your constuction technique. I too make a lot of use of solder wick. And I like copper clad on wood. More room is better than not enough room. And there is a benefit in keeping all the circuitry visible. 73 and thanks, Bill N2CQR

Riveting as always Charlie. Which antenna did you end up using ? You were intending to try just a piece of wire across the shack.

Another fantastic, scratch built, radio. I must have missed it, but I'm intrigued about the variable, vernier-drive tuning capacitor. Where did you get that from. Such things are now almost imposable to find! 73 de VK6AWK

Very helpful and enjoyable. ZL1GH

I second everyone's comments here Charlie. Thank you, 73, VK7IAN

A beautiful looking and sounding radio. Thank you for taking us through the design process. 73, ZL1SHP

Looks good. Sounds good. Enjoy ! I did. 73 PE1LLA

I really like the way you make your circuits. They are very beautifuls and make me want to do the same thing. Also it works well and the sound is amazing, sorry for my basic english !

Great job and sounds great. It's really good to see you make another series of videos. Always enjoy your content.

I would be amazed to see this project receive shortwave and demodulate SSB.

It has become my sole task to learn to write and draw as neatly as you do.

That is looking great and sounding terrific Charlie. Well done! 73, Nick

I would welcome extra rf-gain. For years we, in the Netherlands, have been deprived of the big broadcast transmitters. What's left is an ever changing offer of LPAM stations. (between 1 and 100 Watt).This requiers close proximity and/or a very good radio. Absolutely love your radio. Scrambling for parts now. PE1LLA.

Great

Beautiful work Charlie. I'm guessing that that variable cap has the rotating vanes (and thus the panel contol) grounded, with the stator vanes going to the circuit. That may be why you can touch it with no frequency shift. FB on NOT having shielding around the VFO. Too often dogma and lore has us putting unnecessary metal boxes around this stage. 73 Bill N2CQR

good work !

Anither great radio..the very neat and artistic work...the oscillator capacitor is a piece of art with that gear arrangements..radiofun242 also made experiment once by varrying gains in different sections ..in rf and if...most am radio have tuned fromt end and 1970 80 radios advertised turned rf stage..you completely skipped tuning the rf ...the second capacitor of gang capacitor could be used for rf front end tank circuit...i saw 3 trf stages in a russian ishim radio...the radio you built sound amazing without any of those...i wander if you may need turned front end for weak am stations and dxing....you vedios helps us a lot and its always fun to watch and listen tou doing these stuff...

If only my “ugly” builds were as fine as yours Charlie. Thanks for all your help…. de VK2AOE

It sounds amazing.

Hi Charlie! Great to see you back in the saddle, and your soldering-iron out of its holster! Always enjoy the projects and all the explanations and conversation about circuits and their options. I finally retired and managed to get some pretty good used HP gear, so will be getting back into the lab myself. Anyway, thanks for putting out more great videos! 73...

I am a bit confused by the fact that you put a 910 ohm resistor to ground on the input of the crystal filter. I think you really want to make the output impedance of the Amp driving the input to the filter 910 ohms. What you've done here is make the input of the filter see 910 ohms in parallel with whatever the output impedance of the driver Amp is.

wonderful work as usual, thanks for another learning experience.73s