The Po formula is not correct. For a PP configuration even in class C the 2 is in the numerator. THe formula given around 25:50 is for a single ended amplifier (BPT type). The Toroid King in US claimed 5 W out for a 1 plus one configuration but only in class C configuration. He sold that type of amp using BD 139s and then discontinued it. I have a feeling that people were only getting 3.5 to 4 W out on most builds so he had to look for better RF service commercial BP Tr which he eventually did (that's DIz , who is now dead). An interesting comparison is with the RD16HH mosfet which will give you 16 -17 W linear out at 10 Mhz in the same general configuration with only two devices. But they do cost a lot more. TEF / ZL1Mzr

Nice Project Can you Share Schematic

amazing job Charlie. greetings. sierra queen nine romeo sierra charlie

Thanks for sharing this. I have been making my projects on single-sided board on which I create isolated pads with a small rotary grinder tool with a diamond burr (like a Dremel). However I find it quite hard to translate a circuit diagram to create a practical board which works on the first attempt without too many long 'stretches' for connecting components. I have played with small 'island' pads cut from standard circuit board, but I can see that the perforated board would make life easier. I must try it. I've been buying both plain board and perforated board from Tayda Electronics online. Best wishes from Nelson, NZ. ZL3ABX

Hello Charlie, Thank you for your very informative videos. I am making good progress in building Eamon Skelton's SSB transceiver from his book "Building a Transceiver". I'm at the point where I need to build a PA. Eamon has several options in the book; however, they all specify a toroid "N88AB" from Maplin. Maplin no longer sells these and I cannot find a cross reference to this toroid anywhere. Do you have any idea of what an equivalent toroid might be? Or can you recommend a more modern PA at 100 to 200 watts?

Hello sir. Can you provide the details of the modulation transmformer. Primary and secondary windings. SWG of the copper wire etc. DE VU3IZD

Nothing wrong with your work. You are what HAM radio is all about. Thank you.

Thanks very much for the 5 part series! I especially appreciate how you show the design details. You mentioned possibly a video on the strip board construction--I would love to see some instruction on how you do that. I know nothing about strip board construction--my primary construction is "ugly style" over a ground plane. Thanks. Steve AA7U

Wouldn't a single self bias jfet accomplish the same thing as your buffer and amplifier?

Your AF amplifier... you could benefit from using a BD139 in place of the 2N3904 driver as well as running its bias resistor to the output so there's global negative feedback. Also apply bootstrapping on the upper AF output transistor. Don't bother with the gain control in the emitter resistor on the driver, just leave it with a 22 ohm resistor and do all your controlling upstream

To solve the reflections on the NanoVNA screen, if the camera has manual or at least +/- adjustable exposure try throwing a white sheet over your head and the camera tripod, like a tent. You might need to improvise a "pole" to keep the lens clear. No lighting inside, the camera should adjust to the screen display. The surroundings and your hands will be dark but at least no reflections (caused by the ceiling and ambient lighting) These vids are absolutely great btw - I've only just found them after a 20+ year hiatus in radio construction. Showing your working and assumptions is really useful for newcomers to design/construction/fiddling

At 11:35, when you increase the input level, the 3MHz leakthrough starts to increase sigificantly. My guess is that's due to imbalances "further up the curve" with higher current flow through the diodes. If so, that suggests that by careful selection of diodes, maybe plotting them and binning them at 1mA first, then re-runing each group at at 200uA, 1mA and say 10mA and sub-grouping them again, you could achieve better preformance. Of course, that's a heck of a lot of extra work and would probably need a much larger group of diodes to select from. I suppose it could be a thermal effect too (or instead), so by simply applying heat from a pinch of your fingers at your original DC measuring/selection stage, you could maybe pick the most stable ones within any similar bin group, assuming that there's any noticeable thermal effect. Conversely, it could be some differences or nonlinearity in the transformer cores too. If that's the case, larger cores that would show less saturation curve effect would be better. (I doubt there's much effect of this at these sort of drive levels though) It's already a pain selecting diodes/xtals etc (ask me how I know!) so I don't want to encourage you to do any extra work, just thought I'd put my hunch out on the internet in cae anyone wants to experiment.

Years ago, when the humble CB was very popular, they sold crystals for the CB band in electronics stores (possibly today it is more difficult to find). I read something about SSB filters, and bought a good number of crystals 27 MHz and another batch for 27,005 crystals. It seems that there are two types of resonance, one is the crystal acting as a filter and the other is the crystal acting as an oscillator, which are somewhat different, perhaps related to series and parallel resonance. The thing that in its day with an RF generator and an electronic voltmeter with an RF probe made two SSB filters that worked, but the problem was finding the quartz oscillator to create the SSB signal. I didn't insist and abandoned it. I recently bought a nanoVNA, and I found that nanoVNAs are almost amazing, that what once required sophisticated devices, I can measure or analyze with a nanoVNA: I have checked those filters that I made and indeed, they had a very suitable pass band as a filter of SSB. I also bought some ceramic SSB filters for 455 khz (at a more reasonable price than the quartz ones and I have tested them now with the nanoVNA and they are "very effective", today I imagine that they would be difficult to find if not via China. I have some other filters and SSB crystals resulting from scrapping cheap CBs.

Hi Charlie Morris! May I have the first quaestions on this topic. What does SSB mean? It stands for "Single Side Band", doesn't it? And the PD block after IF2. What is it? A mixer? So your Radio Station would be "DOUBLE SUPERHET"? Thanks for your works and attentions!

Thanks so much for taking the time and trouble to do these videos really informative stuff! 73s Ian G6TVJ

A common base amplifier for the second stage of your buffer amplifier might be an idea as its low input impedance might be similar to that of the output of your emitter follower stage.

hola charlie. felicitaciones por ese trabajo de cristal filtro. te cuento que esa configuración la realice hace unos 30 años atrás aproximadamente. pero en frecuencia de 10 mhz. use en esos años un monitor de estación a válvulas heathkit que tenia incorporado un oscilador de doble tono para ser usado es ssb calibración. me construí un qrp en banda lateral única y lo quería en LSB con cristal filtro . para encontrar el corte ideal no seleccione los cristales de cuarzo, todos fueron al azar, solo que los capacitores fijos entre ellos los remplace por capacitores variables y usando el doble tono encontré los valores correctos para una respuesta decente. fue tan bueno el resultado que cuando salía en 40 metros todos pensaban que era un equipo de fabrica .jajaja. fueron muchas noches de ensayo y error pero el resultado fue espectacular. tu video me hace recordar aquéllos años cuando era un bebe en electrónica pero lo aprendido en general de construir tu propio equipo es impagable. nuevamente felicitaciones y me entretiene mucho tus videos. mil gracias por publicar. atte Enrique Vidal CE5LBM

Really hellpfull video. this helps me with my Diploma this year. Would like to see how i could imput this voltage for an esp32 in terms of amplification and such. 73 de OE8GKE

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.

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E

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 KZbin. 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