Novice 10 DSB XCVR - Part 4 Transmitter

10M rocks! I make my first couple of contacts with the transmitter boards on the bench. The complete transmitter chain is covered.

[@DicedIceBaby314]

We used to wind toroids back in the day. Uphill, both ways in the snow. Thanks for the content man!

[@johnwest7993]

And they were trifilar! And we used just 1 color of magnet wire!

[@MIKROWAVE1]

That's Toroidable!

[@Dazzwidd]

​@@johnwest7993hahaha that's what multimeters are for hey 😉

[@johnwest7993]

I NEVER get bored with discrete leaded component circuits slapped down on copper! They have personality that a commercially built PCB simply lacks. When I go to a swap I'll grab any free ones I see, and pay as much as a dollar for any others I find just to take home and figure out what they do. I find them fascinating, especially when I have no idea what the circuit is or does. I can spend hours staring at them, getting into the mind of the builder, learning about their skill level, observing from their soldering and the bend of the wires what changes they made, how many times, and figuring it all out as if it were a puzzle. Thank you Mike. P.S. Years ago, when I worked as a young R&D tech at a new job I once impressed the senior engineer by figuring out what a bare board did, and what components were used and where, and their values on the PCB that had nothing on it but holes and traces for 5 IC's, a few diodes and transistors, a handful of passives, and holes for a 25 pin D connector. No silkscreen. No bd number. No manufacturer ID. Nothing. Just a chunk of FR4 with holes and traces. I figured it out, then populated it, fired it up and ran it. Then I took it in to work on Monday morning and left it on the engineer's desk. I didn't tell him that I'd spent the entire weekend at it, from Friday evening till Sunday night, sitting at my bench at home surrounded by my notes, parts, and my entire collection of data-books. It was winter, windy and snowing all weekend, so I hadn't missed much. Besides, it was a lot of fun. I'm a geek. And you think you'd lose me at having to wind a toroid? :)

[@jerryuhte1284]

Congratulations Mike!

[@W1RMD]

Great video! I really enjoy you breaking this down into segments like this and seeing this work in it's "JS' ed" state is an encouragement to me. I want over my toroidephobia (which is not curable by big pharma), so a "workshop" is an excellent idea. 73.

[@ctbcubed]

This is what ham radio is all about! Great project for the sunspot cycle peak.

[@MIKROWAVE1]

You got it exactly. Targeted towards the Novice band that is red hot.

[@johnwest7993]

Winding and adjusting toroids, as well as peaking tuned stages with an alignment tool are my very favorite things to do after I've brought an old radio back to life or just finished building a kit.

[@TheGmr140]

Nice little dsb box 😊😊

[@wklinger79]

No issues with toroids. I built an elecraft K2, Tuner, and a K1. Lots-o-torroids here!

[@foxbat888]

There are so few commercially available 10m dsb kits, in fact I don't know of any. You can see from the contacts you made that a good kit would be a killer product, at least during the solar maximum if not generally so keep going!

[@ornithopterindia]

👍Thank you sir.

[@cwebs1000]

Great builds Mike. Thanks and keep them coming. I love home builds. Carl AB1ZI,

[@scottnolde564]

Nice job on the radio Mike! Winding toroid tip, be careful with the enamel coating on the wire. don't scrap the enamel insulation off on the sharp edge on the ferrite core causing a short between windings or to the core it's self. check with an ohm meter set on the Megohm range. I found this out the hard way, Amidon sent me some type 43 cores a few years ago that had no coating on them. Checking the core with my ohm meter showed a resistance of a couple of K ohms! So I dip the unpainted ferrite cores in thin Q-Dope and let dry. Wind the transformer wire onto the core after coating. Powered iron cores are already color coded with paint so no sharp edges on them.

[@MIKROWAVE1]

In college, I had a co-op job where we rebuilt military radios, and winding and stabilizing toroids was something we did with q dope coats and oven cycles. We used the old Boonton Q meter!

[@trevorwoods3367]

Great watching you make those contacts.

[@JCWise-sf9ww]

Mike, I'm looking forward to when you put up a video on toroid core types. I have a few junk box cores of different sizes/types, but don't know what frequencies they are good for. These toroid cores, I've had for quite some time.

[@PapasDino]

Mike - did you consider using a panel mount Powerpole connector instead of the older style? I avoided PP's for a very long time but once I started it was like eating peanuts, couldn't stop...also reduced the radio bench wal-wart count to almost zero with PP distribution strips and one supply. BTW, having a receiver with a calibrated S-meter in dBm is a great piece of test gear; my TenTec RX-340 was a retirement gift to myself long ago! 73 - Dino KLØS

[@MIKROWAVE1]

I found some powerpole ends!

[@Dazzwidd]

I honestly think the simplicity of DSB makes the tradeoffs not much of an issue unless the bandspace available is limited. You don't even need really high carrier suppression as the carrier can be used by the receiving station to get right in the middle of your sidebands so they hear your audio as good as it can be received. The audio can indeed be very good

[@MIKROWAVE1]

I seem to be adding parts like a nut on this. Just another 2222. Ha.

[@Dazzwidd]

@@MIKROWAVE1 I don't think you are doing anything wasteful. Talking about parts, I have a considerable surplus and won't use them. I also think your videos are excellent and can see you really enjoy the true essences of ham radio, which your channel really captures well. I would like to donate components to you but I don't know where to send them.

[@Pixelwaster]

Didn't fear the torroid, never could afford them back in tha day. Learned to use TOKO coils. Nothing beats a pair of adjustable trifilar coils in a balanced modulator. I found a supplier that sold FT torroids cheaper than the small parts guys. Half a key of FT43-50 for the price of 20 😮😮 Now the free shipping is $50 and they only ship overnight. Would you do a DSB 6 meter silicon and/or thermic ion 6 meter rig? The FMLA and Brits couls shift their down to 5 or 4. K1CLL (sk) had a simple hetrodyne VFO if I remember the cover image of 73.

[@johnwest7993]

Ten can be a real joy. When 10 is hot you can follow the conditions all the way around the world over the course of the day with even QRP level signals. That's why I find the CB's running 5 or 10 kW to be so obscene and ridiculous.

[@W1RMD]

Not to mention you can't understand a word they're saying, at least on the first few channels. They all seem to understand each other though.

[@GoonyMclinux]

Torroids are easy with a VNA, and windings are usually near identical in winding count for most uses, shouldn't be off putting because they are quite simple.

[@JackKC8QPG]

Great Information! Congratulations on your Proof of Concept - IT WORKS ! I'm Looking forward to your presentation on Toroid winding. My understanding is that Transformers do not store energy, only step up/ step down a ratio of voltage and the current ratio is inverse. Your goal KISS is going from 13 Ω to 50 Ω and it works with your 4:1 Wideband Transformer.Ω I'm missing something . You have 7 windings. 7 squared is 49. How does the 4:1 come from 7 squared?

[@JackKC8QPG]

Correction: 7 turns on your Toroidal Core.

[@alexkalish8288]

Your understanding is wrong, energy is stored in the B field and is lost when the field collapses. Cheers from a EE

[@MIKROWAVE1]

On the modulator transformer: Three identical length wires twisted and 7 turns. Two cross connected to form a center tap. Thus 14 T against 7 turns so 1:4.

[@Chris_Grossman]

If you put a second emitter follower on the oscillator output would you get better isolation from the transmit and receive sections and avoid needing an extra gain stage since there would be no power loss in the splitter?

[@radioguy19510]

Winding toroids isn't the problem, getting them is. How does a guy know what type to keep around and how do you determine the types such as 37-2 or 50-2 and how do you figure the type if there is no color code?

[@KB4QAA]

Buy toroids from reliable vendors like Fair-Rite or the parts houses like Digikey, Mouser, etc. Random junk box and hamfest sources are not reliable, though one can use a VNA or other testing devices to characterize unknown toroids.

[@Steve-GM0HUU]

Some of them are colour coded (like red for type 2 or yellow for type 6). For the ones that are not, I keep them in clearly labelled bags. I find a small stock of T37-2, T37-6, T50-2, T50-6, FT37-43, FT50-43 covers most of the low power circuits I want to build.

[@radioguy19510]

@@KB4QAA Thanks!

[@radioguy19510]

@@Steve-GM0HUU Thank you. I have many T50-2, T68-2 , some T37-6 and a few others. I am going to the states this weekend and I will try to order an assortment. 7 3 DE: EA4/KF0XO

[@alexkalish8288]

amidon seels them to me, I have hundreds in my lab of various sizes and materials.

[@gd2329j]

I am looking for frequency agility . Just by ringing the output tank circuit can the vxo double a 5.5 Mhz Xtal & get enough output power ? Could a hi Z stage following the vxo help . We all have different design experience . It's definitely a interesting process …....... Questions , Choices , Junk box or new parts , The just why moments , Pi Y/N , The maybe circuits , That'll never work & Wt is that google ... But for home-brew projects normally getting 95 % of the design spec is good enough . You over engineered it in the first place .. LOL PS a diplexer should help after the mixer .

[@gd2329j]

5.5 Mhz Xtal ?? ! It should've been 15Mhz & a bit ….🤦‍♂

[@_wave64_]

I wonder what made you choose material no. 47 for the modulator (instead of higher frequency materials like 61 or powdered iron)

[@MIKROWAVE1]

Great question! At 28 MHz, there is a big overlap between these two ferrite materials, 43 and 61, and you even can use some of the higher Mu Powdered Iron. Conventional transformers are great but Transmission line transformers are even lower loss, and are fairly core agnostic anyway, especially at low power. Even the Red and Yellow powdered iron cores -2 and -6 have an overlap here, and you can use either one with no discernable Q penalty on the tuned transformers.

[@W1RMD]

I've avoided many (all) projects involving ferrite and iron powder forms. Too many variables. What colors for what frequencies? I got these at a hamfester, are they pulls from a switch mode power supply? Who knows? They were REALLY cheap though! How do I test them? I got some from China, They say "ferrite" but they're yellow. I though only iron powdered was painted?! Ug! Not that I'm an expert, but I steer toward pre-1970 projects before these little buggers were invented.

[@Broken_Yugo]

Color corresponds to the material.

[@W1RMD]

What confused me was the Ebay add that said ferrite, but was colored green. I though that the color codes were only for iron powder not ferrite. A lot of fake parts out there. I'm still learning.@@Broken_Yugo

[@alainmichaud8992]

I agree. That's unfortunate because you find them to recycle everywhere. I think one can not rely on color to identify them. Same for paying $50 for a single ferrite core that comes in a plastic bag with the number 234-B47 written on it. There should be a procedure to identify/test it yourself.

[@MIKROWAVE1]

Those nice looking Yellow White Type 26 cores found in ATX Computer Power Supplies are high MU Powdered Iron and are only really useful for Switching Power Supplies, (So LF 30 to 300 kHz ) and Filtering power supplies. So avoid them. The Green Blue Type 52 cores are also LF switching. But the various chokes in the supply with heavy wire are usually ferrite rod based. These cores can be useful for re-winding wideband transformers at HF.

[@alainmichaud8992]

I have a bag of green ones with a ring of blue paint, one inch OD, bought from orient. I was planning to use them as baluns etc. You say they would heat on the 40 80 m band? Also I once tried to crack an other one open. Impossible! It was made of very hard tool-steel like material. What are those for?

[@jimw7ry]

15:22 Mike What are you nulling? What are you truning to get the null? Thanks! Jim W7RY

[@MIKROWAVE1]

The DSB modulator is actually a single balanced mixer and by balancing the bridge perfectly with a potentiometer and a trimmer, you can almost perfectly null out the carrier from the local oscillator (VXO). We do not need (want) a carrier for DSB.

[@jimw7ry]

@@MIKROWAVE1 Thanks! I understand now Mike. 73, Jim

[@nandrews8412]

Id rather wind toroids than surface mount soldering given the choice.

[@MIKROWAVE1]

I dis not mind SMT when I was younger, but the parts got even smaller!