Bush Battery Radio 1936 Part 2 

Thank you Ron. It was good fun and I loved using my new toy bender. The radio works so well I was very impressed, Bush made good stuff. Thank Ron, Take care 🙂

Funny thing about these really old directly heated cathode valve designs -- they were instant-on, coming to life as quickly as an incandescent light bulb. The newer indirectly heated cathode valves took several seconds to warm up sufficiently. However they did enable designs where the cathode was no longer electrically tied to the heater supply.

Thank you for watching Don 🙂

Hi Graeme, thank you 🙂

Thanks Steve, that's quite an inclusive list there and I did have to lay down for a bit after the maths. Part 3 next Friday 👍🙂

Crystal clear sound from a crystal clear mind.!!!!

Hi Wayne, a couple of aspirin will clear the pain 🙂 I did a little happy dance when it worked. Thanks Wayne 🙂

Hi Steve. I looked at what was available at about 140 Volts and they were too expensive, this worked out much cheaper. I like to have as many tools available as I can, it keeps me happy... the wife not so much 😉😄

Thanks for noticing Ian 🙂

Haha... thanks Stephen, it least it's good for 40 minutes 👍🙂🚂

Thanks Radio-Ged. A lot of work for sure but worth the effort I think 👍🙂

Thank you Jacob 👍🙂

Haha... thanks Thomes, I'm glad you included capacitor cooking, that is my forté 😄

Thank you lakrfan 49 👍🙂

Thank you Manuel, glad you enjoyed it 🙂

Thank you Pavel 🙂

Thank Lockdown Electronics 👍🙂

Hi Graham, thank you. If I was doing it to create an income I would be at the soup kitchen 😄 It is satisfying when it's finished and working 🙂

Thank you Super Het. It makes sense for up to be on but we do it the other way, there is probably a reason for it somewhere going back to the 17th century. Anyway it's too late to change, sorry 😉🙂

Thank you Tim. I hope you are having success with your radios. Generally not a lot of profanity when I'm working, if it goes wrong start again. Part 3 and the final next week 🙂

Thank you David, that's a nice compliment from an ET 👍🙂

Thank you LUCKYLARRY. I'm not that good at math either but these are simple calculations so it wasn't too bad. The radio is very impressive, Bush made good stuff 🙂

Thank you Roundy Mooney 🙂

Thank you Johnny 🙂

Thank you birdie399, I'm happy you find the whole journey interesting, it's good feedback thank you 🙂

Hi Michael, sorry I must have skipped over your comment. Thank you, indeed the video takes as long as the repair sometimes, sometimes more. I am subscribed to your channel but didn't have the bell clicked but all fixed now. Thanks Michael 🙂

@@DavidTipton101 Thanks David for subscribing to my channel, I really appreciate it and look forward to seeing your comments.

Thanks Moshe 🙂

Thanks Bill. There were other regulators I could have used but was concerned they might induce switching noise into the set. If I need another power supply I'll let you know. I was more concerned that the cover would inhibit cooling. The whole thing when operating with the cover on only get mildly warm with a temp probe inside the box, it would have been nice to have one side a big heatsink though, I need to sift through some old TVs 🙂

@@DavidTipton101 A linear (non-switching) regulator is the only type I would consider, due to switching noise. I have done successful switching power supply designs with receivers but, you have to carefully "can" the supply in a seamless metal box and use at least a 3 pole filter using feed-thru capacitors to run signals in and out of the box. With heatsinks, most are designed with forced cooling air in mind. In order for convection to take place in a fan-free design, the fins need to be spaced at least 20 mm apart. However, if the heat dissipation requirement is not that great, just conducting the heat to the box exterior is fine. Painting the box black helps as well, as it increases infrared (radiated) dissipation (particularly flat black).

@@billharris6886 Yes that's what I thought with the switching regulators. With the reduction in windings and voltages I managed to lower the temperatures but as I said in the video there would be better ways to do this for sure.

A number of legacy and modern designs of equipment do have passive ventilation holes, so I wouldn't say convection through that counts for exactly nothing compared with a sealed box. It's still less than with forced air, granted. But how many radios and TV sets have fans? Probably uncommonly like zero. I'm one of the pickier engineers on Dave's page and still I think I can see over pickiness. Would clamping a device to the inside of a solid aluminum box work better to dissipate heat? Yes. Did our intrepid DIYer wish to do it? No. IMHO, it would be a bear to test for the non perforated box has to be closed. It might have been nice for Dave to test device temperature with box closed though.

@@SeekingTheLoveThatGodMeans7648, thanks for the comment. I was just sharing a tip with David that I learned in the past through much trial and error. This was in the design of an airborne communications transceiver where the customer wanted 120 watts of dissipation in a small package to operate over the full military temperature range yet, wanted long term reliability to be as high as possible. The real kicker was: No cooling fans or cooling air were allowed. So, many experiments were tried to determine the most efficient means of dissipating heat. The traditional designs of the past were tried: solid covers versus holes in the covers, in addition to numerous heatsink designs. In still air, holes in the cover showed no real difference in reducing interior box temperatures but, the holes did compromise internal circuitry from the elements and allowed more EMI to pass through. In summary, it was found that thermally tying large heat generating components to a low thermal resistance path to the box exterior performed best. The highest heat generating devices (power transistors) were best thermally tied to a large heatsink with fin spacing of 0.7 to 1.0 inch to encouraged the best convection. As far as holes and slots in covers that have been used, I suspect this is somewhat of a tradition, with little thermal testing done to prove the design. With vacuum tube circuitry, these devices are basically modified incandescent light bulbs, in that the temperature of the emitter (or cathode) must be raised to the point causing electrons to boil off. Electron tubes don't mind heat nearly that much however, semiconductors and electrolytic capacitors do. With the much higher heat output from vacuum tubes, due to the higher temperature difference between the inside and outside box temperatures, convection can take place with smaller holes in the cover.

Thank you Dave, I didn't think to do an April Fools video, probably just as well. I'm happy your wife enjoyed it too, that's nice, say HI from me. The video takes as long as the radio sometimes 😄 thanks Dave.

Thank you videolabguy. It was trial and error 👍🙂

Hi Ian, thank you. I'm glad you enjoyed it. The final part next week 🙂

Thanks Nard 🙂

A good attitude I hope, thanks Chris 🙂

Thank you Paul, much appreciated 🙂

Thank you 1974UTuber. I got the winder to rewind output transformers as they go open often and are difficult to get but the winder sat there for 12 months so I seized the opportunity to use it. It turned out to be pretty easy. The guillotine is great, I could have used that a long time ago, it made it so easy 🙂

Hi Stephen, thank you, something a bit different there. Part 3 is up 👍🙂

Thanks Mark. The guillotine/bender is very good, I wish I had one years ago. The vinegar etches the zinc otherwise the paint will fall off, I used a galvanised specific primer as well 🙂

I didn't know what to expect Shannon. More good luck than good management 😄

Hi Mack, to be fair, I said I wasn't an electronics engineer, I was a mechanical engineer for over 40 years but I was happy the electronics part worked, it was quite a learning experience. Thanks Mack as always 👍🙂

Thank you Paul 🙂

Hi Stephen, that's quite a wrap, thank you. I'm doing another transformer now, I will see if the winding machine is more controllable using the Variac. Thanks Stephen 🙂

Thanks Kevin 🙂

Hi Cress, I would have no patience with middle school students though, thanks Cress 👍😄

Thanks Jeff. The bender is very good and perfect for what I do, I could have used it years ago 🙄🙂

Transformer winding is pretty easy, the hardest part is assembling the laminations again. Thanks Alan 🙂

Ikea ?

Thank you Dances with Aardvarks. I racked my brain for sources of mesh, all I could get was large sheets for over $400. The piece I ended up with I got from a local factory as an offcut for $10, I think it is used for making perforated ceiling panels 🙂

I agree, not much on TV these days, much better entertainment on RU-vid. Thanks theDaftman 🙂

Thanks Bill, the bender and cutter have been a great addition to my workshop 🙂

Thank you HH 🙂

Haha... that would be a sight eDoc2020. Thanks 👍🙂

Thanks Graham. The holes were a bit small, they looked much better drilled out. The bender etc is very handy, here is the link so you can search close by: www.vevor.com.au/busbar-fabrication-machine-c_10114/vevor-metal-bender-305mm-3-in-1-sheet-metal-brake-folder-roller-bending-machine-p_010565160838?

Cup of tea and a bickie, perfect 🫖🙂

@@DavidTipton101 OH YES ........... its chocolate digestive ... a dunkers dream

@@meichong8278 👍😀

@@DavidTipton101 Well David that was different , informative and very enjoyable !!! A real display of your skill set .... as always David THANK YOU . Can I also ask is there a radio project you'd like to do but availability or cost doesn't allow it ?

Thank you, it was a little different. I don't have any specific radio I would like to do, I do them as they come up 🙂

The Panthers prevailed but the Bunnies hung in there, it was a good match. The Panthers seem to be on another level to the rest. The guillotine/bender is very good, I wish there were around years ago. They made us do things the hard way in training didn't they, we had to file a 6" square piece of 1/8" mild steel perfectly square with a 1" insert in the centre which could fit in any direction with no light showing through, it took weeks to do 😄

@@DavidTipton101 Aye they did, very old school in my time, white lab coats or the tweed jacket when lecturing us, no parking, few lads with long hair given some stick, couldn't happen now. One lad taking shortcuts using a lathe, lecturer powered off the whole workshop and literally tore strips of the lad concerned as we looked on. They referred to you as "Mr", Mr Sherwood do you know what your doing?....😂 Happy Days

@@kensherwood4866 That's it exactly 👍🙂

Thank you Vern, is there anything Walmart doesn't have? The shear/bender works very well and will be great for little jobs I used to struggle with, I even used the rollers the other day and that worked well too. A stepper motor would be the answer, I'll see if I can find one, thanks 🙂

Thanks cogidubnus1953 👍🙂

Hi Robert, thank you. The bender wasn't THAT expensive and has made life easier. I have another transformer to rewind but will improve my winder before I do it hopefully 🙂

Hi Rene, I'm not an electronics engineer by a long shot, I kinda managed to cobble together something that worked but it took a lot of experimentation to get there, I was happy with the result though. Thanks Rene, I'm glad you enjoyed it 👍🙂

Thank you Chris 🙂

I'm getting tired just thinking about it, thanks Daniel 🙂

Thank you for watching Mr A Coomber 👍🙂

Thank you Keith 🙂

Thank you Seiskid. I was happy with the temperature in the end, maybe 20C above ambient and it looks good in the radio but that's next week 🙂

Thank you Phillip 🙂

Thank you Paul 🙂

Thank you Herbert 🙂

Thank you Phil 🙂

Thank you De Mus 🙂

Thank you Robert 🙂

Thank you Lloyd 🙂

Thank you Dennis 🙂

Thank you Dave 🙂

Hi Mark, indeed, a lot of work in the video production but worth the effort, thank you 🙂

Hi Adam, thank you. You got some parrot clips, that are good aren't they 👍🙂

Thanks VRE, sorry about your cuppa 🙄🙂

Hi Dave, thank you 🙂

Thanks John 🙂

Thank you Zenith Coins and Hobbies, glad you enjoyed it 🙂🙂

Thank you James 🙂

Thanks Jerry 🙂

Thank you aerostar 🙂

Thank you Voyager 🙂

Thank you James, cheers! 👍🙂

Thank you alpcns. The final part next week 🙂

Thank you owwcam and thanks for the coffee 🍵🙂

Hi Kevin, thank you. Hi 🙋‍♂️ I'm in good spirits and chuffing along nicely thank you. It my pleasure Kevin, I enjoy making the videos. CHEERS! 😀

Thank you Andy 🙂

Thanks Fibber's Closet 🙂

Thank you Greg 🙂

My pleasure Neil, thank you 🙂

Thank you Keepers Of Antiquities. The final next week 🙂

Hi Don, thank you 👍🙂

Thanks A Last, I agree 😀

Hi Simon, I started too but I would have to set up for one PCB, it was easier and cheaper to go the way I did. It would have been pretty cool to make one though 🙂

Thanks markpirateuk, amazing what mathematics can do 👍😀

Thank you Bob 🙂

Thank you Jamal, I was afraid of damaging the valves and I have no spares 👍🙂

Thanks Ed, the math is pretty straight forward thankfully. My new bender works very well for the small work I do 🙂

Thanks you Ethel 🙂

Thank you Raymond. I'm not so good at designing electronic circuits is my weakness but I got through this one OK. It takes a bit longer to set up for camera shots but the results are much better so thank you for noticing. Take care 🙂

Thank you Serge 🙂

Thank you James, much appreciated 🙂

Thank you Amaraltimimi 🙂