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News, Updates and Other Minutiae

September 2023 Long time between drinks, but not much happening on the tech front at the moment. Added another couple of rants to the rant page.

January 2023 Updated the AD9833 VFO code to use a 12F1840.

December 2022 Added rant about todays useless (internet) search engines.

November 2022 NEW Project An AD9833 Based Simple VFO. FT101ZD VFO project updated.

October 2022 A replacement internal DDS VFO for FT101Z/ZD rigs. Because the worlds postage system has gone totally bonkers and it is not possible to send a small pcb anywhere except at extreme cost, I am slowly making available the option to purchase pcb's from Pcbway. First up is the Simple DDS VFO 2017 project pcb. Others will be added over time. Noise Canceller kits available again- see Noise Canceller page.

Privacy Policy uploaded. GPDR and all that stuff In accordance with various bits of legislation around the world, either currently in force, about to come into force or proposed, you will now find that annoying "We use cookies" notice at the top of this website. The full Privacy Policy is available at the Privacy Policy link in the footer at the bottom of the page. (If you don't know what GPDR is, Google it. Real scary shit for ANYBODY with a web presence.)

Old Valve (Tube) Radios

I started in electronics, way back in the dark ages in the UK, at a very young age and I can blame it all on my grandfather. While staying with my grandparents on holidays and various other times, they used to religiously listen to a radio series called the "Archers". To keep me quiet during the broadcast, they would put me in the cupboard under the stairs (no, it wasn't punishment or abuse), where there was this wonderous world of strange bits and pieces I could play with. This was back in the Fifties (1950's, that is) and I quickly found out these were old radio bits and pieces. Anyway, moving on a bit, I was given one of those Philips kits that made up various electronic gizmo's. From there, I joined a ham radio club and built my first transmitter, a valve (tube to those in the US) 2m AM rig at age 13. (You can hear the outcry now if you let a person of such young age play with all those nasty, dangerous high voltages these days. The nanny brigade have a lot to answer for). Which brings us to the present. For a bit of nostalgia, I thought I might like to build another copy of that old 2m rig. But where to get those harder to find parts without spending a small fortune? As luck would have it, a flyer appeared in our mailbox, advertising a clearance sale and in among the items were - old valve radio's. To cut it short, I ended up with 8 valve radio chassis, all complete, for the princely sum of $6 and I suspect all but two are in working order. Here are some pic's of a couple, to give an idea of what condition they were in. These first two pic's are from a Precedent 5 valve radio/gramophone chassis. The Precedent was the inexpensive brand of the day, with things like the IF cans being pop rivetted around the coils. Also, notice, in the first pic, the two outside pulleys that the dial cord runs over, they are made of wood. An idea for that next project perhaps? In the second pic, the circular plate that came from where the mains transformer is mounted was used to mount the tuning coils. Despite this, whoever built this particular one took great care in wiring it. Look at how straight the bare wire is and with precise bends. The overall wiring and assembly is very neat.

Top view of old Precedent radio chassis Bottom view of old Precedent radio chassis

These next three pic's are from a chassis, brand unknown, that shows the best use of chassis space. In the first two pic's, both sides of the chassis have been used to mount valves and components. While the third pic shows the variable inductance tuning unit, rather than a varaible cap. That unit still has a nice smooth action.

Front view of unknown chassis Back view of unknown chassis Variable inductance tuning unit

The blue sticker with "ARTS & P" on it is a royalty sticker. Most radio builders in Australia of the time, formed an alliance to make use of patents and protect themselves. The Australian Radio Historical Society and many other sites can provide information, if you want to know more. These and all but one of the others have been dismantled and the parts (excluding resistors and caps) have been kept. Three of them had dial scales which are available for sale of which I will get some pic's and put here shortly sold before I could get them up here.

AWA Radiola 573 MA Repair

A few days ago (Feb 2020), a neighbour dropped in and asked if I could have a look at his old radio. Apparently it had been getting quieter and had finally stopped making any noise. It turned out to be an AWA Radiola 573 MA, which, apart from a broken knob, was in pretty good condition.

AWA Radiola 573 MA picture

Rather than go through a boring blow by blow description of the what, why and wherefore's, it was a simple fix. The grid coupling capacitor to the output valve was near enough shorted because mice had been in there feeding on the wax (weird diets some of these mice). Below are some before and after photo's, keeping in mind this was a repair rather than a resoration, although I did take the opportunity to swap out all out of tolerance components and fit a 3 wire mains cord and fuse. Everything was done on the basis of being fully reversible if anybody in the future wants to do a full restortation on it. Even the mains cable inlet (a piece of irrigation pipe joiner) is only cable tied through an existing hole.

AWA Radiola repair picture AWA Radiola repair picture AWA Radiola repair picture If anyone has a spare knob like this (rear half of the tuning control), I would be interested in it. AWA Radiola knob picture

While doing the repair was an easy job, one annoying part was having to move back and forward to different pages in the manual to find component values and voltage readings for the schematic, so I redrew it and put all the information on the schematic (including the values of the components in later modified versions). There is a pdf version you can download below.

AWA Radiola schematic

PDF download of schematic: 573MA Schematic.pdf

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