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Showing posts from January, 2020

Software Defined Radios for 2020

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Some new technology to add to the new technology for 2020.2-3-2020 Photos of the day..


First we have a photo of Virginia Hall (from Baltimore), a famous WWII Spy working for the Brits and later the OSS. Here we see her pounding brass on a Paraset.

That must be a British version of the GN82 hand crank generator. Notably she had a wooden leg, a result of a self inflicted gunshot wound. She passed in 1982.
Our next photo has a deep meaning...

Maybe this was about their voting for the emperor (with the small e)
After connecting power of the wrong polarity to a circuit how many have said what is on this T Shirt. 

I didn't do that but did put a Teensy 3.5 into a socket, one pin over, and did see a ball of flame come out of the top of the chip. Luckily I had two Teensy 3.5's (now only one). Even more lucky it was not the Teensy 4.0!
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2-1-2020 TEENSY 3.5 ala ZL2CTM, Working Again; But needs further evaluation. 


[My plan is get a Teensy 3.5 …

Back to SDR Radios

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A brief respite from the 1930's...[1-26-2020 ~ Should we be worried? This morning as I pondered yet another project I was just about to hit the purchase button for several amazing technology products that were 'home ported" in Wuhan, China and Hong Kong. Then it hit me! Boom I cancelled! 
Can the coronavirus be hiding out in the packaging that would enclose these electronic jewels. That is a serious question and it needs an answer. Should we stop buying anything coming from China?
I even think about that when I pick up some bargain on eBay that has been lying in a barn for a couple of years. My standard process when I open that box is to use a mask and rubber gloves and I wipe over the gear using  Lysol spray before I start to work on it. More than once I have seem mouse droppings inside of a chassis. 
So why can't coronavirus be hanging out in that packaging coming from China. I just don't know --so those projects are now on hold!
If someone knows the answer email me…

You Saw where this was headed ~ A 1930's Style Station Part 5

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The Pesky Power Supply Problem.
Most stations of the 1930's relied upon either battery power or the building of a power supply that plugged into the regular house mains. In either case you needed DC voltage to run either the transmitter or the receiver.
For most tubes used in the transmitter section this amounted to several hundred volts of DC. Receivers, however, often could get away with having say around 100 VDC on the plates. The All American Five Tube AM Table Radio did something clever. Here the radio designers figured out how to take the 110 VAC standard house power and to string the filaments so that the total filament draw = 110 VAC. 
This required the development of the 35W4 rectifier and the 50C5 audio power amp --yep the filaments for those two = 85 volts. Add in three 6 / 12 volt filament tubes (6BE6, 6BA6 and maybe a 12AU6) and thus the math = 85 + 24 = 109 Volts AC. A simple half wave rectifier like the 35W4 and you had about 120 VDC. Forget that the chassis was hot wi…

You Saw where this was headed ~ A 1930's Style Station Part 4

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Dress for Success!
That sage advice typically was offered to those who were participating in a job interview. Showing up for a job interview for a position entitled Vice-President for Creativity with a three day beard, a somewhat soiled tank top and flip flops only works in Silicon Valley and only for Google positions. Elsewhere requires a very different "attire".
So it is with our hobby -- not the dress itself as what I described previously probably involved comments like what's wrong with that dress from many blog readers. The dress for success point goes to the heart of hams who have either very little or NO test equipment! Test Gear is the Dress For Success for our Hobby!
The recent re-incarnation of the PMR6A involved test equipment that is of old. Yes I do have a some really new and some really old test gear. One critical variable with the  PMR6A are the "toobs". Looking into the radio and seeing if all the tubes light is indeed a test; but they could all &q…

You Saw where this was headed ~ A 1930's Style Station Part 3

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The PMR6A Receiver itself will now undergo the re-incarnation process.1-18-2020 ~ when you know stuff, you can do stuff! Not a uBitx v.6; but a trip back 67 years!

73's Pete N6QW
1-17-2020 ~ It is Alive! 





More Space Filler.
Ham Safety while working with Thermatrons (vacuum tubes). 
Most of our homebrewing taking place today uses 12 VDC and that is not high voltage. Although I do know of a case where a constructor had his hand on a 5 VDC 30 amp power supply output -- seems like his ring got shorted across the supply and the ring nearly melted around his finger, which subsequently I think required amputation. So any voltage can be dangerous.
The voltages in the PMR6A under load show 260 VDC on the lead to Pin #3 on the power connector. [There is a clue here for those who read every word...] The problem with the HV is that it can start your heart (defibrillator) or stop your heart if applied too long.
One of the additional steps I will be undertaking is to provide shield covers over the powe…