Chris' Restoration Mania

 I got fascinated by crystal radio sets years ago. We are extremely lucky that there are still a number of AM radio stations in the US. I've tried a number of things to make a low loss system. This will permit good reception of weak signals and also a reasonably high Q for decent selectivity. (Another post on this at a later time.) Selecting a decent germanium diode is kinda critical. I was curious to know how 1N914 diodes stacked up. How different are they.  This is an IV curve from a single 1N914 diode along with a kind of poor fit for the ideal diode equation.  Another IV curve where I tested a bunch of 1N914 diodes. It's pretty clear from the plot that they are not all equal. I choose to look at the lower end of the plot and see where the rise starts to diverge and grab the one with the maximum current at the lowest voltage.  I think to choose the best diode it is worth buying a pack of them off something like Electronic Goldmine and then sorting them. Happy hunt...

 Sorry I don't regularly blog. I do have a lot of interests and work does have a tendency to get in the way. A lot of my interests revolve around radio. To me the fact that you can transmit information in various methods using EM Radiation of any type is still remarkable to me. To that regard, I'm thinking about putting together a post on how this even works down to the quantum level.  Anyway, the purpose for this post. I'm always interested in how signals propagate. This will apply to a standard radio, but also a crystal radio. There is a nice website that will show you the estimated signal strength at your location. This particular antenna is about 2km from my house and pretty much blasts everything with radiation.  https://radio-locator.com/cgi-bin/finder?sr=Y&s=C&call=WLNA&nav=home The site shows the transmitted power, the antenna pattern and will show you the estimated field strength at your location.  Ham radio operators can get field strength meter...

 Well, a very old friend of mine gift me two objects today for which I am very grateful. Of course I immediately delved into the history of the objects. One is an old crystal radio set around 1922 vintage.  Westinghouse Aeriola Jr. And yes, I took it apart. The circuit is quite clever. The tuning is done using a variometer. I will publish more when I actually hook it up. I have a decent long wire antenna, but not a decent ground. I'm at my alternative location. My home location has both! This is the first set I have had with a real Galena crystal. I'll be curious to see how difficult it is to find a decent contact using the mechanism in the upper portion above the dial.  More can be found here: https://www.radiomuseum.org/r/rca_aeriola_jr.html Sold for a whopping $25 at the time, a princely sum in the 20's.  The other is a unknown vacuum tube set, 3 x 201A vacuum tubes. It looks to be missing some parts. I will at some point draw a schematic of the device. I'm g...

29-Aug-21  I have often thought about starting a blog about all the sundry things I restore. I have been doing this in a bit of a round about way all my life, but it was more oriented to repairing old stuff that people threw away that I could use it in my workshop.  I started to get really serious about this a few years ago. I was at the Maker Faire in Queens N.Y. and I noticed that someone had an old console (like 1940's) based radio, but just the husk. It reminded me of my youth when I would visit my friend Peter. They had a Blaupunt radio that had shortwave and I became enamored with listening to shortwave. (There is a whole story here for another day.) I walked away and vowed to find one.  I think it was about a year later and I went to the flea market in Stormville N.Y. which (pre-COVID) used to happen about 1/month. I didn't know what I was looking at or what it cost and kind of delved in. I found what I now know is a Philco 38-7 (well, I guess I have a photo of the...