Dieselpunks

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The weather is bad, so I had plenty of time for a new project: A crystal detector radio.

Technically it is very easy: A coil, a turnable capacitor, a headphone and a diode. Luckily I had in my spareparts an original radio crystal holder and a an old prewar headphone. A bit of plywood, glue, wood stain an schellac (as finish) and 24 hours of time.

This is the result: For testing I used a Germanium diode, the crystal will be connected later. The coil has 30 windings. As earth I used the water tap in my kitchen (I will make a more durable earth connected to my kitchen sink) and about 1 meter of wire as antenna. I was able to hear our local station (WDR 2 on 720 kHz, about 30 km from here) loud an clear. On the photos you can see the inside and the finished detector radio.

What I need is a more beautiful turning knob and a dial.

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Very nice!

Cool! Weren't  there  also crystal  radios  that used  crude  speakers, too?

 

Yes, it is possible to use a high-Ohm loudspeaker with a horn, if there is a strong transmitter nearby. Otherwise you'll need at least an one valve (triode) amplifier.

Excellent job!

Have you had any success with these even simpler radios?  http://en.wikipedia.org/wiki/Foxhole_radio 

Hello,

yes I tried it many, many years ago. But without success, there is no stronger AM transmitter in my neighborhood. Maybe it is easier where I live now, it is only 30 km to the big transmitter in Langenberg on 720 kHz.

Where exactly do you live?  I used to live in Döttingen (Braunsbach) about 10 km north of Schwäbisch Hall.  

I am tempted to teach the CAP cadets how to make simple crystal or foxhole radios.  There is an AM tower with line of sight to the hangar.  The Boy Scouts have kept crystal radios alive for decades:  http://www.scoutstuff.org/bsa/crafts/science/crystal-radio-science-...  (I never got mine to work.) 

In my mind crystal radios and spark gap transmitters go together: http://en.wikipedia.org/wiki/Spark-gap_transmitter but I understand that the FCC takes a dim view of them.  The idea of being able to cobble together even crude radios is appealing.  You just never know when the next Carrington Event might happen. 



Dr. Zarkov said:

Hello,

yes I tried it many, many years ago. But without success, there is no stronger AM transmitter in my neighborhood. Maybe it is easier where I live now, it is only 30 km to the big transmitter in Langenberg on 720 kHz.

I'm living in Moers, in the North of Dusseldorf (Northrhine Westphalia), in the west of the Rhine.

A spark-gap transmitter is very interesting, but the signals are very broadband. The chances are high that the authorities will not like it. AM is not very popular in Germany. The band was overcrowded,in the past, so everyone switched over to FM (and now to DAB+, the digital standard). The last AM transmitter will be switched off in december 2015. Other countries are a bit slower, so there will be some signals on AM for the next years. On shortwave the situation is better: There will not only be a lot of stations from the "funny countries" like Cuba (good music) and Northern Korea (sounds like Radio Moscow from the 1950s), but there are a lot of new, commercial stations in Germany (and a lot of pirates from the Netherlands). Of course it is possible to build a shortwave detektor.

And of course after a new Carrington Event (or an EMP if the new cold war in Ukraine gets hot) it is much easier to build AM transmitters and receivers from the scratch than any kind of digital information system. On shortwave you can even make television with your homemade transceiver/receiver, look at my homepage: http://www.zarkovision.de ;-)

Your homepage is way beyond my rusty German and electronic knowledge. 

AM radio is far from dead here:  http://en.wikipedia.org/wiki/List_of_radio_stations_in_Alaska

Amazingly Alaska still has "colored airways" which are based on AM NDB beacons and ADF receivers in the aircraft: https://www.faa.gov/air_traffic/publications/atpubs/aim/aim0503.html  This was barely high tech in WW II.  The old ADFs can also be tuned to regular AM radio towers which can help you navigate if you know their exact location.   My plane still has the hardware to remount an ADF antennae and received but I do not think that I would get enough use out of one. 

IF we have time to teach the cadets how to make crystal or foxhole radios you have given me a good idea.  Juneau still has NDBs which broadcast a strong, clear Morse code signal that should be easier for a crystal radio to lock onto. 

Hopefully the Ukraine and other troubled spots in the world will maintain their composure.  I worry about scenarios like one lone idiot with anthrax or a surplus nuke blowing up Tel Aviv or Houston.  The nation(s) targeted would not rest until they retaliate against any nation(s) that they consider responsible.  Sort of like some some insignificant archduke being assassinated.  If things go sour there consider hopping a Condor flight to Alaska or the Yukon for an extended fishing trip. 

AM is perfect for big countries with a small and widespread population, but does not work well in big cities with much electric noises. So in the evening hours there will remain a lot to listen to from Ukraine, Russia, Spain and Northern Africa for me. In the early morning hours from October to April there are even chances to receive stations from "over the pond". Of course you need a good outside antenna or a big frame antenna. Just with daylight AM will be empty here very soon. I will experiment with my own AM transmitter (small, only for my house!). Which is not legal here, but where's no prosecutor, there's no judge...

I just looked up the FCC rules for AM stations in the US:

http://www.fcc.gov/guides/low-power-broadcast-radio-stations

http://www.fcc.gov/guides/how-apply-radio-or-television-broadcast-s...

Alaska is roughly the size of Europe with about 660,000 people and about 2/3 of those people live within 2hours of ("Los") Anchorage.  Our burough is about half the size of the Netherlands with 31,000 people living here.  As you say, not a bad place for AM.  We still have an HF at the hangar for emergencies like Anchorage just had a little 6.1 earthquake and many of the buildings had to be evacuated.  One of these mornings there just will not be anyone to answer the phones in Anchorage again:  http://en.wikipedia.org/wiki/1964_Alaska_earthquake 

Just to tie this back into DieselPunk:  http://americanradioworks.publicradio.org/features/wwii/b1.html 

or these clever crystal radio users: 

Actually a "cell phone"  http://globalmoxie.com/blog/eves-portable-wireless-phone.shtml



Dr. Zarkov said:

AM is perfect for big countries with a small and widespread population, but does not work well in big cities with much electric noises. So in the evening hours there will remain a lot to listen to from Ukraine, Russia, Spain and Northern Africa for me. In the early morning hours from October to April there are even chances to receive stations from "over the pond". Of course you need a good outside antenna or a big frame antenna. Just with daylight AM will be empty here very soon. I will experiment with my own AM transmitter (small, only for my house!). Which is not legal here, but where's no prosecutor, there's no judge...

This is a really clever antenna for mobile use, and very Dieselpunk, indeed. :-)

I have a question about the early days of AM radio:  Why were they not earlier? 

http://en.wikipedia.org/wiki/KDKA_%28AM%29  1920 just seems a little late.  Was there some overwhelming technical hurdle?  The idea of a commercial radio station seems so obvious and what were people listening to on crystal radios for the previous 15+ years? 



Dr. Zarkov said:

This is a really clever antenna for mobile use, and very Dieselpunk, indeed. :-)

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