German Tanks and Drake 2-Bs: We Have the Number!

Hi Bill,

Finally getting back to you. I crunched the numbers... I saw a total of 23 serial numbers reported. The important thing is that these numbers be reported somewhat randomly with no biases etc. I think this is the case, and the fact we have 23 numbers is very very good in terms of the power of this experiment. The highest number reported was 12955. Let m = 12955. The number of reports was 23 so let k = 23. The equation to use (from wikipedia) is below...

Simply applying this equation we get an estimate highest serial number of 13517. So we can estimate that between 13000 and 14000 Drake 2Bs where made. I think I remember someone mentioning that the Drake 2B serial numbers did not start at zero. This is not really a problem. You just need to know at what number they did start, then subtract that number from 13517, and that would be the number of Drake 2Bs ever manufactured.

The lowest serial number reported to SolderSmoke was 2008, so you wouldn't need to subtract more than that. You can think of this equation intuitively (a very SolderSmoke thing to do!). Imagine what happens when we have a single observation. k = 1, so our estimate is about 2 times what our highest observation is. This makes sense because you would guess your observation is most likely to be about half way between 0 and the true top number. If k = 2, then our estimate is about 1.5 times our highest observation. If k = 3, then our estimate is about 1.333 times our highest observation.... as we observe more numbers, we are more likely to have observed the top number so as k goes to infinity, our estimate moves towards our top observed number, which it should.

I hope my explanation made sense. Anyway I highly recommend SolderSmoke listeners who want to know more, to read the wikipedia page. Its quite well written and offers a lot for people who like hard formal explanations and an intuitive description. Keep up the good work!

I love the podcast - hopefully we may catch each other one day on the bands.

73 Scott (K6AUS)

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FT-817 Remote Access and The Perils of PC Board Etching

Mike is looking for some beta testers for his FT-817 remote control system, and for someone who is proficient on VB6 who can help him clean up the code.

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Bill,

Hello I am a 47 year old ham from Pittsburgh,Pa and my call is WA3O. I felt compelled to write you after my Kindle purchase of your Solder Smoke book. I don't usually read books cover to cover but, this book is different I can not seem to put it down. This is the first time I can personally relate to a book. Like you, I started ham radio at the early age of 13 and have built and struggled with the same projects you have. So I wanted to say thanks!...I am half way through the book and I am dreading finishing it because I probably will never find another book I can relate to so well.

My latest project is some software I wrote for the FT817 and Icom radios. I am not a programmer but, I taught myself VB6 so I could write this remote software. After reading in the book about your Iphone “link”I thought you might like it and I wanted your opinion on it. The software is DTMF control of your radio from any phone. With Skype (and a Skype-in phone number) and my software, you can call your radio from ANY phone (not just a smart cell phone). You dial your number and after a security number the program turns your radio on via the printer port and you have pretty much full control of all the functions of your radio with the voice announcer on the radio (Icom) or the voice out on Microsoft computers it can announce frequency, signal, mode etc. you can even TX. The software even has a time out timer just in case of say a cell phone “drop call”. The software has many features like 50 memory recall, selective scanning, band scanning,direct frequency input. If you have a radio like a IC-7000 or a FT-817 and a auto tuner you have access to all HF,VHF and UHF. I brought the software idea up to some local hams and it sounded like it was a bad idea. I use it every day to listen to 160M while I drive to work in my truck without a BIG 160 antenna on it! I also thought it would be great for guys who just like to see what band conditions are on lunch break. Let's face it we all carry a cell phone. So I would really appreciate your opinion on this.

One last comment...while I was reading about your struggles with etching your own board it reminded me of my first experience with etching solution. My buddy etched boards before and told me all you had to do was draw what you wanted with a Sharpie on a copper PC board and throw it in some solution and “rock it back and fourth a bit and it works like magic. So unknowingly we put the solution in a pie tin and palced the board in. It immediately started boiling and put off an orange smoke! I said NEAT! And before my buddy could tell me it was NOT supposed to do that it ate thru the bottom of the pie tin...What a mess! And mom wasn't happy! LOL

So best of 73's and keep up the good work

Mike Lamanna WA3O

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Fessenden's Music from the Outer Banks

George, KB3ODH, found this about 1/2 mile from the Cape Hatteras Lighthouse.

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Bike Radio II

Thanks for all the suggestions on the bike radio. I googled around a bit and found a schematic that seems very similar to the little receiver I'm working with. I almost certainly would be better off starting anew (perhaps keeping the AF circuitry). But it is interesting to see how a simple AM receiver works. That first transistor is an autodyne circuit -- both a mixer and a oscillator.

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Bike Radio

As I mentioned on the podcast, I've been riding my bike to work lately. I really enjoy it. We have great bike trails in this area. They use paths of defunct railroad lines -- I ride Washington and Old Dominion Trail.

My bike is a bit of a boatanchor. It was made in Japan. I bought it 22 years ago when I was in Spain. I've used it in Spain, The Dominican Republic, the UK, Portugal, Italy, and in the U.S.

Of course, my thoughts have turned to putting some sort of HF radio on the bike, probably just a receiver. I still have a little handle-bar AM radio that I added shortly after I bought it. The handle bar mount is still good. See above. I'm pleased to see that it looks very simple, with discrete components. The AF amps are obviously off to the left of the speaker. To the right of the speaker we obviously have the RF and IF circuits. There are some nice tuned transformers there (from the "Chop Shing" company), and three transistors and a diode. What would the standard lineup be for a simple AM radio of this type? Maybe just an RF amp in the front end, a local oscillator, one stage of IF amplification and the diode as the detector?

What do you guys think? Make use of some of the existing circuitry? Start over?

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Alarm from Space

So I was sitting in the shack yesterday morning, drinking coffee and listening to IGY by Donald Fagen on Pandora, when I heard what I thought was an alarm. I thought it might have been a smoke detector going off (always a real possibility in the N2CQR shack!). It took me a moment to realize that what I was hearing was the device pictured above. I'd left my 2 meter HT tuned to 145.950 MHz, and Arissat-1 was breaking squelch with SSTV tones. Very cool.

Later, I was thinking about this as I pedaled along on my bike. I remembered our recent discussion of Copthorne MacDonald, inventor of SSTV. Way to go Cop!

It is easy to join in the fun. Just tune you two meter gear to 145.950 and leave it there. You'll soon be alarmed just as I was.

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Shack Background Music from Pandora Radio

Billy alerted me to Pandora. Very cool. You just give it an indication of the kind of music you'd like to listen to. They do the rest. I started out with Creedance Clearwater Revival, and Pandora proceeded to send me a stream of sort-of similar rock. Streaming audio through the web. And it is apparently all legal (you listen to a commercial every once in a while). This is great for background music in the shack. After all, you can only listen to so much SolderSmoke, and 75 meter SSB chatter is not good for you. I'm not sure if it is available outside the USA. I hope it is.
www,pandora.com

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Big Book Sale

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

The Picture You Heard in SS 136 -- FROM SPAAAACE!

In the last podcast I played a recording of some 2 meter signals picked up by my handheld transceiver from the new amateur radio satellite ArisSat-1. Included in the transmission were some tones that were obviously SSTV. Mike, K2MTS, ran the audio through some SSTV software and got this! Pretty good! From space to my HT, across the room to the SolderSmoke mic, out over the internet in podcast form, back to me in an e-mail, and now, on the blog. Thanks Mike!
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SolderSmoke Podcast #136

http://soldersmoke.com/soldersmoke136.mp3
August 7, 2011
Travelogue: New York City
A Stroke of Luck: Lightning strikes Rome HB DC DSB WSPR rig
It's an IGY thing: Recreating the Sputnik Transmitter
ArisSAT-1 deployed. Audio Clip (Can anyone decode the SSTV in this clip?)
Summertime SPRAT -- ZL2BMI rig and the mysteries of the '602
A writer for "The New Yorker" builds a radio
June Smithsonian Magazine has a lot of Knack
Electric Radio on AM selectivity, Japanese, and the sibilant S problem
Gathering Drake 2-B Serial numbers for use with German Tank Equation
Amazon breaks into oscillation on "Atoms to Ampere" prices
MAILBAG

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Big Nick's Awesome Homebrew Tube Radios

Eddie, KC4LVV, alerted me to the web pages of Nick, KC9KEP. What beautiful craftsmanship! Inspirational stuff! Check out the homebrew capacitors. And the coils! And the coil winder. It's almost too much!
http://www.bignick.net/TubeRadio.htm

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ARISSat Deployed

I just got back from a vacation trip to New York City (amazing place!) and found out that yesterday Russian cosmonauts launched the ARISSat amateur radio satellite. This one looks like lot of fun. It has a two meter downlink. I'll be doing some listening, and my try to get some of the SSTV signals.

Uh oh.... Just read a post from Mark over on Brainwagon reporting on some problems with the deployment:
http://brainwagon.org/2011/08/03/arissat-1-is-off-to-a-bumpy-start/

Details on how to use the satellite can be found here:
http://www.amsat.org/amsat-new/ARISSat/ARISSatHowTo.php

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