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Thursday, April 7, 2011

PACKET MYSTERY FROM SPAAAAACE!

OK guys, please reach back into your memories, back to the late 80's, back to those sad days before the internet, back to the days of TNCs and packet BBSs and all that. I need some help.

I have my little 2 meter packet station running. I'm sending out beacon packets on 145.825 MHz, the freq of the International Space Station. (Is PC-SAT still on that freq also?)

Every morning I go to the old 1994 Satellite Pro computer (thanks to ZL3KE!) and type in mheard to see the list of stations picked up during the most recent passes of the space station. Every day there are several, each with an asterisk indicating that the packets were digipeated, and on this freq the digipeating is done in space.

Here's my question: Two days ago, MY OWN CALLSIGN showed up in the MHEARD list. (Cue ominous music) BUT WITHOUT THE ASTERISK! If I had seen the asterisk, I would have thought that my own packets were being digipeated by the ISS station and coming back at me. But why no asterisk? Long Delayed Echo? Klingons? My misunderstanding of packet technology?

Wednesday, April 6, 2011

SolderSmoke Book -- Now on Kindle!

In response to popular demand, "SolderSmoke -- Global Adventures in Wireless Electronics" is now available as an e-book for Amazon's Kindle.

Here's the U.S. site: http://www.amazon.com/dp/B004V9FIVW

And here's the UK site: https://www.amazon.co.uk/dp/B004V9FIVW

Tuesday, April 5, 2011

Inside the SolderSmoke Microphone

Here's a really excellent description of how an electret microphone works, complete with a dissection of the device.

http://www.openmusiclabs.com/learning/sensors/electret-

Crystal mics are much more interesting, of course, because of the opportunity to chemically tailor the audio response...

Monday, April 4, 2011

The Polyakov QRSS Receiver

Of course, we like it because it is in an Altoid-like box. And because it is Direct Conversion. And because it is used for QRSS, with the output fed to an on-line grabber. But this one is EVEN BETTER because it uses a Polyakov detector!

Check out PA1GSJ's receiver: http://www.qsl.net/dl1gsj/html/qrssrx30.html

View the output (live): http://www.qsl.net/dl1gsj/qrss/

More on Polyakov detectors: http://soldersmoke.blogspot.com/search?q=polyakov

Sunday, April 3, 2011

Snort Rosin's Mighty Mite: The Super Duper X Spy Transmitter

Hi Bill,

Attached is a picture of the remains of my transmitter, "The Super Duper X Spy Transmitter". My little rig didn't sit around; it made QSOs the day it was finished, 41 years ago. Since then it has bounced around in various junk boxes and had some parts robbed for other projects but thankfully it's still mostly intact.

I constructed it based upon the original article in Ed Noll's book, "Solid State QRP Projects", pg. 51, Project 17, "10 160 All-Band Two Watter". That transmitter was later to become known as the Michigan Mighty Mite.

My MMM (or SDXST if you will), features a built-in relative power detector, a microswitch key (upper right-hand corner), room for an internal 9 Volt battery and a jack for external power. The jacks are each different; a BNC for the antenna, a 3.5 mm closed-circuit jack for the key, a 2.5 mm for the relative output meter and a phono jack for the external power. My notes say that I added a .1 uF Emitter bypass and that it increased the power output by 50%. I also used a toroid for the output tank instead of the 1-3/4" coil form called for in the article. Use of the "Sucrets" box was not my idea; I got it from one of the ham mag's. of the day, probably 73.

Your coverage of those little rigs has motivated me to restore mine and make some QSOs for old times sake. With, of course, the proper output filter :-). I'll send a picture of the 'guts' when it's finished.

73.......Steve Smith WB6TNL
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Thanks Steve. Great stuff. But... WHERE'S THE OUTPUT FILTER?

Saturday, April 2, 2011

Lulu Book Sale (20 % off) extended through April 4

Just use the Coupon Code SPLISH at checkout -- save 20% through April 4.
http://soldersmoke.com/book.htm

Friday, April 1, 2011

More on Chemically Tailored Crystal Mic Elements

My mention in SolderSmoke # 132 of this technique to custom tailor the AF response of crystal mic elements has already generated a lot of interest. Here's the e-mail from Italy that alerted me to the work of Dr. Andrea Bugiardo:

http://soldersmoke.com/microphone.htm


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