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Sunday, May 15, 2011

SolderSmoke Podcast #134


May 15, 2011
New "Ikea" microphone

WSPR T/Rouble resolved
Finishing up Rome WSPR rig
Easy-Peasy on Asus eee-PC

Space Station Packet Beacon
Boatanchor News: DX-100, HT-37, "CQR" anchors, 75 meter antenna Drake 2-B history interview by W8SX
Lew McCoy and Ernest Hemingway
Ade Weiss, QRPoetry and Ade's new book
Regen theory

MAILBAG (with a focus on New Zealand)


  1. Hi Bill,

    Just listening to #134. I'm afraid your idea about picking off an RTS signal from USB won't work.

    You need the converter cable (which has a chip in the connector). You can get them online for as low as $7. Or even cheaper on e-bay.

    Paul - K0EET

  2. Sorry, there's no RTS line in USB or anything like it. There are just two high speed serial lines, 5V out and a ground.

    A USB serial adapter is probably your best bet. They aren't all as expensive as Radio Shack! I don't know how you feel about Ebay but they start at $1.25 w/ shipping there.

    Here's another tip with USB serial... Sometimes if you unplug the device and plug it back in without rebooting Linux will renumber it. The first time it might be /dev/ttyUSB0, then the next time /dev/ttyUSB1. You can also get different numbers if you have more than one USB serial device. For example.. this time you plugged the radio in first and then the phone so they are numbers 0 and 1 respectively but the next time you plug in the phone first so they are reversed.

    This is a pain because you have to keep going into Fldigi's preferences and changing the port settings.

    It is possible to tell Linux to recognize the serial number of your usb to serial adapter and give it a 'nickname' that you can use in your Fldigi (or other software) preferences. Then so long as you always use the same device you don't have to change anything. To do this you want to write a udev rule. Hackaday has a tutorial at http://hackaday.com/2009/09/18/how-to-write-udev-rules/. There may be simpler tutorials out there on the net that are more focused on that one purpose but I didn't have time to check them all.

    Or... you could engineer your own USB switching device and write a driver for it. :-) Linux Journal has a nice tutorial for that at http://www.linuxjournal.com/article/7353.

    P.S. I think the mike sounds nice. I do hear birds at the begining of the recording though. They aren't a bother though!

  3. Hi Bill, outstanding episode! Your new mic sounds better than ever.

    USB has no RTS signal - it only has one data signal shared by both sides. Data is on a differential pair of signals (one high when the other's low) called D+ and D-. The other two pins on the USB connector are 5V and ground.

    USB protocol actually operates like a CW QSO. The host computer and USB device take turns on the data channel, sending and receiving, with special symbols for things like RTS to take turns and keep organized. Just like CW ops take turns sending and use call signs, DE, K, special Morse characters KN, SK, etc.

    So to get an RTS signal in hardware you need a USB device controller. That's what the chip in a serial/USB cable does.

    73 de KC7IT

  4. "I read your story...it wasn't very good"...Hemingway to McCoy. That was the best part of this episode, along with the mention of the BLue Note, Johnny Hodges and the Duke (not John Wayne, Ellington). 73

  5. Bill,
    WOW! Audio is first class.

    Sybilant S are non existent. P's are sometimes a little punchy but then they are P's. Even the Gong sounded less sudden and therefore more pleasant.

    Well done. I think its even better than the Rome podcast days. First class! :)

    Still expired - ugh!


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