Sunday, April 1, 2018

Lightweight Interface for Digital Comms


In the ongoing struggle to get this backpacking load under control, enter the Easy Digi interface box. The plans for this have been circulating for years, and there are even kits out there, but given current time constraints pre-built was the way to go.  In fact, it was plug-and-play... almost.  The One Grand Trick was that the sound input on the iPhone is easily overloaded, so it was necessary to crank down the FT-817nd radio's volume nearly all the way.  That step had me stumped for a couple of hours, thinking that something was failing along the way from the radio's output to the phone's input.  But no, it was just an overload problem – the same one I've been running into when audio-linking for years now.  Should've realized it sooner.


Weight... 0.20 pounds.  Throw in the bluetooth kbd and that's another 0.8 lbs (it's a plastic clone of the aluminum Apple kbd made by Anker, about $25).  I'm carrying the phone backpacking anyway, that's "free weight" toward the digital radio endeavor, so the whole thing comes to 1.00 pound even.  Now any extra pounds (even 1.00) are unwanted, but this is 3 pounds less than the 4 pounds for the laptop, SignaLink, and cables to get the same job done.  Anytime you can carve 3/4 off the weight of something going into a backpack, that's a raging success.


Here's the obligatory picture:


It works well, even though PSKer isn't as full-featured and convenient software as say FLdigi.  Got on the air with it by about 11 last night and quickly bagged a contact with a ham out in Utah.  Turns out the guy's a hiker, that was a real bonus!


Now for a few technical notes in case I ever lose the notebook (feel free to skip):



  • PSKer: Setup > Allow Speaker: off
  • iPhone: 
    • Settings > PSKer > mic: on
    • phone output volume: 4-5 bars (adjust with ALC & power meter)
  • Radio Settings:
    • sp/ph switch -> ph
    • vol: all the way down, then ease back up a little – don't overload!
    • VOX (f-menu #10A): on
    • VOX Delay (menu #50): 100ms
    • VOX Gain (Menu #51): 25 35 seems to work better
    • SSB mic gain (Menu #46) to 45-50 range to get ALC right
OK, that's enough nerdy talk for now.  Household/pre-Monday chores call.

Also: re-set these radio settings before packing it way, or you'll never make another voice contact.  Write all the above on a 3x5 card and pack it in the ziplock with your interface box & cables.

ps Monday: So.. how's it working so far you may ask.  Contacts to Utah, MN, NJ, and Canada(!!) so far, all on 2.5 Watts.  Call it a trail-ready success.


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