Saturday, April 28, 2018

D-Star Operation without a D-Star Radio


The other day I was hammering away at FT8 and listening to reflector 30C on my D-Star setup.  I use a SharkRF Openspot and an old Icom 880H.
K1VT was on the air for the first time, accessing D-Star reflector 30C using his mobile phone instead of a D-Star radio.  In fact, he had a fully portable setup and no expensive D-Star radios were involved.  Sounded the sort of thing that many hams would be interested in.  (Normally with D-Star, you need a D-Star radio to access a D-Star repeater or Digital Voice access point.  Using a PC and a D-Star compatible dongle will give you access but then you have to haul your PC everywhere.)
I listen to his description and emailed him to ensure that I had the story right.
The whole thing hinges around the products and interest groups set up by North West Digital Radio <nwdigitalradio.com> and <nw-digital-radio.groups.io>

Here are the basics:
    He was using a NW Digital ThumbDV connected to a Raspberry Pi model 3B.

    The Pi was running Compass Linux which is a derivative of Raspian Linux.

    AmbeServer was the app running on the Pi.

    On his Android phone he was running BlueDVAMBE.  (Note that there are two versions of BlueDV for Android, BlueDV and BlueDVAMBE)   David, PA7LIM, has done all the work on BlueDV.

    From his mobile phone, he connected to the AmbeServer, his desired reflector and then he went straight into the internet and DStar around the world.

    The AmbeServer is also accessible using Windows and OSX devices using special apps.

Tuesday, April 17, 2018

FT8 Skimmer


Recently I stumbled upon another development microcomputer tool, like Arduino or Raspberry Pi.  It's called Red Pitaya and is designed with more of an engineering focus.  It has four SMA connetors so that it can take RF in and out. 

Check out www.redpitaya.com   Pricing ranges between Euros 240 - 350 plus shipping for the starter kits.  Application software is free.

Pavel Demin has created a site with links to a number of tools and applications. 
https://pavel-demin.github.io/red-pitaya-notes/

Pavel has created a multiband FT8 transceiver and collects data as if it were a CW Skimmer.  Dick Williams, W3OA, has done some work with his "aggregator" and can send the spots to the Reverse Beacon Network.  Dick's site is http://www.wake2013.org/bios/W3OA.html

The real practical value for us down here in New Zealand is only for those who wish to follow the Earth Moon Earth (EME) VHF path.   On HF, FT8 signals are concentrated into one 2kHz channel, or there abouts on each band.  With VHF EME, transmissions are not so restricted and there a skimmer comes into its own.



Saturday, April 7, 2018

Early April 2018


FT8 newest version


The beta release of WSJT-X, version 19.0-rc3 is out and you will need it to work any DXpedition that is using the expedition mode to work multiple stations (called Hounds) at the same time.  Go to <tinyurl.com/ZL1LC301> and download a copy for your operating system.  Make sure you read the instructions for the DXpedition mode, although you can get it going as per normal quite easily. 
There have been a couple of US based tests on the DXpedition mode, but unfortunately they have been at the wrong time of the day for propagation down here.

FT8 User Guide

ZL2iFB's FT8 manual is extremely popular.  <www.g4ifb.com/FT8_Hinson_tips_for_HF_DXers.pdf>  The ARRL were pushing it in a recent Contest Update, and it's now been translated into German and Czech.

The Bouvet DXpedition is back on track.  

Visit bouvetoya.org for more details and for some wonderful photos.


A 3D printed Foot Switch 

remoteqth.com/3d-ptt-foot-switch.php  Print it on your 3D printer and add a micro switch.


Worried about your dipole height?




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How High should my Dipole be? Dipole Antennas - the Effect of Height Above Ground I frequently hear the question: how high should my dipole be?
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And the radiation patterns for a dipole.



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Tune Around! SEARCH Topics For Technicians! Loaded with info for new ham radio operators! About Hamuniverse Antenna Designs Antenna Safety! Ask...
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Here's an old one that reminds you to make sure your PC system is regularly updated.