Furlough 40 Hears the World

I'm still working on tuning up the transmit side of the transceiver to see if I can get a little closer to designer N6QW, Pete Juliano's 5 watt specification, but in the meantime I decided to checkout the performance of the receiver.

I ran a weak signal propagation receive test overnight to see how well the receiver is working.  The image all the stations I heard over about 12 hours.  I'm located in Northern Virginia, just outside of Washington DC and I heard stations from Australia and New Zealand. This is a pretty sensitive receiver! Kudo's to Pete for the terrific design.

If you haven’t checked out WSPR,  it is one of the digital modes that I like.  It uses signal processing software from Nobel Prize winning Princeton physicist Joe Taylor.  It is a great way to analyze your station’s reach both in receive and transmit.

The software is available here - https://physics.princeton.edu/pulsar/K1JT/wsjtx.html 

The same software also supports FT8 and other weak signal digital modes. 

The only thing I needed to do to use the software on receive was plug the rig’s phone output into the mic input on the laptop and tune the rig to the 40 meter WSPR frequency on upper side band.  The software does all the work.  Its time based, so you PC’s clock needs to be sync’d pretty close to internet time. 

All stations that run WSPR have the option of uploading the signals they hear to WSPRnet.org, and the WSPRnet database is open and searchable.   The web site I used to produce the map is at http://wspr.vk7jj.com/.  If you use WSPR you should check it out - this is just one of many tools to allow to check your rig's performance,  test new antennas, and so on.  I let WSPR run in receive mode over night and looked at the results this morning.

In order to test how well I am getting out on transmit I need to get some sort of keying control built for the rig – either through integrating CAT control into my Arduino control program – or using serial port keying through a USB interface.  So, in addition to tuning up the transmit circuits, this will be one of my next projects.

73 from Great Falls

Dean

KK4DAS

Furlough 40 - First Ragchew - Homebrew to Homebrew

As promised -

Here is the first extended QSO of the Furlough 40 (and the 4th contact ever).  As a reminder the Furlough 40 is a 100% homebrew transceiver based on the SimpleSSB designed by N6QW, Pete Juliano and built by me - with much coaching from Pete and occasional help and advice from my brother Chris, W6CS.  Both of them are in California and I am in Virginia - so a first QSO with either of them was not in the cards.  When I scheduled this QSO I had no idea if I would be heard at all.

This QSO is with my friend Don, KM4UDX. What makes it even better is that I worked Don on his highly customized, homebrew enhanced uBitx, with which has taken Don to the top of the WSPRNet leader board.  Homebrew to homebrew.

So this was great fun. Have a look and a listen:

Coaxing the rig to life board by board has been a great experience.  Pete's guidance was to build one module at a time, starting with the audio amplifier and that forms the test bed for the next module. That proved to be great advice when debugging the latter stages. I was warned by my other Elmer, N2CQR, Bill Meara that when I got to the final amplifier I would be entering "a world of woe" and it did take a week or so to shake out - with each day starting out with a promise that "this will be the day..." and each evening ending with "perhaps tomorrow..."  But gradually the bugs got fixed, the errors corrected and the rig is on the air.

The rig is on the air but not finished.  Next step will  be going through the modules board by board to see if I can get closer to Pete's 5 watt specification.  And then there are a few final touches I need to complete.  I need wire up the tune circuit add a few more controls and build a proper front panel.  And at some point think about moving it to an enclosure - or maybe not.

But at the moment, I don't want to touch a thing!

As a Scoutmaster of many years I frequently had to remind my Scouts to take a moment and look back at the mountain they had just climbed.  This picture with the storied Michigan Mighty Mite, a 7 component first homebrew project,  was taken exactly four months ago on December 22, 2019

Testing the Michigan Mighty Mite - 4/22/2019

73 from Great Falls,
Dean
KK4DAS