Getting Control of the Furlough 40 and First Week's Log

Adding Controls to the Furlough 40

When I got the Furlough 40 up and running a little over a week ago I was so excited just to make contacts that it didn't bother me that the controls were hanging by wires off the edge of the board, but that got quickly annoying. So it was time to build the control panel.  I decided to keep with the al-fresco look and go with something that more-or-less matched the open, modular construction style.  

The controls consist of:

• Rotary digital encoder for tuning
• VFO A/B select mini-toggle
• USB/LSB mini-toggle
• MOX mini-toggle put the rig in to transmit
• Tone - momentary switch to trigger a 10 second tune tone
• Power button (push on/off, not installed yet)

In keeping with the "Home Depot Homebrew Chic" esthetic, I went with 1/8" aluminum angle stock for the panel.  Having none in the shop and while out on my pre-planned weekly social-distancing grocery run, I stopped in at Home Depot to pick some up along with various screws and a carbide tipped saw blade for my miter saw to make it easy to cut the aluminum stock.

As an aside - this rig is so inexpensive to build that I spent more on the saw blade than all the parts of the rig combined.

Here is a hint - knobs, switches and an assortment of electronic parts can be purchased from Marlon P. Jones - MPJA.COM.  I purchased a pack of 5 knobs for $3 - the knobs are good quality with brass shaft screws - and they have flat rate shipping.

A couple of minutes with graph paper and pencil and I had the layout.  The new saw blade made short work of cutting the angle stock to size.  Carbide tipped drill bits in the drill press and ample WD-40 and I had the holes cut.  The labels are from my trusty Brother P-Touch - I need to get some clear label tape, but for now, the white will do. The whole effort - including trip to the store took about 3 hours. Still to do:

• Mount the display using angle brackets
• The right hand side - audio level knob, mic and speaker jacks

The rig is a pleasure to use now. The tune tone is a terrific feature added by N6QW, Pete Juliano, the designer of the rig. It puts an 988 Hz 1/2 duty cycle tone directly in to the microphone input. This is great, not only as a tune-up tone, but it replaces the need for an external signal generator to put a known signal into the rig for testing. I found out, as Pete advised, that I needed to unplug the mic first - other wise you are feeding the audio in to the mic which turns the mic into a speaker.  I am guessing that is not good for the mic element.  

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Furlough 40 First Week Contacts

This is the first week's log - I don't have much time to work the rig in the morning and evening hours when 40 meters is wide open, but even so I am very happy with the results.  There are a few contacts with local club members but the rest are a result of me answering CQs - all good contacts with call signs and signal reports exchanged at a minimum. Responses varied from "Wow! Three watts? Amazing!" to "sound like 3 watts :(".   The distance ranges from 250 miles to nearly 800 miles on a maximum of 3 watts.  From my QTH in Great Falls, VA near Washington, DC I am doing well up and down the east coast and in to the mid-west.  Only DX so far are two Canadian stations.

I even made my first digital contact with my friend Don, KM4UDX on his uBitx.  Using FLDIGI - for receive, I hooked the speaker out directly in to the PC mic input and for transmit I held the mic up near the laptop.  To make this easier I'll need to add 3.5mm mic jack to the rig and decide how I want to enable PTT.  Pete has a simple USB hardware digital interface that I may build or I might go all-in and port the CAT control implementation from the uBitx firmware for full integration with digital and logging software. 

Furlough 40 - First Digital QSO

That's all for now - for the next post we will go back to the beginning and document the build board by board.  Please subscribe, like, follow, share and tell your friends.

73 from Great Falls,

Dean

KK4DAS

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

Furlough 40 First Contact

It has been nearly a month since the completion of the receiver beginning to build the transmit modules.  I am super excited that this morning I had my first two confirmed QSOs.  I was putting out just over 2 watts of RF magic and confirmed two contacts in Ontario - about 400 miles from here. 

Furlough 40 First Contact - Thanks to Garry VE3XN! 

In the last month I have built the three final modules to enable the transmitter.  The second stage amplifier / TX Driver, the IRF 510 based final amplifier and the 40 meter low pass filter. Note the fancy brass home-brew heat sink on the TX Driver, courtesy of the plumbing department at Home Depot.  As a reminder, this is my build of N6QW, Pete Juliano's Simple SSB Transceiver and inspired by N2CQR, Bill Meara and Pete's Soldersmoke Podcast. 

Furlough 40 TX Driver, Final Amp and Low Pass Filter

There is a tremendous amount of tribal knowledge in Pete's design and I'm really please I went with it for my first transceiver project, because I really, really needed that tribal knowledge to get the rig built.  There are things that a first-time homebrewer like me would never think about, like cutting the drain pin off the IRF 510 and using the tab to connect.  And using the entire PCB as the heat sink for the transistor. And Pete has been an amazing Elmer, coach, nag and grief counselor when things didn't go quite right - like when I sacrificed the IRF 510 while over exuberantly trying to coax an extra watt out of the not-quite-ready-for-prime-time-rig. The good news was, due to Pete's excellent circuit layout, it only took about 10 minutes to replace the dead transistor.

The sacrificial IRF 510 - IRF, I hardly knew ye!

I didn't get to video of the first few contacts but I will make one in the next few days so you can see the performance.   In the meantime, here is the final pre-air transmit test.

The trace shows flat-topping which means I needed to back off on the microphone gain.  After I made that adjustment the output dropped to about one watt. I tried to compensate by increasing the bias on the final and I pushed just a little too hard - at about 4.75V DC on the bias, the IRF 510 gave up the ghost.  With a little more advice from Pete I managed to get everything more-or-less aligned and am now getting 2-3 watts of output pretty consistently.  

Next step will be optimizing each module to see if I can get the output up to the 5 watt design spec.

73 from Great Falls

Dean

KK4DAS