NorCal Forty-9er

M1BUU · 28 November 2022 22:48

At the start of this year I built a Manhattan style N6KR SST-30. I then fell down an N6KR rabbit hole!

I currently have a NorCal 40A (another N6KR design) on my workbench, but it’s a slow moving project.

Whilst researching the NC40A, I found the N6KR Forty-9er. The Forty-9er is a minimalist QRPp crystal controlled CW transceiver for 40m which will run from a 9v battery.

A few weeks ago I began a scratch build Forty-9er project. I used the original article and schematic for authenticity.

The circuit fired up first time and needed no debugging. I did allow myself to change a couple of things from the original design; I used toroids instead of axial chokes and I put a better low pass filter in. I think the use of the toroids instead of axial chokes improved the output power a little. I’m seeing a healthy 0.5w+ from a 9v bench supply.

I fabricated a little case in the same style as the SST from sheet aluminium.

The weather was pretty good today so I took my little Forty-9er, with fresh in the packet Poundland 9v battery to Hutton Roof Crags G/LD-052. I needed a bit of food shopping so figured that I could head to Kendal after my activation to do the shopping there. Another reason to do the activation was to get my teenage son out of the house, to get him some fresh air and daylight!

I knew I would’nt have long to play but I put out a few CQs. I had been interested to see how a minimalist transceiver would work as I haven’t used anything like a Pixie before. I set the TX frequency at 7.02929 in order to try to get callers away from zero beat to give me a bit of tone, however my plan was clearly foiled by modern rigs and their frequency stability and narrow passbands! I worked 3 stations with my little rig before I gave up. I proved the rig worked, however I definitely need to add in some form of RX shift. I was told that I had a few callers, but I simply couldn’t hear them due to zero beating. I guess these old designs without RX offset are just not practical anymore with perfect modern rigs ruling the airwaves.

Keying was total guess work as there is no sidetone! I did seem to light up the RBN a few times, so at least some of my straight key Morse was legible!

So now that I’ve experienced a true Forty-9er, I think that I will add in some RX shift. I think that I’ll leave out the sidetone though, guess work adds to the fun!

73, Colin

G4TGJ · 28 November 2022 22:55

What a great little project Colin. So neat and tidy!

VA2YZX · 29 November 2022 09:38

Wow, impressive !
I built a 49er in the past but as a kit; i have yet to make a QSO with it, and put it in a casing.

Congrats !

Sly
VA2YZX

EA2BD · 29 November 2022 10:15

Hi Colin. Ah! I saw your spot and jumped into QRG and there you were, with a tiny signal at times. I knew you were testing any new rig as your level was unusually faint.

Yes, you were spotted at 7.029,3 and there we went some chasers, zero beating.

I was one of them and was not heard either.
I tried to tx slightly off zero beat but then you dissapear.
I felt there was a kind of issue in your RX. As you said, that 9er needs a RX shift to be okay.

Thanks for sharing details of your new rig, nicely built, as usual.
CU soon, 73 Ignacio

M1BUU · 29 November 2022 14:59

Sorry Ignacio, it would have been great to get you as the fourth QSO!

I could hear all kinds of faint CW, it’s hard to tell which ones are calling you! Fundamentally the receiver seems pretty good. I guess I could pretend to be working split and send ‘up 1’

It won’t be long until I activate G/LD-052 again, so there will be another chance to claim the chaser point!

73, Colin

G4WTF · 29 November 2022 15:37

You were an excellent signal (579) into Hereford Colin. Delighted to hear you on 40m. I called but missed you. Hopefully next time.
Congratulations on the the homebrew.
73’s
Ian

ON7DQ · 29 November 2022 16:09

Great job Colin!
I admire your perseverance to operate a CW rig without offset and no CW filter, hi.

I recently built a Chinese 49er kit from Ali Express, it deviates from the orginal of course, but it does have RX offset, sidetone (twin-T oscillator with one transistor), RX mute on TX. See the circuit in this manual:

http://lz1lcd.spirka.net/downloads/Forty-9erV1.0.pdf

An AF CW filter is not included, so I built a simple filter with one opamp which helps a lot already, but it could do with a better filter.

I made the changes to add a PLL VFO along the lines of an article in QST March 2016. I used an Si5351 module though.
I have a basic version working, but a good friend (known from the OST Morse Box …) is helping me out to add some bells and whistles. Will report about that soon …

73 & happy homebrewing !
Luc ON7DQ

M1BUU · 29 November 2022 19:20

I do go on to 40m quite often, it seems as though it’s now starting to work well again fir G contacts.

I’m looking in to how to implement a simple RX offset in the Forty-9er, I feel it needs to be simple to fit in with the whole ethos of the rig. Supposedly a 100Hz shift is already expected, but I didn’t see any shift in my build.

I’m hoping to get out in to the Lake District before Christmas to hover up some early winter bonus, I’ll definitely spend some time on 40m.

73, Colin

M1BUU · 29 November 2022 19:24

Hi Luc,

I looked at the Chinese Forty9er schematic earlier to see how the RX offset was implemented. I feel that I want to try to keep the Forty9er as close to N6KR’s design as possible.

I’ll keep searching for simple ideas! The Tiny Tornado has a switched capacitor for pulling the oscillator, maybe something like that could work.

73, Colin

VK3AFW · 2 December 2022 06:50

Nice job Colin,

I have used a Pixie with Rx offset and buzzer sidetone. Made 1,400 km on 480 mW on 40 m.

I’ve had trouble with sender’s signal being out of my passband on other rigs but not on the Pixie It is easy to get at least 500 Hz offset on Rx for this design.

You might find it simpler to have some C switched across the xtal on key down.

GL
73
Ron
VK3AFW.

ON7DQ · 2 February 2023 09:34

Like I reported somewhere above, I had my friend Gil ONL 12523 write some new software for a modified 49’er kit, and I can proudly say that it now works very well !

It has programmable offset, pure sinewave sidetone, RIT , SPLIT and a SPOT function for tuning zero beat.
There is a built-in calibration routine for the Si5351, you can also use the rig as a beacon or foxhunt transmitter, it has an unlimited number of CW messages, etc.

I won’t go into much detail here but for those interested, all needed info is on my github, hardware and software manuals, Arduino source code, the whole works.

Enjoy !

73, Luc ON7DQ

M1BUU · 2 February 2023 16:58

Thank you for sharing Luc. An interesting project. I still haven’t got around to implementing TX/RX shift on the Forty 9er.

I wonder if the PLL stuff would work with a RockMite, I don’t have a Forty 9er kit, but I do have RockMites.

73, Colin

ON7DQ · 2 February 2023 18:10

Hi Colin, @M1BUU
Man, what are you going to do with all those RockMites ???
Must be part of one of your next crazy challenges for sure, hi.

I think the PLL stuff can easily be adapted to any simple CW rig with a direct conversion receiver.
Have a good look at the two diagrams on pages 7 and 8 of the Hardware Manual on my github.

The only thing we don’t have is a iambic keyer, partly because the Arduino Nano was almost full, and also because I didn’t ask for one (haha), being a mechanical keying fanatic (see another thread today by @DL1CR )

So you should check if the keyer chip in the RockMite would give some trouble or not, and also replace the sidetone from the PIC by the one from the Arduino.
Pin 3 of the PIC is doing the shift, which you don’t need with our project (so leave out Q2).
This pin could probably be used as the TX/RX input to the Arduino (just check its polarity).
Actually, I blew up the PA transistor with my first try at the code, I had reversed the meaning of the TX/RX line, so my rig was transmitting when I really thought it was receiving, hi. By the time I noticed, it was too late.
The RX oscillator goes to pin 6 of the NE612 (point B in the RockMite diagram, but not connected to R13/R14 at Q4).
TX oscillator goes to base of Q4 (via a DC blocking cap), so can also leave out R9,R10, Y2, D5, D6.
Y1 should be replaced by a wider L/C bandpass filter.
and so on … it all looks very similar.

Even with a superhet rig, it should not be too difficult to change the RX oscillator frequency by adding the IF offset (e.g 4 MHz) in the code. The RX oscillator is separate from the TX oscillator.
But I’ll ask my friend Gil if it can be done with a simple #define statement at the start of the main code, that should make it simple to edit.

Actually, my next project will probably be a rig like the SST or the Norcal40, with a 4 MHz IF, I have already the XTALS … now must find the time to build a prototype, hi.

73,
Luc ON7DQ

M1BUU · 2 February 2023 18:29

I don’t know! What can I say, I’m just a RockMite magnet, they show up on my doorstep without me even requesting them! I had a few boards which I needed memory keyer chips for. The Keyer chips arrived with more PCBs and MVAM109 diodes, which are getting rather scarce.

Probably the easiest thing to do is to do a scratch build. Like you say, most of the PIC function isn’t needed.

Food for thought.

I’ve been lusting after a nice straight key for a while but they just seem so expensive. I have an LTA key from Spain, but it’s quite crude, there’s no bearings, just a couple of cone shaped screws which sit into a hole of the arm of the key. It’s quite difficult to get the right amount of thrust as the cone screws look to be hand made and are not perfect. I also have two Czech keys, they’re quite nice to use but I find them not very pretty to look at.

LTA key

My favourite straight key for SOTA is a W1REX FreeKey - literally a free key!

73, Colin

ON7DQ · 6 March 2023 17:47

Finally found the time to make a video showing what our 49’er software can do:

And an article was published in “The Communicator” (see page 45), a free online magazine from the Surrey ARC (in BC, Canada, not to be confused with Surrey in the UK):

Enjoy !

Luc - ON7DQ