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uBITX works!

 

Simply couldn't resist haywiring the board and trying it out after getting it today! Despite the precautions about trimming leads, I left them untrimmed and all worked well! Photo enclosed... packaging, well, it's so much fun this way... no, I'll work on something...

On 40 and 80 meters it seems to receive very nicely for the broad filter on CW - no mike hooked up yet. Tuning pretty smooth and functions easy to figure out. Worked a few stations on 40 and 80 for the Wednesday night (Thursday UTC) CWT contest, and it was not too hard to pick stations apart even with the SSB width filter - above all, the sound was clean with several stations in the passband so we're definitely on the right track. Heard some pretty weak stations down to the noise and pulled out a QRPer I could barely read. I was happy to note the rig tuned down below 3.5 MHz down to the 160 meter band and into the upper AM broadcast band.

Issues to work on - and I of course will contribute. None are deal breakers for the kind of rig this is, but of course we can constantly help improve:

Pretty hard pop when it goes into transmit.

The keyer is cleverly implemented, but isn't very forgiving of mis-timings in transition from dit to dah. I'm sure there are limits with the multiple voltage scheme (plus you don't get iambic).

Straight keying was glitchy - whether it was my contacts or whatever, it kept going unresponsive or responding oddly to key presses.

Attaching my good old Wilderness Radio KC-1 counter/keyer made for good CW.

The only menu function that didn't work for me was changing the CW tone - tone changed but grounding PTT didn't make the frequency enter. Other functions where grounding the PTT line was required to confirm worked fine.

All in all - elegant simplicity overall, with just a few things the community can help improve - which is part of the point!

Thank you for this design and getting such a radio board out into the hands of the world!

John Seboldt K0JD
Milwaukee, WI

20171220_205801small.jpg

 

John (and all),
I have the exact same issues with my uBITX - Pop, poor keying both hand key and paddles.? I don't have an external keyer to test it with but I'm going to make a solid state (2N7000) switch to work with hand key/bug input and see if that fixes the keying via the hand key jack.? I mostly use a bug for CW anyway and if I can make that work the keyer becomes a moot point.

Also, not sure but possible RF getting into the keying lines externally was suggested by a friend.? I plan on trying .01 uF bypass caps on the key and paddle connections.? Any larger caps than that could possibly upset some of the timings IMO.

Jim - W0EB
Park City, KS
 

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Good ideas. To confirm your hunch, my keyer has a 2N7000 output stage and it works cleanly so you might be on the right track.

Also, is yours packaged up or are you haywiring it for testing like i did? Possible RF pickup on the Radunio lines which might be reduced when packaged and leads trimmed.

John K0JD


On 12/21/2017 08:19, Jim Sheldon wrote:

John (and all),
I have the exact same issues with my uBITX - Pop, poor keying both hand key and paddles.? I don't have an external keyer to test it with but I'm going to make a solid state (2N7000) switch to work with hand key/bug input and see if that fixes the keying via the hand key jack.? I mostly use a bug for CW anyway and if I can make that work the keyer becomes a moot point.

Also, not sure but possible RF getting into the keying lines externally was suggested by a friend.? I plan on trying .01 uF bypass caps on the key and paddle connections.? Any larger caps than that could possibly upset some of the timings IMO.

Jim - W0EB
Park City, KS

 

While digging for parts to build the little 2N7000 key interface, I came across a "Ham Gadgets"? mini keying adapter which was originally designed to allow a low current keyer to work with old Cathode keyed and high current MOPA solid state rigs that had keying currents over 100 milliamps.? Just perfect for checking this out.

Wired it up so I could plug my bug into the uBITX through it.? Baseline test, hooked the bug up direct first.? Keying was terrible and kept throwing garbage into the characters.? I put a .1uf capacitor across the bug as a quick & dirty contact bounce filter which helped a little but didn't cure it.? Next, hooked up the keying adapter and WOW what a difference.? There was still a little bounce problem but a .1uF cap right at the input to the adapter fixed it.? Might have been a bit of RF getting into the adapter through the keying line as I don't have the adapter in a shielded box, just open board on the desk top.?

It appears that the problem with the hand key circuit is contact resistance in some keys is sufficient to upset the sensing in the uBITX and will vary from key to key, with length cable and gauge of wire and a whole bunch of other variables.? In my case it appears the solution is to even the playing field by using a simple transistor switch to present as close to zero resistance between the A4 and ground on "Key Down" intervals.

I can now use my old bug with the uBITX and work on a simple transistor interface for the key paddle inputs as well.? This would give consistent resistance from the paddle inputs to ground which would help the ADC read the voltage drop across the dot and dash voltage dividers.? Just my opinion, but I intend to breadboard a simple circuit to test that theory as well.

Jim Sheldon - W0EB
 

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Very kewl. As a matter of interest, my old NorCal KC1 keyer has a straight key input - finally found the documentation to hook it up. So now plenty good CW until a possible upgrade improves things.

John K0JD


On 12/21/2017 09:37, Jim Sheldon wrote:

While digging for parts to build the little 2N7000 key interface, I came across a "Ham Gadgets"? mini keying adapter which was originally designed to allow a low current keyer to work with old Cathode keyed and high current MOPA solid state rigs that had keying currents over 100 milliamps.? Just perfect for checking this out.

Wired it up so I could plug my bug into the uBITX through it.? Baseline test, hooked the bug up direct first.? Keying was terrible and kept throwing garbage into the characters.? I put a .1uf capacitor across the bug as a quick & dirty contact bounce filter which helped a little but didn't cure it.? Next, hooked up the keying adapter and WOW what a difference.? There was still a little bounce problem but a .1uF cap right at the input to the adapter fixed it.? Might have been a bit of RF getting into the adapter through the keying line as I don't have the adapter in a shielded box, just open board on the desk top.?

It appears that the problem with the hand key circuit is contact resistance in some keys is sufficient to upset the sensing in the uBITX and will vary from key to key, with length cable and gauge of wire and a whole bunch of other variables.? In my case it appears the solution is to even the playing field by using a simple transistor switch to present as close to zero resistance between the A4 and ground on "Key Down" intervals.

I can now use my old bug with the uBITX and work on a simple transistor interface for the key paddle inputs as well.? This would give consistent resistance from the paddle inputs to ground which would help the ADC read the voltage drop across the dot and dash voltage dividers.? Just my opinion, but I intend to breadboard a simple circuit to test that theory as well.

Jim Sheldon - W0EB

Jeffrey Peters
 

Hello Jim and group members

Thank you for posting your results with the "Ham Gadgets"? mini keying adapter.
I just ordered one of the mini keying adapter kits.? Operating nearly most of the time on CW
and using a straight key.? That kit will make a great addition to the Super uBitx transceiver.

72/73,? Jeff K9JP

On Thu, Dec 21, 2017 at 10:37 AM, Jim Sheldon <w0eb@...> wrote:
While digging for parts to build the little 2N7000 key interface, I came across a "Ham Gadgets"? mini keying adapter which was originally designed to allow a low current keyer to work with old Cathode keyed and high current MOPA solid state rigs that had keying currents over 100 milliamps.? Just perfect for checking this out.

Wired it up so I could plug my bug into the uBITX through it.? Baseline test, hooked the bug up direct first.? Keying was terrible and kept throwing garbage into the characters.? I put a .1uf capacitor across the bug as a quick & dirty contact bounce filter which helped a little but didn't cure it.? Next, hooked up the keying adapter and WOW what a difference.? There was still a little bounce problem but a .1uF cap right at the input to the adapter fixed it.? Might have been a bit of RF getting into the adapter through the keying line as I don't have the adapter in a shielded box, just open board on the desk top.?

It appears that the problem with the hand key circuit is contact resistance in some keys is sufficient to upset the sensing in the uBITX and will vary from key to key, with length cable and gauge of wire and a whole bunch of other variables.? In my case it appears the solution is to even the playing field by using a simple transistor switch to present as close to zero resistance between the A4 and ground on "Key Down" intervals.

I can now use my old bug with the uBITX and work on a simple transistor interface for the key paddle inputs as well.? This would give consistent resistance from the paddle inputs to ground which would help the ADC read the voltage drop across the dot and dash voltage dividers.? Just my opinion, but I intend to breadboard a simple circuit to test that theory as well.

Jim Sheldon - W0EB




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