Re: boosting the power on 28 MHz
#ubitx
2n2222a. ?Surface mount or metal can version?
On May 22, 2018, at 06:26, ajparent1/KB1GMX < kb1gmx@...> wrote:
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RIght now I'm using 2n2222A with acceptable results.
The KSP10 might be ok too, I like the price.? ? MPSH10s are on the way already but will not
have time to use them?till next week.
Right now rather than device suggestions I'll take all your free time.? ;)
Allison
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Re: boosting the power on 28 MHz
#ubitx
RIght now I'm using 2n2222A with acceptable results.
The KSP10 might be ok too, I like the price.? ? MPSH10s are on the way already but will not
have time to use them?till next week.
Right now rather than device suggestions I'll take all your free time.? ;)
Allison
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For the life of me I do not understand why the diode is before the fuse.
The fuse should always be first as it needs to operate for all faults even reverse polarity.
Allison
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I know it's not the best but the shunt diode did protect my MTR 5. My problem was I did NOT have a fuse in the line so the smd diode let the smoke out (opened up as it vaporized). I now fuse all B+ lines (or is that A+ in solid state). Thanks for your comments.
Dave K8WPE
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On May 22, 2018, at 2:47 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
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ubitx code version 4.3 for review, testing
peeps, jack, ian, allard, arv
i have created a next version of the base software after thinking hard about it. you can download it from?. I invite you all to test it. if you are not familiar with C code or Arduino programming, I suggest you wait for a few days until we get all the bugs sorted out. This is only for the Arduino regulars.
Sending bugs: Send me the bug reports directly to my email farhanbox@.... In the subject line use the word "#ubitx40". I will try to answer all emails but I can't promise responses to all.?
Before you start reviewing the code, let me give you a heads up of what to expect. Going by the general mood, I have taken the call to substantially borrow from Ian, KD8CEC's code and back port it to the original ubitx code. I guess that the new code has about 10% more lines but it is substantially more robust and useful.? The main features that I cherry picked from Ian's code are:
1. Keyer. You have to choose which keyer to use, but the keying is much better and robust now. This code is a total copy/paste of Ian's keyer. The auto-keyer (that sends out preset phrases in cw) is left out. The Iamabic A, Iambic B and the handkey sending works very well. 2. CAT control. Given the popularity of FT8, I rewrote the cat by following Ian's code but rewrote it to follow the ubitx coding conventions. It is a miminal set. 3. Split operations: My own interest of working with satellites have prompted me to add split operation.? 4. Rationalized menus: The menu system is now more consistent. 5. Tuning mechanism. The accelerated tuning works, though it doesn't jump randomly like before nor does it work at that speed. For very long band changes, it is recommended to do that through the menu option to change the band.
Among the things left out was support for different other types of displays, wspr beacon and many other goodies. The eeprom memory map is kept consistent with the KD8CEC's plan. You can switch between both the codes easily.
I have kept usage of english words at a minimum.??
- f
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It's certainly possible that it works in some cases.
But without a fuse, that shunt diode scheme is not an insurance policy I'm willing to buy.
Worse than nothing, it gives is a false sense of security.
Please add a fuse between the supply and the shunt diode.
Whether that shunt diode fails with a short or vaporises to an open depends on the supply you hook it up to.
Have you ever seen ham gear running off a car battery?
Have you ever seen what a car battery can do to a crescent wrench?
I'd recommend a series schottky diode for 12v into the main uBitx board (but not for PA-PWR into the IRF510's.)
We can well afford a 0.3v drop there.
Ideally, that diode would be rolled into the next rev of the uBitx board.
A 0.5 amp fuse there would also be a good idea, but the diode protects without any maintenance required.
And if you really care, a 12v LDO such as the LM2940-12 to prevent overvoltage,
this part also gives reverse protection so could do away with the series schottky diode.
The IRF510's should have a 3A fuse in the PA-PWR line.
That's likely enough, as the intrinsic diodes in the IRF510's will conduct if that supply is reversed.
Could burn those chokes on the drains, maybe some traces, but that's about it.
Easily fixed.? A shunt diode on PA-PWR after that 3A fuse is not a bad idea.
But just a shunt diode at the power connector and no fuse?
Bad idea.
Jerry, KE7ER
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On Mon, May 21, 2018 at 10:36 pm, WA9PWR wrote:
Tell that to varidur.? Reverse protection diodes are cheap insurance.
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Re: boosting the power on 28 MHz
#ubitx
Hi, is the 330pf across the PA transformer mod all what is needed to get reasonable output (5w) on 28mhz or should I also make the Farhan mods ( Replace C81 from 0.1uf to 470pf Replace R83 from 10 ohms to 2.2 ohm (you can short R83 as well) Replace R97, R98 from 47 ohms to 220 ohms Remove C261, C262)? Should I also change R63? Should I reduce drive via RV1? 73 Franco
Il 21/mag/2018 17:13, "atouk" < atouk@...> ha scritto: Since it's always nice to have someone doublecheck your work, would this be the proper place to add the cap if you mount it on top of the board?
Henry
N2VFL
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Re: Knob adapter sleeve (6mm ID, 1/4 inch OD)
Just use some hear shrink to increase the shaft dia..
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Tell that to varidur.? Reverse protection diodes are cheap insurance.
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Re: Mic doesn't work in bitx40
#bitx40
Thanks for your reply..
I've already swap the leads of the electret mic. But the same thing is happened. What voltage suppose the capacitor showed exactly?
is there any limitation on how big the voltage is to make the mic work?
thank you very much
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Knob adapter sleeve (6mm ID, 1/4 inch OD)
I got a bit frustrated finding a knob to fit the 6mm knobs on the uBitx.? Fortunately I found these adapter sleeves to bring the shaft OD up to 1/4 inch so I can use standard American 1/4 shaft knobs!??? I received them today and they work.? You do have to be careful to pull them out slightly before you tighten the set screws so the knob has enough clearance to be pushed in for the switch to work.
https://www.ebay.com/itm/222983860788
-Jonathan
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This reference suggests silicon diodes generally fail with a short when subjected to over-voltage.
And generally fail with an open when subjected to too much current.
? ??
The uBitx reverse protection diode would likely blow open due to excessive current (and heat)
if the power supply is not fused properly.
Jerry
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On Mon, May 21, 2018 at 08:50 pm, WA9PWR wrote:
Generally silicon diodes will fail with a short circuit, protecting the hardware.
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Generally silicon diodes will fail with a short circuit, protecting the hardware.
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Re: boosting the power on 28 MHz
#ubitx
I just want to say that I'm very happy to see you take this on!
Jerry
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On Mon, May 21, 2018 at 07:30 pm, ajparent1/KB1GMX wrote:
yes and other mods as well.? For now its at best a partial fix.
FYI the IRF510s will deliver 10W and then some at 10M!
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Re: W8TEE vft/tft questions
Tom:
If we are talking about the VFO/TFT board, look for the place where we read the encoder. If this is the BITX code, look for the symbolic constant ENCODERTUNING around line 1720. At line 1729, you should see some scaffolding code:
#ifdef DEBUG???????? ?
Serial.print("Examine Fast Tune: Start = ");??????? // May be useful for setting Fast Tune rate
Serial.print(fasttuneStart);
Serial.print("?? end = ");
Serial.print(fasttuneEnd);
Serial.print("? diff = ");
Serial.println(fasttuneEnd - fasttuneStart);
#endif??????? ?
If DEBUG is defined (see line 36) it will print the info out. (If it's commented out with "//", remove those.) This should tell you if the encoder is working and if the Fasttune parts are working.
Jack, W8TEE
On Monday, May 21, 2018, 5:09:08 PM EDT, tom.mccobb@... <tom.mccobb@...> wrote:
I completed? a build of Jack's board a few months ago, and it was working fine. I even made some mods to his code, adding a 4th button press destination from which I could set tuner increments to 50Hz, 100Hz, 1KHz.? (I never had much luck with the encoder speed routines)
All was fine until just recently.? Now when I rotate the encoder, It will pretty much stay in the the same 2KHz range.? If I spin it furiously, I can get it to move erratically up and down the band, but I have obviously broken something.
Which isn't a complete surprise given how many times I have dismantled the unit to change my front panel layout, swap in a SO-359 for the standard antenna jack, replaced the power connector on the W8TEE board to a screw terminal, etc.? I suspect I laid the VFO down on the metal case with some pins touching where they shouldn't have.
So the? question is where to look.? I have checked and verified voltages.? I backed out my modified sketch and reinstalled the original.? I have swapped in several different encoders (I got a bunch of them).? No joy.? The behavior is the same whether it is driven by the USB power connector when disconnected from the Bit40, or the Bit40 power.? (I am feeding it 12v, btw, as the schematic specifies, not the 7-9v in the assembly guide. Is that a problem?).? In all other respects it appears to work - I think - see below.? I have a spare Mega 2560, and as soon as can get headers on it I will swap that in.??
While troubleshooting, I put the outputs on a scope.? The buffered output looks to be about 2.5-3v , and is a nice clean sine wave at about 60 Hz - and it does not change when the encoder is rotated.? The un-buffered output is about the same frequency, but voltage is several orders of magnitude smaller.? And the square wave output is just noise, or at best a very noisy triangle wave.? Does this indicate a problem with the A9850?? (Yes, it could indicate that I don't know what I am doing with the scope, a Tek 2235).
Any pointers?? It is kind of fun troubleshooting, but I would like to get it working again before the end of the decade.
Thanks.
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Re: Socketing a Nano to the other side of the Raduino
Cuz sheet metal work is not as much fun as burning solder.
Shielding various sections of the radio from each other is not a bad idea.
And the Raduino/display is a good place to start.
Allowing the Si5351 clocks out of the box while disallowing
everything else might be problematic.
Simple solution: move the Si5351 to the uBitx, filter the i2c bus to a few hundred khz and less.
Though I do think that running the processor from the BFO and kicking?
the USB-to-UART out entirely would pretty well solve most interference
from the Raduino.??
Jerry
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On Mon, May 21, 2018 at 07:23 pm, ajparent1/KB1GMX wrote:
Why not remote it some from the mainboard and put a box around the back of it
with the wires sneaking out of? it.? The front of the box is the front panel and the
Raduino is tinned up.? Take care with the signal leads (use SHORT twisted pairs).
Used those tricks for old style counter circuits that radiated digital noise like mad.
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Re: Socketing a Nano to the other side of the Raduino
You could actually have different Nanos for different overall functions and just swap them out since it would be pluggable.
73 Kees K5BCQ
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Re: boosting the power on 28 MHz
#ubitx
yes and other mods as well.? For now its at best a partial fix.
FYI the IRF510s will deliver 10W and then some at 10M!
Allison
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Re: Socketing a Nano to the other side of the Raduino
Why not remote it some from the mainboard and put a box around the back of it
with the wires sneaking out of? it.? The front of the box is the front panel and the
Raduino is tinned up.? Take care with the signal leads (use SHORT twisted pairs).
Used those tricks for old style counter circuits that radiated digital noise like mad.
In my case the height of the board when mounted is a problem.? Solution is change
the board connector into a right angle and then relocate the display with wires.
That lowers the profile.? ?Both boards can easily then have a cover over them
made of soldered up PCB, hobby brass, or copper screening.? Control pins will
exit though the screen box via 1000pf feedthroughs.? I try to keep noise in
the box so to speak.
Allison
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Just to let those know that sent me
prepaid envelopes, I was away for the last 2 weeks, and will send
out the parts tomorrow for the requests that I received during my
absence.
Howard
On 4/17/2018 11:25 AM, Howard Fidel wrote:
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I got my uBitx last week. I was surprised to get it, since it
was sent 3 days before and I paid for India Post shipment, but
it came by DHL, which was a nice surprise. I have assembled
it, and started testing and am doing a number of modifications
in my lab before moving it to its home in the shack.
Today I modified the transmitter to improve the output power
at the higher frequencies. The power out in the original state
is about 3 watts at 28 MHz. My modification brings the power
at 28 MHz up to 7 watts on both the 15 and 10 meter bands. On
my board at least, there is not enough range in VR1 to
increase the power to anywhere near this level without this
modification. The other bands remain unchanged in output,
which I measured at 11 watts.? The output stage could be
modified as others have done by changing the FETs and
transformer to improve it more, but I am happy with this for
now. I plan on adding a power amplifier later, something
between 50 and 100 watts.
My fix is simply to add 3 passive parts. I added:
33 uH inductor in series with R86. I lifted the resistor
mounting it on one pad standing up, and teepeeing the inductor
between the top of the resistor and the other pad.
Add a 270 pF capacitor across both R87 and R88.
The values are not very critical, I calculated that I needed
27 uH and 220 pF, but the values I tried were in the lab.
If anyone wants to try the fix and needs the parts, I have a
full reel of each, so just send me a stamped self addressed
envelope, and I will send it to you by return mail. The offer
is good until I run out of parts.
Next up is adding an AGC and S meter.
I also measured the receiver sensitivity and can confirm that
it meets specifications.?
Howard
WB2VXW
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David Wilcox K8WPE
Nick VK4PP
Jonathan