Low Power Output for Hendricks BitX20A - Watt meters and Scope readings do not agree....
#bitx20
I solved my stability problem for the Hendricks Bitx20A ?kit by applying the?Martiens mod. ? ? Now I need to resolve a low power output problem. ? I had been just calculating the power output from my peak to peak O-Scope readings with a 10x probe. ? However I notice that while I had 70 VPP on the scope with the 10x probe ( ~ 12.2W = (70^2)/400 ); my wattmeters both read a much lower 4 to 6 watts. ? My wattmeters are a NorCal QRP Club watt meter and a Heathkit HM-9 QRP Wattmeter. ? I am driving the microphone input with a 600 Hz phase shift sine wave oscillator.
Interestingly, when I switch to 1X on the probe my reading drops to 42 VPP which calculates out to 4.4 Watts and is more inline with the external wattmeters. ? My scope is a new Siglent 200 MHz dual trace digital unit, with stock 10x/1x probes.
I have been reading up on scope probes and it seems that my 200 MHz probes are good to 200 MHz only in the 10x position. ?In 1X the spec says 6 MHz, well below the 14 MHz carrier. ? ?Based on this alone I would tend to accept the 70 VPP reading as accurate and accept that I am getting 12W out. ? ?However given the lower readings from the external wattmeters I am not sure what to believe.
I have a homemade -20 db coupler that when terminated to 50 ohms at the tap and fed to the scope with RG-58 also agrees with the lower power output.
My older 20 MHz analog scope agrees with the lower 42 VPP / 4.4W readings independent of the 10x/1x setting. ?(Calibration of this scope is reasonable but not traceable. )
All readings into a 50 ohm dummy load.
What am I missing?
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I am (unfortunately) counting in from the right, so my pin numbering?
is reversed from that shown at? ?
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On Thu, May 17, 2018 at 09:02 pm, Jerry Gaffke wrote:
I've got my uBitx Raduino totally unhooked from the wiring harness and the uBitx board,
laying flat on my desk.? Have a USB cable to a laptop to power up the Raduino.
Using a corner mounting hole of the Raduino for ground, I see 4.6 volts on the
first four pins in from the right on the top connector (ENCA, ENCB, FUNCTION, PTT).
The 5'th is ground, so I see 0 volts there.
The 6'th is 5 volts, and I see 4.7 or so because of a diode drop in the Nano.
The 7'th and 8'th are analog pins without pullups, so are pretty much undefined.
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Yup, this one has been hard to follow. Let's keep this thread going, seems a fine title for it. Doing a search for "Rogier", I find these: /g/BITX20/message/47715/g/BITX20/message/49091/g/BITX20/message/49445
/g/BITX20/message/49496
/g/BITX20/message/49518I'm assuming all his posts have been signed "Rogier". It seems he still has the original firmware installed, the Raduino worked at first,? but now it powers up with a display of "LSB A : 7150.000" and fails to respond to the function button or the encoder or the PTT switch. He also reports that? ? "There is 0 volt on pin 6 (red wire for the funktion button) to ground on the yellow wire (pin 4) or common ground on the chassis." His iMac does not see the Raduino when hooked up with a USB cable, but then? that's not unusual.? Many possible reasons for this. ? ########################### I've got my uBitx Raduino totally unhooked from the wiring harness and the uBitx board, laying flat on my desk.? Have a USB cable to a laptop to power up the Raduino. Using a corner mounting hole of the Raduino for ground, I see 4.6 volts on the first four pins in from the right on the top connector (ENCA, ENCB, FUNCTION, PTT). The 5'th is ground, so I see 0 volts there. The 6'th is 5 volts, and I see 4.7 or so because of a diode drop in the Nano. The 7'th and 8'th are analog pins without pullups, so are pretty much undefined. Be very careful when probing the 6'th pin that it does not get shorted to adjacent pins by the probe, but if you see around 4.7 volts there that will verify that the meter is set up correctly. If the Function button pin is low and the others high, could be there is something like a piece of wire or a glob of solder on the Raduino that is shorting it to ground.? With power off, how many ohms from the Function button pin to ground?? I see several mega-ohms. A shorted function button will put it into calibration mode, and it may be waiting for the function button to be released before updating the display. If all four of those pins on the right side are low, that suggests more serious trouble. Perhaps the flash program in the Nano got corrupted?? (I doubt it!) Perhaps the IO cells into the Nano got blown? (Not all four!) I'm betting the other three pins are high, and the Function button pin is getting shorted low somehow, and thus hanging up the processor. ? Jerry, KE7ER
On Thu, May 17, 2018 at 07:37 pm, Gary Anderson wrote:
Rogier has a few threads open on his problems.? Casually, hard to keep up with where he is at the moment.
He has shared more information than is contained in this thread.
I usually _try_ to look a threads I've responded to, to see if progress is made or if additional inputs? / coaching might be helpful.
I can see how using non threaded email, one might not understand this perspective.
So, please if you have an issue where others are trying help. Please stay on the same thread e.g. subject line.? Easier for others taking their time to try an help.
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Re: share your BITX success stories
I've been working FT8 for a few days on my shiny new uBITX tied to a homebrew G5RV set up as an inverted v.? Just finished a 20m QSO with Tasmania.... thats over 9000 miles on just less than 9w! Amazing little rig!
73's de W5JXN?
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Re: Mic doesn't work in bitx40
#bitx40
Thank you for your reply..
So the one that I bought is the electret condenser mic.?
When I didn't connect the mic to the circuit the voltage from 4.7KOhm resistor is about 9.5-10Volt. But when I connect it to the mic, the voltage suddenly drop to the 0.131-0.135Volt.?
And the 1uF polar capacitor, also behaving weird. The positive side is show the same exactly voltage with the output from 4.7KOhm resistor. But the negative side always show 1.4Volt, even when the mic is connected or not.
Please help me. Thank you
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Re: Asking for help solving a Hendricks kit BitX20 PA oscillation problem
I replaced both BS170¡¯s and solved the bias current problem. ??I re-soldered both T1 & T2. ??That may have been a contributor. ?I ended up using a 470 ohm resistor across their drains instead of the 1k resistor. ?Now all is very very stable. ???Currently trying to do a final alignment. ?Hoping that will fix my power output problem which is currently limited to about 4.2 Watts.
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Re: rough draft of how to connect BITX to PC for digital modes wiki
I had the wrong link for the FTDI cable.? It should be ? Also worth noting, you could probably save on shipping to order your parts from less suppliers than I did.? This wasn't the top of my project list so I just kept adding parts on to orders for other things as I thought of it.
--
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Re: share your BITX success stories
On Wed, May 16, 2018 at 09:48 am, Doug W wrote:
I just missed the illustrious 1000mi/w
I guess this is a wishing well because I just hit 1,128.9mi/w with a QSO from Brazil. Just in case this thing works....oh mighty list I still haven't won the lottery. ? --
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Re: share your BITX success stories
Well took it out of the box and wired up the connectors and all and having on the bench spread out.
haven't measured power in any exacting way for at 11V I see 6W at 7mhz.? Receives well.
I then installed my mod for the audio amp to run it at 8V regulated.? It works.? Only one part
used an lm7808.
Changed the resistor on the back of the LCD from 100ohms to 330 to damp down the brightness a bit.
Adjusted pot on the back of Raduino for better contrast.
Flipped the 5V regulator around so it doesn't hang off, my case needed that bit of space for a really
good encoder.
Next step is the bias on Q70 its sitting at 1.6V way too low for good overload results. 16k resistor will fix that.
After that replace q90 with 2n2222A and then check the bias it seems to be at higher current than needed.
At this point I'll break for an order of a dozen MPSH10 and some other RF parts to try.
The case, no matter what they say the drillin and blastin is the work:
While waiting I'm working the fitment of the case and the various parts.? ?Other things that
will need to be on the panel is the power led, some form of metering?for received signal
strength and relative TX power (bargraph but not on LCD).?
Mic jack, headphone, and antenna jack are? on the front panel along with LCD and power
switch.? Then we have audio level and rf-gain.? All this goes in an area 8.x inches by 2.25 inches.
It has the potential for being cramped if I use the larger tuning encoder.? ?The display
eats panel space too.
plodding on..
Allison
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Rogier has a few threads open on his problems.? Casually, hard to keep up with where he is at the moment.
He has shared more information than is contained in this thread.
I usually _try_ to look a threads I've responded to, to see if progress is made or if additional inputs? / coaching might be helpful.
I can see how using non threaded email, one might not understand this perspective.
So, please if you have an issue where others are trying help. Please stay on the same thread e.g. subject line.? Easier for others taking their time to try an help.
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Re: Using IRF530 outputs and 2N3553 drivers in ubitx
I have often thought of using the IRF's in common gate mode to avoid gate capacitance issues. Never came across such a design, gain would be slightly low but should have better stability and better high freq performance after all it was done all the time with tubes.
Rahul VU3WJM
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Re: ND6T AGC implementation for uBIT-X
The AGC and Pop Fix boards have both been redone and are already at the board house. Copies of the new ones are in the "Files" section.....as before.? Some of the changes were very slight but it will make for a better board and more reliable fix .....provided that nothing else got hosed.?
That wattmeter board may work quite well at lower power levels just as long as you have a 30dB span (1mW to 1W, 5mW to 5W, etc) . Testing yet to be done.
73 Kees K5BCQ
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While a soldering iron and a screw driver is all you need to setup the ubitx, i would encourage everyone to experiment with testing and measuring. A resistive swr bridge is just three resistors and a transformer. An RF voltmeter is a diode and a capacitor. An HF oscillator is a one evening project. Raduino, with a different firmware can be a programmable signal gemerator and a voltmeter too. Each of these kind of projects will enhance your understanding and bring immense joy to your hobby.?? - f
On Fri, 18 May 2018, 00:46 Jerry Gaffke via Groups.Io, <jgaffke= [email protected]> wrote: I haven't seen a lot of flames here regarding imprecise measurements.
If you have the Harbor Freight digital voltmeter (often free with any purchase), you are about as well armed
as most folks here in the forum.? If you have trouble troubleshooting, somebody may urge you to build a diode RF probe,
that's about it.
Some do have good lab gear and and decades of experience, can measure filter passbands or
intermodulation distortion or harmonic content, and they then report back telling us what they saw.?
But that sort of thing is definitely not required.
If anybody suggests you should spend more on test gear than you did on the radio,
that's your opportunity to go ahead and flame them good.
Jerry, KE7ER
On Thu, May 17, 2018 at 10:07 am, kq2q2000 wrote:
I¡¯ve been Flamed in the past for not being Precise and well Documented. Opinionated Flamers are ready and armed?24/7.?
It is easier to remain Silent, Learn and Elmer the appreciative Experimenters Locally.?
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Re: Raduino Questions for Bitx40
Then board seems alright. It looks like some raduino wire is grounded?that shouldnt be grounded. Check your wiring carefully against the wiring diagram at HF Signals.
- f
Greeting,
If I may I have a few questions about my Bitx40.? My display will only on power up will show "Raduino v1.01 and will stop there.? I have checked the purple wire going to the center wiper and I can vary it from 0-5volts.? I can also hear the 12 mhz on my other radio. However it will not go on to display the frequency on the display.? So I'm wondering does the "Raduino v1.01" really tell me that the software is working correctly in the nano board? I don't really have much experience with this stuff, just downloaded the IDE? and got a few books on the arduino, I'm on? the path to learning about them.? My bitx40 does not have? L4 and C93 on it,? So does the uno and board that attached to it provide all the signals that the bitx40 needs?? I watched Ashhar Farhan's video on troubleshooting and I did not have a signal at Collector at Q7 the 5 mhz on the main board.? Is this normal if the L4 and C93 are not mounted on the main board?? I feel that I need to get the display working before I go on with this.
Thanks for all input
Tom WD9GON
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What you are missing are some resistors plus these comments from the Raduino source code file? ubitx_keyer.ino:
* CW Keyer
?*
?* The CW keyer handles either a straight key or an iambic / paddle key.
?* They all use just one analog input line. This is how it works.
?* The analog line has the internal pull-up resistor enabled.
?* When a straight key is connected, it shorts the pull-up resistor, analog input is 0 volts
?* When a paddle is connected, the dot and the dash are connected to the analog pin through
?* a 10K and a 2.2K resistors. These produce a 4v and a 2v input to the analog pins.
?* So, the readings are as follows :
?* 0v - straight key
?* 1-2.5 v - paddle dot
?* 2.5 to 4.5 v - paddle dash
?* 2.0 to 0.5 v - dot and dash pressed
?*
?* The keyer is written to transparently handle all these cases
?*
So there is one wire into the Raduino, but the voltage on that single wire
says if you have nothing going on, the straight key is pressed, or the dot or dash paddles are pressed.
Very clever.
Unfortunately, it doesn't work very well.? A little bit of dirt in your straight key contacts and the
resistance there can be enough that the Raduino things it's a dot paddle press.
Here's a hardware fix, your key tells a fet to turn on, which in turn switches the resistor network:
? ??
Some of the newer firmware releases have ways around this problem also.??
Jerry, KE7ER
On Thu, May 17, 2018 at 06:02 pm, Alan Shapiro wrote:
How can the plugged in paddle work when only the tip (or ring) and ground of course,are connected?? Don't both tip and ring have to be wired?? What am I missing?
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Re: ND6T AGC implementation for uBIT-X
Yup, that would work. I'm thinking of something useful for detecting low level RF when trying to figure out why the transmitter is putting out 1 Watt instead of 5Watts. But the scaling resistors in front of your AD8307 could be adjusted as needed. I was also thinking that if the AGC or pop fix boards needed to be redone, you might squeeze in pads for an AD8307. Nik has an AD8307 on his Raduino: ? ? /g/BITX20/message/42237Did anyone try it? Was it quiet enough to be useful? Jerry, KE7ER
On Thu, May 17, 2018 at 05:54 pm, Kees T wrote:
Jerry,??#49555
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Re: A friendly suggestion for Farhan.
I made a mag loop for 40 and am working on the homemade capacitors remote tuning mechanism. I started with an arduino and servo, and now going KISS with a DC 0.6 RPM motor, momentary rocker switch, PWM driver to slow it down more, and a field strength meter to use instead of a SWR meter. I once said before the uBITX was released I wouldn't mind assembling and winding the toroids myself like other kits are. And I too stock parts. Woodworkers stock wood, machinists stock metal, we all stock things for our hobbies as we chose to enjoy it. It's an investment in our continued enjoyment, as well as a convenience. Who likes to wait 6 weeks to start a project?
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Re: Using the uBitx with FT8
By the way, thanks Doug for taking the time to post your work on doing this. I'll very interested in doing the same thing!
Roy WA0YMH
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Re: rough draft of how to connect BITX to PC for digital modes wiki
I followed a similar approach.? Mounted a 4 port usb hub inside
the case.? One port for the radiuno, one for a 6 buck usb sound
dongle, two free for future use (rtl dongle for panadapter and
maybe a pi0 for for something in the future).
I also used an Easy-Digi board simply because I prefer to have
the radio as electrically isolated from the computer as possible.?
The advantage of the USB sound dongle is that the radio gets it's
own dedicated audio in and out channels. This way I can have
WSJT-X running and not lose my main PC audio. ? Disadvantage?? I
used an unpowered hub that puts a load on a single USB port with
the RTL dongle plugged in.? I'll change that later.
The only thing I had to do to tame the audio is to put a 330 ohm
resistor across the output side of the audio out (dongle mic in)
to make the volume adjustment smoother.
I run the CEC software to control freq changes and transmit from
WSJT-X via CAT control through Onmi-Rig.
On 5/17/2018 8:45 PM, Doug W wrote:
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It seems almost
every day (or hour) someone has a question about connecting their
radio for digital modes.? Following are my cobbled together notes
that if the group deems worthy could be the start of a wiki page
on the topic.? My concern is my use of a TRRS jack might be too
specific, but at least this is a place to start.? Your feedback is
welcome.
----------------
There are many
different ways to pair your radio¡¯s audio and ptt circuits with
a computer to work digital modes.? This is not a discussion of all the different
ways.? This is how I
did it.? Most of the
information is readily available if you search this list and
online.
I'm using an Easy
Digi kit for switching PTT and isolating Rx audio.? I found the loss was too
high on the Tx side so I'm going right from the sound card to
the rig for Tx but I will describe using both sides of the Easy
Digi below.? I set up
my radios with a mono jack for the speaker and TRRS for mic/PTT
and corresponding cables on the Easy Digi so everything is
interchangeable.? I'm
using a USB sound card and an FTDI cable.? I have the sound card and
FTDI cable plugged into a small unpowered USB hub with the Easy
Digi hot glued on top with the cables all hot glued for strain
relief.? It is ugly as
sin but sits out of sight and works.? There are links below to
all the parts I used.
Pop the cover off
the USB sound card and desolder the two audio jacks.? Cut two pieces long
enough to go from the sound card to the Easy Digi off the mono
cable.? It is 6¡¯ long,
you have plenty to spare and it is good shielded cable.? Solder the cables where
the jacks were and route them out the holes in the case where
the jacks were.? Now
solder those cables to the corresponding spots on the Easy Digi.? Mic from the sound card
to Audio to PC on the Easy Digi and speaker on the sound card to
Audio from PC.? Now
solder the audio cable with plugs to the Easy Digi board.? Audio to your radio¡¯s
speaker via the mono cable and Mic to your radio¡¯s mic via the 4
conductor cable if doing it like I did.? The last connections are
from the FTDI to the Easy Digi and the Easy Digi to your ptt.? Cut the RJ45 connector
off the FTDI cable and connect the following cables to the Easy
Digi, Black to DIG GND, Green to DTR and Brown to RTS.? Those are the only wires
you will use in that cable.? Now
connect PTT HI on the Easy Digi to your PTT wire and PTT GND to
your PTT ground.? Both
of these are also part of the 4 conductor cable.? Now plug the FTDI cable
and USB sound card in the USB hub and connect the hub to your
computer.? If you are
using Windows, your machine should set both up without issue.? Connect the mono jack to your
radio's speaker jack and the TRRS plug to your TRRS jack or
however you have your mic and ptt connected.
Assuming you are
using WSJT-X, in settings under the radio tab select RTS for PTT
method and whatever port the FTDI adapter cable shows up on.? With a dummy load
connected to your radio click the Test PTT button several times
to make sure it toggles Tx on and off on your radio.
One last very
important thing.? The
heat sinks on the IRF510¡¯s are sized for casual voice and cw
work not the full blast usage of digital modes.? Make sure you have a plan
to deal with the heat.? There
are many other posts on heat sink ideas.? I have found even a
little air flow from a small fan makes a huge difference.
Following are the parts I used:
?
Easy Digi
mono cable with plug
4 conductor cable with TRRS plug
TRRS jack
USB sound card
FTDI cable (do not buy a cheap TTL adaptor, they do not put out
high enough voltage for the opto coupler on the Easy Digi)
USB hub
I found this breakout jack helpful for confirming the wires on
the 4 conductor cable before soldering up the TRRS jack
--
Doug
AC9RZ
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How can the plugged in paddle work when only the tip (or ring) and ground of course,are connected?? Don't both tip and ring have to be wired?? What am I missing?
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atouk