Re: ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio
#ubitx-help
#ubitx
Hi Evan,
An update on the investigation:
1) Radiuno tests:
I was able to buy a used Tektronix 2465 oscilloscope over the weekend for a very good
price and could get started with proposed Raduino clock generator test:
Observations:
- All 3 signals are being generated with the expected frequencies,
- CLK#2 and CLK#1 signals are sawtooth shaped,
- CLK#0 looks very different (pls. see the picture on Google photos),
- Frequency range for signals seem to be ok: CLK#2 varies with when I change
bands or tune within a band, CLK#1 varies based on the 'mode' selection (USB or LSB).
CLK#0:
CLK#1: https://photos.app.goo.gl/1GcupVPLvr7UqjyB8
CLK#2: https://photos.app.goo.gl/tzNNQJNFtaNXQTUs9
Note: The reason CLK#0 looks so different could be related to my home made 1:1
probe (I expect regular 100Mhz probes to arrive in the next few days). Based on the
screenshots for some of the measurements, it seems the home made probe work better
with higher frequencies.
Conclusion:
Raduino seems to work.
2) Audio amplifier tests:
I repeated the 'inject an audio signal' test: I connected the audio signal to VOL_H (instead of
VOL_M) this time and GND.
Observation:
The signal was perfectly audible, volume could be controlled via the potentiometer.
Conclusion:
Audio amplifier seems to work.
3) Q74 test:
Resistence measurements of this MOSFET need to wait until I get the 100Mhz probes with a finer tip -
the measurement points are tiny.
Thank you for your support,
-jens
PS: It would be great to have 'reference' oscilloscope screen shots for all of the measurement points
of the uBitx v5.
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Hello Sascha.
Thank you for keeping us informed and posting the videos.
Some ideas:
1. For my capacitor tuning (L-network, not a loop) I use an RC servo. The cheap SG90 servos (less than $2 on eBay) will do 180 degrees rotation in fact and the angular accuracy is good enough. Less noise but still not silent either. But you can drive the capacitor shaft directly since there is no need for gears and therefore it is easy to make a tiny sound proofing box for them. RFI into the servo was fixed with a simple toroid for the control cables just at the servo entry. If wanted you could cut power to the servo with a mosfet to save energy (a few milliamps) when not moving.
2. For tuning, you can use CW and reduce power by using Ted's method (see /g/BITX20/message/67662).
You would need to change the cat_lib.ino library a little. For example you could create an AM mode in the CatSetMode method that sets an AM flag to use later in the CatSetPTT method.
In the CatSetPTT method on a PTT ON command, if AM mode flag is set, you could use a startTx(TX_CW, 0) followed by cwKeydown();
On a CAT PTT OFF command just reverse with cwKeyUp(); followed by stopTx();
That's the logic I use for my tuner.
That way you don't need to change the loop tuner's code.
Hope that helps,
73, John (VK2ETA)
?????
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Re: Finally started construction
#ubitx
I have a bunch of those inductors.? I can send 10 if you send me a sase and a dollar bill.? If you want to use PayPal, it's $1.70.? My address is good on QRZ.? I'll give you the PayPal info if you want it.
73, Bob. W7HNV
My XYL purchased an Ubitx for me late last year. It is a V4. Board. I had time to start on the recommended fixs this weekend. I have replaced the relays with the Axicoms. Does anyone in the U.S. have the SMD inductors for L5 and L7 for sale? I hope to put this in a pelican style case with a tuner and power source to use for portable ops. Thanks to everyone here for their vast wealth of knowledge. I have learned so much about these radios and electronics in general reading this board.
Russell Ward W8ARD
Columbus Ohio
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Ha! I saw the reply about the "circular firing squad" someone else posted too - LOL.
Jim
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------ Original Message ------ From: "W2CTX" <w2ctx@...> To: [email protected]Sent: 4/15/2019 1:03:50 PM Subject: [BITX20] Nextion Saga Now don't flame me guys....
Reading all these questions about what build goes with what Nextion size and
what options are supposed to be activated reminds me of Abbot and Costello -
Who's on First.
rOn
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Re: Kit-Projects ND6T Ubitx AGC
Lee I sent it over. The updated instructions are in the same download area on the kit-projects website. -- David
?N8DAH
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Re: ubitx mobile in a car
Hi, Many moons and moons ago, i remember seeing a write-up if I remember correctly in QST, about someone experimenting to get better efficiency while operating mobile.
What he did was to get two whips, one attached to the front bumper where it was fed with coax, the other was attached to the rear bumper and? tuned by a series variable capacitor to the rear bumper.
The two whips were bent over and their tips connected together to form a sort of continuous whip from the front to the rear of the vehicle.
He claimed that it was more efficient which it should considering that it was quite longer, at least double the normal length, than a normal mobile whip.and if iI remember correctly there were no loading coils with their inherent losses.
Naturally it would be better for NVIS considering that it was more horizontal than vertical.
One can visualize this setup if one looks at? a military vehicle where the whip is bent over the vehicle for NVIS propagation, but in the case I mentioned the whip (two joined whips) was tuned making the vehicle part of the system and working like a sort of loop.
One problem with modern vehicles is that they have a lot of fibre parts unlike the old vehicles where everything or nearly everything was metal, but maybe someone can try it and let us know about the result.
Hope this helps.
Regards
On Mon, Apr 15, 2019 at 5:56 PM ajparent1/KB1GMX < kb1gmx@...> wrote: The reality of mobile ops is they antennas used will be inefficient for bands below 20mhz.
Reason is loading coils are a required thing to tune out the reactance of a short antenna.
There is no way around that.?
FOr 20M antenna efficiency is about about 8ft tall will be reasonable about 33% as its pretty
close to 1/2 size.? Center fed is about the best.
For 40M its about 1/4 size and allowing for the fact that cars are a terrible counterpoise for
the antenna so efficiency under 10% are the norm.? IF you can tolerate a taller than 8ft
antenna that helps, center loaded is best.? Do not use an antenna tuner as you at the wrong
end of the cable.? Its best if the tuner is at the base of the antenna.
K0BG has a very complete site on how to get the best out of a mobile antenna.
I run 40M mobile QRP using KNQ7A or FT817 and the antenna is a cheap 40M 8ft
centerfed whip?with mods.? The mods are a 9 turn 1-inch dia coil from the base to
ground to load the antenna.? Then the antenna itself has the longest whip section
possible at the top and is tuned by removing some of the plastic shrink and removing
turns to keep it as long as possible.? This is more efficient than shortening the whip
to tune it.? Its good for about 30khz either side of where tuned.? ? Using a tuner to
get more bandwidth results?in?a significant loss in efficiency as they antenna is then
untuned. I verified this with a field strength meter.? However those antennas are
cheap (about 20$) and I can carry two (one for 7163, and 7250) in the bed of the pickup.??
Ignition noise it a problem with the car/truck... fix it and then you hear the other near you.
Allison
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I would recommend first using the standard display to insure that the main board works.? I was able to position the 3.2" nextion display opening such that the standard display could be seen through the hole for testing.? This way you know where to look for any issues that come up at first.? The KD8CEC software is GREAT, however you add a number of other potential issues with version compatibility that are best tackled AFTER any bugs are worked out with the stock parts you are going to keep.? You also get a feel for how the radio sounds and operates first, then add the "extras" later.
The above is my opinion based on my experiences.? Yours may be different.
73
Evan
AC9TU
?
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As I¡¯m waiting for my kit to arrive I have a question for you guys. Initially I was going to build the kit with the LCD display that comes with it and then at some point I want to upgrade to the Nextion display. As I¡¯m planning to build the case I¡¯m thinking maybe I should just build it with the Nextion display right from the start to avoid having to modify the case.?
Any reason I shouldn¡¯t ???
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Re: ubitx mobile in a car
I'd like to hear more about this 40m "center fed" design.? I figured 80m mobile is a pipe dream at BEST for a variety of reasons. If I could get 40 and 20 to work, I'd be fine is it tends to only get easier from there on upward. I built a base loading coil that works well with an 8 foot CB whip back in the early 80s for 40m and which had a tap for 20m. That was out of the ARRL 1977(?) Handbook and worked fantastically. I still have that coil even today. I could try it again though I'd rather try to move to some newer materials; that, and it didn't look so terrible in the back of a 1969 Plymouth Fury III. I'm pretty sure my dear, lovely spouse would not want that on the family's RAV4.
On a different note, about 12 years ago I took a VHF low-band antenna and used the base of the coil as a mount at the bottom of a length of 1.25" PVC pipe.? I then attached a 48-inch whip to the top of that coil form (using the original antenna's cap & set screw) with about 32 ft of wire. A shunt came from the center of the base (from within the PVC form, near the bottom out to the side) - that being an NMO mount for the original low-band antenna - which was used to tap to the external coil at a point found to resonate well on 14.25mHz or thereabouts. This antenna was used exclusively with an MFJ9420 and it kicked a$s. This one, I know to still be in inventory... :)? Also in inventory is an 80m hamstick that could be shortened, shunt-fed, or otherwise repurposed for a different band.
So, please do share, in as much detail as you wish to give, the design on this center-fed 40-meter deal. I'd like to know what was done and what worked. And if nothing else, I've got a known, working 20 meter band base mounted antenna that I can simply use with another hatchback lip mount as was before.
All else being equal, I 'd prefer to have 40m in the car for daytime driving and which I could switch to 20m when the band's open. Sure, I'd like to have 80m as well but I might as well just put a coat hanger out the window and pray. That doesn't cost much.
Thanks much and 73,
Ted K3RTA
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Or a circular firing squad. Have you looked at uBitx.net
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Now don't flame me guys....
Reading all these questions about what build goes with what Nextion size and
what options are supposed to be activated reminds me of Abbot and Costello -
Who's on First.
rOn
|
i2c signal meter/analyser/dsp/cw decoder
Hi, ? Can anybody pl confirm which firmware .hex to run the DSP signal meter & CW decoder option . I use nextion adv 3.5¡±. Fyi, the S-meter function works normally, but DSP1 & CW setup buttons don¡¯t appear on the control menu ??!! ? I¡¯m using ¨C #for 1st Arduino (ubitx): ???????????UBITX_CEC_V1.200_NX_S.hex? (tried v1.097 & v1.10 too !!) ? #for 2nd Arduino (sig.sensor): ??I tried all the below found online, but w/o success CEC_I2C_Meter_V0.8.hex DSPMeter1_V0.7.hex i2cmeter1.ino.hex ? In dspmeterv1-master uploaded few days back ( ) there¡¯s no .hex files !! ? All wiring as per- Standalone Signal Analyzer (I2C Type Signal-Meter) for uBITX #2 - Nextion LCD Standalone Signal Analyzer (I2C Type Signal-Meter) for uBITX #3 - Advanced and FFT ? 73s, Vu3Cgb- Sourav ?  ?? 
? 
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Finally started construction
#ubitx
My XYL purchased an Ubitx for me late last year. It is a V4. Board. I had time to start on the recommended fixs this weekend. I have replaced the relays with the Axicoms. Does anyone in the U.S. have the SMD inductors for L5 and L7 for sale? I hope to put this in a pelican style case with a tuner and power source to use for portable ops. Thanks to everyone here for their vast wealth of knowledge. I have learned so much about these radios and electronics in general reading this board.
Russell Ward W8ARD
Columbus Ohio
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Re: Kit-Projects ND6T Ubitx AGC
Hi David, would you please email me the updated switch diagram for my agc I just received from you a week or two ago.? I did question the supplied diagram.? thanks? Lee ? wb3acc@... ?? 73
On April 14, 2019 at 11:55 PM N8DAH <Dherron@...> wrote:
I have restocked mic's, paddles and AGC's. The AGC doc's have been updated with the correction for the DP3T. 73
--
David ?N8DAH
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Re: ubitx mobile in a car
The reality of mobile ops is they antennas used will be inefficient for bands below 20mhz.
Reason is loading coils are a required thing to tune out the reactance of a short antenna.
There is no way around that.?
FOr 20M antenna efficiency is about about 8ft tall will be reasonable about 33% as its pretty
close to 1/2 size.? Center fed is about the best.
For 40M its about 1/4 size and allowing for the fact that cars are a terrible counterpoise for
the antenna so efficiency under 10% are the norm.? IF you can tolerate a taller than 8ft
antenna that helps, center loaded is best.? Do not use an antenna tuner as you at the wrong
end of the cable.? Its best if the tuner is at the base of the antenna.
K0BG has a very complete site on how to get the best out of a mobile antenna.
I run 40M mobile QRP using KNQ7A or FT817 and the antenna is a cheap 40M 8ft
centerfed whip?with mods.? The mods are a 9 turn 1-inch dia coil from the base to
ground to load the antenna.? Then the antenna itself has the longest whip section
possible at the top and is tuned by removing some of the plastic shrink and removing
turns to keep it as long as possible.? This is more efficient than shortening the whip
to tune it.? Its good for about 30khz either side of where tuned.? ? Using a tuner to
get more bandwidth results?in?a significant loss in efficiency as they antenna is then
untuned. I verified this with a field strength meter.? However those antennas are
cheap (about 20$) and I can carry two (one for 7163, and 7250) in the bed of the pickup.??
Ignition noise it a problem with the car/truck... fix it and then you hear the other near you.
Allison
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Re: Homebrew li-ion battery pack into ubitx
Yes, and one can score some nice LiPo cells from a cordless drill?battery pack?and get a charging controller for the intended voltage (12v, 16v, etc) on eBay with separate leads to sense each 4v step of the battery pack for balanced charging.
Ted
K3RTA??
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Re: Homebrew li-ion battery pack into ubitx
My end-of-the-world build has a kit type bulit into the faceplate and it seems to work OK. I added two switches to switch the two variable caps in or out independently which seems to help in some cases to add or subtract in that way. I haven't logged contacts on that build as of yet though I haven't been out with it, either.
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Re: Homebrew li-ion battery pack into ubitx
The transformer of an EFHW? matching network matches the 50 ohm transmitter
to an expected impedance into the wire of between 2500 and 3000 ohms.
Power is Volts*Amps, or Volts*(Volts/Ohms).
At 5 Watts of RF power,? ? 5watts = Volts*Volts/3000ohms,? ?therefore? Volts = sqrt(3000*5) = 122 Volts RMS.
At 100 Watts, it's still around 548 Volts RMS, not yet kilovolts
The polyvaricons are rated for something around 100 Volts:
? ??
Generally, you can press a polyvaricon somewhat beyond 100 Volts.
A polyvaricon works at 5 Watts for an EFHW, though?an air-variable cap would be a better choice.
If an air gap does arc over, it will self-repair once the ionized air circulates out.
And an air gap capacitor has a higher Q, and thus lower losses.
The qrpkits Sota Tuner successfully uses a polyvaricon:in an EFHW tuner:
? ??
They claim a max of 5 Watts CW, 10 Watts PEP.
On 10 Watt peaks, that would be? sqrt(3000*10) = 173 Volts RMS.
Perhaps they are more concerned about heating than they are about arcing?
Anything other than a resonant EFHW will be lower impedance,
and thus lower voltages across a tuning capacitor.
Jerry, KE7ER
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On Mon, Apr 15, 2019 at 12:33 AM, Sandeep Lohia wrote:
End fed 1/2 wave is a voltage fed antenna Sarma ji, there might be more then kilo volts present even with QRP at end of coil...
Therefore thin PVC variable Gang Capacitor won't help...
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Re: ubitx mobile in a car
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Re: Relationship between IF-S, calibration, and BFO?
That is exactly what I was wondering Vic. I will give it a shot tonight.?
Thanks
Bill
KE8EYM
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Jim Sheldon
N8DAH
Ted