Re: Software support Request for Full QSK BITX40
Gary,
Simulating just the IRF510 and T7, minimal load, driving the gate hard with a 0-10v square wave,
I see spikes to several kV as current through the IRF510 shuts off, but only if I slow the square wave down enough.
The simulation gets kind of weird with a load of 10k ohms or more
At 7mhz the IRF510 stays on, even in the troughs, even though the gate pin goes to zero volts.
I haven't looked at the model for the IRF510, but all it would take is resistance going into the gate?
and miller capacitance from drain to gate to account for this.
So T7 does indeed behave like a flyback transformer at slow speeds, but at 7mhz the IRF510
stays on to where that coil current always has somewhere to go, T7 behaves more like a forward transformer.
Jerry, KE7ER
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On Wed, Jan 31, 2018 at 01:26 pm, Jerry Gaffke wrote:
With no load at the antenna port, the simulation shows an IRF510 drain current that stays near the quiescent 100ma
with perhaps 20ma pk-pk of RF riding on top of it.? (An initial spike that I'm ignoring here, as we would be increasing?
drive at audio rates.)? ? The drain current never goes toward zero, even when Q13 is driven with 400mv pk-pk.
Gate voltage is quite distorted, but does get down to 1.2v which should be enough to shut down the IRF510.
I'd guess that as the IRF510 shuts down the drain voltage rises, the gate-drain capacitance causes the gate voltage to rise,
and so the IRF510 continues to conduct.? ? ?When operating more slowly the IRF510 does indeed shut down as Vgs rises.
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Re: Spare/replacement part
As for T2 remove it from the board and check if the insulation has been removed from all leads. I have seen cases where one lead of coil still had the insulation causing an intermittent connection such as you have described.
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Jerry,
?You can do a ESP32 Widora Air for about $12 with free shipping.?? The ESP32 packs quite a punch in I/O, memory, and processing.? That and Bluetooth and WiFi.?? The Widora particular package is about the same as the STM32 device you're talking about.?
73, Michael
KM4OLT
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On Wed, Jan 31, 2018 at 01:32 pm, Jerry Gaffke wrote:
Scratch that.
The STM32F103C8 has a measly 64kbytes of flash, 20kbytes of ram.
For megabytes, you'll have to shell out $5 for the RasberryPi-zero.
. . .
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Jack,
?The Nextion display only uses a serial port.? Software is written on the processor on the display to change the display contents based on data sent back and forth on the serial port.??? This allows in this case the external processor to deal with data a processing and letting the display itself to handle graphics content.?
73, Michael
KM4OLT
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On Wed, Jan 31, 2018 at 11:48 am, Jack Purdum wrote:
Fred:
?
Are you running the Nextion from the STM32? No driver issues?
?
Jack, W8TEE
?
?
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Re: Audio gone on new ubitx
Have you checked Q71? Try removing it. Go to CW mode and see if you get the CW side tone
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Re: Audio gone on new ubitx
Try a firmware reload?? Also check
connections between board and raduino, and raduino and display.
M
On 1/02/18 10:17 AM, Erik Hokansson wrote:
I
do have 12v at pin 2.. I was able to key up the P tt and use a
keyer to transmit...they key word there is "was"..now the display
just reflects the u bitx version and stays there?
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Re: uBITX Firmware (CEC) 0.30 released (Test version).
#ubitx
Ian should have a guide available shortly to explain his software enhancements as a release version is almost there.? You are using the beta 0.34 version. ??
At top left is the frequency of the other VFO, not currently in use.? So if you have VFO A in use this is VFO B frequency.? The middle section shows the step value on the encoder, and the right hand shows the key type - Iambic A, Iambic B or Straight Key.
I am finding the IF shift helpful, and I like being able to adjust the frequency step value by holding in the butto for about 2-3 seconds.
Mike
On Thu, 1 Feb 2018 at 9:27 AM, Je < emilus@...> wrote: Congratulations to the author at first glance seems OK. But what is the 14.150k on the first line of the display?
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Re: Spare/replacement part
Check to see if coils are touching any smts. One of my bitx coils was soldered to a resistor, I guess during final assembly it was up against it and got hot enough to stick. I’m going one by one checking missing parts, bad solder joint, etc.
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On Jan 31, 2018, at 13:33, Michael Davis < maddmd818@...> wrote: T2 on my Bitx40 is intermittent. By that I mean, if I nudge it my receiver cuts out, if I move it, it comes back on. I have re-soldered the circuit board connections and have removed T2 from an old Bitx40 board. The leads are short and before I attempt to unsolder the bad T2, I though I'd ask if there is a way to buy a spare. I am going to examine the connections more closely with my computer microscope first. Is T1 identical to T2? Any others on the board identical. Thanks
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Scratch that.
The STM32F103C8 has a measly 64kbytes of flash, 20kbytes of ram.
For megabytes, you'll have to shell out $5 for the RasberryPi-zero.
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On Wed, Jan 31, 2018 at 12:14 pm, Jerry Gaffke wrote:
I'm currently playing with a "Blue Pill", has the STM32F103C8, $2 on ebay
? ??
Has the M3 core at 72mhz,? 64meg of flash, 20meg of ram, 12bit ADC.
Otherwise much like like the Nano, IO is primarily 3.3v with some 5v tolerant pins.
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Re: Software support Request for Full QSK BITX40
Gary,
With no load at the antenna port, the simulation shows an IRF510 drain current that stays near the quiescent 100ma
with perhaps 20ma pk-pk of RF riding on top of it.? (An initial spike that I'm ignoring here, as we would be increasing?
drive at audio rates.)? ? The drain current never goes toward zero, even when Q13 is driven with 400mv pk-pk.
Gate voltage is quite distorted, but does get down to 1.2v which should be enough to shut down the IRF510.
I'd guess that as the IRF510 shuts down the drain voltage rises, the gate-drain capacitance causes the gate voltage to rise,
and so the IRF510 continues to conduct.? ? ?When operating more slowly the IRF510 does indeed shut down as Vgs rises.
Jerry
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On Wed, Jan 31, 2018 at 09:40 am, Jerry Gaffke wrote:
One major conundrum:?
When the Bitx40 IRF510 turns off and the magnetic field collapses that energy needs some place to go,
the induced emf in T7 will create voltage spikes that rise as high as it needed till it finds a load,?
perhaps arcing across the transformer.? But my LTSpice simulation of the Bitx40 final with no load
shows no such spike, the output voltage remains pretty much determined by the turns ratio
as if T7 were a straight up forward transformer.
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Re: Audio gone on new ubitx
I do have 12v at pin 2.. I was able to key up the P tt and use a keyer to transmit...they key word there is "was"..now the display just reflects the u bitx version and stays there?
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Hi Mike,
Thank you so much for sharing this with me! Congrats to the whole group!
As for the board corrections, I'll integrate them in the next revision as soon as I manage to finish building V1 ;)
What I'd like to do for the next version is make it ?BitX-compatible: build one configuration, you get a single-band 20-40BitX, build another one, you get a ?BitX. Probably make all the modules the same size might also be a good idea...
I'd love to receive a motherboard, if you don't mind shipping it to Belgium; I can't seem to find your e-mail address though...
Manoel
ON6RF
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Re: #Bitx40 Mic Pre-amp MAX9812
#bitx40
This is w/o the pre-amp .....might just stick with the slight yell to get the audio out. I like the idea of not having to shout but do not like the audio from this version of preamp -- David
?N8DAH
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Re: ubitx relay substitute
The relays in the ubitx are the same as the ones used in the BitX40. I used Zettler AZ822-2C-12DE as a replacement: 73 Allard PE1NWL On Wed, January 31, 2018 21:44, denm178@... wrote: Would the Ormon G5V-2-H-DC12?? relay be a valid replacement for the relays in the ubitx?
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Re: ubitx relay substitute
The relays in the ubitx are the same as the ones used in the BitX40. I used Zettler AZ822-2C-12DE as a replacement: 73 Allard PE1NWL On Wed, January 31, 2018 21:44, denm178@... wrote: Would the Ormon G5V-2-H-DC12?? relay be a valid replacement for the relays in the ubitx?
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Would the Ormon G5V-2-H-DC12? relay be a valid replacement for the relays in the ubitx?
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Re: uBITX Firmware (CEC) 0.30 released (Test version).
#ubitx
Congratulations to the author at first glance seems OK. But what is the 14.150k on the first line of the display?
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Re: MAX9814 mic preamp and DC bias capacitor
I'm working on something similar.? It looks like Q6 is part of the ?B's mic pre.? When TX goes high, Q6 turns on and passes the signal into the mixer and so on.? RX also goes low and turns off Q70.? So if you wanna skip the ?B's mic pre you have to turn off that signal during RX.? This is because TX and RX share all that mixing and filtering and modulating stuff that I don't quite understand yet.
If someone who knows what they are talking about can confirm this, I'll give myself another high five.
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Re: Care and Feeding of SMD Parts
I find it's easier to get the strip started if I put down a strip of double-sided sticky tape on a piece of cardboard, put the carrier for the SMD on the strip and use a small piece of tape on the edge of the strip to lift up the plastic covering. Keeps the strips for my project from wandering off and it holds the carrier and parts down for easy access with my tweezers. lifting up just enough of the covering to expose one part at a time prevents them from blowing away. ?
On Wednesday, January 31, 2018 1:38 PM, Clark Martin <kk6isp@...> wrote:
I’ve been working with SMDs for a few years now and have lost several. ?If the get pressed right they fly off just like a tiddily wink. ?They also tend to adhere to tweezers, probes and soldering irons with very little effort. ?If it’s a cap or resistor I just fetch another one it’s not worth the effort of a futile search.
One thing I do to try to minimize losses is to limit the number of loose parts I have out to two. ?If I need to install more than that I’ll do two at a time and tack solder them into place.
On Jan 31, 2018, at 8:44 AM, Ken KM4NFQ < km4nfq@...> wrote:
To use a component, I press it from the plastic side, through the paper side with tweezers, then put the freed component on the solder-pasted pads. I work over an aluminum tray covered with a cloth. I haven't lost a component yet. Of course, I have only recently started working with SMDs, so take that with a grain of salt. :)
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Re: MAX9814 mic preamp and DC bias capacitor
I used another mic housing with a DPDT switch and wired it so voltage is supplied only when PTT is engaged. I am using a CR2032 3v button cell. Seems to work fine, but I have not compared the stock vs. preamp mic with anyone on the air yet. Definitely has more avg power on the watt meter. I can hear some peaks come thru the speaker when transmitting. I may try installing a pot to dial back the gain.
Jeff
AD6RH
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Michael Monteith
James Lawrie
N8DAH
Allard PE1NWL
Arvo W0VRA