Re: Blown (socketed) TDA2822?
Some of the clones are going for the lowest possible price, and fab/qc is as cheap as possible.
They work well enough for some applications when powered from 5 or 6v.
But depending on where that die was cut from in the wafer, may blow at 8v.
They simply don't meet the ST spec.
Most of them that do have a datasheet claim a max working voltage of 15v
as per the original ST part.
There are exceptions, claiming a max working voltage of 12v, absolute max of 15v.
The WX does not have a datasheet.??
It does not have a spec and might be doing anything it darn pleases.
That's my take.
Jerry, KE7ER
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On Sat, Jun 23, 2018 at 08:18 am, Arv Evans wrote:
It appears that there are multiple versions of the TA2822 audio amplifier, by
several different manufacturers.??
Some are rated 3V to 15 or 16V and others are 1.8V to 12V.? But that doesn't
explain why some apparently have no safety voltage range above the rated
voltage.? Maybe when they say Maximum Voltage = 12V they really mean 12V.
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Remi F1MQJ-
If power consumption is a problem, there are regulator boards that can be had/made that use a torrid to buck-boost the voltage. Much higher in efficiency than a 7805. I have heard a claim of 95%.? The circuit is basically an oscillator at the input voltage that the oscillators' output is rectified/filtered to create a new voltage output.
#2. disable the back-light of the display. Or the entire display when not looking at it. It is only an output and not interactive except to provide information. You should be able to tune around without it for short periods of time. DPDT Center off switch - display- off-? display with back light.
#3. QRP - by definition is transmitting LOW power. Not Low power consumption of the transceiver.? Comparing a 1950's 100 watt station (tubes) to a modern rig today, certainly uses less power at the mains. Likewise true low consumption minimalist transceivers are usually 1 band, CW only- crystal controlled.
?????
#4. Like you, I appreciate QRP operation and years ago used a K1SWL 40M QRP rig, that worked nicely in my sleeping bag as, frequency read out was in CW, it's only mode. My mess kit weighed more than that rig, headphones and key. True backpacker's rig. No longer made, also came in a 30 meter version.
#5. Perhaps a Radunio with cw audio readout will be instituted by others.? "PROGRAMMING ARDUINO" by Simon Mark ISBN 978-0-07-178422-1 has information on a CW sketch, albeit it converts ASCII to a flashing LED. But a good basis. Further application would be visually impaired hams. It could be a Raduino without the display- a Plug in.. or a variant of #2 above.
Regards from Kansas,
Larry W8LM
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Re: Understanding Spurious Emissions
Hi! Farhan and others,
I feel spurii are result of the first mixer being over driven by a large margin. A rough estimate indicates that the 45MHz input to the? 1st mixer is in vicinity of 0 to +1 dbm. This appears to ten times more than the required? level of -10dbm.
I have considered following losses and gain in the reverse transmit path:
Bal mod out put -17dbm loss in pad? ? ? ? ?3 db Loss in 12MHz XF + matching transformers 3 +2 = 5db Gain in 12MHz TIA? 20db Loss in second mixer 7 db Loss in 45 MHz filter and matching transformer 5db Gain in 45MHz TIA 18db
Loss in chain 20db , gain in chain 38db.? Signal at first mixer = -17 + 18 = = + 1dbm
In real world figures may vary a bit or I maybe missing something.??
Rahul VU3WJM
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Re: Blown (socketed) TDA2822?
It appears that there are multiple versions of the TA2822 audio amplifier, by
several different manufacturers.??
Some are rated 3V to 15 or 16V and others are 1.8V to 12V.? But that doesn't
explain why some apparently have no safety voltage range above the rated
voltage.? Maybe when they say Maximum Voltage = 12V they really mean 12V.
Arv
_._
On Fri, Jun 22, 2018 at 11:30 PM Jerry Gaffke via Groups.Io <jgaffke= [email protected]> wrote: You think the WX might be a repackaged TA2822D meant for the SOIC8?
I doubt it.
I think the WX is a cheap copy that simply doesn't meet the 15v absolute max spec
We had reports that there are clones of the TDA2822 (not necessarily the WX)?
that blow when given a supply over 7 or 8 volts.? (Some club project in England)
Didn't have to be putting out significant power to blow.
As I recall, some of the WX failures happened instantly, and all struck me as consistent
with too much voltage for it to handle.
The SOIC datasheet you point to has the same 15v absolute max spec
that the DIP part does.
The primary differences I see between the SOIC and DIP datasheets from ST
have to do with power dissipation, possible that ST was using the same die in both
but the SOIC simply can't deal with the heat.
Failure mode on the SOIC would be due to?overheating under load and take a bit of time.
I don't think that is what we were seeing with the WX.
?
But I'm just guessing.
Could be proven wrong.
Jerry
On Fri, Jun 22, 2018 at 09:59 pm, Raj vu2zap wrote:
You missed my point Jerry. I am not suggesting 2822D. Please see
the spec sheet I attached. It is a lower power version of tda2822.
I think that die is being repackaged as TDA2822 in 8 pin DIP. It cannot
take the load and blows up.
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Re: KD8CEC - Nextion Display - IAN questions
Ian,
First, thank you for the time and effort you have put into this radio and now, a truly nice display to go with it. ?
I'm new to Arduino but your tutorials and instruction allowed me to upload .hex files to the Arduino and the Nextion display. ?Everything works (V1.094) that I've tried so far.?
I started using Raspberry Pi's for all my radio interfacing and digital mode operation some time ago so I could learn that little Linux board. ?They were also used for all the firmware upgrades for the uBITX and the Nextion display. When something didn't go exactly right the first time, I knew it was something I did. Because your software and procedures are top notch.
You sir are doing a great service to this user community and our hobby.
Lowell Haney
Rome,GA
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Here is the Google Translate URL for the article.
https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fwww.carnetdumaker.net%2Farticles%2Ftest-comparatif-de-la-consommation-electrique-vide-de-diverses-cartes-arduino-et-compatible%2F%23les-cartes-arduino-compatibles-chinoises&edit-text=
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Hello Remi,
I measure 168 ma. for my entire uBITX on idle receive (low volume, no input signal, 13.8 volt source). Since I use a 7808 as a pre-regulator my 7805 is cool enough to pinch and hold, the additional heat being soaked up by the cabinet where I mounted the 7808. That keeps heat off of the Raduino and also provides a modicum of additional filtering. I also decrease the LED backlighting on my display which probably helps a bit.
Isolate the loads and check your current. There is something wrong if you measure 350 ma at under 14 volts. With the power off, unplug the Raduino, re-apply power and measure the current. If the drain is coming from the Raduino then disconnect power again and just unplug the display. Then apply power and measure again. Take your time and measure resistances until you see something amiss. Check to see if something is touching mechanically where it should not. Check under the boards. Look for a tiny wire or solder ball. Make sure that you are, indeed, in receive mode. Please let us know what you found. 73, Don
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Re: WD8CEC frequency display FT8
Not exactly sure the issue you are describing.
However, I see your display is moving in increments of 500Hz.?
When I was first trying to get WSJT-X working and the frequency calibrated, I was very puzzled. That is until I discovered that the CEC firmware would only set the frequency via the CAT interface in the same increments as the rotary encoder frequency steps. I had to set the frequency steps for the tuning knob to 10Hz to get my WSPR frequencies to set correctly and then use the PPM setting in WSJT-X to dial in the final frequency adjustment.
Tom, wb6b
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I am going to bend up a case from Brass sheet and I plan to use the case for the heat sink. I will have to use insulators to electrically isolate the finals. It should give me a much bigger surface area to dissipate the heat,? and also shield the uBitx from external fields.
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Re: Understanding Spurious Emissions
I have a receiver here with a first IF of 45 MHz and coverage very slightly more than the ubitx. It has eight filters and very few (maybe none) birdies. In a receiver birdies are a local problem and no problem to the outside world. But still an obvious problem. That is not a suggestion that you must use eight filters instead of four but to serve as a referencence point for future development and for those who want to modify their radios.
For what it's worth, I intend to not modify mine much at all. I will run the modest power on the upper bands (where I almost never venture). The 'CEC' software looks attractive. I will install a level control on that roaring loud sidetone. I will put the insulated mounting kits on larger heatsinks (probably my steel cabinet). And operate, operate, operate :) It is Field Day weekend here in the USA and I will be giving my uBitx a baptism.
73,
Bill KU8H
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On 06/23/2018 01:38 AM, Ashhar Farhan wrote: Hmm...
It may be improper level of LO injection. On the transmit side, the
mixer has _very_ strong input termination and LO termination. It will be
interesting to study this. Mixers can provide endless amount of
fascination or frustration depending on which side of the RF probe you are.
- f
--
bark less - wag more
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Hi Walt,
Others here have reported doing what you propose and had no ill effects. I intend to eventually do the same thing.
73,
Bill KU8H
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On 06/23/2018 12:17 AM, VE7CWS WRSeiler wrote: Hello fellow constructors
I have been thinking about using a common heat sink for the RF power
transistors, insulated with mica washers of course and insulated
mounting hardware. Would there be inter capacitance issues or some other
anomaly. Any thoughts or experience based
observations?
cheers and 73
Walt R VE7CWS
--
bark less - wag more
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Some additional data (sorry it's in french) about consumption trials on arduino boards (genuine and chinese) :
spreadsheet file on
it shows nano consumes 80-100mA (about half the one in the Raduino)
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Thanks Folks, I will go ahead with my plans then, so far so good!!,
I am having a great time, can¡¯t remember so much fun since I built a Heathkit television in my senior year in high school,
guess im dating myself Hi Hi! You should have seen my mom¡¯s face whe I plugged that in and no smoke came out.?
Cheers and 73
Walt VE7CWS
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Re: W8TEE Power/SWR Sketch for Nano
I don't have anything that's driven by the AD8307, only the AD9850. However, the OLED doesn't care since it uses pins A4 (SDA) and A5 (CLK) for the clock and data lines for I2C interfacing. The data feed to the Nano is thru A1 using a voltage divider so we never exceed 5V on the pin. I, too, used the "two color" OLED, but treated them as separate objects, so the output looks like:
As you can see, the top line is in yellow. I made the power figure in a larger font, since that's the info we were interested in. Truth be told, even though we calibrated the output, anything after the decimal point is pretty much a guess. For its rated power level (i.e., 150W) however, I think we're below a 5% error, which is good enough in most cases. To me, it's real feature is that it provides a polite way to tune a rig without splattering everyone else on the band.
Jack, W8TEE
On Saturday, June 23, 2018, 5:50:08 AM EDT, Henning Weddig via Groups.Io <hweddig@...> wrote:
Kees,
after having some trouble I got the sketch from? Duwayne? (KV4qb
blogspot) to play, even with a 0.96?? and 1.3?? I2C display.
See
Really nice but for my "old eyes" a bit soo small.
Henning Weddig
DK5LV
Am 22.06.2018 um 18:52 schrieb Kees T:
Jack,
Don't you have an Arduino sketch for a Nano which uses AD8307s for
input and outputs to a 16x2 screen or one of the 1" OLED displays
via I2C ?
73 Kees K5BCQ? ?
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Hi,
new to uBitx, I've a problem already shown on some thread but more than a plaster on the wound I would like to understand the problem and reduce it.
My 7805 get very hot after few minuts (already seen on threads), looking at current consumtion i found about 0.35A, with 12V input, 5V output that makes 7x0.35 = 2.5W so heat production
My problem is also : 0.35A consumption in receive is not very fine for QRP rig and small battery life
But when i look at datasheet of what is powered, I don't understand where come this great current :
- Led backlight : about 25mA on 5V (measurment and datasheet), 1602 logic : 35-40mA (datasheet)
-Sis5351A : 22-45mA (datasheet)
-FT232 (part of the nano which produce 3.3V for Sis5351A from 5V) : 15mA (i assume + 3.3V consumption) -> 60mA
- so that would mean that the nano board asks at least (assuming max consumption for other parts...) 350-65-45-60 = 180mA, looks a lot, near the PIC max rating (200mA)
Looking at the QCX which use the same screen and same PIC (not on a nano board) comsumption is given to 180mA (half less)
My questions :
Q1 : do you have the same current consumption ? (especially interested by answers with genuine raduino but other firmware)
Q2A : what could be the source of this problem ? (perhaps programming without using power consumption reduction)
Q2B : what could be the means to reduce this consumption ?
if the problem is due to some software features (CAT, ...) it could be nice to disable them to reduce consumption (TMHO the main goal of a QRP is not to work with CAT but on the field with small battery), the "only" usage of Radiuno processor might be when changing frequency or some parameter, staying on a frequency receiving and transmitting might not need any processor cycles? (oups i missed the PTT and CW is processor driven, but it's still true in receiving -PTT could be transfered out of processor drive, but we need to have outputs TXA-B-C remain to proper value)
PS : Some tips are used on QCX to reduce 7805 problem i plan to try them : Powering Backlight directly from 12V with calculated resistor (240ohms), powering Sis5351A directly from 5V with 2 diodes in serial to lower voltage (avoiding using voltage tranverter like ft232, perhaps a consumption reduction by putting it in low power mode ?)
Thank's in advance for answer
73 - Remi - F1MQJ
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I have my power output transistors on a large heatsink with isolators for each. Been using them for several months with digital and voice modes.
Works well with no detectable issues.
Joe VE1BWV
On Sat, Jun 23, 2018, 1:25 AM Jerry Gaffke via Groups.Io <jgaffke= [email protected]> wrote: I believe that should work fine.
Given the significant power and the relatively low voltages,
the impedance at the drain is quite low.? A little bit of extra capacitive coupling
is not too disruptive.
On Fri, Jun 22, 2018 at 09:17 pm, VE7CWS WRSeiler wrote:
I have been thinking about using a common heat sink for the RF power transistors, insulated with mica washers of course and insulated mounting hardware. Would there be inter capacitance issues or some other anomaly. Any thoughts or experience based?
observations?
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WD8CEC frequency display FT8
I have had the fine WD8CEC firmware on my ubitx for about a month, am running the 1.8 version.
Today I just started noticing that the carrier frequency display tracks roughly the modulation frequency on FT8
On 20m FT8, if it is at less than 1000 hz it will drop to 14,0730.
1000-1500hz it goes to 14,07350.
1500-2000 it shows 14,0740
2000-2500 140745
My radio picks up and communicates well with other hams on FT8. 8700 miles is the longest contact.
I was doing some testing on the ft8 frequency with the modulation turned down to -40db and someone caught my cq.?
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Re: W8TEE Power/SWR Sketch for Nano
Kees,
after having some trouble I got the sketch from? Duwayne? (KV4qb
blogspot) to play, even with a 0.96?? and 1.3?? I2C display.
See
Really nice but for my "old eyes" a bit soo small.
Henning Weddig
DK5LV
Am 22.06.2018 um 18:52 schrieb Kees T:
toggle quoted message
Show quoted text
Jack,
Don't you have an Arduino sketch for a Nano which uses AD8307s for
input and outputs to a 16x2 screen or one of the 1" OLED displays
via I2C ?
73 Kees K5BCQ? ?
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The frequency response of the second IF filters of the Ubitx vary from unit to unit depending also where the BFO is set. My unit for example is about 2khz wide filtering out frequencies below 700hz. This it is very good for speech either ssb or AM/CW. In general the less selective/worse the receiver is the better and the less fatiguing is the listening to AM broadcasts. For AM those large ugly portables with HF shine. The Ubitx sounds more a communication or military receiver, at least my unit. In general a 6khz wide filter allow just 3khz frequency response, which is not much more than the usual Ubitx. If the receiver has a passband offset control (PBT) you can possibly recover all the 6khz. In any case most large portable that have no PBT, the filter is so wide you have a more pleasant audio. To have that wide filters in the Ubitx maybe one could remove most of the crystals in the second IF.
Il 23/giu/2018 00:09, "Ralph Mowery" < rmowery42@...> ha scritto: I did not really do much in the way of calculating.? I do have the equipment to check it our.? One way was to feed in a 1000 Hz audio tone into the mic input.? Then measure the output power.? Then go up and down in frequency to where the power makes a big drop off.??
I know that by lowering the value of the capacitors the filter gets wider and going up in value the filter gets narrower.? The first attempt was around 68 pf (or whatever the standard value is near that).? That made the filter way too wide,so I put in the 80 some and that put it close enough for me.
Even going into a hifi amp it will be difficult to make the music sound very good.? If the filter cuts out the highs and lows before it gets to the demodulation part, about all you can do is use an? equalizer and run the audio from less than 500 hz way up and the audio above 1800 way up as there is almost no audio outside 500 hz to 1800 hz.
As the ubitx is, it is a great piece of engineering, but it is also easy to make changes to for anyone that has a bit of equipment and know how.? Many have published their modifications so that people like me only need to do them.
de ku4pt
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Don, ND6T
_Dave_ AD0B