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Re: Blown (socketed) TDA2822?
Summary:? All is well, unless you have a WX branded TDA2822.
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Here's an old post regarding the TDA2822, many other posts in that thread worth browsing: ? ??/g/BITX20/message/43342 Yes, the TDA2822D is still available from ST, would be a good choice if you don't mind?the 50 mil pin spacing.? ?I'd stick with the NJM2073. There was a lot of guessing in the forum when the WX clone chips first started blowing. Many of the WX chips blew when somebody first plugged something into the headphone jack, that seemed to put them over the edge. And some blew when first powered up. But I don't think anything other than a WX chip ever blew. Most of the TDA2822 datasheets spec a max operating voltage of 15v. The UTC clone (never used by hfsignals) gives a max operating voltage of 12v, but does say it will survive 15v. The WX clone does not have a datasheet, reports show it?can blow if they see more than 6 or 8 volts. A power up event or plugging in headphones can be what puts them over the edge and causes them to smoke. If you still have a WX chip, I suggest you either swap it out or add a voltage regulator to it as per? ? ?? That page suggests brands other than WX can blow when the output is shorted. I don't recall any such reports in the forum, let me know if anybody can find such a report. All of the datasheets specify distortion levels and power out as a function of supply voltage, these tables typically top out at 9v or so.? ?So we don't know what the harmonic distortion is at 12v, but that is well under the 15v maximum operating voltage. All except the WX operate fine at 12v, my only concern would be that the chip might overheat when driving a low impedance load (such as a short or a 4 ohm speaker) with?the volume turned up high.? If the chip is not too hot to hold our finger on it, all is well.? A momentary short would not give it enough time to overheat.? ? Jerry, KE7ER On Fri, Jun 22, 2018 at 12:59 am, Mvs Sarma wrote:
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Re: experience with Sunil VU3SUA's enclosures
#ubitx
If you don't get the case in time for his birthday the radio will work fine wired up without any enclosure.?
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Re: Encoder problem
We buy bourns from mouser. If there are better ones, or a more robust model, let us know. Bad quality encoders were the main reason for my original hack of using a pot for tuning. The software was so buggy that I would have killed the developer had I not had a bout of unusual mercy upon the kids.? - f - f On Fri, 22 Jun 2018, 19:47 Arv Evans, <arvid.evans@...> wrote:
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Re: Microscope - - new thread
Here's one of them, though I can't really recommend it. Roy WA0YMH On Fri, Jun 22, 2018, 8:51 AM twowindsbear via Groups.Io <twowindsbear=[email protected]> wrote: How about a link for the $60 Chinese microscope? |
Re: Rx Radio #ubitx-help - broadcast AM
#ubitx-help
I would suggest you meet you local radio club or meet another ham - elmer that might help you. He/she will be amused by the Ubitx, am sure about that. Apply the 4eyes principle when you find something not obvious. Il 22/giu/2018 15:48, "Bill Cromwell" <wrcromwell@...> ha scritto:
> > Hi, > > Those broadcast stations are probably all AM (not SSB). We can bring in those stations by tuning their carrier to zero beat. That method has been around a century or so and is called "vesitigial AM". With the SSB filter in the ubitx you will only get one sideband from the AM station but that is all you need. Another reply has described the zero beating in more detail. > > The filter in the ubitx may be a little narrow for good AM detection. You might have to find a combination of BFO adjustment that helps 'improve' the audio. A couple of people on the list have described a mod to widen the passband a little. That mod would probably help you with your broadcast listening yet still be narrow enough for SSB operation. It would also be better for using ubitx on those digital signals that are all grouped together in a 3 to 5 KHz band. Your computer would then resolve a dozen or more digital (psk, ft8, etc) at one time without retuning your radio. > > I hope this helps. > > 73, > > Bill? KU8H > > On 06/22/2018 04:43 AM, sridhar wrote: >> >> I had ubitx ,currently using for RX Only ,its my first HF set ,Ubitx >> having 3 Mhz to? 30 Mhz Frequency , >> 1)Can i use this for Normal Radio RX i.e SW , i am able here radio but >> audio is not able to recognize. >> 2)? what changes do need to do in this set to added any component to get >> full audio from SW frequency >> >> >> >> de >> vu3pen >> sridhar >> _._,_._,_ > > > > -- > bark less - wag more > > > |
Re: experience with Sunil VU3SUA's enclosures
#ubitx
I ordered mine and it took about six week to arrive. ?I received no prior notice from Sunil about the delivery, but did receive notice from DHL when it was shipped. ?The case is quite nice and well worth the wait. It really makes a nice looking radio.
73 Buddy KJ4ZSI |
Re: Encoder problem
It is possible to build a simple test jig for evaluating mechanical switch type rotary encoders. Use 1K resistors in series with LEDs to show contact closure for phase A, phase-B, and for the push-switch.? By turning the shaft very slowly you can see the phase change and by pushing the push-switch you can see its contact closure.? This might be worthwhile if you suspect problems with an encoder or if you are building kits and will be providing rotary encoders in the parts bag.? Arv _._ ? On Thu, Jun 21, 2018 at 8:00 PM Howard Fidel <sonic1@...> wrote:
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Re: Encoder problem
Dennis Yancey
I had the same issue. It turned out to be the nano was not reading the encoder when running ubit files, either factory or the CEC software. It would allow menu selection but not frequency change. The same was true on 3 Nanos.. but they all came from the same place. I replaced the nano with a new one from another source and the problem cleared right up.?
Also, look for John, VK2ETA, or Jim Sheldon. They are both doing some neat stuff regarding a Raduino diagnostic tools. |
Re: Rx Radio #ubitx-help - broadcast AM
#ubitx-help
Hi,
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Those broadcast stations are probably all AM (not SSB). We can bring in those stations by tuning their carrier to zero beat. That method has been around a century or so and is called "vesitigial AM". With the SSB filter in the ubitx you will only get one sideband from the AM station but that is all you need. Another reply has described the zero beating in more detail. The filter in the ubitx may be a little narrow for good AM detection. You might have to find a combination of BFO adjustment that helps 'improve' the audio. A couple of people on the list have described a mod to widen the passband a little. That mod would probably help you with your broadcast listening yet still be narrow enough for SSB operation. It would also be better for using ubitx on those digital signals that are all grouped together in a 3 to 5 KHz band. Your computer would then resolve a dozen or more digital (psk, ft8, etc) at one time without retuning your radio. I hope this helps. 73, Bill KU8H On 06/22/2018 04:43 AM, sridhar wrote:
I had ubitx ,currently using for RX Only ,its my first HF set ,Ubitx --
bark less - wag more |
BITX QSO Afternoon/Evening, Sunday, June 24, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
John P
BITX QSO Afternoon/Evening, Sunday, June 24, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
Join us as we make contacts with our BitX-40s or uBitXs or anything else on 7.277 MHz in 40 meters! This is a worldwide event for BitX40 (and other QRP)?stations starting at 3PM and 7pm in each time zone. To participate, call CQ BitX on Sunday, starting at?3PM and/or 7PM?your local time. The BitX QSO Night continues through the evening and conditions usually improve after sunset, so it is worthwhile to participate later in the evening. Suggested Best Operating Practices: Work at QRP power levels unless conditions require more power. Report your QSO's, discuss propagation, noise, signal reports, audio reports, antenna type, etc. in this thread. This is an undirected, scheduled event.? The BITX QSO Night relies on you to call CQ BITX to initiate contacts with other stations, so warm up that final and transmit a few calls on Sunday evening.? Talk to you then! |
Somethings gone wrong!
Ok so I have just added a tap to the back of the chassis for my rtl sdr dongle as in this post??
After I soldered to R43 and C32 I tested the radio and noticed the receive had gone very attenuated! I unsoldered the cable and the receive became better but now when I transmit on 20m I am only getting 4w instead of the 8w I was getting. Also mic gain seems very low. I have to really shout to get anywhere near 2w now! I have just recently soldered a 47ohm resistor in parallel with r63 which made the audio so much better too...? Any ideas what could have gone wrong? R43 and C32 both look fine...? Thanks Carl. |
Re: uBITX Version 4 first attempt
#ubitx-help
#ubitx
Hi Dave and all,
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Both of the ubitx kits here came to downstate Michigan via DHL and came the rest of the way via USPS. The terminal downstate was in the metro Detroit area. The first one took a couple of months (or slightly more). the second was more like two weeks. My ubitx is living happily in a steel box I made for it. 73, Bill KU8H On 06/22/2018 05:53 AM, David Wilcox via Groups.Io wrote:
Very interesting and humorous. --
bark less - wag more |
Re: KD8CEC Firmware
Terence :?
After you get the KD8CEC firmware loaded I recommend that you also install his uBITX Memory Manager application on your PC.? One very useful feature is the ability to read and decode the current data/settings from the Raduino and save them to a file on your? computer. ?I recommend doing this right away before using it to modify any settings so that you have a baseline to return to should? something get messed up later. This is especially important if you decide to try recalibration. Cheers Michael VE3WMB? P.S. I got my Nextion 2.8" TFT Display so when a get some time this weekend I plan to move to KD8CEC V1.09b and give that I try. I think that this display is going to be a "game changer" for this rig.? |
Re: Audio feedback during transmit?
#ubitx
I have done this on two units. I bring +5v/Gnd to the board from a
7805 regulator I added in each unit for powering several add-on's by using a tightly twisted pair of wires. Actually the twisted pair is scavanged from a length of cat 5e cable. I've had no problem with either unit. tim ab0wr On Fri, 22 Jun 2018 13:00:49 +0000 "pat griffin" <patgriffin@...> wrote: I have the same issue. Started with installation of agc board. I have |
Re: Audio feedback during transmit?
#ubitx
¿ªÔÆÌåÓýI have the same issue. Started with installation of agc board. I have some relatively long cables owing to use of clamshell cabinet with raduino on one side and board on another and thought that might be cause. Redid shielding grounds etc still no cigar. Finally just took 12 v from tr through v reg so agc board is only on during receive?
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Re: Understanding Spurious Emissions
No, your analogy would be right if you were on the wrong side of the road.?
If you get near even fully driving the modulator the last mixer is easily 10+ db past saturated as result of there being enough IF gain to assure that. For those that never go above 20Mhz its adequately filtered and not an issue. Allison |
Re: experience with Sunil VU3SUA's enclosures
#ubitx
A week after I ordered my case with DHL shipping, I contacted Sunil to find out when I could expect the case. He told me that it had not shipped. At five weeks, I emailed him again and he said it had gone out that day. I received it 6 weeks after I ordered. I was not so concerned as I did not have the time to build up to that point. Sunil responded to my emails and I received my kit. The goodies that come with it are quite nice. I would suggest a bit more patience. I have no qualms about ordering from him again.
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AF5RX Scott.
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