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Re: RF power chain mods and improvements..
Dear Allison,?
Thank you. Just a few clarifications please: ¡° I didn't? try 2n2963A as I didn't have any left in SMT but I suspect they would have been better.¡± I assume that¡¯s a 2N2369A, and what is a surface mount version called, if I wanted to find one?
?
Are the cores for T9 T10 & T11 the same toroids that it came with?? If one wanted to run more than ten watts would a different core be needed?
?
Is there any change in the chokes that feeds the finals? You didn¡¯t change to a bifilar wound choke?
?
¡°the 2n3904s in the predriver and driver replaced with 2n2222A¡± Instead of the TO-18 part, could I use these SOT-223s from Mouser: 512-PZT2222A? How about if I soldered a copper penny (pre 1982) to the large tab for a heat sink?
?
¡°Replaced Q10 with BFR106 for better receive gain at 20mhz and up.? (I may change out the two 3409s).¡± ?Are ¡®the two 3409s¡¯ Q11 & Q12?
?
¡°Add 1K resistor from negative side of C77 to ground¡± Is it C74? Again, thank you for the experimentation and the information, I look forward to trying your mods. jerry aa1of |
Re: Raduino replacement
#bitx20
Mike aka KC2WVB
Kj6etl, did you solve your tuning issue? I remember it as seeming similar to the issue I had. In my case it was what I first expected, ie a bum encoder and the new encoder made the issue disappear.? Mike On Jun 7, 2018 2:46 AM, "kj6etl" <pa1zz@...> wrote: Actually it was the fist time for me doing this with rather modest tools. |
Re: Current Firmware
I¡¯m trying to help you make it run on your Mac and for this have some questions, if you don¡¯t mind.
So you got a hex file or a ino file from Gary and you had to use Windows for uploading or compiling and uploading? Did you use the Arduino IDE on Windows for this or used the ArduinoBuilder? It¡¯s ?somewhat confusing. i don¡¯t think it¡¯s a problem with your Mac if compilation fails. A lot of people, including me use Macs for Arduino development without problems.? First you need to have a proper C ( ino) file, which according to the errors you posted is not the case. You are trying to compile a file with ?html content, so as already mentioned before obviously something went wrong with your download. The same file compiled under Windows would als have thrown errors. Did you use the downloaded ?zip file from GitHub or used another method to fetch the files? 73 Armin, DJ2AG |
Re: Raduino replacement
#bitx20
Actually it was the fist time for me doing this with rather modest tools.
I clamped the board in a small vise and used a spring loaded solder sucker to remove the solder from all the pins on both sides. Ended up using plyes to carefully pull the Arduino from the board. Then pulled the remaining pinns from the board one by one. I think the the most challenging part is to solder the new Arduino back in place and avoid "bridges" between the solder joints. A magnifying desklamp is your biggest friend. |
Re: Removing surface mounted resistor
#ubitx
Btw,? you don't have to remove anything to make the 'pop cure' mod. You can leave that resistor in and add another in series with it on an outboard circuit.? - f On Thu, Jun 7, 2018 at 3:25 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: Could work. |
Re: Raduino replacement
#bitx20
Easy enough I suppose, but I do see a lifted pad there, 4 up from the bottom left.
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The biggest problem with most rework is damage to the board, though that one looks easy to deal with. How did you go about removing it?? My guess is a full blown rework station with vacuum solder sucker. If you clipped the pins first and pulled them out one by one,? I'm curious how you went about clipping them. A socketed Nano is nice, but then it mechanically interferes with the LCD display. I've socketed my Nano on the opposite side of the raduino as per this post ? ??/g/BITX20/message/50027 Quite happy with the result. On Wed, Jun 6, 2018 at 09:08 pm, kj6etl wrote: Its not that hard to replace the Arduino.I have done it on my uBitx and will do it soon on a Bitx40. |
Re: HarleyHeat1ASCH
¿ªÔÆÌåÓýInteresting. Did the proposal go anywhere? Are you continuing development to enhance the proposal or has the project now become a hobby in itself, Mike? Might have all sorts of applications including home brew of the liquid variety. Bill, VK7MX On 7/06/2018 10:18 AM, Michael Hagen
wrote:
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Re: RF power chain mods and improvements..
Tim,
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The reason to add a stage of amplification like that is so we can reduce the amplification of pretty much all the other stages. With reduced gain, they have a much better chance of giving the same gain at 30mhz as they do at 3.5mhz. You could try patching this amp in when operating at 30mhz. Turn RV1 down all the way, then slowly bring it up to get the power you want. But you had best be ready to measure distortion in your signal before getting on the air with it. It could well be that Q90 will not work properly with the 10dB increased input signal and will distort.? Having the amp after Q90? allows you to adjust RV1 down until any stage after the new amp does not have too strong a signal, strong enough to distort. I don't think you want this new amp in there at all when operating on the lower frequencies with an otherwise stock rig.? Too much gain.? I'm just kibitzing here, have not analyzed the Q90 stage. You could take the LT-Spice model for the uBitx power amp from the KE7ER directory in the files section, see what the simulation does when Q90 is driven harder. Jerry On Wed, Jun 6, 2018 at 07:36 pm, Tim Gorman wrote: Allison, |
Re: Raduino replacement
#bitx20
Its not that hard to replace the Arduino.I have done it on my uBitx and will do it soon on a Bitx40.
You can buy a |
Re: IFshift
My ubitx was about 1600 to 1700 khz wide.? By changing the 5 capacitors from the crystals in the filter to ground from 100 pf to 82 pf the bandwidth widened out to about 2400 hz for the same reduction in power/audio bandwidth. ?? That may be slightly too wide, but was the next value down from 100 pf that had.? I did try the next value down first, but it was way too wide.? I have been thinking of paralleling the 82 pf ones with about 5 pf but have not done it.? On Wed, Jun 6, 2018 at 6:11 PM, Eardan <ke4htb@...> wrote: Im currently using KD8CEC skecth and my audio is about 200-1800 and im want to change it to 200-2400 range. i have no problem using the IFS to get it into range but have had no luck changing it in the sketch so that i dont need to use IFS any help to figure this out would be nice |
Re: Removing surface mounted resistor
#ubitx
Another option is to use Chip Quik solder remover. This product is heated with your iron over existing solder joints forming a low temp melting point alloy whi ch stays liquid long enough to lift the part off with tweezers. Then remove the low temp stuff with removal braid.
-- Kevin B. G. Luxford kbgluxford@... |
Re: Noob tx problem
#ubitx-help
¿ªÔÆÌåÓýYou either have miss wired the
connector, or a bad connector.
On 6/6/2018 10:06 PM, davedt1e@... wrote: Just checked the mic at the plug.? It shows no continuity until I push the the button...then about 1.6k when I push the button. Have I wired the mic correctly?
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Re: IFshift
I'm not sure you can do anything to expand the audio range. That is
determined by the 12Mhz filter which has a pretty narrow bandwidth. You could move the bfo to get a 600-2400hz audio but I'm not sure that is what you want. You'll be knocking out a lot of the low-freq audio. tim ab0wr On Wed, 06 Jun 2018 15:11:06 -0700 "Eardan" <ke4htb@...> wrote: Im currently using KD8CEC skecth and my audio is about 200-1800 and |
Re: RF power chain mods and improvements..
Allison,
Jerry, I have my little mmic board built. Would it be ok to add it before Q90 by removing C80 and inserting the input and output on those pads. Doing that would allow me to stick the board on top of the relay that is right beside Q90. It would facilitate testing, experimentation, and parts changeout if needed. It would also be right beside my 7812 voltage regulator so I would have short power leads. Will another 10-12db of gain into Q90 be a problem? tim ab0wr On Wed, 06 Jun 2018 15:42:13 -0700 "ajparent1/KB1GMX" <kb1gmx@...> wrote: One of the factors not reported was the consistency of the gain vs |
Re: RF power chain mods and improvements..
¿ªÔÆÌåÓýAllison you referred to T9 being reduced to 9 turns of #28 bifilar did you mistake it with T8 which is bifilar with one winding not used?Skip Davis, NC9O? On Jun 6, 2018, at 18:42, ajparent1/KB1GMX <kb1gmx@...> wrote:
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Re: Noob tx problem
#ubitx-help
Just checked the mic at the plug.? It shows no continuity until I push the the button...then about 1.6k when I push the button. Have I wired the mic correctly?
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Re: Noob tx problem
#ubitx-help
Thanks for your help.? So I just checked with mic plugged in.? It seems to be shorting the ptt (orange wire) to ground without pushing the button.? Indicating a problem with the mic itself?
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