Re: Latest Build, Mods and results.
Hi Mike, Is that at 12v PA voltage or higher?
Thanks
Marco - KG5PRT?
UPDATE. In addition to my earlier? mods I have incorporated Allison's mods (substituting 2n2222's and a BFR106 for the 3904's). In terms of output power the results are impressive. But in terms of leveling the output... well I measured 12W on 10M and over 35W (that scared me!) on 40M. I finally bit the bullet and used K9HZ's multi relay/pot method for leveling the response. A picture is attached. I was reluctant to use such a brute-force solution for a subtle problem but now I measure 15W on 80, 40, 20 M and 12 on 10M. VICTORY!! Now I can start thinking about other mods. Mike N6CMY.
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Re: Latest Build, Mods and results.
UPDATE. In addition to my earlier? mods I have incorporated Allison's mods (substituting 2n2222's and a BFR106 for the 3904's). In terms of output power the results are impressive. But in terms of leveling the output... well I measured 12W on 10M and over 35W (that scared me!) on 40M. I finally bit the bullet and used K9HZ's multi relay/pot method for leveling the response. A picture is attached. I was reluctant to use such a brute-force solution for a subtle problem but now I measure 15W on 80, 40, 20 M and 12 on 10M. VICTORY!! Now I can start thinking about other mods. Mike N6CMY.
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Re: RF power chain mods and improvements..
Sorry - my error.
I meant Q10,11,12 and Q20,21,22 - I thought I had the correct numbers in my mind and did not check again.
I bought them from a well known distributor here and the markings seem to be correct.
I will check tomorrow with my lab equipment - maybe that will clarify I i am right or if its just my imagination. Just troublesome that i did not take any measurements before to which I could compare to.
Just another question: I also organized the 2n2222A - will changing to them worsen the spurs on the upper bands? And if I change to them - do I also have to make the other adjustments (change R911,R96, R941, R942, R92 and R95 etc.) or are these just further improvements?
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I'm just seeing the two dots with negative signs in the middle too.?
Daniel, W2DLC?
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Re: RF power chain mods and improvements..
I have no clue why that didn't work as expected.? Are you sure those are real BFR106s?
uBitx V3:
Q10,11,12 are RX.? Q20,21,22 are TX.? In V3 schematic uBitx I cannot find a Q23?
Since your part numbers are off is this a BITX40 or other?? If so it does not apply.
Allison
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Re: RF power chain mods and improvements..
I just changed Q11,Q12,Q13 and Q21,Q22 and Q23 to BFR106s and I've got the feeling the reception got worse.
Before I start putting in the 3904s again - did I just forget something?
Should I also change some resistors to adjust the bias? Or should it work without doing so? I thought only Q11, Q12 and Q13 would be responsible for RX - and I? I have never seen a comment that other changes had to made there than pure substitution?
Sascha
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Re: Keypad for Raduino...?
Jon? KZ1G
With careful choice of resistors in a resistor network keypad encoding scheme we
get 1023 / 16 = 75.18 steps between each key value.? Then by using if-statements
to convert the key values into ASCII characters " if k <512+37 and if K >512 - 37 "
it becomes easy to determine the specific keystroke value within that 75 step range.??
It is working for me in my present proto-board layout without any glitches or false
decodes.? This is with several different keypads, some being relatively new and
others that are quite old and abused.?
Years ago I tried individual port based keypad decode with a 6502 processor but
contact bounce was very difficult to control.? With the Arduino all I had to do to
eliminate contact bounce was to read the ADC once to determine if any key has
been pressed, then read it again after a small delay to load the actual value.? This
accomplishes both debounce and takes care of the single-read error in an ADC by
giving the ADC internal charge capacitor time to fully settle.?
RF interference may become an issue, but with some bypass capacitors and a
slightly longer delay I'm guessing that things will work well.? I will know if that is
true after a little more progress with this project.?
Selection of keypad is not yet settled but I have several Minikey KL-series units that
look nice and should be easy to do an overlay to re-label some keys for specific
functions (Left, Right, Up, Down, Enter, and Menu).
This project is coming along slowly because I am old-and-slow.? More info will be
provided as it becomes available.?
Arv
_._
On Wed, Jun 27, 2018 at 1:13 PM Jon Titus, KZ1G < tituskz1g@...> wrote: Texas Instruments also has a programmable I2C I/O expander that lets you configure eight pins individually as inputs or outputs.? See TI part no. TCA9534A.? You already have an I2C port, so the expander IC adds only one component.? I have seen the A/D-input technique several times a,d would advise against using it because of electrical noise and the lack of precise measurements.
--
Jon Titus, KZ1G
Herriman, UT USA
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This is what I see: 
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That's strange, I have the pictures on
the one I received. It is also in the thread on the website.
On 6/27/2018 3:17 PM, Alex KA3BQE/9 wrote:
toggle quoted message
Show quoted text
>From Howard's
post I only see two do not enter signs. I see everyone else's
photos but not Howards??
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Re: RFI from uBitx TX after AGC and other mods installed
Thanks for all the testing Rowland. It sounds like just attaching the AGC board to the coax coming from the volume control is enough to bring in the RF. Even de-powered. What are you using to connect the antenna connector to the main board? Is it just a twisted pair? How long? There must be something to radiate that much signal in the area. If that is a twisted pair then it should be short as possible since more than 3 inches or so could be an issue. Replacing that with coax would be a good thing. If you are picking up a signal in the audio with just the AGC board "swinging in the wind" with nothing else attached then it must be a big signal or a very good detector. If the coax doesn't work then try the other AGC board. Try to find a difference between the two boards with your multi-meter. A good comparison is very useful. Another fix would be a good ferrite bead choke at the take-off from the volume control but finding the cause would be more beneficial for the rest of us. 100 mv of audio into the AGC board input should produce about 2.8 volts at J1. 200 mv should produce about 4 volts at J1. 73, Don
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On Tue, Jun 26, 2018 at 01:53 pm, <pa0jen@...> wrote: There was a typo in my last message. Corrected line 3:
The only big difference is that the footprint of this mixer is actually a mirror image of the original ADE-1.
73, Han
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Re: Enclosure #parts and cooling
#parts
That would probably work, but I don't really need anything that elaborate. I think a fan with some ferrite beads on it will do.
Jack, W8TEE
On Wednesday, June 27, 2018, 3:47:17 PM EDT, Arvo KD9HLC via Groups.Io <arvopl@...> wrote:
On Wed, Jun 27, 2018 at 12:16 pm, Jack Purdum wrote:
3M took it and circulated the liquid over electronics for cooling. I'm trying to locate some of it for my uBITX!
I scavenged a heat pipe system from a laptop.? It has a pad that was in contact with the CPU, and a set of fins that were ducted to the fan. Is that what you mean?
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Re: Enclosure #parts and cooling
#parts
On Wed, Jun 27, 2018 at 12:16 pm, Jack Purdum wrote:
3M took it and circulated the liquid over electronics for cooling. I'm trying to locate some of it for my uBITX!
I scavenged a heat pipe system from a laptop.? It has a pad that was in contact with the CPU, and a set of fins that were ducted to the fan. Is that what you mean?
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Re: RFI from uBitx TX after AGC and other mods installed
Hi Don -- here are the results of my test:
1)? Unplugged AGC board from main PCB.? Jumpered the header on the main PCB.? Left all wires connected to the AGC board that was now "hanging in space" above the main PCB.? Result:? much reduced RFI - still audible but at a tolerable level
2)? Same as (1) with jumper removed from header on the main PCB.? Result:? same as (1) - RFI present but much reduced
3)? Same as (2) plus disconnect S-meter lead.? Result:? Same as (1) and (2)
4)? Same as (3) plus short J1 to ground.? Result:? Same as (1), (2) and (3) - actually no difference with J1 or J4 shorted to ground - I have J5 shorted to ground in all cases.
Similarly, with the AGC board plugged into the header on the main PCB, none of the changes in steps (3) or (4) affect the level of the RFI heard.
Two other things that come to mind:
1)? I don't think AGC is working - I don't see any shorts or disconnected components on inspecting the AGC board, but I'm not noticing any difference in received signals.? So perhaps a problem with my construction of the board and could this cause the RFI?
2)? I used Dupont jumper wires to connect to the headers on the AGC board (and soldered the other end of the Dupont wire to the appropriate control.? Wondering if the use of a header and push-on connector could be introducing RFI?? It sure has been useful in trying A/B test cases though!
73,
Rowland K4XD
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Re: Enclosure #parts and cooling
#parts
I did not know what it was called. Still, at $472 (smallest quantity I found), I'll probably stick to a small fan!
Jack, W8TEE
On Wednesday, June 27, 2018, 3:19:49 PM EDT, Stephanus K6NG <stephanus1@...> wrote:
On Wed, Jun 27, 2018 at 12:16 pm, Jack Purdum wrote:
3M took it and circulated the liquid over electronics for cooling
Flourinert FC-72
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Re: Enclosure #parts and cooling
#parts
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From Howard's post I only see two do not enter signs. I see everyone else's photos but not Howards??
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Enclosure #parts and cooling
#parts
3M used to allow anyone who wanted to do so, to experiment in their labs. One guy invented a liquid that had unique properties, including letting animals "breathe" in it completely submerged. Also, it was totally non-conductive. Still, the guy walked away from it as interesting, but non-commercial. 3M took it and circulated the liquid over electronics for cooling. I'm trying to locate some of it for my uBITX!
Jack, W8TEE
On Wednesday, June 27, 2018, 3:09:32 PM EDT, Arv Evans <arvid.evans@...> wrote:
Hmmm...maybe power the RF PA section through the Peltier device with a
heat sink on the outside of the case and another one with small fan on the
inside of the case to stir the cool air.?? 8-)
Arv
On Wed, Jun 27, 2018 at 12:44 PM Jack Purdum via Groups.Io <jjpurdum= [email protected]> wrote:
Probably a higher power draw than I want.
Jack, W8TEE
On Wednesday, June 27, 2018, 1:33:37 PM EDT, Larry Smith < 815cpu@...> wrote:
How about the Peltier Cooling Device for an idea.? Exhaust the hot air through a check flap/valve idea 73
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Re: Keypad for Raduino...?
Texas Instruments also has a programmable I2C I/O expander that lets you configure eight pins individually as inputs or outputs.? See TI part no. TCA9534A.? You already have an I2C port, so the expander IC adds only one component.? I have seen the A/D-input technique several times a,d would advise against using it because of electrical noise and the lack of precise measurements.
--
Jon Titus, KZ1G
Herriman, UT USA
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Hmmm...maybe power the RF PA section through the Peltier device with a
heat sink on the outside of the case and another one with small fan on the
inside of the case to stir the cool air.?? 8-)
Arv
On Wed, Jun 27, 2018 at 12:44 PM Jack Purdum via Groups.Io <jjpurdum= [email protected]> wrote:
Probably a higher power draw than I want.
Jack, W8TEE
On Wednesday, June 27, 2018, 1:33:37 PM EDT, Larry Smith < 815cpu@...> wrote:
How about the Peltier Cooling Device for an idea.? Exhaust the hot air through a check flap/valve idea 73
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Don, ND6T
Arvo W0VRA