Re: Highest quality uBitx Case ever!
jim, your submissions here have no text, only a small graphic of what looks like a LSB filter passband. Is that your 'Like' emoji?
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Re: VK4PP uBitx LPF BANK add-on Board
Mad Radio Modder;
I'm interested in how you put the qrp labs filter board into the ubitx. I built one and have not put it in yet. Looking for good ideas.?
Thanks, Mark N7HWR
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Re: Highest quality uBitx Case ever!
no plastics, No pollution looks interesting.. ?
On Saturday, September 1, 2018, 6:41:27 PM PDT, Adam Goler < adamgoler@...> wrote:
when in doubt, make it out of cardboard.? a sometimes ya just gotta go with what works for you
Jim
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On Saturday, September 1, 2018, 4:03:24 PM PDT, ajparent1/KB1GMX <kb1gmx@...> wrote:
What are you using for Q90 and all the other 3904s? Words would make the posting informative. Allison
_._,_._,_
Just changed only the one resistor ...Nothing else consider ..Ft of 2n3904 is about 250 Mhz ...If beta rolls off at 6db/octave, then =at 250 Mhz, beta = 1..125 Mhz beta 6db better? (3db doubles =beta 2, 3db doubles beta 4)..60 Mhz 12 db better (4 doubles? 2,4,8,16)...30 Mhz 18 db better .(6 doubles 2,4,8,16,32,64)..
gain bandwidth product...gain of 1 to 250 Mhz,gain of 6db to 125 Mhz, gain of 12 db to 60 Mhz, gain of 18 db to 30 Mhz 18 db isn't great, but it'll do...besides when I dead-bug style bread-boarded Q90 I got 30 db gain rolling off at about 45 Mhz. Thought the measurements would be of some use, maybe someone else will measure their power out across the bands and compare to see whats what
as I sed, q911;912 is next and looking at the biasing between q90 and 911/912 and q92/93/97/98 I don't see a nickels worth of difference between them
Jim
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Re: Highest quality uBitx Case ever!
On Saturday, September 1, 2018, 6:41:27 PM PDT, Adam Goler <adamgoler@...> wrote:
when in doubt, make it out of cardboard.?   a sometimes ya just gotta go with what works for you
Jim
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Re: Which xmit transistor is blown?
Sean,
Occasionally I get power drop and fluctuation and I found it was the power connector. 1-2A is a lot for the
pin contact.. pull the power plug from the board and put it back a couple of times and see..
Raj
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At 01/09/2018, you wrote: I have had periodic issues with the ubitx that led me to believe that my finals (IRF510) were blown, and the radio seemed to work as expected after replacement, so perhaps they were.
I have a question though...is there a good way to tell what has gone out in the xmit power chain? I recently replaced Q90 with an mmbt2222a (smt version of the 2n2222a), and then the next two stages with 2n2222a's (in TO-18 form). No other changes to the radio.
It worked fine for a few days, though the 2n2222a's would get hot to the touch in digital mode transmit (which I think is to be expected). Today I started to experience 'bouncing' power readings during transmit (as shown in the meter on my tuner) before the radio simply stopped putting out much power at all. Nothing feels hot...and nothing looks burned or heat stressed to the naked eye.
So...before I start replacing things, I wanted to ask how to diagnose the problem. Is it most likely that I cooked some transistors, and how do I best till which ones?
73
Sean
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Brent,
Not afraid to dig into it, just wondered if there was a simple solution..but after reading all the posts I'm not surprised. I have a bunch of 2n2222 as well, so will hopefully replace those transistors you mentioned in your earlier post.
Thanks again
People have been hoping for a magik pill solution for over three months.
Wish there was one.
Allison
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Re: ubitx, TX flapping relay...
That did it! Thanks!
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Adam,
The microphone is polarized.
The switch you had received is connected between PTT line and GND and not in series with the microphone.
The microphone is connected between GND and Mic input. On the microphone capsule you can see that one of the pads is connected to the aluminum shell. That pad goes to GND, the other pad to Mic input.?
When you press the switch you should hear the relays engage and see an increase in current consumption. When you speak the current consumption should increase.
Don't forget to have a dummy load or an antenna attached to the Ant connector.
73,
Ion
VA3NOI
-- Adam Goler, PhD Cell: (425) 985-8700
"Fear is the mind killer."
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Allison, yes the 'traditional' approach has much to recommend it. I'm in the middle of just such a project myself.? 9MHz IF etc, single conversion all hf bands.
glenn
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Easy enough to get the si5351 to hit 115mhz.
One possibility, just run the vco at 920mhz instead of 900 mhz,
a wee bit out of spec but will work fine.
No changes to the code other than some constants in the si5351bx code,
must the recalibrate of course.
Alternately, use the second PLL inside the si5351 to 85 to 115mhz out to clk2,
si5351 output divider for clk2 fixed at 6.
Might be possible to do this using the etherkit si5351 library,
or a major hack to the si5351bx routines.
The G0UPL library might also do it, though I believe it is restricted to two outputs.
Jerry, KE7ER
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On Sat, Sep 1, 2018 at 03:59 PM, ajparent1/KB1GMX wrote:
Also the HFO (osc-3) has to go from 85mhz to 115 mhz and that meas you
exceed the SI5351 code by 6mhz.
// the output msynth dividers are used to generate 3 independent clocks
// with 1hz resolution to any frequency between 4khz and 109mhz.
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Highest quality uBitx Case ever!
when in doubt, make it out of cardboard.?  
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On 9/1/18 2:58 PM, ajparent1/KB1GMX wrote: ...
IF you using external filters. disable Kt1-3 and run a coax from power
amp to K3. Use external filters.
... Just to be clear, that means run a coax from pin 5 of T11 to pin 16 of K3, and cutting the trace from T11/pin 5 to KT1/pin 12 (referring to the V3 schematic). Also cutting or removing the existing trace from K3/pin 16 to KT1/pin 5 and cutting the traces for TX A/B/C from the Raduino (perhaps use them to switch the external filters). Is that correct? I have a set of QRP Labs LFPs for the bands I'm interested in and the matching relay board that I'm planning to use. Haven't decided on the switching scheme yet. Mark AA7TA
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Thanks Allison?
Not afraid to dig into it, just wondered if there was a simple solution..but after reading all the posts I'm not surprised. I have a bunch of 2n2222 as well, so will hopefully replace those transistors you mentioned in your earlier post.
Thanks again
Brent
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Useful tip - I was in the deep end and this helped me get out.
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Glenn,
Thanks,
If I build I will use other topologies that I know work.
Since I do not lust for continuous tuning an low IF in the 8 to 11mhz range
can do multiband well.? Single conversion is simple and can do all the
desired bands.
A good example is the Atlas210 using a spare 9mhz filter. Likely fewer parts.
Lots of filters and relays.
Allison
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Ok Allison, I was thinking more along the lines of a total rebuild. With the obstacles you mentioned, hopefully overcome.
glenn
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What are you using for Q90 and all the other 3904s?
Words would make the posting informative.
Allison
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Glenn, Use them in good health.? Note 3904s have gain of maybe 3 at 82.2 so you have to rebuild the 45mhz amp completely.? Also layout at 82mhz is getting fussier than at 45mhz. Changing the filter will not cure the output from the power amp getting into the wide open 45/82.2mhz amp and contributing spurs though I may move them around. Also the HFO (osc-3) has to go from 85mhz to 115 mhz and that meas you exceed the SI5351 code by 6mhz.
// the output msynth dividers are used to generate 3 independent clocks
// with 1hz resolution to any frequency between 4khz and 109mhz.
They are most like 15khz wide but could be much wider for data use. I can't use them as I said experiments and mods have reduced mine to a collection of junk.? ?? One magik pill. Allison
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I'm sure our Indian folks will back me: I'm sure 'Karma' here should be 'Kudos'. Karma is the 'therefore that' result of 'because this' - the immutable eternal Logic.
73 de ZL2DEX
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On Saturday, September 1, 2018, 3:41:13 PM PDT, Glenn <glennp@...> wrote:
Appros of nothing, but not to start a new thread ...My current mods and results Summary: replace T11 and change bias on Q90....appears Q911-912 need help too
Jim
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Raj vu2zap
Brent Seres/ VE3CUS
