Re: uBitx VER 4 BRD AND Compornents
On Tue, November 27, 2018 6:54 pm, chuckr@... wrote: What are the components Q942 and Q952 for? These were missing from my
factory assembled board. The main problem I am having is each time I
power up the receive works ok etc, but the second I hit the cw or ptt key
the finals blow, drain shows grounded.. Three times in a row now, first
time i thought there might have been a shorted wire when mounting board,
no and blew a second time, check for shorted land etc. and the land from
power in to the finals was burnt into, fixed with small jumper, repalce
finals for third time and checked for shorts etc. best i can. made a temp
fuse by using a one strand of small copper wire to postive connection and
it burnt almost on contact, tried again and the receicer works as before?
but also just as before the finals went, saw what i thought was la little
some from maybe a bias pot not sure, just pulled the finals again.? Just
about to give up on the project but maybe some of you could give me some
thoughts , advice , help anything at this point.... :)
chuck
just found that the RV3 pot had only two leads attached, third one was not on pot ????
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Re: Great Results with Mic Preamp
I breadboarded the amp, fed it at C1 with tones from a 2-tone generator, and applied some noob Rigol magic at the output.? It looks like the amp draws about 2 mA at 8V and 4-5 mA at 13.8V.? It also looks like it's running class AB as the negatives are clipped.? Is that expected or should I play with R1 until it's class A?
Thanks!
Andy, KG5RKP
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OT: Farhan's satellite - ExseedSat-1 - Possible launch?
Looking at: and? Looks like there is a Falcon 9 going up in the next day.
Nov. 28 Falcon 9 ? Spaceflight SSO-A
Launch time: 1831:47 GMT (1:31:47 p.m. EST; 10:31:47 a.m. PST)
Launch site: SLC-4E, Vandenberg Air Force Base, California
All the best.
?
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uBitx VER 4 BRD AND Compornents
What are the components Q942 and Q952 for? These were missing from my factory assembled board. The main problem I am having is each time I power up the receive works ok etc, but the second I hit the cw or ptt key the finals blow, drain shows grounded.. Three times in a row now, first time i thought there might have been a shorted wire when mounting board, no and blew a second time, check for shorted land etc. and the land from power in to the finals was burnt into, fixed with small jumper, repalce finals for third time and checked for shorts etc. best i can. made a temp fuse by using a one strand of small copper wire to postive connection and it burnt almost on contact, tried again and the receicer works as before? but also just as before the finals went, saw what i thought was la little some from maybe a bias pot not sure, just pulled the finals again.? Just about to give up on the project but maybe some of you could give me some thoughts , advice , help anything at this point.... :)
chuck
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Yes I guess my reply e-mail never made it. They are all shipping out tomorrow, save the UK gentleman.
I have 1 kit left and 10 more on order.
--
David
?N8DAH
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Re: Great Results with Mic Preamp
On my ?BITX (V3), with 13.8VDC in there's 13.2VDC on the unloaded mic connection.
Andy, KG5RKP
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On Tue, Nov 27, 2018 at 02:21 PM, Richard Spohn wrote:
Dale, be sure your mic input has the 8vDC on the positive audio lead.
QST has another schematic for mic inputs with a separate, third pin
carrying the 8v, which is to connect this pin to the collector of Q1
and insert a small capacitor in series with the positive audio lead to
block DC from appearing on the audio pin. - Rich WB2GXM
On 11/27/18, Dale Brooks KG7SSB <kg7ssb@...> wrote:
Thanks Paul for the schematic of the dynamic mic amplifier stage. I'll give
this a test run and see how she does. Dale
On Mon, Nov 26, 2018 at 10:26 PM Paul Dobosz <pjdobosz@...> wrote:
Here is the schematic ... Assumes phantom power (~8V DC) is on the Mic
Audio line. Can be sky wired and shrink wrapped into a small assembly
with
fly leads that will fit inside of many dynamic mic bodies.
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1? left
Dave I got yours set aside and will check with the post in the morning on shipping to the UK
--
David
?N8DAH
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AndyH,
Don't know if the clock signals are interfering with reception, but some noise is interfering with my scope measurements of the low level RX signal path.? With no antenna and high audio, can hear a tone in the background and significant microphonics from the ubitx board.? Not so noticeable with antenna and signals.?? No encoder ticks...
To help explain the difficulty presented when trying to trace RX signals through the chain, see the attached image. ? Hard to get a lock with counter on the "noise" - jittering.? Sometimes, for some TPs, seems to be in the 50 MHz range. It may be something other than clock signal...(?).
I downloaded the MAR-3+SM graphs.? They do show gain at 3 different currents, but only down to 28 ma.? Was wondering about even lower currents.?? ...But it seems to work, bringing the gain way down as the current approaches zero (actually the device voltage of 5). ? Was mainly wondering about linearity and IP3 at the very low supply currents.
Since my first Nano died, I am using Jim's raduino clone.?? FWIW, the original Raduino began to work when I tried the good Nano in it. ? Now have 2 working mother boards and one working nano.
Woody? -?? KZ4AK
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On 11/27/2018 20:16, AndyH wrote: If you've got so much clock signal floating around that you have trouble receiving, you might want to find the problem.? My radio is dead quiet with no antenna attached, as is my BITX40.? I can sometimes hear ticks from the rotary encoder without an antenna, but that's it.
What sort of raduino-like-object are you using?
_._,_._,_
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Re: Great Results with Mic Preamp
Dale, be sure your mic input has the 8vDC on the positive audio lead.
QST has another schematic for mic inputs with a separate, third pin
carrying the 8v, which is to connect this pin to the collector of Q1
and insert a small capacitor in series with the positive audio lead to
block DC from appearing on the audio pin. - Rich WB2GXM
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Show quoted text
On 11/27/18, Dale Brooks KG7SSB <kg7ssb@...> wrote: Thanks Paul for the schematic of the dynamic mic amplifier stage. I'll give
this a test run and see how she does. Dale
On Mon, Nov 26, 2018 at 10:26 PM Paul Dobosz <pjdobosz@...> wrote:
Here is the schematic ... Assumes phantom power (~8V DC) is on the Mic
Audio line. Can be sky wired and shrink wrapped into a small assembly
with
fly leads that will fit inside of many dynamic mic bodies.
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If you've got so much clock signal floating around that you have trouble receiving, you might want to find the problem.? My radio is dead quiet with no antenna attached, as is my BITX40.? I can sometimes hear ticks from the rotary encoder without an antenna, but that's it.
What sort of raduino-like-object are you using?
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Just reduces the gain.? See the data sheet for the part.? They explain it there. ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Woody
Sent: Tuesday, November 27, 2018 1:54 PM
To: [email protected]
Subject: [BITX20] Preamp question?
Now that Raduino working, still trying to resolve RX issues.?? There is so much clock signal floating around that it masks the RX signal when I try to trace with scope.? So...
Now trying a brute force approaches to low RF sensitivity and low, distorted audio.? They sort of work...
Audio:
Bypassed board audio amp section and used a LM358 to feed the audio PA IC.? Much improved, but does want to oscillate if gain set too high.
RF:
Built a MMIC front end amp.? I can now hear noise when I connect the antenna!? Signals notably stronger.
Would like to add a RF gain control.? Found that controlling the voltage to the MMIC (thus the current), the gain will change from maximum to a very low value, perhaps even attenuating the signal.
Here is my question:
What are any negative effects of operating the MMIC at currents much lower than specified?
Thanks, Woody? -? KZ4AK
-- ¡_. _._
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Now that Raduino working, still trying to resolve RX issues.?? There
is so much clock signal floating around that it masks the RX signal
when I try to trace with scope.? So...
Now trying a brute force approaches to low RF sensitivity and low,
distorted audio.? They sort of work...
Audio:
Bypassed board audio amp section and used a LM358 to feed the audio
PA IC.? Much improved, but does want to oscillate if gain set too
high.
RF:
Built a MMIC front end amp.? I can now hear noise when I connect the
antenna!? Signals notably stronger.
Would like to add a RF gain control.? Found that controlling the
voltage to the MMIC (thus the current), the gain will change from
maximum to a very low value, perhaps even attenuating the signal.
Here is my question:
What are any negative effects of operating the MMIC at currents much
lower than specified?
Thanks, Woody? -? KZ4AK
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HI David, ? ? ? ? ? ? ? ?? An ideal add on for my u bitx,put me down for a completed zero beat board please and let me know the total cost posted to the uk.Regards Dave G0AYD .
On Tue, 27 Nov 2018 at 16:37, N8DAH < Dherron@...> wrote: I have 3-4 left (waiting on some payments)
--
David
?N8DAH
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I have 3-4 left (waiting on some payments)
--
David
?N8DAH
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I would expect different machines to use different COM ports. If I compile for a Nano, it's COM4. For a Teensy, its COM6. I would not be surprised by different COM ports. You can use the Control Panel - Device Manager to see how the ports are allocated.
Jack, W8TEE
On Tuesday, November 27, 2018, 10:53:46 AM EST, Kevin Timm <kevindtimm@...> wrote:
I'm pretty sure that COM3 is correct as?that's the value?I used when I reloaded the firmware.
K5KDT
Kevin
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I'm pretty sure that COM3 is correct as?that's the value?I used when I reloaded the firmware.
K5KDT
Kevin
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Re: uBitx Go Box 3d print
Thanks. Prusa i3 Mk3. Highly recommended. Google Prusa Printers. They are a Czech firm. I built it from a kit. It took a day or so but instructions very clear. You can buy assembled too. Good luck!
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It looks fantastic.?? What kind of 3D Printer do you use?? It looks very smooth.?? I'm thinking of doing something for a 7" JackAl add-on.
--
Lee - N9LO? "I Void Warranties"
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Re: uBitx Go Box 3d print
It looks fantastic.?? What kind of 3D Printer do you use?? It looks very smooth.?? I'm thinking of doing something for a 7" JackAl add-on. -- Lee - N9LO? "I Void Warranties"
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Holiday pricing on TSW's BITeensio and Raduino Clone boards & Kits
#ubitx
#bitx40
TSW (The Triumvirate Skonk Worx) is announcing discount pricing on the BITeensio and Raduino Clone bare boards and kits for this holiday season.? Prices are valid from now through December 31, 2018.
See the TSW Website, and look for the green highlighted prices.? To take advantage of these prices, please use the email link for W0EB on the TSW page to request ordering instructions.
Thanks for your interest,
Jim - W0EB
TSW Project Coordinator
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Nick VK4PP
N8DAH
MadRadioModder
Lee
Jim Sheldon