In the pjhotoabove , i suggest the regulator be mounted physically on the marked location in the attachment, and wires extended to the PCB.
?It helps.
On Fri, Oct 6, 2017 at 10:20 AM, John P <j.m.price@...> wrote: On Thu, Oct 5, 2017 at 09:03 pm, Paul Avona wrote:
The STM voltage regulator on the Raduino board gets really hot. Is that normal?
also, it sticks out and i¡¯d Like to bend it back so my display panel fits in my box. No issue bending it (carefully), right?
thx
paul
As I recall, I removed mine, turned it around, then laid it down flat. Here's a picture:
?
--
John - WA2FZW
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On Thu, Oct 5, 2017 at 09:03 pm, Paul Avona wrote:
The STM voltage regulator on the Raduino board gets really hot. Is that normal?
also, it sticks out and i¡¯d Like to bend it back so my display panel fits in my box. No issue bending it (carefully), right?
thx
paul
As I recall, I removed mine, turned it around, then laid it down flat. Here's a picture:  ? -- John - WA2FZW
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Why not add a heat sink if not already done?
?Secondly you mught fix the regulator on the metal enclosure body, if you used one.and extend wires to the raduino pcb. ?I dont recollect whetyher the backlit isat 5V? !!? I generally separate it out and connect to 12V with 1 watt higher value resistor like 560 ohms. Tothat extent, the load is reduced on the regulator. all the best ?sarma ?vu3zmv
On Fri, Oct 6, 2017 at 9:33 AM, Paul Avona via Groups.Io <avonap@...> wrote: The STM voltage regulator on the Raduino board gets really hot. Is that normal?
also, it sticks out and i¡¯d Like to bend it back so my display panel fits in my box. No issue bending it (carefully), right?
thx
paul
|
The STM voltage regulator on the Raduino board gets really hot. Is that normal?
also, it sticks out and i¡¯d Like to bend it back so my display panel fits in my box. No issue bending it (carefully), right?
thx
paul
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Again sorry, but Link please? We don't all have a n archive? that comprehensive, and Group's search is pants.
73, Dex
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BITX QSO Night, Sunday, October 8, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
Join us as we make contacts from BITX40 to BITX40 on 7.277 MHz in 40 meters!
This is a worldwide event for BITX40 stations starting at 7pm in each time zone. To participate, call CQ BITX on Sunday, starting at 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.
Call and listen for CQ BITX on the hour and every quarter hour.
It is helpful if you call CQ BITX with your callsign, name and location.?
Repeat your callsign a number of times during your CQ BITX and during QSO's.
Start a QSO by confirming the callsign, location, name and signal report of the other operator.
Say the callsign, name and location of the other operator so others can hear.
If the frequency is busy, avoid long conversations.
After your initial QSO is complete, ask if there are any other stations who would like to contact.
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!
--
John - WA2FZW
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Could Sunil's agc be used? I think it is inserted somewhere in the IF??? I've downloaded the docs on it, but I'm not smart enough to understand all I see. I have the VU2ESE AGC, and I can't tell a big difference, but it does seem to mellow the audio. I like how it sounds, but you still need to ride the volume control.
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That is nice, and so simple, I think I could do that one too, Vince. I'm wondering if a person could change the transformers to 10uf caps like the duinovox has. I may need to try it just for fun. The duinovox will stay in my rig. It is working really well with 10 watts. I imagine, if a person were smart, they could find some uses for those extra pins and memory on the second nano in the radio.??
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Well, I just got my Bitx40 Raduino....Let me build and test that out and I'll get to the uBitx. I want to mate them with a 25W PA I plan to design. Why? Because I want to try to make a broadband PA w/o needing LPFs...
--
AncelB, MIT EE6002
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Re: W8TEE Software Release 1.07-09
Yep. The cost is $8, domestic shipping is included. Use PayPal to econjack@.... Be sure to add your shipping address.
Jack, W8TEE
From: "robert.m.cox@..." <robert.m.cox@...>
To: [email protected]
Sent: Thursday, October 5, 2017 1:14 PM
Subject: Re: [BITX20] W8TEE Software Release 1.07-09
Is it still possible to purchase the TFT/VFO boards for this project??
73,
-Rob
N4MN
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No, Pat. RC is still at FET gate, just FET drain via C to Q1 base. Value of C could alter the severity of the FET's effect, but would still not have much effect on overall action. If connecting C to Q2 or Q3 base likewise, though I'd be cautious of messing up Zout of Xtal filter. I'd be trying around 100pF there, same as the coupling cap.
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Jerry et al: Q1 should be fine, to 'normalise' the chain. 'messing up impedances' will only occur once the FET becomes resistive, i'e. Vg > (turn-on threshold), at which point all that happens is reduced throughput, the original intent - self-normalising. I'd keep it pre-demod - Z there really matters! And strong signals will always cause havoc. If AF detection, they'd need to be reasonably close to tuned-f to do much damage.
PIN diode schemes evidently work best, but this would be far simpler and thus less expensive, plus easier to understand and still with tolerable performance.
73 , Dex
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Here's the thread on distortion: ?? /g/BITX20/message/32043
You need to detect the signal level somewhere after the crystal filter,? since you only want the signal you are receiving to engage the agc action. Top of the volume control pot is probably good enough. Most solutions posted to this forum attenuate after the audio pre-amp at Q16. But as Henning points out in that thread, Q16 is limiting our dynamic range. So the AGC circuit should attenuate the signal before Q16.? Exactly where you should attenuate isn't terribly clear to me. If attenuating at Q1, the noise level when strong signals are present could be louder than it needs to be. Messing with Q1, Q2 and/or Q3 will affect impedances there, which may impact the performance of the BPF, ring mixer, crystal filter, and maybe even the demodulator. I'd probably just use a pin diode attenuator at the output of Q3 as noted in the above thread. Jerry
On Thu, Oct 5, 2017 at 03:47 pm, Dexter N Muir wrote:
For anyone using this scheme: I recall someone encountering distortion due to something in the Rx before this point. I had the thought (that still remains): why not 'feed-forward' like AM AGC? My replacement Raduino is currently en route, and I haven't yet had the chance to try this - has anyone else done so? I envisage detecting the audio level at the top of the Vol pot as this does, but taking the FET drain to Q1 base via 0.1uF and with time constants in between adjustable for fast/slow "hang". What say, folks?
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I have it apart now working on a new case so I can't verify it. ?It's not 5 secs though. ?It's more like 1.5-2 secs and I guess that is due to the interaction of the threshold, ?% of charge, and RC. ?It is a pretty smooth gradual increase back to full volume.
?Is your idea to move the RC circuit to the base of 2n2222?
Pat Griffin
http://www.cahabatechnology.com/aa4pg.html
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BTW, Pat - 100uF, 47k? T=CR - mics x megs = seconds, 100 * .047 = 4.7s. Is there a threshold? or do you have around 5 seconds of gradually-increasing signal?
73, Dex
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Further thought, Pat: FET might not turn on till about .5(Vpeak) ... threshold :) ?
73, Dex
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BTW, Pat - 100uF, 47k? T=CR - mics x megs = seconds, 100 * .047 = 4.7s. Is there a threshold? or do you have around 5 seconds of gradually-increasing signal?
73, Dex
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Pat, it's all said - think about it. 'Normalises' signals through the whole Rx chain once respectable level achieved, leaving it running at full gain until then. Transients knock it back till 'hang' fades out. Same as AM. Just concept, untried ...
73, Dex ZL2DEX
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I haven't gotten around to it but I was thinking of changing the hang time by adjusting the 100k and 47uf cap on the 2n7000 gate. ?The hang is about right with a 100mf instead of 47mf but that is just what I happened to have. ?Say some more about your idea
of doing it at the 2n2222 base.
Pat
Pat Griffin, CPA, PhD
http://www.cahabatechnology.com
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For anyone using this scheme: I recall someone encountering distortion due to something in the Rx before this point. I had the thought (that still remains): why not 'feed-forward' like AM AGC? My replacement Raduino is currently en route, and I haven't
yet had the chance to try this - has anyone else done so? I envisage detecting the audio level at the top of the Vol pot as this does, but taking the FET drain to Q1 base via 0.1uF and with time constants in between adjustable for fast/slow "hang". What say,
folks?
73 de ZL2DEX
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For anyone using this scheme: I recall someone encountering distortion due to something in the Rx before this point. I had the thought (that still remains): why not 'feed-forward' like AM AGC? My replacement Raduino is currently en route, and I haven't yet had the chance to try this - has anyone else done so? I envisage detecting the audio level at the top of the Vol pot as this does, but taking the FET drain to Q1 base via 0.1uF and with time constants in between adjustable for fast/slow "hang". What say, folks?
73 de ZL2DEX
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Ok, so it also has a resistor and a couple of caps. Anyway, here it is:
While wsjtx doesn't put a steady tone on the opposite channel from the data, it does put out data in both channels. That data is more than enough to turn the fet on and transmit. Until the other day, I was only putting out a bit over a watt into a long wire with an unun. I still managed to make several contacts with this circuit as an interface.
Vince.
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On 10/05/2017 08:18 AM, Vince Vielhaber wrote:
Rather than the duinovox I found a simpler circuit for interfacing data.
It consists of 3 small audio transformers (got 10 for a little over $1, a
couple of 1N4148 diodes and a 2n7000. I won a cheap ($4) USB sound card
on ebay so I built it all onto a circuit board and put a mic connector on
it to just plug into the Bitx. Next to the sound card, the mic connector
was the most expensive part.
I'll post a link to the schematic later today when I get home, unless I
can find it again sooner.
Vince.
There was quite a bit of interest in this over in the FB group, so thought
I would consolidate and add here. The project is call the "duinovox" by
KB9RLW. I built this very simple, low cost circuit and added in the bitx
enclosure. The wiring for the pots and interface jacks are hanging loose
just to see if it would work before drilling more holes. Also a picture is
attached of my very first CQ? on 7.074, at 2 watts, and two stations
replying. Serial 719 is getting a workout. If you do this, take
precautions with the final irf510 because of the heat generated by the
long transmissions.
--
Michigan VHF Corp.
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Ancel