Lots of QSB and QRM, but worked Tom VE3THR and Paul KC8WBK. Heard N2CQR, KC1FSZ and KI4PSR plus a couple of others.
Conditions didn't start to improve until about 7:30 or 8pm.
AL - VE3RRD

Hi All (in the UK)

?

I recently received my BitX40 but was a bit surprised to be charged VAT+DHL fee (of a similar amount) for handling the VAT. These added 40% to the total cost (including the extra shipping charge). I just wanted to check that others had the same charges applied?

?

73, Graham M6LSO

On Sun, Jul 30, 2017 at 07:37 pm, Jack Purdum wrote:

Please let me know if you find any bugs.

Didn't find any bugs! As a matter of fact, I'm not sure where to find the?software!
?
--
John - WA2FZW

For audio less than 1uF use mylar caps. They're good for bypassing DC for audio stages too, but I'd use ceramics for bypassing RF stages where microphonics and such things as self-inductance are inconsequential.

Ceramic capacitors turn out microphonic. Maybe the input or in the preamp stage coupling stage.
As you say with volume turned up fully means that it is coming from preamp stage or earlier.

Raj

Lots of hits on the web for "LM386 pin 7 mute". ?Most pull pin 7 low, though pulling high works too. ?Allard's now routing PTT through the Raduino and driving a transistor to turn on the relays. ?So we could have a second 2n3904 with base and emitter in parallel with Allards 2n3904 transistor, ?the collector of this new 2n3904 pulls down on LM386 pin 7. ?Add a cap from pin 7 to ground, discharges almost instantly but would take a few miliseconds to charge back up through the LM386's internal 15k resistor?when PTT is released, long enough to?keep the LM386 quiet till after this exit noise is gone. ?So a 2n3904 plus a cap replaces Gian's 2n3906+resistors+diode plus Joe's relay, assuming you are going to implement Allard's "TX-RX Line Wiring" mod anyway. ?Beware, I have not tried this.

Pin 7 is meant to be bypassed to ground through an optional 10uF cap, preventing power supply noise from disturbing the diff-amp input.. ?But the Bitx40 has some serious external 12v filtering going into the LM386, so no large cap on pin 7 is probably fine.

Not being an analog kind of guy, fully figuring out the LM386 from the datasheet's internal schematic is quite the puzzle. ?I think one key is to assume the IN- pin is grounded (as it is in the Bitx40), so the collector of the NPN at the top of that side of the diff-amp is always two Vbe above ground, or about 1.2v. ?The current mirror below the diff amp draws an equal amount of current from the two sides of the diff amp, any excess current on the right side goes off to drive the output stage. ? This guy: ?? says the gain of the LM386 is equal to ?2*Z(1-5)/(150+Z(1-8)), ?where Z(1-5) is the impedance between pin 1 and pin 5 (typically just the 15k internal resistor) and Z(1-8) is the impedance between 1 and 8 (typically just the 1.35k internal resistor, unless you have an external cap across those pins to increase the gain as the Bitx40 does). ? The 150 comes from the internal resistor between pin 8 and the top of the left side of the diff-amp, the factor of two comes in because of the diff-amp. ?That all sort of makes sense, though I'm not convinced my understanding is complete. ?When muting, I assume bringing pin 7 to gnd or vcc upsets the diff-amp to where it's no longer functioning as a diff amp. ?Could be that going in and out of mute like this creates its own pops, I'll have to try driving pin 7 both high and low, see if either works better.

This guy does a dc analysis without just too much hand waving. ?
He's trying to get the LM386 behave like an op-amp, no internal feedback, so he can add an output stage to the LM386 and have the feedback loop go around everything. ? He says that at 125mw driving headphones, the LM386 is clean enough. ?Ask for more power from it to drive a speaker, and it distorts badly. ?The uBitx has moved to a better amp.

Here's an interesting webpage on cheap and simple and easy to understand alternatives to the LM386. ?He gives up on the LM386, drives an output stage with an op-amp with good results, written long before the above article: ? ?

I like how those two articles show the process of figuring these things out. ?Both seem quite competent, and they're not afraid to describe stuff they try that didn't quite work. ?Even the simplest circuits can keep a good engineer scratching his head for days.

Kind of amazing the LM386 is still such a popular chip at a hoary 34 years of age. ?Hobbyist interest on the web seems equally divided between qrp rigs and guitar amps. ?In 20 years the kids will be messing with their DSP algorithms to get a guitar amp that sounds grungy like those badly overloaded LM386's, having no clue how an overloaded vacuum tube amp would sound.?

Jerry, KE7ER?

All:

This release fixes a bunch of bugs, presents a smoother frequency tuning, and more even scrolling through the menu options. The code requires an mcufriend TFT display (2.4" to 3.95" should work) and a Mega 25760 Arduino board as it uses external interrupts not available on the Nano or Uno. (If you're not using any other interrupts, you could move my interrupts to INT0 and INT1.)

Please let me know if you find any bugs.

Jack, W8TEE

What type of relay works best for this?

Called CQ from 7 EDT until 7:15. Nothing heard!
--
John - WA2FZW

I have spent some time txing with the mod.? I get a buzz or rumble in my headphones that is from my voice.??

Audio reports are good.

Sometimes? frequency bumps down a tenth of a kHz or two when I key down, and bumps up when I key up.

I will try to reroute wires to limit rf into the audio amp.

John, I love your mic. Too bad you're not "Adam" or you could call it your "Invisible Hand Mic."?

Dave, The mic is built around a piece of single sided copper clad pc board cut to fit in the pvc pipe. I scraped away strips to make the traces and soldered in the cap and the element that comes with the kit. I had a larger momentary switch that I liked better than the one from the kit so I used that. I feels good in the hand but I haven't had enough feedback on air yet to know how it really sounds. It seems to get the job done though. I haven't put in any kind of screen yet, but I plan to. It's very close to Jack's design but I had originally made it a couple years back for a Hendricks Bitx 20a that's towards the back of the project backlog.?

Keith, you're right, it's 10kHz, and thanks for the keyword, I didn't know it was referred to as galloping.?

Jerry, thanks for the tip!

Vince, I don't remember what it came out of. I wanted the case to be as "up-cycled" as possible so I used a bunch of random circuit boards I had laying around from various parts scavenging forays. It was probably from something non-functional that someone gave me at some point. Maybe a Sony TV? I found some boards that were roughly the right size and shape and depopulated them with a heat gun. Then I cut them down to the right size and used them for the top, front, and rear panels. The other sides are bent sheet metal from a big-box hardware store. I'm pretty pleased with the way the case came out!

73 de KB1VNA
Eric

Conditions are tough, they may improve later in the evening.

I called CQ, no response.? I listened and heard a W4.??Then I heard?N2CQR (VA) in QSO, later he called CQ, I answered and heard him return my call, then nothing.? After about 1/2 hour, I went QRT.? CU next week, 73, de Karl, KO8S

开云体育

It came from an example.? It worked immediately so I left it?

It deals with the registers directly.

So, sorry I can't answer your question, and it is a good one!

I guess we could find the code in AttachInterrupt in the library to see what it does?

I added #defines and made version 1.09 into a conditional assembly file.?? That was what I was trying to explain, not

to have a fully working version.

I think any version could be now done easily.? I have 4 line LCDs, but not in my nice radio case.

I think that would be the answer so all the new features that use line 2 would not get written over by the Step display.

Or, I will have to share line 2 with the step display.? It would be easier by just adding lines.

Mike

?

On 7/30/2017 3:51 PM, Norberto Modanesi wrote:

Hi Don:

Why do you use PCICR |= (1 << PCIE2);//Interrupt setup ?to enable interrupt insted of AttachInterrupt?

73 - LU5DNM

?

Norberto Modanesi
San Nicolás

----- Original Message -----

From: Don Cantrell via Groups.Io

To: [email protected]

Sent: Sunday, July 30, 2017 4:58 PM

Subject: Re: [BITX20] Help with rotary encoder code, please, anyone?

John,

Rotary encoders by using polling has some difficulties, as you now realize. Interrupts work for me. Attached is a simple example (REserial.ino) that just reads direction to your serial monitor as you were doing. Also attached is a BITX Raduino application that demonstrates a practical sketch (EZ_RE_S_P.ino). Does this help? If you have any questions my email is ND6T@... and I would be glad to try to assist.
73,
Don,ND6T

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...