Date   
Re: JackAl Encoder question...

Jack, W8TEE
 

Other than putting another hole in the faceplate, I don't think it would be a bad idea to use encoders w/o the push button switch. The reason is because some encoders have a stiff switch, which requires you to hold the µBITX case since it doesn't have enough mass to sit still. (Place one of those little mats that you use to untwist jars under the µBITX helps keep it in one place.) A NO SPST push button could be used, and just run it to the pin reserved for the encoder switch, or use an open I/O pin. If anyone does this, report back here and lets us know what you think.

Jack, W8TEE

On Wednesday, January 9, 2019, 1:45:59 PM EST, PeteWK8S via Groups.Io <pmeier@...> wrote:


The main encoder does not have a pushbutton but I still intend to add the second fine-tune encoder which does have a push button.

As for isolating the headphone jack I'm using an enlarged hole and thin, clear plastic washer to insulate the jack's round nut. That plus paint in and around the hole should do just fine.

Re: ND6T AGC Troubleshooting

Don, ND6T
 

What is the voltage on the base of Q1? What signal source are you using when you see no voltage output? Are you measuring at the junction of C3, R3, the cathode of D2, and the gate of Q2 to ground? Did you measure the resistance from the other side of that pot to the point that you are using for ground? 73, Don

Re: Harmonics and Relay Replacement

Jerry Gaffke
 

Spoiler alert!















I mean that if not staged, she would soon be nursing some nasty 3rd degree burns.
Of course, I've never done anything like that.  ;-)

Jerry


On Fri, Jan 11, 2019 at 04:05 AM, Bill Cromwell wrote:
You mean the complete lack of any solder or other tools anywhere in the photo? Shouldn't there be *something* in her other hand? And where is the solder smoke? I noticed all of that *after* I noticed she really is a pretty girl just as the label says:)

Re: uBitx V4 test point measurement chart #ubitx #ubitx-help

Ted
 

Good day, Raj.

A DC chart would be great.  What I have for diagnostics besides a few good DVM's are a dual-trace oscilloscope, an audio signal tracer, a single tone source, and another HF radio. Back when I worked in a business-radio shop with a proper service monitor, a popular trick was to take a piece of RG-58 from the instrument's RF input and put about a 20mm loop of the inner conductor folded around and back to the shield as a "sniffer". That's what I've done to find the last place the signal appears with any noticeable force at all.  Crude, but effective. Without knowing what I should see at Q90 and beyond, I'm basically just guessing. 

Nothing is obviously burned or exploded except my self-respect at this point!


Thanks,
Ted
K3RTA

Re: uBitx V4 test point measurement chart #ubitx #ubitx-help

Ted
 

Outstanding.  Looking forward to it. Thanks.

-Ted

Re: JackAl Encoder question...

bands11
 

I’ve got several BITX varieties and I’ve put standalone pushbutton switches on every one.  It’s great to be able to just push the button instead of anchoring my BITX with one hand and pushing the encoder switch with the other.  I simply wired them in parallel so I keep all the functionality as well.

Bob, KE7QEQ


On Jan 11, 2019, at 8:19 AM, Jack Purdum via Groups.Io <jjpurdum@...> wrote:

Other than putting another hole in the faceplate, I don't think it would be a bad idea to use encoders w/o the push button switch. The reason is because some encoders have a stiff switch, which requires you to hold the µBITX case since it doesn't have enough mass to sit still. (Place one of those little mats that you use to untwist jars under the µBITX helps keep it in one place.) A NO SPST push button could be used, and just run it to the pin reserved for the encoder switch, or use an open I/O pin. If anyone does this, report back here and lets us know what you think.

Jack, W8TEE


Veni vidi visa ... I came, I saw, I charged!


Re: ND6T AGC Troubleshooting

WA6PXC Rich <sigma@...>
 

Hi Curt,
I have tried a number of the AGC circuits floating around out there.
They all seem to work, but do not handle large (>1000 microvolts) signals.
Out of frustration, I have developed an AGC controller which controls the RF path
instead of the audio path. It begins to control the signal at about 30 uv and continues
to provide very good control up through about 7000 uv.
It essentially uses a BS170 FET in place of R12.
I have a neighbor 2 blocks away running 500 watts on 40 meters. His signal is not distorted
now...
If you are interested I can lead you through the process of building one...
Kind Regards..
Rich

-----Original Message-----
From: "Curt via Groups.Io"
Sent: Jan 10, 2019 6:54 PM
To: BITX20@groups.io
Subject: [BITX20] ND6T AGC Troubleshooting

I am beside myself that I cannot get this simple circuit doing something with the ubitx.  I am starting with the simple version with a single MOSFET, and I may add the series one later. 

I built one unit - nada.  So I build a second one, and left off the MOSFET.  I have its input attached to high side of the volume control pot (I think it is 10k in the Sunil case version), the ground attached to a connector in the closest corner of the board, and 5 volts from the raduino.  No matter how huge the signal -- I get no rectified voltage output.  What could I be doing wrong?  With hundreds of these boards in uBITX I am surprised by my result thus far. 

I am using a 2n2222A for the NPN, I have tried 3 different devices.  Yes the diodes each work on the DVM, and they are proper orientation. 

I also could not get the VK3YE AGC to work either.  The ubitx receives wonderfully and I am testing on 40m. 

73 Curt

PS - I do have a hybrid cascode but I am thinking to use it in a homebrew Rx -- not sure I wish to 'break' one of the bidirectional amplifiers here.  my goal is just to AGC the very largest signals. 

Re: MAX9814 as AGC preamp for output

Ted
 

Hi, Wayne.

My apologies inasmuch as the hyperlink didn't embed correctly. This was what I used, though not ideal -

https://www.ebay.com/itm/MAX9814-Electret-Microphone-Amplifier-Module-AGC-Auto-Gain-Control-for-Arduino-/272290839552

Lots of vendors sell those ^.  The other gentleman had shown one of these other boards, or similar -

https://www.ebay.com/itm/Microphone-Amplifier-Electret-MAX9814-perfection-with-AGC-Features-For-Arduino/253379344340 

........and if I were to start over, I'd have used the latter of the two simply because it's better suited for this kind of work.   Give it a run.

Re: Case for uBITX with Nextion Display

Ted
 

Until you add the shipping.  Ebay - Free   Banggod - $5+  and both are on the slow boat from, well..........

Re: Harmonics and Relay Replacement

iz oos
 

She's complaint..


Il 11/gen/2019 17:53, "Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> ha scritto:
Spoiler alert!















I mean that if not staged, she would soon be nursing some nasty 3rd degree burns.
Of course, I've never done anything like that.  ;-)

Jerry

On Fri, Jan 11, 2019 at 04:05 AM, Bill Cromwell wrote:
You mean the complete lack of any solder or other tools anywhere in the photo? Shouldn't there be *something* in her other hand? And where is the solder smoke? I noticed all of that *after* I noticed she really is a pretty girl just as the label says:)

Re: Harmonics and Relay Replacement

Jerry Gaffke
 

For those not sure where this thread is coming from, here's the photo in question:
    https://groups.io/g/BITX20/message/63764


On Fri, Jan 11, 2019 at 08:53 AM, Jerry Gaffke wrote:
Spoiler alert!

Re: ND6T AGC Troubleshooting

Curt
 

Don

reply gratefully appreciated. 

base is biased at 0.67 volts, and collector is at 5.07 volts as the raduino supply.  so this looks okay in terms of biasing the transistor. 

I have the rig plugged into a MA8040 vertical with a nice radial field here on the east coast.  I tune across 40m and look for huge signals.  A loud SSB, or much higher a shortwave broadcast has me cranking the volume down as low as it can go to stand it with headphones. 

resistance across the volume control pot is 9.9 k ohms, and I get same value when I touch the screw at the corner of the main board. 

At this point, in the circuit installed - I only have a 100k resistor and a 2.5 uF capacitor (non-polarized, I measured it to confirm) loading the output of the rectifier.  I built this board as a take 2, the other one is behaving similar with a MOSFET installed. 

the diodes each measure around 0.58 on diode setting of my DVM.  They seem to be diodes. 

Curt

Re: Harmonics and Relay Replacement

Doug W
 

so we're not entertaining any ideas that she could be some kind of self repairing cyborg/cylon/android/terminator?
--
www.bitxmap.com

Re: Case for uBITX with Nextion Display

Doug W
 

On Fri, Jan 11, 2019 at 11:35 AM, Ted wrote:
Until you add the shipping.  Ebay - Free   Banggod - $5+  and both are on the slow boat from, well..........
If you are in the US, click the little down arrow just right of the shipping method and select free shipping.  YMMV in other lands.
 
--
www.bitxmap.com

Re: ND6T AGC Troubleshooting

Don, ND6T
 

I'm just sorry to hear that it isn't working for you. From your description it all seems correct. It would be nice if there was some substantial signal that you could tune to, something steady and strong. If you had a signal generator or some local signal source that you could tune into the audio pass-band then that would help. Barring that, a good AM broadcast signal, even WWV, would be nice. Use the carrier as the tone. I have usually obtained about 3 volts or more (at the point where you are testing) with a strong 1 mv signal. That mosfet needs a half volt to begin to conduct and if you aren't getting that there is a problem. A strong signal should be measurable at the high side of your volume control when using a DVM on the AC scale. If you can get that, then you should be able to walk it back up the AGC circuit and see what is going on. Yes, the Q1 bias is about right and the forward barrier voltage of your diodes are in the ball park. Maybe a short, open, or faulty component. -Don

Re: Tracing receive signal for low signal

jim
 



On Sunday, January 6, 2019, 7:43:06 PM PST, jim <ab7vf@...> wrote:


Just as a suggestion ..Use the "VOL-H" point as a reference on testing rf levels ...that way both the V3 and V4 boards will be applicable

Jim

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Re: ND6T AGC Troubleshooting

Don, ND6T
 

Curt,
Just to make sure, I opened up my uBIITX and checked voltages. With a 50 uV (S9, -73 dBm) there was about 1 to 2 millivolts RMS on the top of my volume control. But with 1,000 uV (about S9+27, -46 dBm) there was a substantial .6 VRMS at the top of the volume control. That gave a nice 1.1 VDC at the AGC bias with it active. This is the dual mosfet model so it was giving me a pleasant output. That will hold up to nearly 4 volts before it runs out of control headroom and cannot attenuate any more at around S9+50! Your single mosfet should hold it up to S9+20 at which point that test point will read about 4 volts DC. Those measurements were taken with the signal about 1 KHz from the displayed frequency, just a constant CW tone. That allows the digital meter to track without resorting to peak holding.
-Don

Re: ND6T AGC Troubleshooting

Curt
 

Don

Thanks for wealth of info. Possibly with low solar flux it dawned on me that maybe signals are down a bit. I can see what my ft950 reads for largest signals. I have a fcc2 dds that has audio output, and a scope. So I will take some more data. This second unit I built very conservative,  I have measured to affirm its okay.  I seem to be confirming I don't have signals large enough to bias the diodes. Nor do I have plans to add a 40m yagi. The jackal agc does use rectifier diodes, with more audio stages. For now I am content with lcd display, so will continue with pursuing a stand alone agc.

Curt

Re: uBitx V4 test point measurement chart #ubitx #ubitx-help

Sascha Bohnet | DL5SMB
 

There already is a diagnostics guide for V3 by Ufi Auttori, who is a regular here too (at least so I think).
You can download it here uBitx Diagnostics Guide V3

The differences between v3 and v4 aren't so big, so hat this might be of help.

Re: JackAl Encoder question...

PeteWK8S
 

Are encoder switches needed for both encoders?  As I stated previously my main encoder does not have a switch but the secondary (ALS) will have a switch.
I can add a small momentary push button if the main encoder requires a switch.

What are or will the encoder push switches be used for?

Pete WK8S