Date   

Re: Broadcast Interference filter for Ubitx

Sam Tedesco
 

@Laurence... I picked up a filter to try. Is it really directional?


more questions

Sam Tedesco
 

Hi everyone,

I just go my case from Sunil and I'm mapping things out in my melon. Question... I would like to run a bci filter and an rf gain (5k pot) control. Both will be on the rx line. Should I run these in series or parallel after I cut the trace?

If series, bci or rf gain closer to k1?

Thanks again!


Re: uBITX 4 Encoder

Doug Person <doug@...>
 

Thanks Mar. I'm not entirely sure what kind I have. But I guess experimentation is the best approach. I agree about having a separate switch. That might be something I implement.

73, Doug -- KJ0F

On 3/29/2019 9:42 AM, Mark - N7EKU wrote:
Hi Doug,

The one that comes with the board is a standard mechanical quadrature encoder with a mometary NO switch.  You can replace it with another quadrature encoder either mechanical or electrical.   I don't know what the resolution of the standard one is, but it's not super high so you would want to be careful with that.  The switch can be separate (and I am starting to think it would be better this way so that the encoder doesn't change settings when pushing the button).

73,


Mark.
-- 
73 de Doug -- KJ0F


Re: uBITX 4 Encoder

 

Hi Doug,

The one that comes with the board is a standard mechanical quadrature encoder with a mometary NO switch.  You can replace it with another quadrature encoder either mechanical or electrical.   I don't know what the resolution of the standard one is, but it's not super high so you would want to be careful with that.  The switch can be separate (and I am starting to think it would be better this way so that the encoder doesn't change settings when pushing the button).

73,


Mark.


Re: 2N2222A getting super hot

Allen Hill
 

Jim, do a web search for USB powered microscopes. Some are < $50 and amazingly useful. I have one that connects to PC has built in LED lighting, allows you to snap pics, etc. Some also have numerous accessories (stand options, etc). Not infared, but mine has saved me many times.

KI4QCK
73



On March 29, 2019, at 8:40 AM, Jim Strohm <jim.strohm@...> wrote:


This is a little off-thread --

With the advent of SMDs everywhere -- does anybody know of a CHEAP thermal / IR camera for PCB inspection?

I know that you can get a thermal /IR videocam for several hundred dollars, but we basically just need the imaging module and enough of a lens that we can focus on a 6x6 inch PCB, or section thereof.  

Thoughts?  Some of the older Sony camcorders used to see into the infrared, and with an infrared filter over the lens gave a decent IR image, although in B&W. 

A compact, cheap thermal / IR cam would be a very useful tool for troubleshooting.

73
Jim N6OTQ


Re: 2N2222A getting super hot

Tom, wb6b
 

On Fri, Mar 29, 2019 at 05:39 AM, Jim Strohm wrote:
does anybody know of a CHEAP thermal /
If you are into DYI here are a couple of possibilities. 

https://learn.adafruit.com/adafruit-amg8833-8x8-thermal-camera-sensor/arduino-thermal-camera

https://shop.pimoroni.com/products/mlx90640-thermal-camera-breakout

I have one of the Melexis MLX90640 devices I bought from Digikey. The example software I found (that someone hacked to run on the RPi) wrote directly to the frame buffer of my RPi, so had issues with it being overwritten by the desktop. I bought a tiny color OLED display and when that day comes when I have some spare time I'll port the example code to display on the external OLED display rather than the main HDMI monitor. 

The example code uses too much RAM to work on a basic Arduino, but might work on a "Blue Pill" microprocessor board. For the fun of it I tried running the SD card from my "regular" Raspberry Pi on a Raspberry Pi Zero. Seems the Desktop UI of a full RPi linux install has grown to the point the RPi zero could not reliably run it. (Although I need to check with a different brand/size SD card to be sure SD card compatibility was not the issue.) But, a cut down linux install probably would work on the Zero; making for a small portable thermal camera.

Tom, wb6b


Re: Shaking my head in disbelief....

Kelly Mabry
 

Paul, I too remember  the good old days, but it's been about 40 years since I built anything...
Heathkits were my rigs of choice Dx60B & HR10B & the HG10 vfo. Until I received my kenwood TS520. Now I run a TS590SG; but I am falling for this ubitx more and more.
I do believe I am turning the corner on this thing. I am investigating things this A.M. Having fun!

Kelly K5AID 


Re: Amateurradiokits wiring error

Martin Potter <ve3oat@...>
 

Thanks, Carl. I actually had no idea what Philip was talking about and the "AGC kit" was just a guess.
Vagueness seems to be a necessary qualification for posting here. HI
73,
... Martin VE3OAT


Re: PTT no releasing or ?

_Dave_ AD0B
 

Sounds like you are having rf on your ptt wires. And elsewhere.
Choke that puppy.


Re: 2N2222A getting super hot

Jim Strohm
 

This is a little off-thread --

With the advent of SMDs everywhere -- does anybody know of a CHEAP thermal / IR camera for PCB inspection?

I know that you can get a thermal /IR videocam for several hundred dollars, but we basically just need the imaging module and enough of a lens that we can focus on a 6x6 inch PCB, or section thereof.  

Thoughts?  Some of the older Sony camcorders used to see into the infrared, and with an infrared filter over the lens gave a decent IR image, although in B&W. 

A compact, cheap thermal / IR cam would be a very useful tool for troubleshooting.

73
Jim N6OTQ


Re: 2N2222A getting super hot

 

Joe,

Which version is this ? In my V4 boards even the 3904 run hot.

Raj

At 29-03-19, you wrote:
Hi,

I performed Alison's mod and replaced the 3904’s with 2N2222A T08. I also paralleled the 22 ohm resistors to get the 11 ohms. Not to mention I changed q90 and replaced the resister with 2.55kohms. The 2n2222a’s that have their resistors lowered to 11 ohms get really hot. the other set of drivers that don’t have their resistors lowered ( im not sure why) dont get that hot but they get warm.

when testing amp draw from brown wire in line with amp meter and rv2 and 3 fully clockwise I get 0amp on key up. I turn up one 100ma, then the other. now im at 200ma. If I talk in the mic It swings to 400ma+. With CW key down it jumps to under 1amp.

I am on a dummy load

I dont have a power meter.

Does this make sense after doing that mod. is there a reason why those 2n2222a are getting so hot, can i bring RV1 and 2 up so its drawing more current?


Joe,
KD2NFC


Re: Shaking my head in disbelief....

Paul Galburt - K2AYZ
 

Gordon,

I too built a triple 811 linear amplifier (when I was about 15 yrs old). It was grounded grid and the bifilar coil for the filaments was a tricky part - no toroids in those days. It had a surplus roller inductor PI network for antenna matching. Put out about 300 watts on most bands I think.

It did not have a lot of gain, but was super stable, and the glow of the filaments and the mercury vapor rectifiers was great, and all those ceramic plate circuit connectors - I loved that box and wish I still had it.

Ah, the old days - when things glow now, it's generally NOT a good sign :)

This stuff can sure jump start a career - 63 years later I am still at it every day.

73,

Paul


Re: Shaking my head in disbelief....

Wayne Leake
 

 Regarding the micro USB connectors, there are 2 different kinds.
 The one looks to be the most common type as used on my android and rechargeable flashlight.
 The other, as is found on the Raduino I have, is the same as is used for my Nikon camera.
 I found this one on Ebay easily.
 The one used for my android, I get at the Dollar Tree. You may be able to get them cheaper. as per the picture, the Old Verion is the one my Nikon and raduino use.
 TheMicro USBVerion, as I said, looks like the more common as my Android uses.

image.png


Re: Amateurradiokits wiring error

Carl
 

Martin, 

Phillip is talking about the volume pot on the ubitx case made by Amateurradiokits.in

Carl
M0CLS.


Re: Shaking my head in disbelief....

Ted
 

Here's an archived "scan" of the 2005-ish kit instx I followed. It so happens that I found the circuit board and plans but not the parts in the Great Abyss, so I ordered the few parts not also found in the Abyss -




Note the advice on swapping a few resistors for more gain.  I did that, then added a trim pot on the output to fine tune the with/without audio levels.  The result at home is that filtered CW comes put slightly hotter than straight audio; you can set as desired. It really punches a hole through noise or a crowd, and, it's cheap & simple (like me).


Here's another way to do the AGC thing AND really suckpout the weak signals from the mud - get the wideband RF preamp from Kitsandparts (.com) and a 5-watt audio amp module, and have a preamp that auto-levels its operation in AGC form [as I've worked the transistor at the input and at the output, seeing equal performance either way].  The manual gain is nice to have, too, and doesn't require runnng RG174 cable from two trace cuts up to the dashboard-mounterd pot -


Re: Amateurradiokits wiring error

Philip
 

dont know, just reverse the wires. As it’s wrong


Re: 2N2222A getting super hot

Ted
 

Joe,

RV1 & 2 "can" be brought up to more than 100ma each, at the cost (very possibly) of toasting your IRF510 final output devices :)   I don't recommend it.

Like yourself, I note the 2N2222 replacements in the predriver and driver getting warm. My "warm" may be your "hot" due to perspective, maybe not. Can you keep a finger on it for 10 seconds without experiencing real pain?   If you get a genuine burn injury,  it's probably running hot; my suspicion is that, as this is a terribly common upgrade,  a bit warm or very warm is just fine.

As an explanation, follow the circuitry.  Those transistors are basically shorting 12 volts to earth/ground at an RF rate, save for the 11-ohm resistors that govern the process.  The result at each point is to take a sample of the stage before it and make that energy "wiggle" the next transistor, whose job it is to almost short out the next stages' 12-volt feed at an HF frequency rate. Virtually draining B+ current through the resistor creates heat (how an oven works, etc etc). The whole reason for swapping the 22-ohm resistors for 11-ohm chips is that the 2n2222 can handle the greater workload - the more direct conduct of B+ to ground due to reduced resistance  - and delivers greater output as a result.  That more heat is produced, should be expected within reason.

Hope this helps.


Ted
K3RTA


Re: Shaking my head in disbelief....

Kelly Mabry
 

Graham, I have just loaded an SD card with your suggested file.  It is the only file on my card, so I am headed out to the old shack to load and test 

Many thanks!
Kelly K5AID 


Re: 2N2222A getting super hot

Gordon Gibby <ggibby@...>
 

Maybe check with an ohmmeter to make sure you ended up with 11 ohms. Then measure the voltage across the resistors while turned on, use ohms law to figure out the current through the transistors

Allyson told people what current she preferred.

Measure the voltage from the emitter to the collector, multiply by the current through the transistor, to figure out the resting dissipation; compared to the specified for the device.

Somewhere in there you’ll probably find your problem. There might be an incorrect biasing set up.

Gordon

On Mar 29, 2019, at 02:44, Joe Puma <@kd2nfc> wrote:

Hi,

I performed Alison's mod and replaced the 3904’s with 2N2222A T08. I also paralleled the 22 ohm resistors to get the 11 ohms. Not to mention I changed q90 and replaced the resister with 2.55kohms. The 2n2222a’s that have their resistors lowered to 11 ohms get really hot. the other set of drivers that don’t have their resistors lowered ( im not sure why) dont get that hot but they get warm.

when testing amp draw from brown wire in line with amp meter and rv2 and 3 fully clockwise I get 0amp on key up. I turn up one 100ma, then the other. now im at 200ma. If I talk in the mic It swings to 400ma+. With CW key down it jumps to under 1amp.

I am on a dummy load

I dont have a power meter.

Does this make sense after doing that mod. is there a reason why those 2n2222a are getting so hot, can i bring RV1 and 2 up so its drawing more current?


Joe,
KD2NFC






Re: Shaking my head in disbelief....

Kelly Mabry
 

Curt,
the more I listen and get used to this radio, the more I find I love about it. I did indeed get the Nextion display and the CEC software working.  I LOVE IT. I wished I could have gotten the 5inch screen! I also feel I need to adjust the bfo, based on threads I have read here. I haven't transmitted with it, as I sometimes I just enjoy listening.  I plan on getting a condenser microphone for it. The ND6T agc will be next. 

73, 
Kelly K5AID