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

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

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?

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

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?

Ted, I would really appreciate your plans with the OP amp and parts. I had located the sota beams filter, but if I can build it, it would fit in with the project better, and save my wallet. And yes I intend to get the ND6T AFC in April. I also want to add internal lipo batteries as well, so my budget is limited to small improvements each month.

Thanks!
Kelly K5AID?

Kelly,

One approach to "low audio", and it works well for me so far in development, is to add nd let the AGC you're going to add govern the w-i-d-e range of levels you'd otherwise experience.? One can build the earlier ND6T version out of spare parts, or get his newer, ready-to-drop-in board which soldiers in place very nicely.

If you want a narrow CW fiter, kits exist for about US$ 12-15 or I can upload the plans from one using a simple O2A op amp & a few common resistors/capacitors. You'd be amazed...

73,

Ted
K3RTA

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

Also, POP fix for earlier boards, and a HPF on RX for BCI option.

On Fri, Mar 29, 2019 at 11:59 AM, Kelly Jack wrote:

Perforations to separate the lpf section for a different location if desired??

I could, But the idea is that is plugs in at the front for the Audio connector and then lines up at the back to sit in the same foot print as the original LPF section.

I will align the mounting holes to use the front right main board hole, and then another 2, with easy to drill locations, I am thinking maybe the GND connector of the original(now unused) antenna connector.
and then a convenient/unused via some where on the other edge....

I have basically done all these mods but as separate boards at this stage, and although it works, I think a single board would be much neater, I did even toy with the idea of integrating my RaduinoI2C boar into it as well... well maybe... maybe not...

If i go ahead an produce these in a large quantity, I will do a proper PDF manual with nice build photos. But it will be a few weeks/months till then, I have an unfinished uBitx here that a very patient gentleman is waiting for to be complete....

73 Nick VK4PP

Yes, there are [Android] audio spectrum analyzer apps that work fine; I'd bet at least a nickel that the Apple Store does as well.

Phillip,
Are we talking about their AGC kit for uBITX?
... Martin

开云体育

Thank you. That was exactly my problem. When volume was low the meter was dead. Turn the volume up and meter went up. I ended up putting the audio in for AGC on relay side of R70. But there was still a difference in signal strength from volume low to high. I thought those wires were crossed. You confirmed it.?

--
David

?N8DAH

On Fri, Mar 29, 2019 at 12:19 PM, Nick VK4PP wrote:

HI Everyone.
I'm working on a nice little add-on board for the uBitx.
It contains:
- 200hz CW Filter
- Mic Preamp (SMM2167 Module)
- VK3YE LED AGC
- LPF section (Dual relay per filter)
I will try do it all TH, but the 100uh inductors underneath will need to be 1206 SMT...

Maybe $5 a board + post (VK-$1, DX-$3)

Here is a prototype picture:


73 Nick VK4PP

Nice. I want one. Perforations to separate the lpf section for a different location if desired??

Regards


Simon
VK3ELH

We have added some 3d printed mini mic housing and paddles.

All hardware is included (Mic's use the stock element and tac button that came with your bitx40 or ubitx) you need only solder or glue for magnets on the paddles

We have Red and Black right now and Grey coming soon! If you would like a color and don't see it drop us a mail: info at kit-projects dot com

?

Agc's are still in stock over 100 sold!
--
David

?N8DAH

HI Everyone.
I'm working on a nice little add-on board for the uBitx.
It contains:
- 200hz CW Filter
- Mic Preamp (SMM2167 Module)
- VK3YE LED AGC
- LPF section (Dual relay per filter)
I will try do it all TH, but the 100uh inductors underneath will need to be 1206 SMT...

Maybe $5 a board + post (VK-$1, DX-$3)

Here is a prototype picture:


73 Nick VK4PP

Thanks guys! I'll give it a whirl when I get some more time.??Will see if I can use my tablet.

Trying to fix a problem I pluged the Radunio ?? board into main board ? reversed? and it smoked
I can't seem to find a replacement.

Thanks

Ed

N1AHO

V4 board, Noticed at uncertain times I heard my auto-tuner going in to a crazy auto tune mode and after a bit it would settle down by the time I got from the living room to the rig. It would only do it once or so in a 5 -6 hour time frame. Then now much more often. Suspect was the auto tuner so today after watching it closely while transmitting on 7.074 it would do its thing but each time I notice the freq. monitor on the tuner was fluctuating around 10.?? mhz. Still suspecting the tuner I swapped out to the manual tuner. Tuned and started to do some ft8, but just as before something would stick the ptt line and the meter on the tuner was pegged both ways... ie off freq. (prob. the 10.00 mhz) thing. I noticed I can stop the runaway by doing mike key or cw key causing the relay to cycle and it would resume normal for a shorter and shorter time till it went crazy again. This seem to say it is not the tuner but something going on with the rig. Please all help, suggestions or directions to where to look or do would be appreciated.