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Re: uBITx v6 original 2.8" LCD
On Sat, May 25, 2024 at 08:55 AM, Calvin Burnham wrote:
Can the original LCD be programmed similarly like the Nextion displaysNo, the SD slot on the original display is just there to be accessed by what ever MCU you might be using. If you look closely at the SD slot, the traces go over to J4 connector, (not used), to be accessed by what ever you want but don't really have anything to do with the display. Joel N6ALT |
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SBITX V2 for sale
I’ve been told I have to sell a radio before I buy another one, so I’m selling my SBITX V2 with Pi4. ?I traded a TenTec for this rig last fall and have used it on CW and FT8, as well as PSK31. I added the V3 software but haven’t modified the hardware to V3 yet. ?Everything works great and it still has the plastic protector film on the screen. Includes the power cord with power poles added, manual, space finals, and mic (which may have had the cord repaired by the previous owner). I no longer have the original box. I can send pics to anyone interested.?
Adam N0ZIB |
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Re: Limiting current to protect finals?
Scotty,
the idea is good, but as you can see in the software version of the program, there is no one who would implement all this. For different reasons: those who could do it don't have free time for hobby solutions, and those who have free time are just trying because they've never done it before. To all, Since I don't like half solutions either, I started implementing what I can.? Since I've had the device since last April, but I didn't have time to use it, I started with just a few modifications. When the shipment arrived, I first checked the screws. Here, the FET amplification was the problem. I modified this. Then I noticed that there is no output power for the dummy load. I looked for the reason and in the swr circuit around the diodes, one of them led both ways. I replaced both diodes because I had the opportunity to select ones with almost the same opening voltage from a previous purchase. I made this setting (according to the instructions from early May). Unfortunately, the power display is not accurate (it shows a higher value than the external swr meter placed on the output) but I noticed that I don't have a good idea how to modify it, so I didn't dive into the solution. However, I didn't like the Bias setting at all, so I modified it so that the temperature of the FETs is monitored by the 6 Si diodes connected in series and thus affects the Bias voltage (the idea comes from F5NPV). I have published several pictures, this and my cooling solutions can be seen in the photo. I did the cooling because ft8 and especially the sstv mode has a long transmission time. I don't like to change parts often, so I pay attention to what needs to be cooled better. Unfortunately, initially I only used the device on battery power. When I tried to set the transmission or the Bias (I don't remember which one anymore), one of the final stage with FET was shorted. From then on, I only use it from a power supply with a current limiter, and it (knock-knock) still works with my first installation. However, there were more than 4200 qso's (in ft8, ft4, sstv, js8call modes). That's why I recommend this power supply to everyone. One more thing: I definitely wanted to exclude the use of an antenna tuner, so I built an antenna that works well on several bands. This is a vertically fed loop antenna installed at an angle. I had a similar antenna in previous years, which I tuned to several bands with the Drake L4-B output tuner. At the moment, I can only use this one antenna and it does not need a tuner. It is rated at 7MHz, which can work well at 14 and 21 MHz.? We are close to QRP performance, so a good antenna is very important, I think. This is proven by the fact that 3D2CCC also answered in ft8 mode, and several dx stations also succeeded. Of course, for that you had to be in the right place at the right time. -- Gyula HA3HZ |
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Re: I need help reviving my sBITX V3
Just wondering,? are you going by the silkscreened markings on the board for voltage polarity? I think I heard somewhere that some of them? in the past were labeled wrong? Maybe a different radio, can't remember.? It might be a good idea to trace the wires to actual components to verify before reapplying power, just in case. Scotty WD4PYT? On Fri, May 24, 2024, 6:40 PM Evan Hand via <elhandjr=[email protected]> wrote: Aaron, |
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Re: Limiting current to protect finals?
Although a hardware solution is definitely a valid option,? being a software defined radio, I would guess that a setup option giving the opportunity to tell it that you use a tuner, adding a tune soft button to the screen,? could lower power for a special tune up delay.? Scotty WD4PYT? On Fri, May 24, 2024, 2:46 PM Jeff Duce via <jefe_de_estado=[email protected]> wrote: So I cooked a set of finals recently with no obvious reason why.? Most of time my radio uses my raingutters as the antenna, which means I'm using a 9:1 unun with my ATU100 tuner.? When I switch bands the tuner takes a second to do it's thing and for a brief period of time the SWR and power output can be very high.? Gyula mentions that he uses a current limited power supply to reduce these power spikes.? That got me thinking.? I found a chip and made a quick design which could be placed between any standard power supply (battery, AC/DC converter, etc) which would limit the maximum current drawn from the source.? I got a decent way into the PCB design, but then this morning on my drive to work, I got thinking that this approach maybe doesn't do anything...? Help me understand this, I may not have this right in my head: |
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Re: I need help reviving my sBITX V3
Ok this is so darn ridiculous that it isn't even funny anymore. I'm really starting to lose hope here.?
I burned up 20 of these voltage regulators. Or I found 20 steps closer to stepping from this hobby and be done with it. Here is my? steps:
I really appreciate everyone who has helped me with this but this current path is just not leading anywhere.?? -- '72 Aaron? |
Adam N0ZIB
Joel Caulkins/N6ALT
HA3HZ
Scotty R
Aaron K5ATG