开云体育

1) use a frozen watermelon 2) drill vent-holes into the case 3) glue a small heat-sink on the top of the SI5351 chip 4) relax the SI5351's overclocking (lower its frequency) 5) increase the SI5351's

I as well would like info on buying one On Thu, Jul 16, 2020 at 6:20 PM, Darrell Carothers<rescuemedic1@...> wrote: That is correct. Darrell Sent from my over-rated IPhone 7 Plus.? Any

The results are in, it is the si5351. On the first attached sweep the chip was not cooled, the other sweeps were made while holding a frozen cotton swab against the chip for increasing amounts of

DiSlord took the thermal pictures, and I am guessing it is his NanoVNA-H4, which I am also guessing does not have a problem. I have a NanoVNA-H, not a NanoVNA-H4, and mine has a problem. I do not have

This may be why the VBAT is now enabled all the time...that would mean no diode startup time. That would mean a steady state current of maybe 30 to 36 uA over the battery discharge cycle. I wonder if

The ?T is 18°C; 13°C; and 15°C. Some of the cold spots are actually on the circuit board. The two closest to the IC packages may be holes for mounting. I would not consider the holes significant.

44degC at the packages is not too much, unless you do beefy overclocking :)

In this wiring the diode does not represent a source of "instability", imho, except its -2mV/K TC. The current via the diode is in, say, 35-40uA region (with 100k divider) and that is almost constant

Hot pictures! Looks like all three chips are candidates for a heat sink. I installed the old 0.8.4.5 firmware, then I put the NanoVNA in the freezer for a few minutes to see if I could make it through

Made thermal photo NanoVNA Heat si5351 (1.jpg) generator and LD01 DCDC (3.jpg) CPU (2.jpg)

Thanks DiSlord, but I need the H version. Looks like it is not in the files section yet. Gary AG7TH

You can try this firmware (it my last test variant) I revert some fixes added in 0.8.4.6 (Alsi it contain last UI, need reset config)

As I indicated in one of my posts, my new H4 crashes with 0.8.4.7fw every 10-15mins 0.8.4.6fw every 10-15mins 0.8.4.5fw does not crash. all at around 25degC ambient. I haven't mess with the threshold.

Well, if it is always on, then the circuit draw 4V / 100K ohms = 40 e-6A = 40 uA. If the battery is a 400 mAh battery, then it will take 10 000 hours to drain the battery. Is that a concern? With the

Skipping over "most probably" as an excellent example of what was not shared in the early days... We come to "There are no external dividers needed." But...again, according to the early design...the

That is correct. Darrell Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar errors are due to my IPhone auto correct feature.

NanoVNA-H V3.4 DiSlord 0.9.3.4 firmware I performed and open calibration only with no cables. The temperature in the room is 80 degrees Fahrenheit. First picture was taken when device was turned on.

Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar errors are due to my IPhone auto correct feature.

No 3-D printer here. So I modified the very nice box my H-4 was shipped in. I provided some large open cell rigid packing material to hold items in place. The small bottle holds the calibration

I looked at the case, I had similar thoughts, but I would have holes for the coax cables to connect to the NanoVna and also an extention to mount whatever test board you are using, in my case the