Re: My NanoVNA is overheating
The ?T is 18¡ãC; 13¡ãC; and 15¡ãC. 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.
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John Nicholas
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#15324
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Re: My NanoVNA is overheating
44degC at the packages is not too much, unless you do beefy overclocking :)
By
igor-m
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#15323
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Re: VBAT resistor voltage divider, polynomial fitting, VBAT sampling
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
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igor-m
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#15322
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Re: My NanoVNA is overheating
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
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Gary Hale
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#15321
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Re: My NanoVNA is overheating
Made thermal photo NanoVNA Heat si5351 (1.jpg) generator and LD01 DCDC (3.jpg) CPU (2.jpg)
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DiSlord
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#15320
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Re: My NanoVNA is overheating
Thanks DiSlord, but I need the H version. Looks like it is not in the files section yet. Gary AG7TH
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Gary Hale
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#15319
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Re: My NanoVNA is overheating
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)
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DiSlord
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#15318
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Re: My NanoVNA is overheating
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.
By
igor-m
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#15317
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Re: VBAT resistor voltage divider, polynomial fitting, VBAT sampling
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
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Rich NE1EE
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#15316
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Re: VBAT resistor voltage divider, polynomial fitting, VBAT sampling
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
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Rich NE1EE
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#15315
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Re: Protective Case for H4
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.
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Darrell Carothers
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#15314
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My NanoVNA is overheating
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.
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Gary Hale
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#15313
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Photo as requested
Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar errors are due to my IPhone auto correct feature.
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Darrell Carothers
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#15312
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Re: Protective Case for H4
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
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John Nicholas
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#15311
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Re: Protective Case for H4
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
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Mikek
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#15310
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Re: Protective Case for H4
That is cool. 1. Do you have pics to share to show? 2. Are you going to make any to sell, for those of us without 3D printers? (Yes, there are still some of us out there)... [image: photo] *Bob
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Bob Willey K3RLW
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#15309
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Re: Protective Case for H4
Looks to be this https://www.thingiverse.com/thing:4543549 Dave-KB1PVH Sent from my Galaxy S9
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David Webb
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#15308
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Re: Protective Case for H4
What¡¯s the thingiverse number? Thanks, -rick, K7LOG
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Rick Commo
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#15307
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Re: Protective Case for H4
I just don¡¯t have exact measurements to verify the fitting for the other models. Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar errors are due to my IPhone auto correct feature.
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Darrell Carothers
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#15306
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Re: nanoVNA Saver exports s2p files with S11 = S21
#nanovna-saver
On my own PC and with my nanovna firmware 0.8.0 or dislord's current one and with my nanovna v2 0.3.6-rc2 works more reliable as v0.3.4 and a lot better then v0.3.0 but some quirks seems to exist, but
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Holger M¨¹ller
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#15305
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