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Hi Bob,You can buy several chips at a time( like 5pc) from China or you can do a transplant from a cheapo power pack from a dollar store as they sometimes use the same chip.
Have a look at this post: /g/nanovna-users/message/3296
Remove the "m." from the start of the URL so you don't get a huge photo/webpage.
Forum member hugen also suggested replacing the 10uF caps but I tried that on my white Gecko version and it didn't help.
I'm going to change the coil next - the Banggood devices use a 4.7uH and the Nano uses a 2uH - worth a shot.

More points means more long measurement and more high probability of some
interference spike. I think may be there is need for a median filtering,
but there is too small memory in order to do median filter
for a large amount of points

I will try to sort some light-weight filter

I glued nanoVNA shell command Python script:


.. with a bash script to get 100 values at some frequency:

$ cat scanraw100.sh
ch() {
# echo python /g/Gateway/my/nanoVNAsaver/nVcmd.py "$*"
python /g/Gateway/my/nanoVNAsaver/nVcmd.py "$*"
}

if [ -z "$1" ] ; then
do="scanraw 1 100000 0 1 1"
else
do="scanraw 1 $1 0 1 1"
fi

for (( i=1; i<=100; i++ )); do
ch "$do"
done

$ sh scanraw100.sh > x100
gnuplot> p 'x100' u 1 w l
gnuplot> load 'png.p'

Most likely out of the price ball park but I have just ordered a moRFeus

Seems a good choice,
if DIY unit parts costs exceed half that,
and the intent is actual use vs fiddling.

Hi

The RFzero may be exactly what you are looking for:

The RFzero? board is an Arduino compatible GPS controlled Si5351A RF signal source. The typical use of the RFzero? is as a beacon (IBP, SPB, CW, FT8, JT9, PI4 and WSPR), signal generator, VFO, Qatari Oscar 100 dual LO or a low cost 10 MHz GPSDO. More than a dozen programs (sketches) are integrated into the Arduino IDE for easy upload to the RFzero? so you don’t need to write the software yourself if all you want to do is e.g. operating a beacon.

Bo

Thanks.

Having a really good? day full of seniors moments.

Did exactly as above and got one for a phone to cut up when the new screen arrives.

--
Terry VK5TM
( )

You can get 5 pieces of IP5303 for less than 2$ shipping include on Aliexpress

Hi Rich -

This is really a 2nd order polynomial...it seems to be entirely adequate.

Oops, I first asked for cubic fit, but gnuplot was not converging well,
so dropped back to quadratic, which IMO fit well enough to estimate RMS noise.

I habitually use cubic for piece-wise fits..
Something about draining the swamp in the presence of alligators.

Hi All,

Most likely out of the price ball park but I have just ordered a moRFeus - RF Upconverter and Downconverter, Wideband Mixer and Signal Generator. $99.00 US. Awaiting delivery. I will update the group when I have had a chance to test it.
Regards
orni

Tcxo-s have long and short term drift. Short term drift better. Many precision time signal source available on shortwave. Easily measure drift if you have good ssb receiver and computer. Tune 1 khz lower or upper the tuner. With sound card spectrum analyser (for example free Spectrum laboratory) drift easy compute. If you worry sound card internal oscillator precision easy check with free sstv software msstv with time signal. Another way if you have two chanel oscilloscope and good reference signal simply check phase difference. If phase not sifted quickly, both generator frequency near same.

Now exactly know the error, simply correct matematically the compensation factor. If tcxo 25 000 000 and real is 25 000 100 hz simply use the corrected value.

Many amateur grade vna use this method.

Many chinese low cost tcxo-s fake. 0.5 ppm drift error not real many cases.

On Wed, Oct 30, 2019 at 07:34 AM, <pgc1682@...> wrote:

Reference clock source frequency error easily compensate by software in
firmware or with external program. i requested it.

This is actual for simple crystal oscillator with large error. But NanoVNA uses TCXO which has temperature compensation and small error. I don't think that it will be easy to add correction for TCXO. TCXO already has good enough precision. Get better is not easy task and actually this is don't needed.

On 30.10.2019 04:08, Terry VK5TM wrote:

So does anybody have a link to where to get screen protectors?

Get screen protector for any cell phone that is large enough and then cut it to right size for NanoVNA.

--
73,
Pedja YT9TP

Checkout:

Reference clock source frequency error easily compensate by software in firmware or with external program. i requested it.

In the USA the Dollar Tree stores often have large screen protectors
that are labeled for some device but may be adapted ...? kd4e

So it seems that the IP5303 should be replaced.? I opened the unit and found it but don't know where to obtain a replacement part.? My usual sources have no listing of this.? The only data sheets I can find are in Chinese.? One diagram shows 9 connections where the part is only 8 leads SMT.
Who sells this part?
Bob

So does anybody have a link to where to get screen protectors?

I've just had to order a new screen for my NanoVna.

Raymond Domp Frank wrote:

Resistive ... Pen pressure makes the two layers touch

I have found that the best and most accurate pointing device to use with the Nano is the stylus from an old Panasonic Toughbook. That was a hardened laptop series that are being recycled of late in favour of cell phones and "phablets" and the like. (Toughbooks are the kind of machine you see bolted to the hump between front seats in a police cruiser; 6 kilos or more of tough-as-nails machine, you can truly drop-kick one and expect to pick it up working. I have salvaged several, they take Linux a treat once you disable the weird touchscreen, and I am writing this email on one....)

Sharpish point. Medium-density plastic. They are fine-pointed enough to be very precise on these small screens. MUCH better than the foam-tipped sort, which require a lot of pressure to work at all, and make a much-too-large contact area (not a very precise result).

Same sort of stylus was used in old PalmPilot PDA devices. Haunt the thrift stores and re-use shops, you can often get a first or second generation Palm for less than five bucks. Steal the stylus for your Nano, yank the battery to recycle at the battery store, and toss the rest to the electronics recycler.

(Told you I was "one of those." Drive a Prius, too.)

--
W Will
N9KDY

Where is this related topic?? I'm not too good with the seup here.
Bob

many peoples reported issues with IP5303 charge controller chip.

You can find related topic here. It has some workaround for bad IP5303

I went to use my unit today and it came on for only a few seconds and shut itself off. Sometimes it won't come on at all and other times just a few seconds.

Any ideas?