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Has anyone tried using the TinySA for AM broadcast NRSC test measurements?

The idea is to eliminate heavy, bulky power consuming equipment in remote locations.

On Sat, Feb 20, 2021 at 02:21 PM, Rick Sherman wrote:
?In my last post I should have Identified the 2 pics. They both shw the same signal. the pic on the left was done with a good USB Cable and the other with a not so good one.

The tinySA-App seems to work ok.? So USB comms appear to be working.? Just when uploading firmware it always finishes with an error.
By shortening the St-Link pins I can leave them soldered on.?

If you look at the attached pics it looks like I probably need to get some better quality USB cables. It still won't upload the firmware with the good cable.

I have an over the air TV antenna "system", i.e. VHF/UHF outdoor antennas feeding a mast mounted preamp, then a distribution amplifier, etc.? The TinySA is a fantastic tool to troubleshoot the signals at various points along the signal chain when there is an issue.? There is one "watchout" I have noticed, though - even though my strongest UHF channel is only about -40 dBm (right after the antenna preamp), if I leave the AGC setting in the TinySA at either ON or AUTOMATIC, the HI input range is essentially unusable, with a 20 dB in the noise floor which obscures most of the 6 MHz wide TV channels.? I did not see the same effect with the LO input.

I am not sure if this is due to other very strong signals that are out of band (I live within 0.5 mile of four cellular towers and an FM broadcast station), but just wanted to mention that at least for my TV antenna system, starting with the AGC turned OFF is a key factor..

Does communication with tinySA-App work?
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This morning I tried to update to the current firmware via USB and got the white screen again. 100% failure rate via USB.? I guess future upgrades will have to be via ST-Link. Kind of a pain to solder the header pins on each time though.

The UART is currently NOT enabled in any of the SW
If you want to use something else than serial over USB (DFU mode) you will have to use an ST-Link with STM32CubeProgrammer and connect it to GND, SWCLK and SWDIO

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So, now, a 'original' tinySA from Zeenko Store is on it's way from China to me.

Monday 22. Feb. Aliexpress should step in to finalize the dispute I have opened with
the Toolbox-Store. Toolbox-Store answers are either 'cheating' or they have no idea
what and why I complain about their delivery, even shown in pictures & videos + text
from my side.

Nevertheless, the com port on the 'bad clone' does not work via USB-C - no way!

If I bring the device into DfuSeDemo? mode and connect via the UART pins on the board
will this allow me to access and upgrade the firmware?

On the board, the TX and RX port, are they labled as 'TX has to go to the 'TX' and 'RX
goes to RX' port of a serial USB device, or cross-over?

Looks good. Do test the switches as contacts may deteriorate over time and you may have to clean them.
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How about attenuators such a these? They are both 50 ohm and give you a lot of attenuation options.
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Scott Richardson AA6U

yes it seems ok firmware has updated and still selftest is ok

On Fri, Feb 19, 2021 at 04:16 PM, Rick Sherman wrote:

After several tries I was able to get it going again with the ST-Link.

Happy to hear!
?
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The tinySA is used as signal generator and a spectrum analyzer in combination with an old vacuum tube AM/FM receiver. Both AM and FM signal generation and reception is demonstrated and, using one tinySA as signal generator and a second tinySA as spectrum analyzer, the various 455kHz and 10.7MHz IF stages are probed. Also the probing of the LO is demonstrated. The AM IF signal levels were lower than the FM IF levels because I forgot to connect the tinySA back to the AM antenna input when probing the AM IF

https://www.youtube.com/watch?v=oGqdLQ1ex64

To be sure you should upgrade to latest FW and run selftest again, but on first sight it seems OK

Its OK!
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?

passes self test and appears to work ok
not tried updating anything?

eBay seller “health_home”?

Sadly found the group after purchase?
to be fair mine passes self tests and seems to work?
no idea if it’s a fake?

Trying to align something like an IFT when feeding directly into a 50ohm input is almost certainly going to load the circuit and give erroneous results unless to point that you are monitoring at is sufficiently isolated from the item that you are adjusting.

What you need is a high impedance, low capacitance, RF probe. There are many designs if you Google it, some are passive but some are active so as to compensate for the loss. They are not difficult to build.
You could try a normal 10X scope probe, but even on an ITF it may have too much capacitance and load the circuit if you use it directly on the IFT itself.

Regards
Jeff

There are videos in YouTube, search for ?receiver if alignment“. Like this:?

Ah, yes, forgot to shift the 50MHz point to 30MHz. It will not have any noticeable impact on performance