I also just bought one, which software are you using. Occasionally when running a 0 db sweep I get the below spikes. I was also looking to do the filter mod and found the newer versions of the LTDZ has it already
I have a PlutoSDR, designed by Analog Devices as a learning/demo for their 6GHz transceiver (on the pge sais 3GHz but can be unlocked to 6GHz for both Rx and Tx if you don't care much about accuracy).
https://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/adalm-pluto.html
Nice toy w a 6GHZ ADI transceiver, 12 bits ADC, a dual core Zynq FPGA, open source, runs Linux, has support for Matlab, GNU Radio, etc.
There are some applications like SATSAGEN that can make a PlutoSDR act as a very basic spectrum analyzer or generator upto 6GHz:
https://www.eevblog.com/forum/rf-microwave/adalm-pluto-as-simple-spectrum-analyzerw-tracking/
http://www.albfer.com/en/2020/10/11/satsagen-0-4/
If you want it for learning SDR, too, there is a free book from ADI and some uni classes, too:
https://www.analog.com/en/education/education-library/software-defined-radio-for-engineers.html
https://pysdr.org/
Thanks for the software. I ran the tests, the descriptions for each test is in the file name. I ran all of the tests uncalibrated.
To see what is happening when I get those spikes I scoped the ADC and RF_OUT and what I found out is when the spike occurs there is no signal coming out of the RF_OUT. I am thinking the Firmware I have V1.19 has a bug with the SPI timing.
What version firmware does your LTDZ have.
Also owner of a LTDZ analyzer, I now made the modification and soldered out the 50 Ohms resistor at the receiver port. Thanks for the hint.
Now the result, measured with my NanoVNA V2:
By the way, did you clean your PCB from flux? I clean it with ethanol
Do you have installed 50 Ohm resistor on the ground at RF in connector (after capacitor)?
I don't know. My LTDZ reports firmware version FW:1.19:V10 (Version: 77, Variant: 0a).
But it doesn't means that our firmware is really identical. Needs more deep check.
I've found this github project for D6: https://github.com/joseluu/D6_firmware
It looks that D6 firmware works with LTDZ, but it uses 12 bit ADC format and different NWT command style, so it is incompatible with existing LTDZ software, but it can work with WinNWT.
This is true, I did a memory dump of my firmware and compared with your dump and some parts were the same. So I took a chance and flashed your firmware. After flashing I tried your software with the newly flashed LTDZ and found it does not work. I then reflashed with the dump I did and now the board does not work at all with any software.
Did you used STM32 ST-LINK Utility for flashing?
Can you give me your LTDZ STM32 dump?
Yes, I used STM32 ST-LINK Utility for flashing
Its 3:00am here in the US, I am going to get some sleep.
NWT4000 is better than D6 is better than LTDZ.
NWT4000 is better than D6 is better than LTDZ.
There are mods published for D6 to improve performance, I don't know of any mods for the LTDZ. It has basically a too high noise floor.
I have looked into the firmware and I don't see any dramatic improvements being possible just by changing the FW (except what my software already does anyway).
<RawMode_0dB_Reference>2040</RawMode_0dB_Reference>
<VerticalResolutiondB>0.048</VerticalResolutiondB>
Adding this fine link: https://www.rudiswiki.de/wiki9/SpectrumAnalyzer_LTDZ
Regarding SDR, RTL, HackRF, ...
These are different type of devices altogether. They are normally based on the RTL2832 chip and use Fast Fourrier Transformation (FFT) as opposed to swept spectrum analysts (SSA). They allow "realtime spectrum analysis" on the supported frequency bandwith, which varies from around 2MHz to 10MHz (or more) depending on the devices.
This is nice for very fast spectrum refresh rate and, especially nice, because these devices allow DEMODULATION of the received signals!
However, as a spectrum analyzer they offer less precision and no tracking generator (TG) functionality. You *could* implement your own, but I have not seen any sofwtare doing so.
Then there is the problem that few devices/software support sweeping this FFT window over larger spans.
There is the ADALM Pluto, a decent and cheap device, for which there is a software implementation of a spectrum analyser.
Also, there is a nice spectrum analyser software for the HackRF.
Overall, for the RF enthusiast, I would definitely recommend a HackRF One with the Portapack. Both can be bought at fairly cheap prices from China. Such a combination offers a lot of possibilities!
Software-wise, GNU Radio is very interesting to explore, too.
Take a look at this website for further RTL/SDR based devices: https://www.rtl-sdr.com/
Regards,
Vitor
How about building your own SDR with the ability to demodulate (not simply a spectrum analyzer) from a signal generator, a mixer, and a low noise amplifier and filters, and maybe some of those skyworks switch chips? The noise figure should be determined from the front end devices, is it possible to take a modular approach to build a receiver?
is that practical?
Note: SMA-male is the input and SMA-female is output for such attenuators, don't confuse otherwise the attenuator may burn out due to large amplitude.
I did not know this, I thought they were bidirectional, attached for clarification
What does it mean:
"Here is another firmwarwe for LTDZ:" ?