Way more complex when getting into the microwave range. Just watched a Keysight presentation noting how every section of a circuit in a system has to be studied to understand the affect... where I perceive is like an antenna basically so not to cause reflections, impedance mismatches, losses, etc.
Speaking of filters the next one I need is going to be for broadcast AM, I need to get into VLF soon
@James Finch very true, as you go up in frequency even the PCB material can affect the signal/circuit
Well, every part of a RF transmission system has to be matched to achieve optimal performance
@Signals Everywhere/KR0SIV any thoughts about Software Defined Antennas (for hobby use)?
and yeah, it can get tedious quick
@Max-Felix Müller What do you mean software defined antennas?
@Signals Everywhere/KR0SIV Totally, the demonstration was just a via causing the losses around 20GHz.
microwave is really finicky :P
@Max-Felix Müller or I suppose you're asking what antennas to use with your SDR?
@Signals Everywhere/KR0SIV antennas that can be tuned by software to have specific directionallity and/or use different frequencies
A lot of it is still magic to me xD
like https://en.wikipedia.org/wiki/Plasma_antenna ?
or more beamforming?
Generally you want a tuned antenna if you can, 2m antenna for 2m, L band antenna for L band etc..
However for general reception you could go with a discone antenna
Or phased-array like radar.
The antenna is the MOST important part of your radio system, doesn't matter if the radio cost $10M if your antenna is crap it's not going to work
I am picking up Spanish AM/FM? stations up around 500 MHz on the RTL_SDR V3? Any idea how it gets mixed in. My Spanish is not good enough to tell which station. In terms of algorithms, it would be nice to have standard ways to identify strong interference sources, frequency drifts, sferics (lightning), and identify stations location and information automatically.
beamforming is already done by an array of antennas; if you can vary the phases going to the antenna elements; you can "steer" the array electrically
I use a discone on my FlightAware SDR and I find it to be a poor performer. Could be the long and lossy feedline, to be fair.
@RichardCollins It could ben a strong harmonic mixing or intermodulating
I'd tune around to see if you can find which station it is in the broadcast band
There must be an FM nearby--very nearby--to get images at 500 MHz.
then look it up with the FCC to get the location
While talking antenna questions, I just typed this one up, n00b question incoming:
Great chat, thanks for it. Quick question. Wondering what the term is for what I ran in to this past winter.
I had (still use) a cheap 800mhz Yagi antenna and at this point I had it distributed to many (6 or 7?) RTL-SDR v3's all monitoring the same (800mhz) P25p1 system via UniTrunker/DSD. I'm sure this distrib/amp thing was not the best choice but it worked: https://www.amazon.com/gp/product/B002M1EPL0 And this sytem worked for a good long while but sucked in that it was LSM system with UniT and bad quality.
Well this past winter I stood up a...
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