Dan Maloney
RF will never cease to baffle me...
ah ok as for aerial i use a discone antenna buit from pipe fittings and stainless steel rods
Put it on a service monitor/sepctrum analyzer and feed a noise source into one side while changing the length of the open coax and you'll see the notch frequency change
RF will always be magic to me :)
:)
@Dan Maloney I think it's like optics too... there's some wave particle duality think going on. :-)
What kind of bandwidth does a filter like that have?
There is always more to learn and I love it
It's amazing. I got the opportunity to get a basic look into it at university :)
think = thing
And I am glad to be able to practice RF
and communications systems in general :D
@Dan Maloney I'm honestly not too sure, it's not a lot but it's enough that we've used them in commercial situations before to notch out a nearby interfering frequency on our repeater input
Well, I mean, a notch is a notch, right? Should be pretty tight, I'd think.
Yeah it's tight I just don't recall the exact bandwidth
Read like a good scenerio to demonstrate in a video and/or write-up.
it'll notch out a 25khz wide FM signal so I'd say at least 30khz
Mathematically it's just the one frequency
I should measure it some time
Maybe can incorporate into the RTL-SDR way cost effective toolkit as a way to measure? Maybe compare with a better performing device to see capabilities?
@James Finch you can use a noise source, RTL and an RF bridge
Planning to do a video on that too
@Signals Everywhere/KR0SIV - If I can put my $0.02 in and request a video on what you can do with an SDR and a digital scope to troubleshoot and design filters, etc. I think that's what you were mentioning before, but just wanted to plug for that. I'd find that super-useful
https://www.rtl-sdr.com/tuning-an-hf-antenna-with-an-airspy-swr-bridge-and-noise-source/
Tuning an HF Antenna with an Airspy, SWR-Bridge and Noise Source
Over on his blog Anders J. Ørts has created a good writeup showing how he used the combination of an Airspy SDR with SpyVerter upconverter, SWR-Bridge and a noise source to tune his HF dipole for the 40 meter and 20 meter bands.
Oops - missed @James Finch while I was typing. Same thing basically
@Dan Maloney for sure, I want to do one filters and such, I may not have the work space to build a filter right now but I can take a ready-made cavity filter and tune that to show how the tools work
Sounds awesome!
It's crazy how much you can do with SDR these days
Yeah... the Airspy HF+ with Spyverter looks good (maybe better in some freq ranges) compared to the SDRplay RSP1 and SV1AFN DC-55MHz upconverter.
Heh I feel like I'm going crazy sometimes, I honestly have more than 50 ideas I could rattle off right now for videos I want to do (and have parts to do most of them) it's just a lack of time that keeps them back sometimes
@Dan Maloney We need the redundancy... it's like a survey without the website.
@James Finch Suposedly the RSP1 has true DB measurement which would be extra useful
I still need to test mine out. Wound up working on outside projects.
Wondering how the Spectrum Analyzer application performs also. The noise floor is great on those systems too.
The analyzer software is hit/miss sometimes
@James Finch - Basically I'm too cheap to buy a legit spectrum analyzer but I still want the capability
There is one for the RTL that does 'okay' but I prefer the SpectrumSpy software
I'll be using an AirSpy for my videos on filters/antenna tunning just because the software available is better
@Dan Maloney Welcome to my life lol :)
SpectrumSpy... I'll have to read into that. Is that what comes with the AirSpy?
Thank you @Signals Everywhere/KR0SIV this was all very interesting and I can't wait to get home and continue playing with my RTL SDR:) But for now I have to go. Bye
I was lucky enough to get one of these though
@James Finch yes it comes with the SDR# software/airspy
Yeah... @Dan Maloney I was all over the web find ways to hack the FFT option to use on the TDS-520 and TDS series of oscilloscopes.
https://www.rtl-sdr.com/spektrum-new-rtl-sdr-spectrum-analyzer-software/
Spektrum: New RTL-SDR Spectrum Analyzer Software
Recently a reader of RTL-SDR.com, Pavel wrote in to let us know about a new program called 'Spektrum' which he has written. Spektrum runs on Windows and Linux and turns an RTL-SDR dongle into a spectrum analyzer in a similar way to rtl_power GUI front ends and RTLSDR Scanner.
The RFExplorer and RTL-SDR wasn't cutting it at the time. I could only do so much with microphones and Spectrum Lab and am still planning to invest in a better microphone.
That's what could be used with the RTL
It works but finiky
Spektrum is handy... that's what I've used with the RTL-SDR.
Not a bad application by any means but I'll probably still use spectrumspy over it given the choice
I use it in this video where I was playing with a cheap ADE passive mixer
a HackRF & qspectrumanalyser is a nice option too. i was recently using it with a near-field probe set for some EMC pre-compliance work
I didn't even realize SpectrumSpy is bundled with the somewhere in 2016 and later SDR# downloads:
https://www.rtl-sdr.com/spectrum-spy-new-spectrum-analyzer-software-for-the-airspy/
@Mike Walters VERY true! Wow how did I forget that one, it was the first thing I used
iirc @James Finch it's also bunled with adsb software or at least used to be
Does qspectrumanalyzer work with RTL-SDR's also?
Here is a reference for the record: https://www.rtl-sdr.com/tag/qspectrumanalyzer/
There is one dedicated for the HackRF too that works alright, it sometimes causes the HackRF to lock up on re-tune but you just re-plug it and it's fine https://github.com/pavsa/hackrf-spectrum-analyzer
[Arsenijs] will have to try that one again - IIRC last time I tried that spectrum analyzer, it just segfaulted on me all the time.
yeah, qspectrumanalyser works with RTL-SDR too. the nice thing about using it with HackRF is the tuning speed - it sweeps at ~8GHz/s
^
50mhz - 6GHz iirc and it scanned like no tomorrow
wow, that sounds amazingly fast!
I used HackRF spectrum analyzer to find my cell phone signal
Too much bandwidth can be a henderance sometimes but other times... it's exactly what you need to find something odd over a swath of bandwidth
for this ability alone I'll always have a HackRF
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