Newbie : listening 3Khz to 148 Khz with upconverter ?

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v1nce
Posts: 2
Joined: Wed Dec 04, 2019 8:04 pm

Newbie : listening 3Khz to 148 Khz with upconverter ?

Post by v1nce » Wed Dec 04, 2019 8:10 pm

Hi,

Is it possible to listen to 3Khz to 148 Khz ?
(ideally for a budget of less than 100$)
With a upconverter like SpyVerter Upconverter ?

If so will I just need to "plug" it to a rtl-sdr like
RTL-SDR Blog R820T2 RTL2832U 1PPM TCXO SMA Software Defined Radio with Dipole Antenna Kit ?

Thank you.

V1nce

From France

snn47
Posts: 192
Joined: Tue Dec 27, 2016 11:00 pm

listening 3Khz to 148 Khz with upconverter ?

Post by snn47 » Thu Dec 05, 2019 4:49 am

Yes, If the upconverter is not limited by a High-Pass and really passes all signals received to the mixer and provides an upconversion. You can verify receptions using one of themany strong time reference signals closest to you, e.g. DCF-77 on 77.5 kHz in Mainflingen Germany, which are used e.g. by clocks as reference.

Reception also requires that you have an antenna that provides suffiently strong signals at frequencies below 100 kHz. Since at 0.1 MHz the wavelength is 3000 m, even 10 to 20 m wire are short compared tothe wavelength. See my previous comments here viewtopic.php?f=4&p=13029#p13028.

PS: These comments are no tintended to discourage you or anyone, but I am trying to point out that at such low frequencies, you can only try to find the best compromise. Due to the much larger dimensions of the wavelength, when compared to a few 10m at shortwave, you cannot built a halfwave dipole or 1/4 wave groundplane (Eifeltower would be good for about 200 kHz).

Alternatives to wire antennas are ferrite antennas (a coil on a ferrite rod) used in radios that provide LW reception, or you untuned coil often called loop antenna. Ferrite antennas are also used for MW radios, but I have never checked if the ferrite rods used for MW work also well on LW or lower frequencies.

alanzfq
Posts: 66
Joined: Thu Oct 04, 2018 11:18 am

Re: Newbie : listening 3Khz to 148 Khz with upconverter ?

Post by alanzfq » Thu Dec 05, 2019 7:42 am

Vince,

Yes you can.
Results may be good or not be too good.
I've used similar and a LPF in front helped a lot by getting rid of unwanted spurious signals.
The antenna does not need to be big, just give a good signal to noise.
The best antenna I have for LF is a discone! It was the only one I had that received the Russian "Alpha" stations 11.905-16.881KHz.
You must be prepared to experiment.
Alan

radiolistener
Posts: 58
Joined: Thu Jan 25, 2018 10:48 pm

Re: Newbie : listening 3Khz to 148 Khz with upconverter ?

Post by radiolistener » Thu Dec 05, 2019 8:49 pm

The best SDR receiver for 0 Hz to 96 kHz is to use good quality sound-card "line-in" input. It will be much better quality than RTLSDR and other cheap SDR receivers (include upconverters) with price below $500. The only bad thing is that it's max receiving frequency is limited to about 96 kHz.

With hi-fi 24-bit sound-card which allows to sample at 192 kHz you can receive 0 - 96 kHz with almost 140 dB dynamic range. This is very high. Such dynamic range is available only in top-class SDR receivers. But you can get it with almost any, even cheap sound-card.

To get best performance and dynamic range, you're needs to buy high-end studio-grade audiophile sound card, such as E-MU or something like that. The parameters that you needs to take into account are:
- ADC resolution bits (24 bits must have)
- sample rate (higher sample rate = more wide bandwidth coverage)
- IMD
- SNR

Note, you're don't needs DSP and other effects and marketing stuff, just best audio parameters and ADC specifications.

But you can start even with cheap integrated sound-card, which is available at almost any computer these days. It will have a bit worse dynamic range and noises, but still works very good for such purposes. Most of today computer sound-card allows to capture sound at 192 kHz with 24-bit resolution, this is good enough to start use it as receiver even if has bad and noisy frontend.

In order to use it, you're needs to install HDSDR software: http://www.hdsdr.de/
And connect antenna into "line-in" jack of your sound card.

In some cases you may needs LNA and BPF for better sensitivity, but in most cases sound-card already has a good enough sensitivity and dynamic range to work directly with antenna with no LNA and filters.

v1nce
Posts: 2
Joined: Wed Dec 04, 2019 8:04 pm

Re: Newbie : listening 3Khz to 148 Khz with upconverter ?

Post by v1nce » Mon Dec 09, 2019 12:35 am

Thank you all.

@radiolistener "And connect antenna into "line-in" jack of your sound card."

As simple as that ?

Then I'll search for an audio card that's able to sample @192kHz because internal is limited to 48kHz and it looks like I'm hunting for 63,4 kHz and 74 kHz.


For those wondering what those frequencies are it's French Linky CPL energy managment signals that disrupts AC.
I wanted to "record" the AC but it looks like it's not possible (at least not in a cheap and safe way) one of my friend suggested rtl-sdr could be an indirect way to get them.

Yeah I know I sound like a moron when I told people CPL makes me sick.
But it does. (Or at least I'm sick since the CPL got installed)

alanzfq
Posts: 66
Joined: Thu Oct 04, 2018 11:18 am

Re: Newbie : listening 3Khz to 148 Khz with upconverter ?

Post by alanzfq » Mon Dec 09, 2019 8:01 am

Yes, a soundcard can be used.
I see cheap 192KHz USB are available but be sure it has an input that can record at 192KHz.
Many cheap dongles are playback only.

Also note many motherboard sound devices will work (mostly badly) at 192KHz. See if you have or can borrow something.
Alan

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