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SDR Starter

kf4kd
Posts: 1
Joined: Tue Sep 08, 2020 1:07 am

SDR Starter

#1

Unread post by kf4kd »

I am brand new to SDR. I own a HackRF One and a RTL-SDR.com. I do not know how to tune these radios. In a few days I have rec'ed local FM stations. I see signal spikes, but I do not know how to set up on the radio functions to enable to receive different types of broadcast. I've beena SWL listner since age 8. Love it. I also have a advanced FCC licnese. Where can I go to get instructions on how to tune these two radios? Any help is appreciated. Thank you.

jdow
Posts: 358
Joined: Mon Aug 10, 2020 8:17 pm

Re: SDR Starter

#2

Unread post by jdow »

That is a really tall order as I have no idea of your expertise, chiefly because you ask that question. It sounds like you have not delved very far into the equipment you've been using. Presuming you have SDRConsole and the rtl dongle working at least well enough FM broadcast comes in I can offer a little starter information that might help.

With the rtl dongle selected and running with the home menu selected along the ribbon you should see an "RF Gain" setting. Set it to the 19.7 dB setting. The "AGC" selection should be off. "Bias-t" should be off. And "Visual Gain" should be 0 dB. That should set your sensitivity to a useful level that can be fine tuned later if you wish. I would strongly suggest you select the "2.4 MHz" setting in the "Bandwidth:" drop-list.

On the left hand side you should see the Receive DSP panel. The first line on it will be "Receiver". If not select the "Receive" selection on the ribbon bar. Then click on DSP to make the "Receive" panel appear and vanish.

On the Receive DSP panel going down you should see sections named "Receive", "IF Display", "Mode", "Filter", and so forth. These sections can be expanded or hidden by clicking on that name bar. The "Mode" selection should be pretty obvious as a way to change from "BFM" to "NFM" or "AM", the other two modes of usual interest within the RTL dongle's frequency range. If you've been an SWL for a long time you probably know what kind of signals appear on what frequencies.

You can select the center frequency of the dongle many ways. One way is to look at the bottom frequency bar. Click on the highlighted (central) portion and slide it left or right. Another way to change it is the "Frequency" setting selection on the home ribbon bar. The fancy little keyboard to the right side of the bottom frequency bar also brings the same dialog up. For format select "Frequency, Bandwidth". Then struggle through entering a frequency maybe 100 kHz away from the one you want to receive. (Hitting it exactly does not work as well for arcane reasons.) And leave the "Bandwidth:" setting unchanged. Then to tune a receiver to the desired frequency use the Receive DSP panel's frequency indication. Move your mouse over a digit and move it up and down with the scroll wheel or with the left mouse button on the top bar or bottom bar as they appear. Hint: You get a handy special action if you do this with the shift key pressed.

That should get you started. From there you can experiment with the various controls to see what they do. That's how I learned as a teenager way too many decades ago to contemplate. Note current setting, change it, see what happens. Restore to original and learn another control. Once you learn the controls fiddle with then to make everything do what you want. Note that with SDRConsole you can open multiple "Receivers" all within the 2.4 MHz centered on the dongle's frequency setting. That's a fairly advanced use.

And to be honest, I am a little surprised you have not figured this out for yourself. If all this scares you "SDRSharp" is a simpler tool to play with for starters. But more or less the same concepts apply.

For a college level receiver design course I charge more, a WHOLE LOT more.

{^_-} Joanne

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