Suggestions for antennas to use with four channel coherent RTL-SDR

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Justin Smith
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Joined: Thu Sep 12, 2019 6:38 pm

Suggestions for antennas to use with four channel coherent RTL-SDR

Post by Justin Smith » Sat Sep 14, 2019 2:23 pm

I have a new four channel coherent RTL-SDR (Kerberos) that came without antennas. I welcome any suggestions for the type of antennas that I should use with this radio. I will need four identical antennas that will attach to the female SMA connectors on the radio.
Thank you,
Justin Smith

rtlsdrblog
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Re: Suggestions for antennas to use with four channel coherent RTL-SDR

Post by rtlsdrblog » Mon Sep 16, 2019 4:28 am

Justin Smith wrote:
Sat Sep 14, 2019 2:23 pm
I have a new four channel coherent RTL-SDR (Kerberos) that came without antennas. I welcome any suggestions for the type of antennas that I should use with this radio. I will need four identical antennas that will attach to the female SMA connectors on the radio.
Thank you,
Justin Smith
We're working on getting some mag whips out soon. They're a bit delayed but on the way.

Otherwise if you can't wait, just any basic magnetic mount whip will do.

Justin Smith
Posts: 2
Joined: Thu Sep 12, 2019 6:38 pm

Re: Suggestions for antennas to use with four channel coherent RTL-SDR

Post by Justin Smith » Wed Sep 18, 2019 4:16 pm

Thank you for the suggestion. I appreciate your quick reply.

73

Justin Smith
W2ANN

WhereAmIFlying
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Re: Suggestions for antennas to use with four channel coherent RTL-SDR

Post by WhereAmIFlying » Thu Nov 07, 2019 1:20 pm

I'm looking into KerberosSDR for direction finding on an airborne platform, ie without a large metallic ground plate such as a car roof.

As I understand it (complete RF noob here), the suggested magnetic whip antennas do require the metallic ground plate. Which antennas would you suggest instead, if this plate is not available? Would a standard dipole antenna such as the ones included in the "RTL-SDR Blog Multipurpose Dipole Antenna Kit" be appropriate?

Frequency ranges between 100 MHz and 1.2 GHz but not simultaneously (separate Antenna sets are acceptable!)

Thank's very much in advance!

HighSNR
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Re: Suggestions for antennas to use with four channel coherent RTL-SDR

Post by HighSNR » Thu Nov 07, 2019 1:49 pm

Can you elucidate on 'airborne platform'? Is this a fighter jet, microlight or a hot air balloon for example? Where on the platform do you envisage placing the antennas?

WhereAmIFlying
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Re: Suggestions for antennas to use with four channel coherent RTL-SDR

Post by WhereAmIFlying » Thu Nov 07, 2019 2:58 pm

Fighter jet would be exciting!

This is a research project that is currently in a very early stage. Probably it's either going to be a medium-sized fixed-wing UAV (~2-3 m wing span) or a run-of-the-mill small-ish multicopter, with a physical size of about 1 m or so.

At this point in time, flying the aircraft is not even a secondary task, first we need a ground based testbed. However, assuming no large metal ground plate is important, I guess.

rtlsdrblog
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Re: Suggestions for antennas to use with four channel coherent RTL-SDR

Post by rtlsdrblog » Fri Nov 08, 2019 4:24 am

You don't absolutely need a groundplane, but it will certainly help a lot. The antennas might be too heavy for the aircraft though, 4 of them are already close to 1kg.

If you have space for it, i'd recommend using 4 dipole antennas. But hard to see, but this photo shows a typical DF dipole setup https://www.ece.ucdavis.edu/mdasl/resea ... n_antenna/.

HighSNR
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Joined: Mon Sep 18, 2017 8:14 am

Re: Suggestions for antennas to use with four channel coherent RTL-SDR

Post by HighSNR » Fri Nov 08, 2019 8:05 am

Dipoles would work fine. Or you could have a sleeve dipole, if you only want the antenna to protrude out in one direction(to avoid snarling up on landing for example).

One thing worth thinking about for use with Kerberos is that you need to have the antenna well isolated from the cable. That is, you want the received signal to come from the antenna rather than than being picked up from the cable. A good balun and or ferrites on the cable are possible ways to help with this.

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