RTL-SDR Dongle & Antenna

[turkeysneck]

The RTL-SDR Dongle & Antenna doesn't have a very long lead, is it possible to extend the cable by putting a usb extension cable between the dongle and the pilotaware box.

[Ian Melville]

You can, but it all starts getting a bit messy with dongles placed in odd places. Likewise you could extend the antenna coax with an extension lead, tidier, but signal wise is a bad idea. I have a strong dislike of additional joints and would replace the whole antenna lead with one of the length I need, but only if it was really necessary to get the antenna in a better position. If you don't like the thought of putting an MCX connector on a RG174 cable buy an extension cable, cut one end off and attach to the antenna, after dismantling it.

There are other way to sort this out neatly, but it would depend on where you want to mount the antenna, and on what aircraft.

[turkeysneck]

Thanks for that, I'm thinking of placing it on the underside of a trike on the pod, but not sure the lead is long enough yet.

[exfirepro]

turkeysneck,

Remember that the 1090MHz signals that the SDR Dongle is looking for are comparatively high strength (compared to the P3i side), so antenna positioning is much less critical than for the P3i Bridge Antenna. I use standard (P3i) dipoles for both, fitted inside each side of the pod of my trike with an SMA to MCX adapter on the end of the cable for the SDR one. I have also done an installation with the standard 1090MHz antenna sitting on top of the Base Tube inside the front of the pod and this also seems fine.

Regards

Peter

[turkeysneck]

So if I position the aerial in the fuel tank area which is enclosed do you think that will be good enough ?

[bnmont]

Hi, This is what I did on my Flexwing.
Mounted the PAW unit underneath the instrument panel, remote mounted the GPS dongle on the bottom of the front strut.
Shortened the antenna to about 60mm and mounted to the side of the fron strut.
Seems to all work fine in that location.
Regards Brian

[turkeysneck]

OK thanks.

[exfirepro]

So if I position the aerial in the fuel tank area which is enclosed do you think that will be good enough ?

Not quite sure what you mean by 'in the fuel tank area'. If you mean inside the rear skirt, this would probably work, but the signal will be screened to the front by the fuel / passenger / pilot and to the rear by the wing pylon, engine, radiator etc. Your highest collision risk is generally to the front of your aircraft, so somewhere inside your front screen (as recommended by Brian) or inside the front of your pod is generally a far better choice. Remember you can shorten the 1090MHz antenna to about 70mm (as Brian has done) without any detrimental effects.

Alternatively, I have one colleague who runs his PilotAware in the storage pocket inside his side skirt of his flexwing, with the 1090MHz antenna fitted to the top of the engine mounting frame just behind the seats. It will of course be partly screened to the directly opposite side by the metal pylon, but picks up approaching traffic well before it gets into the blind spot.

Hope this helps.

Regards

Peter

[turkeysneck]

Yes I mean on top of the fuel tank just behind the skirt. I'm confused now, I'm told that the position of the SDR dongle antenna is high strength and is much less critical in it's positioning. So I'm getting confilcting information.

[exfirepro]

Not conflicting information. What I said was that the 1090MHz signals that the SDR Dongle is looking for are comparatively high strength (compared to the P3i side), so positioning of the 1090MHz antenna is much less critical than for the P3i Bridge Antenna. It is still good practice to try to avoid positions where the signal is likely to be blocked by metalwork or attenuated by big bags of fluid (e.g. people). I'm not saying it won't work, but it's likely that your reception will be skewed in the direction away from any obstruction. My advice is give it a try and see how you get on and be prepared to try an alternative position if you realise you aren't getting a signal from any particular direction.

Regards

Peter

[EricC]

Screen shot, shows range of transponder transmissions received
with a 69mm long aerial, located on my house roof feeding
a standard PAW.

[turkeysneck]

Thanks for all the information, guess I'll try it out now and see how it performs.