FlightAware Discussions

Coax?

Thinking about upgrading to an outdoor antenna. The only issue is minimizing the coaxial cable run to minimize loss. I “think” I can get my coax run to less than 30’. What type of coax will give me the best bang for my buck?

I’ve read a lot about RG-6 quad shield. I also know that LMR-400 is decent, but bulky and expensive.

What do you all recommend if I decide to go outdoors?

In case you are in the US, this is good coax in different lengths: https://www.amazon.com/gp/product/B00QZEQ5EA

RCA or Phillips RG-6 quad shield from your neighboring Walmart store should do the trick.

Cool, so RG6 quad shield it is! I do have a length of LMR-400 at my disposal that I forgot about… Given a choice between the two, what would you choose?

Run will be appx 40’.

Check the attenuation at 1090 MHz for both types of cable …
Also consider which connectors you want to use, those can add issues with water ingress for example.

It all depends on what you want. You could also run a shorter length of coax to the inside of the house and then place an LNA there.
You will have more loss with the RG6 compared to the LMR400, i’m pretty sure about that without even knowing which exact make of RG6 you’re gonna choose.

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LMR400 is a lot harder to work with, but I think if I take my time I can manage. Is it acceptable to use a short run of flexible coax once I get inside my house to go into the FlightAware dongle stick?

You can always suspend the dongle from the cable :wink:

Don’t misunderstand, i’m not saying RG6 doesn’t work, just that the loss is higher when you use it.

A flexible pigtail is unlikely to add more than half a dB of loss, probably less.
Don’t overthink it either, if you are trying to optimize every last bit, you soon start thinking about the large DPD antenna (which gives very nice results).
What is more affordable and in my experience gives better results than the prostick+ is the rtl-sdr filtered LNA with the v3 dongle (or an airspy mini if you want to spend extra money).

You should also check this: What is the Maximum Range I can Get?
If your maximum range is 180 nmi or less, gear doesn’t matter that much any more. Then you run into the terrain limitations even with a mediocre setup.

(1) For Beginners - How-to Connect FlightAware Antenna, Filter and Pro Stick - Connectors and Cables Required

(2) How-to Protect Outdoor Connectors and Cable From Ingress of Moisture (Due to Rain & Snow) and Resulting Short circuit, Corrosion, and Drop in Performance

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I’ve said it before and I’ll say it again. Buy the best coaxial cable you can afford. Don’t scrimp on quality when it comes to coax and if your aerial and receiver are both 50 ohm then buy 50 ohm cable, don’t use 75 ohm feeder.

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Fully agree

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Totally disagree.
This may be tru for a transmitter, but not for receiver.

The mismatch loss due to two transitions (50Ω to 75Ω at aerial and 75Ω to 50Ω at receiver) will cause an attenuation of 2 x 0.177 dB = 0.354 dB. Peanuts.

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In my opinion, any loss is bad loss and if I can avoid it by simply using 50 ohm cable, then it’s a no brainer.

We’ve had this discussion before :slight_smile:

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Several times, but never reached an agreement / consensus :wink:

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Once you add the adapters to F connectors which most people end up with, you have something along the lines of 2 dB i’d estimate.
Which won’t kill performance, but it’s surely not improving it.

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That’s because there is no single answer that covers all situations

Better coax is only “better” if it has been assembled competently with quality connectors and adapters.

50Ω vs 75Ω alone is unlikely to produce a noticeable difference, but that assumes all else is equal.

The rest of the system also needs to be taken into consideration: eg. I have a dongle with an F-socket so it makes no sense to run 50Ω coax.
Similarly, I’ve got dongles with SMA’s and prefer to use 50Ω coax for those.

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