FlightAware Discussions

Use POE to put dongle at antenna, or use an LNA at antenna

Gas ones.
https://www.amazon.com/s?k=gas+arrester+coaxial&ref=nb_sb_noss

Are these Amazon no-name arrestors worthwhile? They aren’t THAT much cheaper than a name brand gas discharge version.

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ROFL - bunch of poor attitude, overtrained monkeys! :rofl:

Many can eavesdrop using this as well (depending on area): https://www.liveatc.net/

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Haha ya nobody makes fun of pilots as much as we do ourselves! Shout out to all my pilot buddies out there. This is the worst hit to the aviation industry ever, and lots of pilots and others in the industry are hurting real bad.

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@Hampstershorts Well… I didn’t test them, but the technology inside is pretty dumb. I would not be surprised if the “name brand” arrestors are in fact the exact same thing, with a pretty label.
Polyphaser units are nice, but they are 8-10 more expensive. My receiver dongle didn’t cost that much, and I have an Airspy R2.

As for the economy, that’s a bad year for everyone else. My brother works in a big-ish airport ATC (IT support for the actual software) and they have reduced shift personnel. Traffic dwindled, but the ATC still needs to be operational.

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Ok next question. Has anyone used Davis Bury-Flex? Seems like a popular cable in the USA.

But I have a question about bend radius. It’s specs give a 2 inch minimum bend radius. But LMR400 lists a 1 inch minimum bend radius. So you can bend LMR400 tighter than Bury-Flex? Is it wise to bend LMR400 that tight?

That’s a 1" radius for a 1/2" cable. Doesn’t sound like a good idea to me.
If you have to go that tight, perhaps consider a slimmer cable.

I don’t think I have to go that tight, I just pulled that spec right off the Times Microwave datasheet though. You wouldn’t think they would BS on their installation data.

Sure - but that will be with well supported cable preventing tension on the bend.
If you can support the cable that well, it should be fine, but keeping to a larger radius is still preferable.

Gotcha. I was planning on using a 3/8 inch cable clip every 2 feet or so in my install so that should be possible. But I am also planning to make all bends no tighter that a 2L Coke bottle if possible.

I have an LNA at the antenna and then I used a 75ohm RG6 cable to inside my house. 150 ft of it.
I don’t think fancier cable is needed after a two stage filtered LNA.

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Nope. Never used(or heard of) Davis Bury-Flex. Must be stiffer than LMR-400 or have a more brittle component to require a larger bend radius.

I use the cheap gas discharge lightning arrestors too.
90+V and it blows through the center feed line disconnecting it from your radio. Prolly not worth testing since lightning would definitely blow it. Just make sure the one you get is low insertion loss, and rated for the frequencies you are receiving, as some aren’t good around 1GHz.

SMA

N

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I’ve actually been chatting with the company that makes Bury-Flex. It’s popular with HAMs and people with rotators. It has a stranded center conductor and is much more flexible than LMR400 with just slightly worse attenuation. The 2 inch bend radius they list is for repeated bending, compared to 4 inches for LMR400. Fixed install bend radius is less but they don’t bother listing it. It’s more flexible and easier to work with than LMR400 and usually much cheaper. It’s also good for direct burial at that price.

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I don’t use LMR-400 for the pigtail, I’m using 1/2" Heliax Superflex FSJ4-50B
Minimum Bend Radius, multiple Bends - 31.75 mm | 1.25 in

Full specs here

Since you are setting up a stationary feeder, you don’t really need to worry about bend radius anyway.

I couldn’t find a full Datasheet for Bury Flex with all the test data,
this is all I could find
http://www.davisrf.com/buryflex.php
but I added it to my attenuation table for reference.

For fun here is the LMR-400 one

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