Double negation type of deal 
Now is the time for me to repeat my favourite, well worn mantra.
“Buy the best 50Ω coax you can afford”
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I’m an engineer. Every day I wish I can convince my clients to buy the “best”, but always have to do a pesky cost benefit analysis. Diminishing returns to the increased cost is a real life situation. Sometimes even “no returns” happen.
Sure, anyone can buy whatever cables if they want… it doesn’t mean they will get any more range (or more planes) out of them.
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Agree… and for receive, the difference between 50ohm and 75 ohm is minimal. If you can only afford RG-6, well, puth your LNB staright at the antenna, but that rule should apply even if you use expensive coax. A LNB at the antenna followed by cheapish coax will still be better than the antenna followed by a long run of very expensive coax with the LNA situated at the receiver. If you do the N/F calculations, you will see, and face it, for ADSB, thw biggest challenge is having suitable dynamic range. Very few people will have just a ver weak signal at the limits of reception where a cooled LNA with minimal noise figure is the most important. For the vast majority of use cases, you might have a few low-level signals, distance determined by the earths curvature, whereas the receiver has to handle strong signals at the same time. Most commonly available receivers can only handle 70-80dB in dynamic range, and even that is pushing it.
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Several years ago, before invention of ProStick, I have used low-cost off-the-shelf RG6 cable, 50 feet length between Antenna and Generic DVB-T Dongle. I had to use an RF Amplifier (RCA D903 Satellite Amplifier 950 ~ 2050 MHz, 18 dB) near antenna. No problems of range or plane count due to cable.
I had to use such large length of cable because the dongle was plugged into a Desktop PC located in a room whose window faced a very large building just across the street. I therefore had to place the antenna near a large window in another part of my apartment, which has lesser obstruction by surrounding buildings. I then had to run about 50 ft of RG6 coax on floor/under carpet to connect antenna to dongle.
Hence my “you can afford” caveat 
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Your wife probably loved stepping on that
That is so true!
To avoid Her Majesty’s anger and expected demand to remove the coax, I have neatly run the coax on floor along the walls, touching skirting and mostly behind furniture, so it was out of her way and out of her sight. 
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Today, I got me some metal…
…to replace the antenna in the middle:
Now I just have to wait for some good weather while I have a day off…
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I can tell you don’t live in Seattle. 
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Rude!
We have a name for a sunny day that follows two straight days of rain: Monday.
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Those require 12-15VDC or somewhere around there, don’t they? How did you power it?
Made a DIY Bias-T using a 200 pF ceramic capacitor and a 3.3 miro Henry axial inductor housed in a 2-way recycled TV splitter housing. Power supply to Bias-T was a 15 V DC adaptor.
Please see this Sep 2013 post which shows photo of my installation with detsils:
https://forum.planefinder.net/threads/ads-b-diy-antenna.23/post-210
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Ah, thanks. I was thinking of getting one if I find that an amp is needed once I get my 8-plus meter mast put up but I think I’d just use a 5VDC bias-t powered one. My old eyes aren’t what they were and soldering’s difficult for me now. I’ll still bear it in mind, although I really don’t think an LNA will be needed. My total maximum coax loss will be 4.2dB at the mos per the Times Microwave calculator, using 10 meters of LMR240 plus an optional additional meter of RG174 only if needed to reach my Pi, or 3.1dB without the RG174. I’m using a FA Pro orange dongle which has an internal LNA: an additional one at the antenna would probably do more harm than good.
You are right.
As you have seen in my Sept 2013 post, I was using 2 satelite amplifiers in seres, one at antenna, other down at Bias-T. This was because at that time I believed “more is better / bigger is better” 
However after couple of months, I decided to remove the one near bias-t to see how much the reception will degrade. I was shocked to see that instead of degrading, the reception improved 
With just 10 m of cable you are about in-between. A 10dB LNA would probably work OK.
However, in my past, I was able to use the yellow dongle with high levels of signal (LNB plus short cable), if the gain in the software was at lowest setting, something like 0 to 6.
I guess I don’t understand what the advantage would be in adding an LNA at the antenna then compensating for its extra gain by lowering the dongle’s gain on the other end?
Its regarding the NF.
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Because LNA can have a lower NF than the dongle tuner (that you are lowering the gain).
Plus you can add filters in this configuration, without reducing performance.
I also added a gas surge arrester. And I could use normal 75 ohm cable without being worried about mismatched impedances (another source of losses).
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