Well, sooner or later. The Sphinx in Egypt lasted longer.
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I already tried the un-branded AP20 about 3 years ago. It did not work at all 
May be a defective unit, OR contrary to it’s lable, it is very wide band and amplifies FM, Air, Fire, Police, TV (VHF & UHF) also and overloaded/choked the dongle. I did not have a filter at that time.
On the other hand the RCA D903 worked very good without filter, showing that it complies to the narrow bandwidth written on it’s lable (950 to 2050 Mhz). After all RCA is a reputable company.
That likely explains why it only cost me $1.99. I won’t waste my time then.
Well, I was trying a different setup yesterday involving one of these (like the AP20 above).
under-powered by my own bias-T (12Vdc 1A instead of 14-16Vdc) and to my surprise it
almost matched the prostick plus performance (see below)
the setup is canANTenna(*) ← 4m coax RG6 ← LNA ← bias-T → FA filter → nooelec blue 820T2.
(*) now the antenna
I’ve ‘stolen’ one of these from my wife 
(don’t know what is called) and a coil of thick electricity wire.
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There is a possibility my unit was defective.
The other possibility is that it may work ok in combination with a filter.
Since you already have it, no harm trying it when you get a biast. First try without filter, then try with filter. You have FA filter already.
I may give it one chance, one only. 
No way I’ll spend as much time as I spent in the last antenna experiment. My back still hurts.
My third RPi is no longer needed where it was originally deployed. I think I’ll setup a 3rd station.
One more and you have your personal MLAT network 
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I wish it was so. My garage would become the center of the aviation universe. 
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Dont try the amp with the antenna on roof. Try it with a DIY Spider in your garage, and a long coax on floor.
That sounds like a plan. Also, taking a laptop computer to the garage would save me the up/down the stairs to check results.
Yeah, the HAM I got the tower from gave me three 50’ lengths of RG8 with factory PL259s on them. Not knowing any better, I assumed it was better than plain ol’ cable TV coax.
The antenna is now mounted 2’ off of the tower, but at 35’ it was clamped directly to the tower, so I think that’s a non-issue.
I’m not opposed to running another coax line up there - I could use the RG8 for my DYI 1/4 wave ground plane airband antenna.
I may, though, have a hard time spending the $$$ on LMR400 with factory ends - I have bills bills . What I also have is half a spool of RG11 network coax that I could put N connectors on. Any thoughts on the suitability of RG11?
I still might end up needing a LNA, but that also means needing a N-to-F adapter to go from the FA antenna to the LNA, a bias-T and a power supply, all of which I’m not well-versed in (yet). Thankfully, some of you are!
Or I could all-out overkill. I may have a way of aquiring a couple hundred feet of this https://www.commscope.com/catalog/cables/pdf/part/1330/LDF4_5-50.pdf.
Not sure how I’d fit a SMA connector on it, but hey, why not? 
RG 11 signal loss at 1000 mhz is 5.6 db per 100 feet.
LMR 400 signal loss at 1000 mhz is over 4 db and less than 5 DB per 100 feet
So anyone on a budget will try the RG 11 - BUT this issue I think is the connectors and conversions. In your case seeing that money is indeed an object, and the fact that you already have the cable, sounds like the way to go.
But as you have found out the best is an unbroken, unspliced, cable with no conversions and no small itty bitty flexible cables to help make it easier to bend and connect things.
Most cable companies and Satellite companies use scanned cables with crimped on waterproof ends because they work. Then they pump a whole crap load of signal down the wire and then install a distribution amplifier in your house.
Remember the fewer connections and the fewer the conversions the better.
Good luck.
As is was tooling around the net I found a great tool on qsl.net
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LDF4.5-50 is definitely an over-kill, and will lead you into termination problem as well as being mechanically stiffer than other cables, bending and installation will be harder.
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It’s was kind of a joke (kind of). I imagine it would be like using 12-gauge Romex as earbud wires.
I think termination would be a huge problem.
Heliax with N-connectors is pretty much the standard for UHF and higher frequencies when used on a tower. Termination is done on the ground side by having the coax end at an N-connector bulkhead fitting so that no tight turns are needed. The indoor receiver then connects to that bulkhead with short, smaller, more flexible jumpers and coax using BNC, TNC or SMA fittings.
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Not if you have the right tools and experience.
All coax is hard to terminate correctly if you don’t have the correct equipment and the correct technique.
At least with a properly terminated single run of Andrews LDF450 you know that the loss will be slightly less than 3dB per 100 feet.
There are also techniques for dragging a long length of coax up a tower and supporting it appropriately so that the weight of the coax does not fracture the inner conductor.
S
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a friend gave me few meters of this ‘LDF4.5-50’ to try it (he told me mainly is used for transmission antennas). waste of time. used crocodile-clips for connecrtions, the performance was veeerrryyyy loooow. so went back to RG6.
Not to be rude butt: crocodile clips really?
It has nothing to do with the coax you used and all with the connections.
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