Amplifiers to help with long coaxial runs


#1

Hi All,

I have gotten really into using Raspberry Pis’ to track airplanes. We have a hangar at the airport, but, due to placement, we are unable to have power or internet near the Piaware. The run is ~15 meters of cable, but, the performance is hideous relative to when we used the Low Loss Reverse SMA Female → N-Type Male that was 8 meters at home. We experienced a drop of 80-90% on message rate and aircraft.

Do you all recommend any inline amplifiers to help with longer cable runs? We already have the flightaware ADS-B 1090MHz Band-pass SMA Filter which has a built in 20 dB amplifier.

Thanks in advance!


#2

I am not aware of an FA filter with an Amp, other than maybe the flightfeeders.
I use the HAB/Nevis Amps on some of my RPIs.
store.uputronics.com/index.php? … duct_id=50
I have all three, 1090, 1090Ceramic and 978Mhz.

Many have had success with Satellite Amps.


#3

I use an LNA4ALL near the antenna --> coax run to dongle & pi

lna4all.blogspot.co.uk/

Good performance at a decent price and versatile methods of getting voltages to run it.


#4

(1)What type of cable you used to connect the antenna to DVB-T/Raspberry Pi? The various types of cable commonly used are LMR400, LMR240, RG6, and RG58.

I understand the length of cable between antenna and Pi is ~15 meters. Am I right?

(2) Do you use generic DVB-T (black or blue) or Flightaware’s ProStick (orange)?


#5

you mention reverse sma in your post do you definitely have the right connectors on your 15m cable as i am surprised to see that much loss.


#6

we are just finishing up an install with a 30 meter rg6 cable run with a high gain antenna, rg6 satellite tv cable, satellite tv amp at the antenna, DirecTV 21volt power injector, and pro stick. Great range. Removing the amp reduced range. Less stuff is always better if possible.

Have another install with high gain antenna and 20 meters of cable to a pro stick with great coverage

Have others with high gain antenna, amp, 20 meter cable and generic stick and they work great also.

Also have one test spider with amp, 20 meters of cable and generic stick. It also has great coverage.

we always have an amp and injector available when we install. First we try reception without amp. Then. if the range is down, we put the hammer to it with amplification and that fixes the problem.

First thing I would want is the pro stick. It has a 19 db gain, low noise amp built in. Even though it is on the receiver side of the cable, it really improves performance compared to the generic sticks.


#7

There is no FlightAware Filter with built in amplifier.

What cable are you using and what connectors?


#8

Could you give me an example of what kind of amps you use with the DirecTV injector? I’m going to be doing a rig later this month, and want to ensure I’m buying the right stuff.

FlightAware Antenna -> RG6 -> In Line Amp -> DirecTV Power injector -> Flightaware stick Pro. Right order of operations?


#9

Flightaware antenna > adaptor > direct tv-amp (wrapped in self amalgamating tape - against water) > rg6 > voltage injector > pro stick

You might want the discrete FA filter between the antenna and the amp (just check it blocks DC) to prevent amp overload (all wrapped in self amalgamating tape)

all that said - get decent coaxial cable and don’t bother with the antenna amp unless you have a really long downlead.


#10

Any model amp I should be looking for on eBay or Amazon? Most say 18v; worried about frying them. Send any pertinent links.


#11

=> 102$ for 98% of best achievable that would cost more than 1,000$ for 100%


#12

I used an lnb amplifier … it’s designed for 18v.

The amp tommuc mentioned is excellent, it used to cost much more.

I’d still just go with a high quality download and the flight aware receiver stick with built in amplifier & filter … see how you get on


#13

I’ve been using PCT fixed slope in line amp #PCT-SIA-20.

most any amp will work fine. fixed slope means it has 20 db amp at 2150 and 10 db at 950 and around 13 db amp at 1090.

Some do have seal problems so it is a good idea to cover with tape or liquid seal.

Be sure to get the old 21V Directv injectors. The newer models are 28V and can cook the amp after a few months.
Nice thing about the Directv injector is the robust protection they build into them for spurious electrical issues


#14

Are you sure your connectors are good? What pi and dongle are you using?
When I first set up my current system, I was using 15m of quad core RG6. No amps or filters. Now it is in its final configuration I have trimmed the coax down to 7-8m with no noticeable difference in receiving traffic. A few days ago the adapter pigtail for my FA prostick (orange) arrived, that has made the biggest difference with a large increase in positions in the 120Nm - 200+Nm range.