Antenna in attic, pi in basement?


#1

I have the fa antenna, I have no power in my attic, but what I do have is a pass through tube from the attic to the basement.
Would I lose too much signal to mount the antenna high in the Attic and run maybe 50 ft of coax to the basement to the pi?

I could run something like power over Ethernet up there but then the temp and accessibility is a concern to have the pi in the Attic.

I could put the dongle up there but I don’t think a 50ft USB cable is an option.

Maybe it isn’t worth it and I should just leave it all in a second story window? I already have too much in this little project so I don’t want to spend a bunch more.


Attic Installation Power
#2

50 feet of a good RG-6 (75 Ohm cable) won’t be too bad, and isn’t that expensive. Low loss 50 Ohm cables such as LMr-400, are more expensive and harder to work with.

Running a long Ethernet cable, such as cat5E, and using POE to power everything in the attic would result in much lower loss between antenna and SDR. POE kits are available for cheap on Amazon – power supply, injector, and pick-off. Many references on these forums; look for 802.3af POE adapters.

If you’re using a quality micro-SD card, temperature in the attic shouldn’t be much of an issue. There’s a built-in command to report cpu temperature; I define it as an alias to make it easier to get to:

alias cputemp=’/opt/vc/bin/vcgencmd measure_temp’

cheers–

bob k6rtm


#3

pretty well inline with Bob

Temp isn’t your biggest problem - I live in the tropics and my roof space never drops below 30C. Just add heatsinks and fan to your Pi.

USB is Spec’d for 5m. I’ve had some devices work over 15m, but many don’t, so 50ft is a bit of an ask. Apart from the data timing (the official, the voltage drop

Using a good quality length of Quad Shield RG6, 50ft will attenuate the signal by 4dB if properly terminated (badly terminated or poor quality cable will be worse).
eg.
belden.com/techdatas/metric/5339Q5.pdf

As you suggest, there is little point improving your antenna position just to loose the improvement in the cable.

A thin extension cable (or POE) allowing you to power the Pi close to the antenna will give you the best performance.

All you have to do now is decide how much the performance increase is worth!

cheers,
ian


#4

AF-compliant PoE Equipment:

Injector TP-Link TL-PoE150S
amazon.com/gp/aw/d/B001PS9E5I

Splitter TP-Link TL-PoE10R
amazon.com/gp/aw/d/B003CFATQK


#5

During 2013 & 2014, when I did not have RPi, I used DVB-T pluged into my Windows Desktop.

The cheap quality RG6 cable between my antenna and DVB-T/Desktop was about 45 feet. I used a Satellite in line amplifier, Model RCA D903, L Band (950 to 2050 MHz), Gain 13-18 dB, and it worked fine. You can see details & photos I posted in Sept 2013 here:

https://forum.planefinder.net/threads/ads-b-diy-antenna.23/#post-221

If you have a Pro Stick, or Pro Stick Plus (which have integral Amplifier), may be you can still manage with 50 feet RG6 without a Satellite Amplifier. I hae not tried it as now my two ProStick+Pi combos are less than 15 feet from antenna.


#6

FWIW, I have the antenna and amp in the attic, PI and receiver in the basement. I’m limited by terrain and LOS blockage more than cable loss over 50’ of LMR-400. I prefer to keep the PI in a conditioned space, but did run the PI+receiver+antenna in the attic in my old house for a year without issue, and that PI 2 lives on 3 years later…


#7

At a buck and change a foot is the lmr400 worth the cost over rg6?

Hopefully 50ft will do it, tough to say, might have to buy 75 just in case


#8

LMR400 Attenuation = 4.1 db/100ft (13.5 db/100mtr) @1000 Mhz, Attenuation for 50 ft = 2.05 dB

LMR240 Attenuation = 8 db/100ft (26.2 db/100mtr) @1000 MHz, Attenuation for 50 ft = 4 dB

RG6 Attenuation = 6.5 db/100ft (21.5 db/100mtr) @1000 MHz, Attenuation for 50 ft = 3.25 dB

IF you have a Pro Stick (or Pro Stic Plus), OR Satellite Amplifier, these have Gain of about 18 dB, which can easily overcome Coax loss for all above types of 50 feet Coax. I dont think it is worth wasting money on LMR.

For initial 1.5 years of this hobby, I have used cheap quality 45 ft RG6 between antenna and DVB-T/Desktop. I purchased a 50 feet coil of RG6 for Canadian $ 6.99 from a Dollar Shop, and with a low cost 18 dB Satellite Amplifier, it worked great. Please see my system’s photos and Maximum Range Plot here: https://forum.planefinder.net/threads/ads-b-diy-antenna.23/#post-221


#9

I have the pro stick plus. I’ll just get a spool of rg6 locally and crimp on some connectors then, thanks.


#10

When you install the 50 ft Coax, you may need to increase your current gain settings by say 3 to 4 dB to cover for coax attenuation. Determine best gain value by trial & error.


#11

When connecting the FA antenna to RJ6, what are the connect adapters? Are these them?

FA antenna to RJ6 cable: amazon.com/female-straight- … B00WQ4QQ06
FA antenna to Satellite in line amplifier: amazon.com/Type-Straight-Ad … B00WQ4QYY4
RJ6 cable to FA stick: amazon.com/Male-Female-Coax … B00BXT9MS8


#12

What does this have to do with my Pro Stick and Pro Stick Plus issue???


#13

Seems you have posted in the wrong thread.

This thread is NOT for your issue “Pro Stick and Pro Stick Plus”. It is for “Antenna in attic, pi in basement?”


#14

I am fully aware of that. The email sent contained:

You are receiving this notification because you are watching the forum,
“ADS-B Flight Tracking” at “FlightAware > Discussions”. This forum has
received a new reply to the topic “Antenna in attic, pi in basement?” since
your last visit. You can use the following link to view the last unread
reply, no more notifications will be sent until you visit the topic.

viewtopic.php?f=21&t=39303&p=208518&e=208518

Instead of the one we are working on which should be:

You are receiving this notification because you are watching the topic,
“Pro Stick and Pro Stick Plus” at “FlightAware > Discussions”. This topic
has received a reply since your last visit. You can use the following link
to view the replies made, no more notifications will be sent until you
visit the topic.

If you want to view the newest post made since your last visit, click the
following link:

discussions.flightaware.com/vie … 5&e=208515

Which remains unresolved.


#15

All three adaptors seem OK.

However, for the last one at Pro Stick end (F-female to SMA-male), I will recommend a pigtail instead of solid adaptor. The pigtail will reduce mechanical force on Pro Stick due to heavy RG6.

https://www.amazon.ca/gp/aw/d/B01N7FLAXV

https://images-na.ssl-images-amazon.com/images/I/41-ULqLkemL.SY400.jpg
.


#16

Changed my mind. It’s cheaper to use Poe and just put it all in the Attic than buy the adapters


#17

Unless you KNOW how to do connectors for GHz signals PROPERLY, buy it with connectors properly installed.

You will save yourself a world of hurt.

–bob k6rtm


#18

Good advice, thx


#19

90 today and the pi is running 76c in the Attic with no fan, just heatsinks. But it’s running. Good reception in the Attic.


#20

That is more or less my setup. The Pi (Flightfeeder) is in the server room downstairs and antenna in attic. I can’t recall how long the cable is, it’s one of the predefined lengths when you order the Flightfeeder. I think it’s like 10 or 15m or something. I can pickup planes from over 200miles depending on direction. Not all directions are equal.

Another option is to run POE to where the attic hatch is, put the Pi there, then have coax go to the attic. I just have a small piece of conduit that penitrates the ceiling and is taped up good to the vapour barrier, and then passed wiring for various things up there and then shove a plastic bag to seal the pipe half decently.