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 Post subject: Giving this another shot...
PostPosted: Sat Mar 04, 2017 3:56 pm 
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djmd808 - FlightAware user avatar

Joined: Wed Jul 08, 2015 5:23 pm
Posts: 46
After more than a year, I'm giving this another go! I had an earlier Pi with a wifi dongle and it constantly required rebooting, so I gave up. Well, 6 months ago I bought a Pi 3-b and yesterday I finally opened it. Loaded up piAware... I'm a ham guy so I threw it on the 144/440 antenna on the roof. I was surprised how well it actually did on an antenna designed for such lower frequencies.

However, today I found a panel mount SO239 down on the bench so I whipped up a 4-radial spider, and put it on top of 32' of military mast. It's pulling in a lot of planes! Mast isn't guyed so if we get any winds I gotta take it down, but I'll figure out something more permanent. It's on a 50' piece of mini-8 with a couple adapters... but I have tons of LMR-400 so I will probably make something more or less custom. I found one adapter to replace two, and gained 15 planes instantly, so I think going up to bigger coax will help too. But some kind of guying will be a must.

Glad to be back!

73!

Dave, K8DJW (Home Airport KLUK)

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 Post subject: Re: Giving this another shot...
PostPosted: Sat Mar 04, 2017 7:24 pm 
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k6rtm - FlightAware user avatar

Joined: Tue Nov 18, 2014 10:18 pm
Posts: 420
Location: Silicon Valley
Going from mini-8 to LMR-400 will make a big difference! (about 8 dB for the 8x and about 2 dB for the LMR-400)

Welcome back

73 de bob k6rtm


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 Post subject: Re: Giving this another shot...
PostPosted: Sun Mar 05, 2017 12:48 pm 
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djmd808 - FlightAware user avatar

Joined: Wed Jul 08, 2015 5:23 pm
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k6rtm wrote:
Going from mini-8 to LMR-400 will make a big difference! (about 8 dB for the 8x and about 2 dB for the LMR-400)

Welcome back

73 de bob k6rtm


Holy moly did that make a difference. I was able to get away with about 10' shorter, but used one less mast section to add a wee bit of stability.

I'm seeing approximately twice as many planes now, and even getting some in the 200+ range. 600+ msg/sec. Woo!!


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 Post subject: Re: Giving this another shot...
PostPosted: Sun Mar 05, 2017 2:50 pm 
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jcinnb - FlightAware user avatar

Joined: Wed Sep 14, 2016 4:40 pm
Posts: 136
That is great. Congrats and welcome back. I did not start until last fall, but the stuff I am using has worked for months with no attention.


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 Post subject: Re: Giving this another shot...
PostPosted: Sun Mar 05, 2017 3:22 pm 
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djmd808 - FlightAware user avatar

Joined: Wed Jul 08, 2015 5:23 pm
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I'm still using the Nooelec SDR. From the reviews on Amazon, it looks like the Flightaware stick is definitely worth the $20??


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 Post subject: Re: Giving this another shot...
PostPosted: Sun Mar 05, 2017 4:40 pm 
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djmd808 - FlightAware user avatar

Joined: Wed Jul 08, 2015 5:23 pm
Posts: 46
Here's my scrappy antenna. I decided to solder the radials on this, cause I could never get the bolts tight enough on the last one.

Don't mind the dirty laptop. It's amazing how much crud the flash shows.... ew.

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 Post subject: Re: Giving this another shot...
PostPosted: Sun Mar 05, 2017 5:35 pm 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
Posts: 2033
Location: Toronto CYYZ
Many hobbyist do not use SO239 connector for making an ADS-B Spider, as it is rated only up to 300 MHz.
Instead they use an N-type Panel mount connector, which is rated for GHz frequencies.
Image . Image


Many users have reported that 8 Legged Spider performs better than 4 legged one.
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 Post subject: Re: Giving this another shot...
PostPosted: Sun Mar 05, 2017 7:57 pm 
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k6rtm - FlightAware user avatar

Joined: Tue Nov 18, 2014 10:18 pm
Posts: 420
Location: Silicon Valley
djmd808 wrote:
I'm still using the Nooelec SDR. From the reviews on Amazon, it looks like the Flightaware stick is definitely worth the $20??



Splurge -- get the pro one with the filter. That will cut out a lot of the off-channel crap.

And add a few more legs on to your spider -- clean the surfaces to get rid of flux and crud, then give it a shot of RTV or other silicone seal, and it will be good outdoors for years. You still have to seal it to the coax, but that's easy.

bob k6rtm


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 Post subject: Re: Giving this another shot...
PostPosted: Sun Mar 05, 2017 10:48 pm 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
Posts: 2033
Location: Toronto CYYZ
k6rtm wrote:
.........
...........
You still have to seal it to the coax, but that's easy.

bob k6rtm


Forum member Jepolch sealed his SO239/PL259 connectors and Coax using Self-Fusing Tape:
Image


Self-Fusing Tape used by Jepolch:
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 Post subject: Re: Giving this another shot...
PostPosted: Mon Mar 06, 2017 9:21 am 
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djmd808 - FlightAware user avatar

Joined: Wed Jul 08, 2015 5:23 pm
Posts: 46
Yeah, this one hasn't been waterproofed yet, and as luck would have it, it rained this morning... hopefully not too much damage done. I wanted to wait until I got it all dialed in before sealing it up.

Regarding the UHF connector... I do understand that 1090 is well above the intended use, but I've got a PL-259 on both ends of the LMR-400 and I feel, at least, that I'm pulling in some respectable numbers. I wonder how much of a difference it actually makes when receiving low-power signals vs. transmitting high power "out of band." I probably will end up with N in the long run, but don't have a means to crimp N at this time, and probably not going to invest in any additional tools. I have a lot of factory crimped LMR-400, mostly 100' lengths though, and would need to cut one end anyway to get it through the 1/4 holes to the ham shack.

Ordered the Pro Stick Plus last night, can't wait to see the results!


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 Post subject: Re: Giving this another shot...
PostPosted: Mon Mar 06, 2017 10:44 am 
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obj - FlightAware user avatar

Joined: Tue Sep 30, 2014 7:14 pm
Posts: 3557
http://www.hamradio.me/connectors/uhf-c ... sults.html suggests that the insertion loss of a SO-239/PL-259 at 1GHz is somewhere between 1dB and 2.5dB
(see http://www.hamradio.me/graphs/connector ... 1_1000.png)


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 Post subject: Re: Giving this another shot...
PostPosted: Mon Mar 06, 2017 11:13 am 
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djmd808 - FlightAware user avatar

Joined: Wed Jul 08, 2015 5:23 pm
Posts: 46
obj wrote:
http://www.hamradio.me/connectors/uhf-connector-test-results.html suggests that the insertion loss of a SO-239/PL-259 at 1GHz is somewhere between 1dB and 2.5dB
(see http://www.hamradio.me/graphs/connector ... 1_1000.png)


Thanks for the link... looks like pretty solid data. I guess the next antenna will be N on the antenna side, and provided I can borrow a crimper, they make Male SMA connectors for LMR-400, and attach directly to the FA stick...


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 Post subject: Re: Giving this another shot...
PostPosted: Mon Mar 06, 2017 11:43 am 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
Posts: 2033
Location: Toronto CYYZ
If you want to use a cable with SMA-male at both ends, use an adaptor "N-male to SMA-female" between cable and "N-female Panel Mount".

Image . Image . Image



The ProStick & Filter both have SMA-female connector, and SMA-male of coax will fit these.

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 Post subject: Re: Giving this another shot...
PostPosted: Tue Mar 07, 2017 6:17 pm 
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jonhawkes2030 - FlightAware user avatar

Joined: Tue Jan 05, 2016 4:15 pm
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Location: NYC
Consider trying the FA filter with the pro stick plus. I may help it urban areas.

Also, optimising the gain can also work wonders for some people.

You may want to give the old dongle a try with dump978.


Last edited by jonhawkes2030 on Tue Mar 07, 2017 6:17 pm, edited 1 time in total.

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 Post subject: Re: Giving this another shot...
PostPosted: Tue Mar 07, 2017 6:17 pm 
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djmd808 - FlightAware user avatar

Joined: Wed Jul 08, 2015 5:23 pm
Posts: 46
Alrighty... luckily the Flightaware Pro Stick Plus came from an in-state Amazon DC, so it got here quickly. I'm thrilled with the results.

I also built a new Raspian SD card, with the Pixel GUI, cause I wanted to display the local dump1090 map on the screen in the hamshack... and, would like to start using that pi more. Anyway, I made the Raspbian SD first, and installed Piaware. Left the old SDR on there to make sure my baseline stayed the same more or less, and it did. Then after a few minutes, I put the FA stick (with the built in filter) on there. My aircraft seen went from 160 to 250. I'm happy!

Gotta say this also, the new SDR allowed me to eliminate 1 adapter. I was going from MMCX to N to SO-239 to the PL259 on the cable. Now I'm going SMA to SO239 to the PL259.

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 Post subject: Re: Giving this another shot...
PostPosted: Wed Mar 08, 2017 5:19 pm 
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djmd808 - FlightAware user avatar

Joined: Wed Jul 08, 2015 5:23 pm
Posts: 46
jonhawkes2030 wrote:
Consider trying the FA filter with the pro stick plus. I may help it urban areas.

Also, optimising the gain can also work wonders for some people.

You may want to give the old dongle a try with dump978.


I'm in a fairly suburban area, about 15 miles outside of the "big city." Not only that, but I am just about in the highest spot in the county, so I have an advantage there. I think I'm gonna leave things alone for a few days. I'm currently seeing 240 aircraft and getting over 1100 msg/s. I could go higher (in 4 foot increments) but that would make my mast a little sketchy.

I need to install dump1090-mutability to have access to the gain, correct?


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 Post subject: Re: Giving this another shot...
PostPosted: Wed Mar 08, 2017 5:26 pm 
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obj - FlightAware user avatar

Joined: Tue Sep 30, 2014 7:14 pm
Posts: 3557
djmd808 wrote:
I need to install dump1090-mutability to have access to the gain, correct?

piaware sdcard images know how to set the gain from a config setting
see https://flightaware.com/adsb/prostick/setup/


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 Post subject: Re: Giving this another shot...
PostPosted: Wed Mar 08, 2017 5:45 pm 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
Posts: 2033
Location: Toronto CYYZ
If you have written Piaware 3.3 image (SD card), the procedure is as follows:

Check Current Gain Setting
Quote:
pi@piaware:~$ sudo piaware-config -show rtlsdr-gain
28.0



Set/Change Gain:
Gain value which takes affect, is in file /boot/piaware-config.txt
Either edit file /boot/piaware-config.txt
OR
Give following command (easier):
Quote:
#set
pi@piaware:~$ sudo piaware-config rtlsdr-gain 32.8
Set rtlsdr-gain to 32.8 in /boot/piaware-config.txt:92

#check
pi@piaware:~$ sudo piaware-config -show rtlsdr-gain
32.8

#For new gain value to take affect, either reboot, or easier, restart dump1090-fa
pi@piaware:~$ sudo systemctl restart dump1090-fa

#finally check gain value set by dump-fa at restart
pi@piaware:~$ sudo systemctl status dump1090-fa -l


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 Post subject: Re: Giving this another shot...
PostPosted: Wed Mar 08, 2017 7:03 pm 
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djmd808 - FlightAware user avatar

Joined: Wed Jul 08, 2015 5:23 pm
Posts: 46
Ah, currently I'm running the latest Raspbian with Piaware installed. I'm getting -10 back as the gain.


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 Post subject: Re: Giving this another shot...
PostPosted: Wed Mar 08, 2017 7:06 pm 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
Posts: 2033
Location: Toronto CYYZ
The above method is applicable if you have written Piaware 3.3 image (SD card) on your microSD Card.

If you have written Raspbian Jessie image on your microSD card, and then installed dump1090-fa and Piaware data feeder, the file /boot/piaware-config.txt will not exist. In this case you have to edit the file /etc/default/dump1090-fa to change gain value

Quote:
pi@raspberrypi:~$ sudo nano /etc/default/dump1090-fa

# Generated automatically by fa_config_generator
# This file will be overwritten on reboot.
DECODER_OPTIONS="--max-range 360"
NET_OPTIONS="--net --net-heartbeat 60 --net-ro-size 1000 --net-ro-interval 1 --net-http-port 0 --net-ri-port 0 --net-ro-port 30002 --net-sbs-port 30003 --net-bi-port 30004,30104"
JSON_OPTIONS="--json-location-accuracy 2"
RECEIVER_OPTIONS="--net-bo-port 30005 --fix --device-index 0 --gain 32.8 --ppm 0"



For new gain value to take affect, either reboot, or easier, restart dump1090-fa
Quote:
pi@raspberrypi:~$ sudo systemctl restart dump1090-fa

#finally check gain value set by dump-fa at restart
pi@raspberrypi:~$ sudo systemctl status dump1090-fa -l


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