ABCD567: well, we are not all as clued up as you in terms of antenna construction and, as you said, your freedom to test and experiment makes you an invaluable resource to the rest of us! Wish I could get hold of some of the parts you can get.
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Originally posted by HermanZA View PostABCD567: well, we are not all as clued up as you in terms of antenna construction and, as you said, your freedom to test and experiment makes you an invaluable resource to the rest of us! Wish I could get hold of some of the parts you can get.
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Originally posted by HermanZA View PostAlthough I have about 310 flights per day in my reception area, It's not deemed "busy enough" by any of the networks to invest in hardware for this part of Africa. And with the local currency so pathetic against the US$ / Euro, purchasing is a *very* expensive option. Take listed price times 11 for $ and about times 16 for Euro.
T-Shirt-front.JPGT-Shirt-back.jpg
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Originally posted by 1090 MHz View PostIt's still possible they may want you as part of their enhanced MLAT network, no harm is submitting an application. You may wake up one day to find a box left on your front door step like I did. I also got a nice quality T-Shirt in the box !
[ATTACH=CONFIG]3344[/ATTACH][ATTACH=CONFIG]3345[/ATTACH]
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This looks interesting !
A manufactured for the purpose, active ADS-B antenna, sold on the Mode Beast site so it must be good.
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Originally posted by 1090 MHz View Post.....The Flight Aware box, which I've looked inside, contains a very nice and expensive dual channel Mode-S Beast Mark II radio card ........
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Originally posted by abcd567 View PostIsn't it an over-kill to use such costly equipment for a simple, single fixed frequency, receiving job like ads-b?
It would be good if they had a low cost alternative to send to places where the use of the expensive box can't be justified.
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Originally posted by abcd567 View PostIsn't it an over-kill to use such costly equipment for a simple, single fixed frequency, receiving job like ads-b?
Dongles are usually very broadband devices as they are intended to receive wide TV channels. Professional devices as the Beast have SAW front-end filters and are more selective and therefore more immune against close-in noise.
Dongles have a low sample rate that can only sample the RF spectrum with around the same clock as the Mode-S chips are spaced. Professional devices as the Beast are able to sample at multiple times the chip spacing, so they can much easier detect a packet- Dongles can compensate partly for this disadvantage by doing some digital filtering (interporlation and decimation), though.
Dongles have built in a 7 1/2 Bit linear ADC, therefore a very limited dynamic range that is subject to doughnut effects etc. Professional devices use a logarithmic decoder that has a dynamic range of around 65 dB with the ability to detect strong and weak signals at the same time. The dongles can compensate for some of their little range with a sophisticated AGC, if it is fast enough.
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Originally posted by 1090 MHz View PostSure a $10 DVB-T USB dongle can pick up ADS-B, however it can't compare to a full scale commercial receiver like the Beast.
Dongles are usually very broadband devices as they are intended to receive wide TV channels. Professional devices as the Beast have SAW front-end filters and are more selective and therefore more immune against close-in noise.
Dongles have a low sample rate that can only sample the RF spectrum with around the same clock as the Mode-S chips are spaced. Professional devices as the Beast are able to sample at multiple times the chip spacing, so they can much easier detect a packet- Dongles can compensate partly for this disadvantage by doing some digital filtering (interporlation and decimation), though.
Dongles have built in a 7 1/2 Bit linear ADC, therefore a very limited dynamic range that is subject to doughnut effects etc. Professional devices use a logarithmic decoder that has a dynamic range of around 65 dB with the ability to detect strong and weak signals at the same time. The dongles can compensate for some of their little range with a sophisticated AGC, if it is fast enough.
You are right that Beast is far superior to DVB-T Dongle.
I think I can better explain my view-point by pictures below:
Which weapon will you use to kill the target?
Weapon 1
Fly-swatter.jpg
Weapon 2
Cannon_Fire.jpg
Target
fly.png
.Last edited by abcd567; 2014-02-18, 15:32.
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Originally posted by abcd567 View PostYou have done a good analysis, showing that you have good depth of knowledge about electronics.
You are right that Beast is far superior to DVB-T Dongle.
I think I can better explain my view-point by pictures below:
Which weapon will you use to kill the target?
Weapon 1
[ATTACH=CONFIG]3352[/ATTACH]
Weapon 2
[ATTACH=CONFIG]3353[/ATTACH]
Target
[ATTACH=CONFIG]3356[/ATTACH]
.
I can't afford any of Weapon B, the target is free to multiply exponentially and to win.
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Originally posted by 1090 MHz View PostSure a $10 DVB-T USB dongle can pick up ADS-B, however it can't compare to a full scale commercial receiver like the Beast.
Dongles are usually very broadband devices as they are intended to receive wide TV channels. Professional devices as the Beast have SAW front-end filters and are more selective and therefore more immune against close-in noise.
Dongles have a low sample rate that can only sample the RF spectrum with around the same clock as the Mode-S chips are spaced. Professional devices as the Beast are able to sample at multiple times the chip spacing, so they can much easier detect a packet- Dongles can compensate partly for this disadvantage by doing some digital filtering (interporlation and decimation), though.
Dongles have built in a 7 1/2 Bit linear ADC, therefore a very limited dynamic range that is subject to doughnut effects etc. Professional devices use a logarithmic decoder that has a dynamic range of around 65 dB with the ability to detect strong and weak signals at the same time. The dongles can compensate for some of their little range with a sophisticated AGC, if it is fast enough.
I guess you never tried ADSB#?
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Originally posted by Jarod View PostI guess you never tried ADSB#?
Actually I have never played around with DVB-T USB dongles. I was lucky enough to be given FR24 and Flight Aware radio equipment to host, both of which provide their own Virtual Radar Servers available locally on my LAN. I just installed the Flight Aware radio yesterday and now have both radar scopes running at the same time. I'll provide some more photos later of this dual installation.
FR24-FA.jpgFR24-FA-2.jpgLast edited by 1090 MHz; 2014-02-18, 22:09.
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Originally posted by 1090 MHz View PostActually I have never played around with DVB-T USB dongles. I was lucky enough to be given FR24 and Flight Aware radio equipment to host, both of which provide their own Virtual Radar Servers available locally on my LAN. I just installed the Flight Aware radio yesterday and now have both radar scopes running at the same time. I'll provide some more photos later of this dual installation.
[ATTACH=CONFIG]3359[/ATTACH][ATTACH=CONFIG]3360[/ATTACH]
Sent from my N762 using Tapatalk 2Last edited by abcd567; 2014-02-18, 22:43.
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