I am running ADSBScope through an RTL2832/E4000 based dongle with external 5dBi antenna. I have seen framerates as high 8800 frames/minute.
Question is, if I am able to process this high a framerate, is there any advantage to getting a Mode-S Beast?? My region has multiple ADS-B FR24 tracking locations. Everything that FR24 is showing from the other sites is showing up on my ADSBScope. It seems like I have sufficient processing power. Thoughts?? thx
Ignoring framerates for a moment, what range are you getting and how many aircraft are you receiving?
I'm getting 100nm in 3 quadrants and about 175nm in the fourth quadrant. I routinely see 20-30 aircraft displayed. one number I don't understand is at the bottom of Radarscope. Next to frame rate is a number in brackets. when ADSBScope says 8800 frame rate, the number in brackets might be (140). Would this be frames/sec? thx
Thanks.
Can you post a screen capture of these message rates?
sure. I'm on the road right now but will be able to do so within 48 hours.
so, back to the op, do you think a Mode-S Beast would help me improve rates? Thx
I don't see the value of measuring and comparing frame rates.
What matters is how many aircraft messages are being received and decoded. And in my experience, the antenna location adds most value and my DVB-T dongle compares favourably with the SBS-1/3 and Mode-S Beast on the same antenna.
I'm really not trying to start an argument. I simply want to know if I will see more ADSB aircraft or what is the advantage of running a ModeS Beast, SBS1 or SBS3 over the E4000 dongle.I m currently runnong. given my current ranges and rates. thx
Quote from: thekubiaks on September 17, 2013, 04:25:58 PM
I'm really not trying to start an argument.[/quopte]
Nor am I.
Without knowing where your antenna is positioned and where you're located, I can't tell if you'rer getting the optimum results from your current setup.
In my experience, another receiver may deliver a higher frame rate but that doesn't equate to more aircraft messages.
I repeat, side by side on the same external antenna, the Dongle delivers comparable results to a Beast and other specialist receivers. How long a cheap dongle lasts and whether it comes with technical support is a different topic.
Here are the screenshots you asked for:
My 5dBi antenna by lz2rr is mounted 30 feet above the ground and 10 ft above my chimney but it still doesn't have a completely unobstructed view in all directions.
http://www.ebay.com/itm/190887916388?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
It looks like I got some max range tracks:
SOUTH = 195NM
WEST = 152NM
NORTH = 132NM
EAST = 60 – 110NMse
ADSB Sharp 1.0.11.1, ADSBScope 2.6f3 Win7, FlightRadar24 [T-KLOU3]
Framerate in the 8000's and about 150 frames/sec
Would I get more range if I replace the RTL2832/E4000 with a ModeS Beast, SBS-1, or SBS-3?? Any news on Radarcape??
Thx for the replies.....
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Thanks for the screenshots.
My guess is an SBS-3, Beast or RadarCape could deliver some extra messages and may extend your range marginally.
It really depends what you want to achieve? I doubt you're "missing" local traffic within range of your antenna (check FR24).
The only thing that I can guarantee is that you will be spending a lot more dollars. And you may be disappointed.
Having compared a cheap DVB-T USB stick to all avaliable receivers, I'd have been disappointed if I'd started with a $20 DVB-T and then spent $800 on a replacement to gain a higher frame rate.
For me the data presentation software and database is equally important, as too is receiver reliability. I hear of many DVB-T's failing after a couple of months use.
You can get a lot of $20 DVB-T USB sticks for $800 ( 40 +/-) i have also read that running 2 dongles in tandem with the rtl1090 software improves things too.(not got round to trying it yet)
My beast does pull in more signals especially in bad weather but the difference is not as large as one would expect considering the price difference. Reliability as Anmer mentioned could be a problem but up till now mine are working fine. I did have to send the beast for repair though as the antenna static protection hadn't been installed and blew the amps.
Maybe a preamp might even things, and definately good cable and antenna make a difference.
Yes,
I do have an LNA I am getting ready to hook up. Perhaps this will increase my range somewhat, I'll report back ASAP. ;D
http://lna4all.blogspot.com/
So is the LNA4ALL good for nothing or worth the money?
Reading the comments, I can just said that any DVB-T dongle can have side/side performance with any big bucks ADS-B receiver, of course using the proper setup.
I do have the DVB-T dongle with E-4000 tuner and can get the planes up to 400km radius from my location in Croatia, so up to Munich using just a simple ground plane homebrew antenna.
My location is nothing special, some 260 ASL.
I did measure the sensitivity of the DVB-T dongle with the E-4000 tuner and there is no problem.
The trick is in the filtering...
have fun
Adam
Quote from: kered on September 23, 2013, 10:16:33 AM
You can get a lot of $20 DVB-T USB sticks for $800 ( 40 +/-) i have also read that running 2 dongles in tandem with the rtl1090 software improves things too.(not got round to trying it yet)
My beast does pull in more signals especially in bad weather but the difference is not as large as one would expect considering the price difference. Reliability as Anmer mentioned could be a problem but up till now mine are working fine. I did have to send the beast for repair though as the antenna static protection hadn't been installed and blew the amps.
Maybe a preamp might even things, and definately good cable and antenna make a difference.
I have put up another antenna on the other side of my apartment, linking it to another R820T dongle, and then chaining both dongles to the one computer. A cheap and very effective way of getting improved coverage without spending a fortune.
Stephen
Adam,
How are you filtering?? I just hooked a LNA4ALL up to my E-4000 dongle. I verified that the LNA was pulling the proper current & volts (12.3VDC). My framerate dropped from 8400 to about 1400. My reception ranges dropped by 50%. It was as if the processor was choking on noise??? maybe it was something else but when I took the LNA back out of the system, my framerates and ranges jumped back up to normal. Thanks
Quote from: 9a4qv on September 25, 2013, 03:31:47 PM
So is the LNA4ALL good for nothing or worth the money?
Reading the comments, I can just said that any DVB-T dongle can have side/side performance with any big bucks ADS-B receiver, of course using the proper setup.
I do have the DVB-T dongle with E-4000 tuner and can get the planes up to 400km radius from my location in Croatia, so up to Munich using just a simple ground plane homebrew antenna.
My location is nothing special, some 260 ASL.
I did measure the sensitivity of the DVB-T dongle with the E-4000 tuner and there is no problem.
The trick is in the filtering...
have fun
Adam
Hello,
this is nothing unusual (losing the traffic after inserting the LNA before the DVB-T dongle).
This is why:
I hope that there is some basic RF knowledge which can help understanding and most important resolving the problem.
The main reasons why the dvb-t stick is poor performer is no selectivity (means no filters at all at the input) and bad dynamic range.
The selectivity can be solved with the filters, but the dynamic range is limited by the A/D converter used in the stick, presently 8bits.
The same stick have the problem that saturate very fast.
If there is no filtering, it will saturate because all the strong signals from the gsm base stations, broadcast radio, TV transmitters etc. are saturating the E4000 even not tuned to this frequency, just because there is no filter at the input.
Adding the LNA you saturate the DVB-T even more because the strong signals are amplified even more.
Hot to resolve the problem, without the filter?
First, uncheck the both AGC options.
Decrease the Gain (manually) with the slider to the lowest number.
Start to increase the gain with the slider, of course with the LNA in line.
You will notice that the number of packets increasing.
Proceed and monitor the number of packets increasing.
At one point, approx 3/4 of max slider gain you will notice the drop of the signal!
This is the point where the DVB-T dongle receiver is saturated and the reception is bad.
Decrease the gain just a little bit lower to have good reception.
With the LNA inserted, you shoud have at least 10% better range than without the LNA, so more planes and packets.
If you insert the proper filter in line with the LNA and DVB-T then you can have the maximum gain set on the DVB-T controll, or both AGC checked and there will be no saturation of the DVB-T dongle at all.
This is the setup I have where 400km radius is covered just with the simple ground plane antenna.
Try to do the procedure i explain and give us the feedback, how does it work for you.
Thanks
Adam
Adam,
Thanks for the reply. I went out and ran the LNA with my E4000 R820T as you described. I could see the "choke" point as I moved the gain setting up. I was only able to get about 12dB of gain before my E4000 was saturated. The maximum framerate was about 1500 frames/minute. I took the LNA back out of the system and immediately hooked my antenna up directly as before and framerate shot up to > 6000 frames/minute.
Perhaps I am in a noisy RF area and the LNA is simply amplifying all RF around 1090mhz?? I think the secret might be in the filtering as you mentioned previously. What filter do you recommend? Thanks
*** UPDATE *** I decided to make a 1090mhz band pass filter, I'll report how it works ASAP.... in the meantime, have a look at the first few posts on this thread
http://www.rcgroups.com/forums/showthread.php?t=1758166
Hello,
The notch filter from the link is a good thing, but it does not covering all RF strong signals.
The better approach is to use the bandpass filter as you said.
I do have a very (excellent) quality professional bandpass filter with a low insertion loss and high out of the band attenuation.
I can say that the signals just 100MHz of the 1090 are attenuated for more than 90 dB with sharp skirt so I do not have any problems with the cellular towers running on 960Mhz, and no problems at all from the nearby AN-FPS117 radar running on two channels on 1260Mhz plus two sub radar channels.
The simple filter to build may be this one:
http://www.w6pql.com/microwave_filters.htm
I will make some photos of my setup and will post it here this days.
Adam
SUCCESS !! :) I installed a filter that eliminates most everything below 1090mhz and above about 1500mhz. I looked at it on my spectrum analyzer to verify. My framerate shot to over 13,000 using the filter with the LNA4ALL, WOW, I never had a framerate over 8800. My ranges are farther too, I am getting at least 10 -20% further contacts. So, bottom line is, even if you don't have a LNA4ALL, I think filtering out signals < 1090mhz > is the key.
Look at the big jump in framerate on the second picture.
By the way, the band pass filter from the previous post (RCgroups) wasn't good.
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I am glad that we sort out the problem.
See how easy was to do that 8)
I agree, more important is the good filter than the LNA in case where the cheap DVB-T dongles should be used.
Why is good to use the LNA with the filter and DVB-T dongles?
Well, if you go through the DVB-T tuners datasheet you can notice the quite high noise figure number (from 4-6dB).
This is quite high number.
Adding the losses in the filter before the tuner, this number is even bigger, depending on the losses in the filter.
If you add the LNA before the receiver and the filter, just after the antenna your overall noise figure of the system will be much lower.
You can download free ACAD Agilent RF software to simulate and calculate the gain and the NF of the system.
Adding the LNA will result lower NF and the signals that are buried in the noise will be received with the lower noise figure, means more packets and more plains. This weak signals will not be masked with the higher noise figure (without the LNA) and can be decoded.
So the main purpose of the LNA in the DVB-T setup is not to amplify the signal but to improve the overall nose figure of the system.
Anyway the gain and the sensitivity of the DVB-T dongle is quite good.
JUST USE THE FILTER AND YOU WILL BE FINE ;D
Adam
Just to add, I have the latest lab measurement of the LNA that you are using, reporting NF 0.7dB and gain 17.1dB @ 1296Mhz, so you should have even better figures on 1090MHz
Adam,
Thanks again. I am running Antenna > Hi/Lo pass filters > LNA4ALL > DVB-T > ADSBSharp > ADSBScope. I peaked out today at 17348 frames/min (Double my non-LNA/filter rates and at least 20% range increases, I'm over 175 miles in 3/4 sectors. I think I'll try that w6pql filter you use, it looks nice but I'm not sure I can top my new setup?? maybe I can, you've been right on the money about the filters and noise floor. ;)
Cheers..
btw, what do you think about SAW filters?? I've had good luck with them filtering out GPS signals for my Radio Control hobbies.
=================
Quote from: 9a4qv on September 27, 2013, 10:33:09 PM
I am glad that we sort out the problem.
See how easy was to do that 8)
I agree, more important is the good filter than the LNA in case where the cheap DVB-T dongles should be used.
Why is good to use the LNA with the filter and DVB-T dongles?
Well, if you go through the DVB-T tuners datasheet you can notice the quite high noise figure number (from 4-6dB).
This is quite high number.
Adding the losses in the filter before the tuner, this number is even bigger, depending on the losses in the filter.
If you add the LNA before the receiver and the filter, just after the antenna your overall noise figure of the system will be much lower.
You can download free ACAD Agilent RF software to simulate and calculate the gain and the NF of the system.
Adding the LNA will result lower NF and the signals that are buried in the noise will be received with the lower noise figure, means more packets and more plains. This weak signals will not be masked with the higher noise figure (without the LNA) and can be decoded.
So the main purpose of the LNA in the DVB-T setup is not to amplify the signal but to improve the overall nose figure of the system.
Anyway the gain and the sensitivity of the DVB-T dongle is quite good.
JUST USE THE FILTER AND YOU WILL BE FINE ;D
Adam
Just to add, I have the latest lab measurement of the LNA that you are using, reporting NF 0.7dB and gain 17.1dB @ 1296Mhz, so you should have even better figures on 1090MHz
I am not using the W6PQL filter, I just mention that it is easy to build and good performance for the time/money invested.
I have a professional filter ( 7 pole I think) silver polished...
SAW filter may help a lot, it is true that IL is quite high, but who care, there is the LNA covering the losses in the filter at the end.
SAW is the simple plug and pray option,
Adam
Quote from: 9a4qv on September 28, 2013, 08:17:12 AM
I am not using the W6PQL filter, I just mention that it is easy to build and good performance for the time/money invested.
I have a professional filter ( 7 pole I think) silver polished...
SAW filter may help a lot, it is true that IL is quite high, but who care, there is the LNA covering the losses in the filter at the end.
SAW is the simple plug and pray option,
Adam
Adam,
Can you tell me about your 7 pole filter please? I am interested in building and testing projects like that. By the way, I am peaking at a framerate of about 18,000 frames/min. I'm not sure if that is traffic related or E4000 related. I did try turning the AGC off and manually adjusting gain. Running with Tuner AGC provided highest framerate. Thanks.
If you have a filter inserted then yes, the AGC turned on will give you the best results.
Meantime I check my filter, it is 8 pole filter.
The filter is professional one that I took from the cellular base station running on the 960 Mhz. I do have also the original LNA that goes together with the filter but I am not using that one.
So after my attempt to tune the filter on 1296Mhz I decide to re-tune it on 1090 which gave much better results then on 1296 which is too high for such a filter.
I do not have the design for this filter but this software can help you to construct a really sufficient filter for you.
Just a spectrum analyzer may not be enough to tune the filter properly. Time domain will do the job properly, some network analyzer will be nice.. if you have such a possibility.
Two or three pole filter can be tuned used the method tune to maximum, but more than that it is very difficult and require a lot of practice and lot of time.
check this out:
http://www.vk3um.com/interdigital%20filter.html
Adam
Don't want to go too far off topic, but would the LNA4ALL be any good as a pre-amp for the SBS-3 ?
Strait from the heart, I do not know.
I never check the architecture of the SBS-3 or any other receiver for the ADB-S.
If you have some schematic or block diagram, then i can tell you yes or no. Without it, it is not easy to predict what will be the result.
The LNA4ALL have no problems working with the any receiver, it can be used also like transmitting amplifier producing up to 150mW over all range.
The problem may appear in the receiver itself, too many gain can saturate the receiver. If poor filter or no filter at all, then another problems...
You do not have to spend the big bucks to find out that, use the cheap terrestrial TV antenna amplifier to see the difference. If SBS-3 can handle that, then it will handle most probably LNA4ALL.
Adam
Quote from: 9a4qv on October 02, 2013, 12:13:19 AM
If you have a filter inserted then yes, the AGC turned on will give you the best results.
Meantime I check my filter, it is 8 pole filter.
The filter is professional one that I took from the cellular base station running on the 960 Mhz. I do have also the original LNA that goes together with the filter but I am not using that one.
So after my attempt to tune the filter on 1296Mhz I decide to re-tune it on 1090 which gave much better results then on 1296 which is too high for such a filter.
I do not have the design for this filter but this software can help you to construct a really sufficient filter for you.
Just a spectrum analyzer may not be enough to tune the filter properly. Time domain will do the job properly, some network analyzer will be nice.. if you have such a possibility.
Two or three pole filter can be tuned used the method tune to maximum, but more than that it is very difficult and require a lot of practice and lot of time.
check this out:
http://www.vk3um.com/interdigital%20filter.html
Adam
Adam,
I like that filter, I think I will build it, I have the test equipment to tune it. By the way, my framerate for the E4000/LNA4ALL/filter combo exceeded 21,000 so I still haven't found the upper framerate limit. :)
Regards
Hello,
at the end, I don know what filter you have presently ::)
there is another trick you can try, but this is just if you want to have reception from the sector.
Use some highly directional antenna. I did some test with the 20dB dish antenna with a very interesting results.
Attached my setup with the GP antenna, Filter and LNA4ALL
Adam
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Would be very interest in trying this program. One question I need to know is can it be used to feed BaseStation.
Thanks in advance.
Quote from: Oldfella on October 09, 2024, 07:35:40 AMWould be very interest in trying this program.
What Program?
Sorry Anmer, I thought I was on the ADSB.im discussion page. Will re-ask that question back on that page again
Apologies :D