AirNav Systems Forum
AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: covernotes on January 25, 2010, 01:09:43 PM
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Hi All,
I have had my AirNav Radarbox for less than two weeks.
I am situated in Melbourne Australia.
The supplied antenna has been comfortably been receiving aircraft in a radius of up to 40 nm
Today I made and installed the 1090 Mhz ADS-B Vertical Antenna (10/08/2006).
I have been very disappointed with the results.
It has only increased my catchment by approx 25% to a radius of 50nm extending to 70nm due south over Port Phillip Bay.
I have attached pictures of its construction. Any clues where I have gone wrong or how I can improve its range.
http://img200.imageshack.us/img200/3553/aerial007.jpg
http://img59.imageshack.us/img59/5025/aerial008.jpg
http://img686.imageshack.us/img686/4458/aerial010.jpg
http://img402.imageshack.us/img402/7271/aerial019.jpg
Many thanks......
Covernotes (Melbourne)
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Hi Covernotes,
When you used your standard antenna, did you have it on the roof as well? Losses in the antenna cable at 1090MHz can be significant, so if you are running a long cable, you could easily be reducing the advantage of having the antenna up high.
The standard RB antenna is actually very good. I see aircraft out to 150 miles with the standard antenna in the window ledge of a third floor building. I'm surprised that you were only getting 40 miles before.
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Test for a short across the coax plug into the RB to make sure the coax and fly lead is OK. It should be open. Connection into RB ok?
J.
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Hi,
Dont know if you should maybe get your box checked. When we started out we used the standard antenna on our ground floor windowsill and got around 200 nm, sometimes more. This was obviously in the direction the window was pointing but the other side of the house was 50nm or more.
Claire
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Hi,
Dont know if you should maybe get your box checked. When we started out we used the standard antenna on our ground floor windowsill and got around 200 nm, sometimes more. This was obviously in the direction the window was pointing but the other side of the house was 50nm or more.
Claire
Depends where/how he installed his original antenna. If it was inside or on the end of a long cable, he would have been lucky to get much more than 40 miles!
Of course it does depend just what traffic is around too!
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Interested in testing my setup as I only get approx 100 miles in range. Thru necessity I am some distance from my aerial by have used a very low loss coax cable.
Now this is academic for my as I'm only interested in what I can see from my vantage point and 100m around does give me ample warning. But would like to know if the are simple tests I can perform to see it my setup is losing signal.
Thanks
Graham
PS complete novice to this side of things so explainations may have to be fairly basic ;-)
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Graham,
Very easy - install RB on a laptop and take it out in the open along with your RB and the standard antenna.
I was somewhat distressed to see that I could get better range with the standard RB antenna on the roof of the car out in the open away from buildings - than I can from my external antenna mounted 30 feet higher than the roof of the car. This can only be due to cable losses I guess.
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mmm. I'll try but lots of houses around so unless I can get on the roof not sure I can get a good enough replica of the potential field of view. Still when the weather warms up maybe I'll try from the car roof ;-)
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Hi Covernotes,
I notice you used a PL259 fitting on your antenna,personally i would have used an "N" type as PL269s are not very efficient at high frequencies.Also i noted the 2 loops at the bottom of the antenna and into your house,by using just 1-4" bend at the gable end you will be able to reduce your co-axial length by about a metre,Also try not loop the co-axial on itself as this too may have an adverse effect.
Best Regards Terry.
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Thank you all for your advice.
I will take it all onboard.
The supplied RB antenna was ever only used inside on a window sill.
The only antenna that has been on the roof is the new home brew.
I was unable to source 3.0mm copper wire in Australia.
I used 2.5mm copper wire that is used in car starter motors.
Is this measurement critical.
Things to do - Shorten the co-ax run-in by 20%.
Get on the roof top with a laptop and test the home brew on a short lead-in.
Also test the RB supplied antenna on the roof.
Try out a commercial ground plane collinear antenna. (N Socket) (for comparison)
Can anyone help me with a schematic of a simple pre-amplifer for 1090 mhz.
Any advice where one could be purchased cheaply.
I am open to any other advice that anyone wishes to give.
Thank you all again...
Covernotes (Melbourne)
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I built a homebrew 9dB gain collinear antenna similiar to the commercial DPD. It consists of 10 1/2wave sections of coax. It is discussed here:
http://www.airnavsystems.com/forum/index.php?topic=3995.0 (http://www.airnavsystems.com/forum/index.php?topic=3995.0)
It works very well and I get aircraft out to about 220 nm. I have it on a tower at 30 ft and fed it with very low loss LMR coax.
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The standard RB antenna is actually very good. I see aircraft out to 150 miles with the standard antenna in the window ledge of a third floor building. I'm surprised that you were only getting 40 miles before.
I couldn't agree more with you Allocator. Also your point about sticking it on a car roof serves to emphasise the "eccentricity" of aerial reception.
Like most I have experimented with different aerials, different cables and different positions and after a year's effort would offer the following advice:
Signal loss from aerial cable is considerable but there is no loss from USB cables. Replacing 12 metres of antenna cable with a 12 metre USB and moving my box away from the PC but close to the aerial totally transformed my expectations. Do you need to get at the box? If not, then bung it up near the aerial and cut out as much antenna cable as possible.
For indoor & loft use I have found that the supplied antenna is as good as, in fact better than, any of three "specialist" (expensive) antennas I have tried.
Position is clearly everything but it's seems to me to be a black art. For reasons I cannot explain, distances as little as a foot (or less!) seem to make vast - and I mean vast - differences. My supplied aerial is now perched on top of large round metal biscuit tin as high as possible in the loft. One would have thought dead centre would be best? Forget it. It is not placed centrally lengthways, but 3/4 of the length and is also a touch off-centre widthways.
It took a couple of weeks of trial and error to get it exactly right and as a result MyFlights have risen to 90/120 - an astounding figure considering that my virtually sea-level site is amid other houses and all previous efforts suggested 50/60 would be absolute maximum.
My Loft is now locked shut!
Good luck covernotes- it's worth persevering.
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Hi Covernotes
I build two of this antennas and both works fine. (better than Wimo)
Receiving 240 NM from clear line of sight areas.
The first thing i noticed from your pictures is that You used a VHF coax connector... The right thing would be to use a UHF connector Type N.
Tell me please what coax cable did you used and how long running it is.
It needs to be a low loss cable suitable for UHF frequencies, and preferrable not exeding 10 meters...
Also the antenna needs to have a clear line og sight to horizon in all diections (very seldom possible)
Cheers
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Hi covernotes, I have that same antenna as you and I can receive almost to the NSW / VIC border - I live in Burnie,Tas ......beyond 250nm
http://www.users.on.net/~silver.eagle/ADS-B.html
I have 10 mtrs of heliax attached - I used a "N" type connector
Dimensions need to be exact to the 1mm , so you might need to try trimming / extending the top section 1 mm at a time, then try it for a day or so.
Unfortunately building antennas blindly at these freqs without test gear is purely hit and miss (in my experience) . Also try to use a single length of coax - no adaptors or joiners as these introduce huge losses
Keep at it
Mike
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Thank you one and all.
Clambered up on the roof with a laptop only to find that the pin in the SMA connector had disappeared.
That was before I attached it to the RB.
It does not appear to be in the RB as the RB antenna still attaches smoothly.
I have done all the wrong things.
20 metres of cheap co-ax cable, lots of adapters and I did not use an N connector in the construction of the antenna.
I plan to rebuild the antenna using an N connector (no adapters)
Also will use 15 metres of LMR 400 low loss cable.
The question I ask is will the the loss from this run of cable still be too much.
Mike from Burnie is an inspiration.
I will listen to any further advice that may be offered.
Covernotes.
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The case of the disappearing pin has been mentioned before. The pin sometimes goes back into the cable and all you need to do is push it out
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Hi Covernotes, 20 mtrs is a huge run of coax, you will get lots of loss even with good coax. Try to get your antenna as close to your shack as possible, as long as it is in the clear - ie it is clear of the roof and any nearby objects. Any extra height requires more coax and more loss. So the small amount of extra distance you get with height will be lost in more coax. One thing you could do is move your radarbox up into the roof space and run shorter coax through the roof. Then use a usb extension back to your computer, there is no loss in the usb cable. I am testing another antenna, its a 1/4 wave (65mm) on an aluminium groundplane, I can get over 100nm with it and it has 6 mtrs of rg58cu coax
Good luck
Mike
Burnie, Tasmania
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These are just the circumstances where a 1090 pre-amp (eg Kuhne or Elad) could be of great advantage!!
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Thanks Mike
Your solution appears the best way for me to go.
After the antenna rebuild I will give it a go.
There is certainly nothing wrong with the RB.
Took it out into the back garden with the supplied
RB antenna and it immediately picked up an
aircraft at 88.3 nm.
I was holding the RB in one hand and the RB antenna
in the other.
Cheers
Covernotes.
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Hi Mike,
Have followed your advice.
Made up a usb extension back to the computer.
Maybe 15 metres.
Getting the following message on my computer-
USB Device Not Recognised.
One of the USB devices attached to this computer has malfunctioned and windows does not recognise it.
For assistance in solving this problem, click the message.
The clicking did me no good.
Is the computer too far away from the RB?
Is the RB not getting enough power from the computer? (through 15 metres of usb extension).
Setup the RB again with the RB antenna near the computer and it works fine to 40 nm. (Inside house, RB antenna on the window sill)
Any solutions or ideas from anyone?
Cheers
Covernotes.
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Did you say you "made up a usb extension" ??
Or did you use a commercially made one. If the former, I would check that its wired correctly. You could also test it with another usb device - eg thumbdrive
Mike
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You need an active USB cable like this: (similar to what I'm using)
http://cgi.ebay.co.uk/10M-USB-2-0-EXTENSION-ACTIVE-REPEATER-CABLE-10-METRE_W0QQitemZ270517645397QQcmdZViewItemQQptZUK_Computing_USB_Cables?hash=item3efc1bb055
or longer. I've seen (but not used) 20mtr advertised.
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Hi Mike,
Have followed your advice.
Made up a usb extension back to the computer.
Maybe 15 metres.
Getting the following message on my computer-
USB Device Not Recognised.
One of the USB devices attached to this computer has malfunctioned and windows does not recognise it.
For assistance in solving this problem, click the message.
The clicking did me no good.
Is the computer too far away from the RB?
Is the RB not getting enough power from the computer? (through 15 metres of usb extension).
Setup the RB again with the RB antenna near the computer and it works fine to 40 nm. (Inside house, RB antenna on the window sill)
Any solutions or ideas from anyone?
Cheers
Covernotes.
Maximum length of a USB cable is normally 5m - see the link below:
http://www.usb.org/about/faq/ans5
I use a CAT5 USB extension similar to this:
http://www.lindy.co.uk/usb-extension-cat5-usb-extender-premium-up-to-50m/42801.html
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I can thoroughly recommend this one!
http://www.lindy.co.uk/12m-usb-2-active-extension-pro-4-port-hub/42783.html
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I'm currently running a twelve metre USB cable, incorporating 5 mtr of active cable.
No problems whatsoever.
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Alternative is a USB-server, a usb2tcpip interface.
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I have a 5 mtr normal usb extension cable and it works fine with ANRB connected to my laptop
Mike
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Its good to know that USB 1.1 extenders work with ANRB.
A mate of mine is looking at extending his 50m so I will
try USB 1.1 extenders as yours seems to work ok
Paul
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Hi Covernotes, just a few words of advice re antennas for 1090Mhz. All the info passed on to you is correct. However, with a bit of care may of the losses in feeders can be overcome. I`ve been messing with the following idea - see attachment for result. I`m using 45 feet of best quality satellite coax - yes i know, it`s 75 ohms and the purists may howl a bit but as a standby it does work. I havn`t bothered with connectors and have spliced the feeder to the box and antenna which is the standard curlywhirly supplied - no preamp. A word of warning about splicing. The majority of good quality satellite coax is sheathed in aluminium so will not solder. Strip a good amount off both ends to be connected. Solder the inner and cover the joint with an inuslator then fluff the shields together and bind tightly. If done correctly the losses in comparison with connectors are minimal - i can hear the purists howl again but as a standby it works. The attached picture is a four day polar diagram. I operate as a radio ham on 23 cems - 1296Mhz - and wouldn`t dream of using the splice system on anything connected to a transmitter but for the Radarbox..........., proof ot the pudding is in the eating so they say. Experiment! Bi now, Roger PS, antenna is at 30 feet and the only clear sight to the horizon is NE to SE
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I wish to thank everyone for their advice.
I have not been on or in the roof for the last 2 days as it has been 100+ in Melbourne.
Plan A. A disaster.
Plan B. Rebuild antenna with N connector. (Padded bag arrived from the UK today empty. The case of 2 missing N panel sockets.) Add another weeks delay.
2 metres of LMR400cable from the antenna into the roof connecting with the RB.
3, 5 metre active USB 2.0 extension/repeater cables to the computer.
Plan C. Incorporate 2 powered USB hubs.
PlanD. Go with g0sengs setup.
Maybe if Plan B fails I will go straight to Plan D.
g0sengs post is very impressive.
I will cool my heels for a week, wait for the N panel connectors and hope for cooler weather.
Any thoughts on my plan of actions.
Covernotes (Melbourne)
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Hi again Covernotes. Don`t sound so fed up - mind you, we all go through the `gloom` stage thinking the box has gone wappy etc. If i was closer, i`d give you the ruddy cable to get you operational!! All you`re risking is a few bob for whatever satellite cable you can get hold of and cutting the supplied feeder cable for the aerial in half - that`s about it! In other words, unless you make a complete bobo of soldering the ruddy thing together it will not fail! Keep the feeder as short as possible and as high as you can get - the picture you sent of the installation of the one you made seems fine for height. One word of warning. When you solder the centre conductors together ensure it is NOT plugged into the radarbox or computer - DO NOT FORGET! Tell you what, if it doesn`t work i`ll buy you a new curlywhirly - how`s that! Bi now and give it a go! Roger - By the way, i`m knocking 70 so you have to take into consideration i might be totally gaga but i ain`t - i think!!
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Hi Covernotes, the attached picture is titled spot the curlywhirly! I`ve put them up where they usually are - always temporary as i`m forever pratting about with them hence the grubby look. You can clearly see the transition between the antenna coax and the satellite cable. The one with the Roses sweet box lid grounplane is a homebuild and that`s the one in use at the moment. It`s temporarily mounted on one of the groundplanes of the 2metre antenna but that one`s only used for receive airband. The other antennas for 6/2/70 are on the roof of the house. The antenna at the top of the mast is for 23 cems - 1296Mhz. Don`t forget to spray the antenna with something to protect it or it wont last very long - i use stuff called `Dampstart` - you can use ordinary varnish spray as a last resort. Good luck- wish i had your weather at the moment. Well below freezing here and we`ve got light snow again. Lived in Cyprus for years in the RAF and we had temperatures like yours - ah, turn back the clock! Bi now, Roger
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Inspirational stuff g0seng,
What type of satellite cable would you recommend on the curlywhirly?
I wonder whether the signal would be degraded if it was housed in a 13-14 inch length of 50mm PVC pipe with a PVC cap on the top?
Then mount it on a 5 inch diameter ground plan cut from an old aluminum pizza (as in food) dish?
The hot weather....no no no no.
Last year we got one day of 120 degrees.
Then we had the big fires with a massive loss of life.
Global warming should be called global warning.
I hope someone is listening.
Cheers
Covernotes Melbourne.
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Morning Covernotes. As for putting the curlywhirly in a pipe, well, i don`t know if the stuff is RF transparent - you`ll have to experiment with that one. As for the groundplane, no, it must be ferrous or you won`t get the magnet to stick. Any tin lid will do for a start as long as it`s a reasonable size but it`s not critical. Main thing is to get you operational and then you can experiment. As for the feeder, ask for the best available but use as little of it as possible. I paid 17 UK pounds for 100 metres of the stuff and although it`s not the best it does the job. Actually, i`ve been given some of the best available but havn`t got round to testing yet - we`ve got snow! As for the weather, your point taken but spent years in the warm and at my age it makes the difference. I`m very wary of this global warming business - tend to think of it as a natural phenomena/cycle. Average volcanic eruption produces more output in a day than man does in a year so i`m told - although we do get an increase in global temperatures before an ice age - and we`re due one! Bi now, have a good day. Roger, frozen Pontefract.
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I put both my radar box and the computer up on the loft , and running VncWiever to access the computer. Works great and i can check my RadarBox screen from ewery remote site (including cellular phone).
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Update on the antenna installation. The antenna (same as previous) now has an N type panel connector insitu. 3 metres of LMR400 cable from the antenna (mast head) to the RB (now situated inside the roof) 15 metres of USB cable through the roof and down to the computer. The result. 200 nm plus. From Melbourne across the border into New South Wales and also South Australia. Picking aircraft up both taking off and landing on the tarmac at Melbourne Airport. I just hope the RB can weather the Australian Summer heat in the roof. Cheers Covernotes Melbourne.
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Hi Covernotes, glad to hear that all is well now - bet you`re glad to have stuck it out. Regards, Roger
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Hi Roger, Thank you for your thoughts. Yes, I feel much happier with the result now. Though, I guess in a week or two I may well be trying to increase the antenna's performance. Regards Covernotes.
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Hi Covernotes, thanks for reply. Take it from me, you`ll spend the rest of your life trying to increase range etc - same in amateur radio actually - and nearly all radio hams are dedicated `got to do better` men. Bi now, Roger
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Hi all...In the search of the holy grail I decided to try for even better performance than I was currently getting from my home brew vertical antenna. (http://www.tech-software.net/). Not that I should complain. The home brew constantly had a range of 225 nm and constantly placed aircraft 200 feet above the runways at Melbourne Airport (YMML). I live 13.5 nm SE of Melbourne Airport.
I opted for a commercial antenna (to remain unnamed) My overall range immediately dropped by 50 nm. I immediately lost aircraft well out from Melbourne Airport, still over 1000 feet in altitude.
Needless to say the home brew antenna will be returning to its rightful position on the roof. I plan to elevate the home brew antenna another three metres and place the RB in a suitable weatherproof box on the mast.
Any advice on a suitable weatherproof box.
Cheers from Melbourne Australia, Covernotes.
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Hi to all.....Still in search of the holy grail. Have just roof tested the Radarama Trans-1090 Base 1090 MHz Aircraft Transponder Antenna. A real cheapy from Rocket Radio in the UK. Value for money, this is an absolute boomer. Effortlessly picking up aircraft 225nm distance. An added plus is that it is small in size and very unintrusive. I am still trying to source a masthead box suitable to house the RB. Any help would be greatly appreciated. Cheers from Covernotes, Melbourne, Australia.
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Hi all,
I am Renald from Malta and I am having the same problem that covernotes was experiencing. The only building screening I have is the church that is about 200 meters away from my home. My Airnav standard antenna is on the roof about 30 feet from ground level. The tracking is not very satisfactory about 50nm round. I saw the link posted at the very begining (http://www.nodomainname.co.uk/Omnicolinear/2-4collinear.htm). I am thinking of doing one like this. Do I need a pre-amp? and another question, What is the best that I connect an adapter to the Ntype female to sma and then run with an sma cable or run with a uhf cable(what is the best type?) and then an adapter to sma straight in to the radarbox?
thanks renald
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Hi Renigade,
I made several of the project you posted the link, obviosly calculated for 1090 MHz.
The best performance was achieved with 8 and 10 dipoles.
This works very well and does not need preamp. Recommended not tu use more than 12 meters low loss cable.
Screen-shots from two Rbs using the aforementioned antennae :
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thanks :) i will try to do one and let you know with the reuslts obtained.
cheers
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Hello Renigade
I've had my radarbox for nearly a month.
As covernotes did I made the 1090 Mhz ADS-B Vertical Antenna (10/08/2006) too and temp mounted it to try it out. It's only fed with RG6 and patch leads ATM. I'm using a Jim M-75 pre-amp to compensate for the loss in the cable but it works well as shown in the polar image.
Just bought a BS1105 antenna but it's not going up until the cable arrives which is 7 metres of LMR400.
The homebrew antenna works well good quality cable is important (low loss)
Steve
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I am still trying to source a masthead box suitable to house the RB. Any help would be greatly appreciated. Cheers from Covernotes, Melbourne, Australia.
Jaycar.
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hi all,
I was experimenting with the standard antenna, and i found that if I increase the height with about 10 feet (about 40 feet from the ground) I will cover most of sicily from malta!! When i was experimenting I saw aircraft taking off from LICC and LICZ from LMML(Malta). I bought 5 meters of sma extension and I will locate the airnav outside under the pipe i'm installing and then I will use the cat5 usb extender. Do you think that 5 meters of sma extension and the 2.5 or 2 meter standard lenght od the antenna will be too much ??? do you think it will lose signal?
Thanks to all