AirNav Systems Forum
AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: stevebarker12 on May 10, 2009, 09:31:31 AM
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I have installed a proper aerial on my roof (via airbandonline) and it gives good reception for my RB.
It was put up by an installation company and the 10m cable lead down into an upstairs room where my PC & RB are located
I have read that a pre-amp may make it even better - but I don't want to
either go up and install a pre-amp next to the aerial (don't fancy the climb!) or get someone to do it.
My question: is it a waste of time to purchase & install a preamp next to my PC/RB
in my upstairs room? ie is a pre-amp only of benefit if located right next to the aerial.
Advice appreciated
Kind Regards
Steve
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Hi Steve,
You would only be amplifying any loss induced noise at the receiver end of the feeder so an amplifier would be of limited use in this case. If it made any difference at all I would expect it to be minimal.
hth
Chris
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Hi steve. I agree with Chris. You state you have good range so i would leave things as they are. How is your polar diagram range? As a ham (G6XHK) i will not use them in my radio work.Not impressed with the hype. Discussion please.
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Hi Steve
thinking of getting an proper aerial myself got the radarbox from ABOL so thinking of going back for aerial . Can you give me an idea of price and price for installing as i dont fancy going on roof myself (chicken) thanks
Bryn
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Thanks to Chris & ''imropes'' - yes, i suspected as much.
Bryn:
I purchased from airbandonline a 10m cable and an aerial-see attached link
http://www.airbandonline.co.uk/kapl_sbs1_aerial.htm
ie a A HBA-1090 Home Base Aerial
Overall cost ca £110 -not cheap but it made a big difference to my range.
Good advice from airbandonline given.
Installation - I had a normal TV aerial + RB aerial + Airband scanner aerials all installed at same time (3 in total).I bought cable/aerials/stub masts -but not fixings/brackets.
This cost £130 - a rip off if ever there was one. Took them just over 1 hour max.
I live in Preston and towards the top of a hill - but not on top and I have very close tree/houses (we live in a semi).Height & proximity to other obstructions is the main thing
If you go ahead make sure they put the RB aerial separated from other aerials and as high as possible. It would be better if you bought fixings (bracket/aerial cable) yourself like I did -any extra brackets/cable they charge over the odds for (labour really) but its difficult knowing what fixings they need.
Hope this helps
Steve
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Thanks for that Steve i also am in Preston Ribbleton Blackpool Road area so not so far away from you
Thanks again for info
Bryn
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Just a quick follow-up on my question which may be useful to someone - for £40 i decided to buy a preamp and put it next to my RB/PC (my aerial is on roof).
Not expecting it to do much I am quite shocked to find it made a big difference -lots more contacts
What shocked me more was that twiddling with the rb/aerial connectors made a vast difference as well. I read on another post that the internal wire connections to rb can make a big difference - screwing/tightening the nut on the rb makes a big difference as does other aerial/connector contacts.But don't overtighten!
My advice would be to tweak your screw connectors to optimise reception
Steve
Preston
UK
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What shocked me more was that twiddling with the rb/aerial connectors made a vast difference as well. I read on another post that the internal wire connections to rb can make a big difference - screwing/tightening the nut on the rb makes a big difference as does other aerial/connector contacts
If this is the case then IMO you either have poorly fitted plugs/sockets/connectors on your cables....or a dodgy ant socket on the box .
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Yes I'll check this out
Steve
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Hi Steve, as Dave says above this does sound like a dirty or poor connection, but please keep us posted as to what you find, by going back to standard twig only and then with pre-amp - to my mind there is no logical explanation, the pre-amp at the back of the box although boosting desired signal, will subtract its own loss. What amp did you buy - at that price, unless s/h, isn't going to have the very tight filters requires to take out the out of band crap and noise and just retain the 1090 signals.
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After experimentation I have concluded the pre-amp next to the RB/PC does not give
improvement. (**). However, I have stopped further experimentation because I don't want to keep connecting/disconnecting the RB leads.
I suspect the pre amp to RB connectors should not have undue stress put on them by keep disconnecting them. The connections are very sensitive making a big difference to reception - the preamp -rb -connector leads needed to be completley horizontal.
I used a Watson WRP-1300 (25-1300MHz) Pre amp from CPC products Preston which cost £40
** When i connected this preamp to an airband hand held scanner - right next to the scanner in between the radio and small aerial - it DID improve reception - ATC can be heard better (bit more more noise across the scan range which can be removed) so i will be keeping this connected up
Looks like a pre-amp next to the aerial is the only option. I'd recommend to anyone that if they put an aerial up then go the whole hog and pre-amp it as well while your at it
Kind Regards
Steve
Preston
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Any recommedations for radio scanner pre-amps in the sub £60 price range? I was thinking specifically of the Moonraker MRP-2000 MK2 wide band pre-amplifier. Does anyone know if it's worth buying?
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Any recommedations for radio scanner pre-amps in the sub £60 price range? I was thinking specifically of the Moonraker MRP-2000 MK2 wide band pre-amplifier. Does anyone know if it's worth buying?
hi Bethsalem
In my home town a preamp is useless on the air band owing to it being am signal, FM around say 145 mhz to 560 mhz was OK using the preamp, now that's just my home town yours will be different.
all the best pat
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A preamp should always be just below a stub at the antenna! Otherwise you amplify the loss on the cable. The masthead is where the amp should be. Period!!!!
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I have the Elad preamp and it is installed inside the loft midway between the RB and my Radar Extender antenna. It is nice and dry in the loft.
The difference it makes is phenomenal! I live near Leeds at 150 mtrs asl but I am in a bungalow surrounded by houses but with the preamp on I can see aircraft in myFlights across into Belgium, Holland, right down to the south coast of England and up as far as Aberdeen. NI OK but Eire not very good. Without the preamp at least 50% reduction.
I once tried the preamp right next to the RB with quite good results as well.
Terry
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In my humble opinion using the shortest length of the best coax money can buy, using the proper plugs for that cable and paying careful attention to the preparing, soldering, assembling, connecting, waterproofing the joints & running the cable is the biggest single improvement you can make and is far preferable to just sticking a pre-amplifier in-line.
Not quite sure about the earlier definition about amplifying loss on the cable(?) but obviously you cannot amplify a signal that is not there in the first place! ;^)
Although the preamp will probably have narrow bandpass filters on board by definition it cannot differentiate between noise, rfi, signal etc. and so just amplifies everything!
Terry, if you read this can you just share your experience on replacing your original coax with Westflex 103 and the proper connectors?
I know you run a masthead preamplifier (on the original cable also) but yours is a great example of what can be gained by just changing the cable.
I believe your MyFlights roughly doubled? This with just a coax change!
I have had a 1m length of W103 with the proper plugs (£6 each) pre-installed arrive today so intend to fit my Kuhne masthead preamplifier - it is a lot of work to drop my antenna array and it would be much easier to just stick the Kuhne in-line in the loft but it is not called a masthead preamplifier for nothing!
This all assumes you have a good antenna properly mounted and are using the correct preamplifier for your chosen frequency band of course...:-)
Kind regards,
-=Glyn=-
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Hi Glyn,
Yes i replaced the co-axial cable from the pre-amp to the bias tee with Westflex 103 and its an incredible difference over the thin stuff,before i was getting 300-400 A/C on my flights,now my highest number is 689,but its usually around 450-510,plus i`ve pulled in 4 contacts at 297.8nm and i had to re-set the polar diagram as i was a bit dubious on the distance,which was duplicated on the 2nd polar diagram,i have re-set again today and await to see if it will triplicate this.I run 1mtr lead of 103 from the antenna to the pre-amp which is sited just under the ground planes of the antenna,6mtr of 103 from the pre-amp to the bias tee,2ft of thin cable from the bias tee to the RB(this i wiil shortly change to 103).As Glyn rightly says if possible use the best co-axial cable and i think vital,the very best connectors you can afford(i know its expensive but gold plated are superb),and make sure the co-axial is PROPERLY cut,soldered,tight fitting and there`s not a whisker of outer braid anywhere exposed which would or could give a cross contact,at these frequencies even the smallest loss gives a significant reduction in reception.
Regards Terry.
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Terry,
Your attention to detail is creditable but believe me, changing a 2 ft patch lead will not make any decernable difference, assuming connections are good and that the impedence of the cable is 50 Ohms.
For interest I have an outside antenna mounted on the chimney on a bungalow so the aerial is at about 20ft. I run 10m of 103 and then 2m of small coax to the RB. I am surrounded by trees and not particularly in the clear or high up. I can 'see' 100NM radius, have 100-150 flights on My Flights @ 400 Msg/Sec (80). What does the number in brackets mean?
How am I doing??
Jeremy
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Hi,
AirNav told me via email that the number in the brackets is:
its just a way they are processed. The messages are compatcted together for better processing, i.e a lot of messages don't contain usefull data or the same data again.
Terry
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Hi Jeremy,
Sorry i`ve took so long to answer you but i`ve been at Glyns helping him to put a pre-amp on his antenna array.Yes,you are doing a fine job from your location and i take your point on the 2ft patch lead,but i`ll give it a try just to satisfy my curiosity as i used to use 934mhz radio some years ago and found through trials that every little bit helps at the microwave end of the spectrum.
Best Regards Terry.