antenna placing

Blackthorn · November 12, 2008, 06:34:08 PM

Hi Tom

Well some people have all the luck, clear skies and a WB57 on the same day!!!

I am not sure about using a patch lead because of introducing loss in to the cable. Back in the days of my SBS I paid to have the Kinetic antenna installed on the roof and that resulted in little improvement over my loft setup so I am relectant to throw too much money in to antennas.

Kevin

tarbat · November 12, 2008, 07:02:37 PM

Worth considering a pre-amp if your antenna is in the loft. Mine's been running in the loft for a few weeks now with a pre-amp, and I've now seen 100% improvement in coverage over the standard antenna without a pre-amp.

See previous thread - http://www.airnavsystems.com/forum/index.php?topic=1302.msg10765#msg10765

RodBearden · November 12, 2008, 07:23:32 PM

Tom - it's here: http://www.airnavsystems.com/forum/index.php?topic=543.0

Rod

mdobuk21 · November 12, 2008, 08:20:30 PM

hi antenna reception was shocking in the loft wih only 34 flights in mylog! from 12am to 7:45am!

Mark

Blackthorn · November 12, 2008, 09:55:10 PM

Thats a shame Mark but it was worth trying, I am currently tracking 72 in myflights.

viking9 · November 12, 2008, 10:55:20 PM

Quote from: Blackthorn on November 12, 2008, 06:34:08 PM
Hi Tom

Well some people have all the luck, clear skies and a WB57 on the same day!!!

I am not sure about using a patch lead because of introducing loss in to the cable. Back in the days of my SBS I paid to have the Kinetic antenna installed on the roof and that resulted in little improvement over my loft setup so I am relectant to throw too much money in to antennas.

Kevin

Luck! Luck didn't come into it Kevin. I've spent at least ten days in total waiting at the Hall for that aircraft to show up. I was lucky with the weather though. I've posted a couple of the pics in the 'Interesting Aircraft' thread.

Regarding the patch cable, I was only suggesting a short length, perhaps a couple of metres, to allow you to get a bit more height. As a former radio ham I know all about losses in cables. I've found that to have any improvement from the Radar 100 vertical which has a 6 dB gain at 1090 MHz, over the supplied whip, I have to keep the cable length down to 3 metres. Testing it yesterday I was getting between 190 and 205 messages/second as opposed to 75/120 with the whip.

Tom

Blackthorn · November 13, 2008, 06:58:28 PM

Tom, when you get sunshine and a rare aircraft at the same time thats luck in the UK ;-)

Kevin

CoastGuardJon · November 13, 2008, 08:25:46 PM

Quote from: viking9 on November 12, 2008, 10:55:20 PMAs a former radio ham I know all about losses in cables. I've found that to have any improvement from the Radar 100 vertical which has a 6 dB gain at 1090 MHz, over the supplied whip, I have to keep the cable length down to 3 metres.

Hi Tom, I have to ask, what cable are you referring to, to get such losses, could there be a poor connection somewhere?

viking9 · November 14, 2008, 05:41:10 PM

The cable is RG58/5mm. The loss per 10M @ 100MHZ is around 1.5 dBd. I've no idea what it is at 1090 MHz.

Tom

CoastGuardJon · November 14, 2008, 07:37:41 PM

Hi Tom, I've had a dig around, this is the spec. for Maplin's RG58

A screened RF cable having a stranded core 17/0·19mm tinned copper conductor with a solid polyethylene insulator and a braided copper screen.Sheathed overall in black PVC.

Back to Top
Technical Specification

Specifications:
Overall diameter: 5mm
Centre conductor: 17/019mm
Nominal impedance: 50?
Attenuation per 10m: 2dB at 100MHz
76dB at 1000MHz

I must admit I'm astonished that the losses are that high, from what I remember 3db loss = 50% reduction of signal?

CAM · November 14, 2008, 09:10:29 PM

I have recently moved my aerial and box into the loft, using a USB extender. My flights have increased from an average of 30 to aroud 70.

I have only really moved the antena about another 6 foot up but the increase is amazing.(Plus there is another 4 foot to go, after some DIY)

I can now receive flight at high altitude over north London & south Wales.

Not bad for only £20.00, well worth a try.

Cam

Tailwinds · November 27, 2008, 08:46:19 PM

Quote from: Blackthorn on November 11, 2008, 10:47:52 PM

The roof tiles do not obstruct my reception only the house next door

Try it, you may be surprised.

Well I did. Crikey! I'm amazed. I'm using the supplied ANRB antenna and I placed it in the loft almost to the apex. I drilled a little hole in the bedroom ceiling for the antenna cable to go through and my Radar box is right up near the ceiling on a little shelf. My reception has improved a great deal. I now pick up a regular 80/100 in "My Flights" whereas before, when it was on the upstairs bedroom window cill, I was only getting approx 30/45 in "My Flights".
I thought that the roof tiles would block out the signals but surprisingly they haven't.

Blackthorn · November 27, 2008, 10:34:23 PM

Hi Tailwinds

I am glad someone else has the same success as me using just the whip antenna in the loft.

Kevin

nbquidditch · November 28, 2008, 09:05:58 AM

I'm glad I live on a narrowboat! The boat is steel hull so I simply mount the antenna directly onto the roof. I can see as far East as the Wash and right down to the South Coast and North as far as Blackpool form my position on the canal. I'm almost smack in the centre of England & right on the flight path's for Coventry, Birmingham & East Midlands! I'm getting over 1000 flights a day:)

NBQuidditch