PilotAware

British Forum => General Discussion => Topic started by: Nigel waller on October 29, 2015, 08:11:43 am

Title: Rx Tx antenna seperation
Post by: Nigel waller on October 29, 2015, 08:11:43 am: How far apart do the antenna's need to be could they be next to each other and not cause
interference to each other?

Nigel
Title: Re: Rx Tx antenna seperation
Post by: The Westmorland Flyer on October 29, 2015, 09:00:38 am: For a single PAW there is only one transmitter - the P3i signal via the ARF antenna. There are two receivers though - the P3i signal, again using the ARF antenna and the ADS-B receiver using the smaller antenna connected to the DVB-dongle.

I am nervous of having the antennas too close together although tests seem to have shown that the ADS-B receiver is unaffected. I suspect the reality is that the P3i transmissions are so short that any blocking that does occur has no noticeable effect on ADS-B reception. It is unlikely that the P3i signal is strong enough to damage the DVB dongle, especially if the ADS-B antenna has been cut down to be resonant on 1090MHz.
Title: Re: Rx Tx antenna seperation
Post by: Ian Melville on October 29, 2015, 01:24:06 pm: John, don't forget there is also a WiFi dongle.
Title: Re: Rx Tx antenna seperation
Post by: The Westmorland Flyer on October 30, 2015, 11:17:37 am: Yeah, I thought of that after I'd posted. So yes, two transmitters and four receivers... there really is quite a lot of wirelessy stuff going on isn't there! I think, though, that we can practically ignore any EMC issues with the WiFi system as it is way up there at 2.4GHz. Similarly I'd not expect the P3i transmission to interfere with GPS reception.

869.4MHz Tx and Rx: P3i
1090MHz Rx only: ADS-B
1575MHz Rx only: GPS
2400MHz Tx and Rx: WiFi AP

All rather fast wiggles for me: I tend to do most of my wirelessry between 1.8MHz and 30MHz!
Title: Re: Rx Tx antenna seperation
Post by: rodent0_2 on October 30, 2015, 12:43:41 pm: "All rather fast wiggles for me: I tend to do most of my wirelessry between 1.8MHz and 30MHz"

must be a fellow radio ham ?
Nick.
Title: Re: Rx Tx antenna seperation
Post by: The Westmorland Flyer on October 30, 2015, 01:31:03 pm: G3WGV
There's quite a few of us on this forum!
Title: Re: Rx Tx antenna seperation
Post by: rodent0_2 on October 30, 2015, 01:45:56 pm: G1JJT

The Rodent aka Nick..
Title: Re: Rx Tx antenna seperation
Post by: Paul_Sengupta on October 30, 2015, 04:52:47 pm: G(W)1YJY...
Title: Re: Rx Tx antenna seperation
Post by: sandy on October 30, 2015, 10:06:16 pm: Another...GM4IBI
Title: Re: Rx Tx antenna seperation
Post by: Bill Maxwell on October 31, 2015, 05:19:11 am: Another here, for what it's worth VK7MX
Title: Re: Rx Tx antenna seperation
Post by: Ian Melville on October 31, 2015, 07:24:15 am: Not Ham, but got a City & Guilds Radio C, which I am told is the equivalent to the Uk Amateur Radio exam.
Title: Re: Rx Tx antenna seperation
Post by: Richard W on November 02, 2015, 01:19:44 pm: You are all very bad people :) The last thing I need is another hobby, and you have induced me to look at the RCF Foundation course. It has revived memories of the CCF network in the 'sixties, using a WS12 and an R107.
Title: Re: Rx Tx antenna seperation
Post by: The Westmorland Flyer on November 02, 2015, 01:28:58 pm: Be very afraid ;D. Beyond Foundation lie the Intermediate and Full licenses. And Morse Code. And another very engaging hobby, albeit nowhere near as expensive as flying!
Title: Re: Rx Tx antenna seperation
Post by: tfede on November 02, 2015, 01:41:46 pm: Another one here, IK4YGE :)
Title: Re: Rx Tx antenna seperation
Post by: the_top_pilot on November 02, 2015, 02:02:46 pm: In my latest config with great ADS-B reception and very good P3i coverage my antenna are as close to touching as I can get them separated only by the radius of the small mag base (on the subject of mag base I have broken the magnet out and discarded and 'Hook and Loop' fastened the antenna to the box).