Nearer of further....location of underbelly antennas

[CliveJ]

Hi folks, I'm installing proper antennas under the belly of my aircraft and have an option as to which of the two goes nearer the plane's TXP antenna, this is mounted off to one side so using the same position for the transmit and receive one will be nearer the TXP antenna than the other, which is best where?

Thanks, Clive

[PaulSS]

From similar questions I've asked in the past, it would seem you are best mounting the ADSB antenna as far away as you can from the transponder antenna. This is because the transponder will be transmitting and receiving on 1090MHz and your poor ADSB antenna (receiving on 1090MHz) is going to get its ears blasted by a transmitting transponder.

[exfirepro]

Hi Clive,

It is always good practice to try to maintain as much separation as possible between any antennas, though this has to be balanced against the space available and the downside of using excessively long coaxial cables. Based on practical tests which I carried out over the past year with external antennas under the pod of my flexwing, however, I certainly support Paul’s recommendation to keep the PAW 1090 Receive antenna as far away from your transponder antenna as is reasonably practicable.

Let us know how you get on.

Best Regards

Peter

[CliveJ]

That was my thinking too but thought maybe the filtering would handle it and maybe the transmit would be better further away from the TXP.
I'll go the way suggested above and see how it works.

The other challenge is the finding the SMA connection with the pin in the right end, female/male with pin or socket, trying to figure the terminology to get the right one, anyone know how to differentiate? Currently going by the pictures....

Just back from the airfield and brought everything back except the PA transmit antenna, can anyone tell me is the pin in the antenna or in the unit?

regards, Clive

[exfirepro]

Hi again Clive,

The SMA connectors used by PilotAware are all ‘Standard SMA’ - i.e. the ‘female’ has the external thread for attachment of the ‘Male nut’ and a recessed ‘receptor’ inside to receive the male ‘pin’. Both connectors fitted to Rosetta are ‘Female SMA’ connectors. The standard Rosetta antennas are both fitted with ‘Male SMA’ connectors, with the male ‘pin’ in the centre and an external ‘nut’ for attaching to the female.

The opposite type - often used for WiFi routers - are known as ‘Reverse Polarity SMA’, with the ‘pin’ inside the externally threaded female and the ‘receptor’ inside the captive nut ‘male’.

Hope this is clear enough.

Regards

Peter

[CliveJ]

That's excellent info, thanks very much Peter for making sense of the subject of SMA standards.

I'll see if I can get a suitable cable to minimise the amount of adaptors that I seem to need now......

Regards, Clive

[CliveJ]

An update, managed to minimise the connectors cable set up without too many adaptors. Links below to what I purchased. I did search for a few hours for a single cable solution for the receive but couldn't find one.

Flew on a 'maintenance flight' all all seemed good but as you would expect (last Tuesday) there wasn't much traffic to check the PAW out with.

https://www.ebay.co.uk/itm/123460167627 MCX Male to SMA Female adapter connector
https://www.ebay.co.uk/itm/272609061466 1.8 M Metre - Male SMA to Male BNC RF Adapter Cable (50 OHM Impedance)

https://www.ebay.co.uk/c/27022644427#oid163866965408 VK-162 GPS Navigation Module with Antenna USB Interface G-Mouse Waterproof Black

https://www.ebay.co.uk/itm/231438693846 SMA Male To BNC Male Convertor Adaptor Gold Plated 0206K
https://www.ebay.co.uk/itm/174005348009 SMA Female To SMA Male RF Connector Adapter WIFI Antenna Extension Cable Cord

[Keithvinning]

Hi Clive

Whilst we encourage folks to install the antennas externally and DIY dont forget we have installation kits that give you correct parts to do this. Make sure that the cables you use are low loss 50ohms. Flexible LM240 or better. Using low grade cables is false economy.


Cheers

Keith

[CliveJ]

Got the antennas off you last year, mine's a classic and the parts were buttons off the BAY.

Added parts list to save Classic people looking for all the bits from scratch.

All good now thanks.

Regards, Clive