Question re BNC/SMA adaptors

[DAFO1711]

Good evening all.

Can I ask for some advice / opinions.

Today whilst at my local Maplin (in Hereford) I bought a cheapy mutli band scanner aerial.
Four aerials on one base- receives between 25-2000mhz with a 4m rg58 coax and a BNC plug. Aerial cost £21.99
Also bough a BNC/SMA convertor plug (£2.39) to allow me to connect to me RB and returned home expecting in fairness for it not to work or if it did - be not very good!!

Ten minutes later, I was receiving aircraft 65 miles away with the new aerial and BCN/SMA connector. It seems to pick up aircraft just as well as the antenna supplied with the RB.

I often read on the internet that you cannot / shoud not use a straight forward BNC/SMA
convertor but instead use a short patch lead- does anyone know why that is? Patch lead seems to cost about £10.

Am I doing any damage to the RB using a BNC/SMA convertor plug - as I say it picks up the same range as the RB antena which is great and cheap!!! Whats the difference with the more expensive aerials (is it just range)

Thanks all for your views and advice

Dave Ford
Hereford

PS If I connect the new twig to my scanner on 133.6 I can clearly hear both a/c in SE Ireland and also London Control - clear as day!

[AirNav Support]

Your not damaging it, people say to use the patch lead as there is loss in converting BNC to SMA to the signal. In a patch lead the loss is less.

[CoastGuardJon]

Your not damaging it, people say to use the patch lead as there is loss in converting BNC to SMA to the signal. In a patch lead the loss is less.

Hi AirNav, I would always use a patch lead of 30-45 cms in length - nothing to do with losses - it subjects the SMA socket to a lot less leverage and physical stress, but if you're saying use an adapter in preference to a patch lead, who am I to argue?

[E14]

Currently have a PL259 plug going into the SMA adaptor.
Anyone know where I can get a patch lead PL259 - SMA???
Cheers

[CoastGuardJon]

Hi E14, if you're the right side of the Atlantic (Mercator Projection!), try

http://www.garex.co.uk/patch%20leads/patch%20leads.htm , I think you'd need the 3rd one down, but if you're US side

http://www.rfcomp.com/index.asp?PageAction=Custom&ID=35

[Jollygreen]

Referring to Dave Ford's comments re the base station aerial from Maplins has given me an idea and was wondering if it would work with the AirNav RB.
I currently have mounted externally a Scanmaster B1300 aerial and was wondering if I got a BNC / SMA adaptor would I be able to use this aerial with the RB to save having to put up another mast and aerial as I already have this plus the Sky dish on the chimney breast.

MTIA

Nigel

[viking9]

Nigel,

If your antenna covers 1090 MHz it will work after a fashion but for best results you need a narrow band antenna that has an SWR of 1:1 at 1090 MHz. A small whip such as those made by MyDEL will suffice.

Tom

[E14]

Mydel Aerial £85.00. The spare whip is £8.31.
Seems wuite a bit extra to pay for a small metal base and a couple of clamps.
Compared to scanning aerials I do find 1090 aerials very costly for what they are but guess there is not the demand yet.

[viking9]

Mydel Aerial £85.00. The spare whip is £8.31.
Seems wuite a bit extra to pay for a small metal base and a couple of clamps.
Compared to scanning aerials I do find 1090 aerials very costly for what they are but guess there is not the demand yet.

Get a MyDEL AS-1100-A mobile and stick it on a metal disc for a groundplane (a sweet tin lid will do). I use one and get up to 300 msgs/sec and 89 aircraft at peak times and I live in a valley.

Tom

[DAFO1711]

Hi Nigel,

For the cost of a BNC/SMA adaptor itsa worth a go - try it and let us know if its any good. - love trying new ideas to see what works and what doesn't.
As I said, spent £25 at Maplins, expecting it to be a lot of rusbbish!!

Cheers Dave