Tuned Low Profile Antenna for 1090

[neilmurg]

I'm getting 2 of your antennae, 1 for each freq. Can I cut down the one for 1090 tp 1/2 size(ish)? What total length
And is their any issue in reducing the 3m lead cable to, say, 0.5m, easy to do?
Regards neilmurg

[exfirepro]

Neil,

I have never tried cutting the Tuned Low Profile Antenna down to length. There is in theory no reason why you shouldn't do so,  but I would advise 'proceeding with caution'. FWIW, they usually work fine as they are on both 869 and 1090. If you do decide to try cutting one down, each 'leg' should be approximately 66mm long for 1090MHz.

You can shorten the co-ax cable fairly easily by cutting it to length and fitting a new 'crimp on' MCX connector. This is fairly easy to do if you have the correct crimp on connectors and tool - I have done this myself with several examples.

Let us know how you get on.

Regards

Peter

[neilmurg]

Peter,
Thanks for that, my current 1090 aerial is a tiny 1/8th (I think, maybe 35-40mm) wavelength and works great. I'm hoping if 1 is shorter (for C/S/ADS-B) there's less chance of blanking the Pi antenna, and it doesn't need to be big due to the transmission power vs Pi.
I'm not confidant in my coax skills for shortening but, I guess I'll learn. I only need 0.3m, and If there's 2.7m left curled up, it looks like a solenoid...

[Ian Melville]

Caution: GA traffic has a much lower power than Big CAT. It also is more likely to transmit away from your aircraft while manoeuvring. Hence the signal strength will be much weaker. That GA traffic is what you want to hear from, please don't exclude it by de-tuning you antenna.

[Admin]

Neil
Please pm Keith Vinning
Keith is working on various installation types for all aircraft, he will need provide the best advice
Regarding antenna and coax

Thx
Lee

[neilmurg]

Please pm xxx

Thanks guys, I appreciate it, ask away if I can reciprocate

[Keithvinning]

Hi Neil the tuned antennas are a couple of weeks away. The horn antennas have 2M of cable on them.
Anyone want them shorter and is so what lengths should I get (I need to buy in batches to get other lengths)

Keith

[neilmurg]

I've received them now. It's smaller than I thought (I thought it would be as long as the endfeed dipole, but it's not, only 3/4 length). I can fit both easily out of the way on the windscreen, pretty close to vertical, good view of 180deg forward and the extra co-ax will fit neatly in the cubby hole with the Pilotaware. I have a(n) USB extension cable to site the U-Blox GPS on the coaming away from the heat. I'll let the avionics guys tidy it up more the next time we service the panel.

It's just in time for the Vienna trip, thanks! I needed the extra dipole as my last one looks a bit drunk / wobbly.
I'll upgrade to Rosetta after, and put in an extra low power SDR (DVB-T) Software Driven Receiver for weather after that, cooling down the SDR and having a fan to control it better. The cubby hole also keeps it out of the sun.

[Keithvinning]

Hi Neil

Can you send me a picture of the antennas that you have got please. I don't understand the bit about them being shorter?

Thanks

Keith

[exfirepro]

Keith,

Presumably the standard 869MHz ‘Horn Dipoles’ from PilotAware Hardware - which are physically shorter than the standard P3i end-fed ‘sleeve dipole’.

Regards

Peter

[neilmurg]

Can you send me a picture of the antennas that you have got please. I don't understand the bit about them being shorter?

These are the ones I used before getting the dipoles, this is why I thought I might cut down the 1090 one, but there's no need as the ones you've supplied are a nice size.

[Ian Melville]

I don't think that short one is PilotAware supplied. In fact I have several that came off a router and are more likely 2.5Ghz. They do not perform well as 1090 ADSB antennas.

I did use one, modified, as the base for a whip antenna, that worked well, but was prone to being bent.

[Paul_Sengupta]

I have a similar one which doesn't perform well on 1090. However, I have a similar sized one which I use on my classic, and it works out to about 60 miles.

It's one of these sort of things.

https://www.ebay.co.uk/itm/900-1800MHZ-SMA-male-90-GSM-GPRS-Antenna-Wireless-Data-Transfer-5CM-Chili-/222099444914

[neilmurg]

I don't think that short one is PilotAware supplied

No it's not, someone mentioned it on the forum I think, I got one and it works fine. It also makes the classic a handy portable unit to carry from aircraft to aircraft, I only need it to work up to 5 miles, I can't see farther than that anyway. I only sent the pic in to explain (to Keith I think) why I was thinking of cutting down your standard dipole for the 1090 receiver, but the dipole is short enough that I don't need to do that. I'm attaching suckers to them so the whole unit is still transportable

I have a similar sized one which I use on my classic, and it works out to about 60 miles

Yes Paul mine works too, and it's on a pigs tail, so no strain on the SDR, both aerials on the same side so fits well on the coaming (although I'm keeping it out of the sun  and using the dipoles and the GPS on a(n) USB extender from now on). These aerials will stay with me for extra flexibility for the unit.