Kumusta from the Philippines

[JayM]

Hi. I'm a Yank living in Metro Cebu, "the Queen City of the South." I got a Nooelec NESDR SMArt HF bundle a few weeks ago and cobbled together a shortwave antenna for it that works quite well. However, in my location almost all I ever hear is China National Radio which is getting somewhat boring so I decided to explore the world of 1090MHz. Right now I'm just using the short 800-2000MHz antenna and the magnetic mount that came with the bundle, the antenna being 9 feet in the air on a pole outside of my ground-floor window. I'm able to see airplanes up to around 50nm though. I've ordered some parts to build a cantenna or something along with a 125MHz airband dipole and am waiting for them to arrive. I plan to mount both antennas on something and hang it in an open upstairs window as I don't have the space for a tall mast and there's no way I'm going to try to get up onto the roof of a 2 story house at my time of life! I'm hoping they'll improve my radar range as well as let me hear some voice traffic which so far is nonexistent even though the airport's only around 8km away with no hills or skyscrapers in between. (I'm kind of shaking my fist at the third story my neighbor added to their house two houses from mine but I think the window I plan to use has a clear shot past their house to the airport. I guess I'll find out in a few weeks when I get my antennas built and set up. I can always make changes later if performance isn't very good.)

[Anmer]

Welcome and thanks for the introduction.

An antenna for 1090 Mhz, low loss coax cable and a high as possible location will be the best options.

I have a number of antennae in different locations, including one on an outside window (for testing) and it does pretty good.

So good luck and do let us know how you get on.

[JayM]

I plan to use 10 meters of RG6, a lot less lossy at higher frequencies than the RG58 on my HF antenna. I hope I chose wisely. This will connect to a splitter that's good for up to 2GHz with short coax jumpers between the splitters and the antennas. That way I'll only have one more coax coming in through the downstairs window. Otherwise there would be so many I'm afraid I'd get them mixed up. Not to mention any antennas I may decide to build in future. I'd forgotten how much fun building an antenna, using it and thinking "I made that" can be. It's much more satisfying than simply buying them.

I forgot to mention, my SDR dongle's connected to my PC running Debian Linux and I'm using Dump1090 and VirtualRadarServer's Linux version running under Mono 6.8. It seems to be working well except that clicking the link to the web page in VRS tells me it can't open my default web browser, in this version of mono only, but there were other issues with both older and newer versions. I simply added a bookmark to the page in my browser's toolbar instead of using the internal link in the app.

[Anmer]

Make sure the cable's impedance is 50 ohms.

RG6 is usually 75 ohms.

[JayM]

75 ohm coax would give me perhaps a 1.5:1 SWR. I think the low high-frequency loss of RG6 is worth the compromise. (A staffer at FlightAware seems to agree unless I'm misunderstanding his post.) BTW the RG6 I bought is Cignal brand from PerfectFlex meant for satellite TV not just regular cable television. I'm limited to what's available either in the Philippines or obtainable from China and this seemed to be the best-quality option. Ideally I'd use something like RG8 or perhaps LMR240, but remember that it will be connected to a USB dongle on the back of my computer via an SMA adapter and the weight of the thicker, heavier cable might pull the dongle loose, not to mention just being difficult to deal with in general, like a garden hose in the winter, as well as costlier. I've also purchased a NanoVNA antenna analyzer so I'll test everything with that and see what I can do with i.e. ferrite chokes to tune it the best I can. (I've never had to deal with such a high frequency before, my radio experience has been on the 11 meter and commercial VHF bands, so this is all something new and fun to learn. At least I don't have to worry about blowing the finals in a transmitter.)

[Anmer]

A staffer at FlightAware seems to agree

FlightAware's "official" recommendation is to match the coax cable impedance to the receiver, 50 ohms.

But use whatever you prefer.

[JayM]

I'll just try it and see what happens. In any event it has to be better than what I have now, and if there's room for improvement I'll address that later. The experimentation is part of the fun, to me anyway. Cheers.