TRX-1: GREAT airband audio!

[rayvelcoro]

... meant to say: "To air band listeners..."

 

[K2RNI]

Hertzian - On the airband, do find that the first few milliseconds gets cut off on each transmission? My TRX 2 does that. I usually miss half of the first word spoken. I have it set to AM (as opposed to auto) and my squelch is at the very minimum I can get it before the "white noise" stays open.

This is normal. Even my WS1040 does this occasionally.

 

[nanZor]

My main radio is the TRX-1 but I have the say, the little BC-125AT handheld is incredible for planes. Affordable, too.

I'll agree with that. Especially if you need mil-air. Even more affordable if you don't need alpha tags is the BC-75XLT which is no slouch either for vhf airband.

Even Whistler's WS-1010 simple classic model works great, and the seemingly louder audio output, which might be an issue if you are monitoring at say the outside visitor center (burger-run lunch tables) at GA airports, is a plus over the 75 or 125.

In all of these cases, they benefit greatly, especially the Whistler 1010 from the use of the airband-specific Icom FA-B02AR antenna designed for Icom's commercial transceivers. They are very *narrowband*, and help provide an additional level of front end filtering if you will, to a scanner.

I'm really at a loss as to why places like HRO, Universal Radio, Scanner-Master etc don't sell these. To get one, you have to order online at a pilot shop, or visit your local FBO sales office where they may have them over the counter.

No bs. It really is narrow. Put one on an antenna analyzer and you'll see.

Uniden or Whistler - for VHF airband, I don't run without the Icom FA-B02AR duck.

 

[Ubbe]

No bs. It really is narrow. Put one on an antenna analyzer and you'll see.

But it has to be wide banded? The airband covers 118-137MHz, that's a 20% bandwidth and a normal 1/4 wave or 3/4 usually have a 10% bandwidth where the SWR are acceptable for transmit. You can introduce resistors and other components, even mechanical solutions, in a rubber antenna to increase bandwidth but to the expense of reduced gain effeciency.

/Ubbe

 

[scannersnstuff]

I concur that the Whistler ws-1010 is a fantastic vhf air band performer. Plus it has great signalsweeper capability. As a public safety scanner,it's pretty far from good. The intermod is bad.

I wish that the ws-1010 would have covered milair,but for the price, it does not.

 

[TailGator911]

To iar band listeners:
My main radio is the TRX-1 but I have the say, the little BC-125AT handheld is incredible for planes. Affordable, too.

I have to say I have tried both my TRX-1 and my SDS100 on air band, and milair, and the BC125AT knocks them both out of the ballpark. Fantastic scanner for air band vhf/uhf milair. The proprietary software Scan125 is great for programming and the ability to alpha-tag your channels is a major plus. Now, when I go on a mobile excursion, I take all three scanners - SDS100, TRX-1, and BC125AT, and I use them according to their individual merits. The SDS100 for public safety decoding the Ohio MARCS system, the BC125AT for air band and vhf/uhf, and the TRX-1 for DMR and everything else. I don't miss much.

Some people are prone to put down the TRX-1 since the SDS100 came out, but that scanner holds its own. Before the SDS I would monitor the OH MARCS system on the TRX and it did a surprisingly good job at decoding LSM.

JD
kf4anc

 

[nanZor]

But it has to be wide banded? The airband covers 118-137MHz, that's a 20% bandwidth and a normal 1/4 wave or 3/4 usually have a 10% bandwidth where the SWR are acceptable for transmit. You can introduce resistors and other components, even mechanical solutions, in a rubber antenna to increase bandwidth but to the expense of reduced gain effeciency.

I'll have to let you cut one open, but I think for rx uses, there might be a capacitive loading component, not resistive is at play here. Unlike other ducks or whips, if you place your fingers on the tip, you can detune it so badly that a very *strong* signal just goes away. Hence for pilots, you don't want to get that tip near the aircraft frame. This is good advice for anyone obviously, but the amount of detuning compared to other whips and antennas I have is pretty noticeable.

Try one - the proof is in the pudding - listen to a broad front end scanner that has FM broadcast capabilties. Compare the Icom FA-B02AR to most common broadband fav's, like the Diamond RH-77CA, or any other "airband-resonant" consumer scanner antenna, and you'll see / hear the difference.

We can talk about it all day - and I thought it was BS. Until that is, I placed it on a double-conversion scanner with a wide front end (ahem simpler GRE/RS/Whistlers), and any 2nd IF images were just gone. FM broadcast, VHF Hi, pagers, noaa and all that other stuff is just totally attenuated more so than any other antenna I've used.

Plus, when doing a wx-scan, and hearing nothing from my local firebreather, I was sold.

 

[Ubbe]

If the antenna are sensitive when you touch the tip it means that it is high impedance and have very little capacitance, like on the end of a 1/4 wave antenna.

Get a telescope antenna and you can adjust the lenght to any frequency you would like to listen to and get that narrowband effect and it will be much cheaper than any special airband antenna and more flexible as you can adapt to any frequency. To keep the lenght shorter than 50cm, which is a 1/4 wave at airband, they have used a shortening coil in the airband antenna. But it is even more efficient with a full 1/4 wave antenna.

What I consider a wideband antenna are 20MHz bandwidth and narrow are 5MHz. You say narrow when you mean single band and wideband when you think of multiband antennas like scanner antennas on portables that usually are made with a helix for 155Mhz and 3/4 wave wire for 800Mhz.

If you can handle a 50cm antenna I suggest getting a $4 telescope BNC antenna instead of a special antenna approved to be used in an airplane cockpit, that has to be made of non flammable material and just to cover the cost of the approval are more than those $4 for a telescope antenna for scanner use.

/Ubbe

 

[nanZor]

I have many telescopics and other ducks from many years of scanning.

All I'm saying is that the Icom Airband antenna does *something*, perhaps having a much higher out of band reactance than ANY other of the 100 antennas in the drawer which attenuates anything much out of it's designed bandwidth, which is a plus for weaker front-end scanners.

Trust me, I'm not commenting on something I don't own, or speculate about. There IS a major difference. I think you'd be very happy with one. Seriously, not a backhanded remark.

 

[nanZor]

Ubbe - you gave me a great idea. Although really we have strayed far beyond audio into antennas ...

Without cutting the Icom FA-B02AR open, my gut tells me this is not a conventional helical wind.

It is acting much like a typical hf mobile antenna, that has the loading coil well past the half-way point - perhaps 60-75% up the mast. Yes, that additional coil winding is lossier than putting it below, but it sure becomes narrow when you do that.

So - somewhat beyond this discussion is for anyone who wants to build their own single narrow-band "duck", to carefully make and tune the loading coil about 70% "up the duck" rather than just wind a simple helix.

Hmmm.... mind is racing now...