advice wanted: Emergency Radio

[Stroh21]

Hello VAF!

I am about to get started on my panel up-grade and have one last piece of equipment to figure out. I'd like the ability to tie a hand held radio into my audio panel for Comm2 and have a blade antenna mounted under the fuselage to give it a little more reception capability. The radio will mostly be used for ATIS, but also as a backup if Comm1 fails. Any suggestions on which radio and antenna to purchase would be greatly appreciated!

Thank you for your time,

Matt

 

[Canadian_JOY]

There's perhaps an easier way to do this... There are several different antenna switching boxes available on the market (search function here will help you for specific manufacturers). This is essentially a box that has two coax connectors on it - one "in" from your comm radio, one "out" to the antenna. On the face of the box is what looks like a mini stereo jack. The unit is provided with a coax cable that has a BNC on one end and a stereo plug on the other. This cable is used to attach to your hand-held radio. Once it's plugged into the stereo plug, your primary comm radio is disconnected from the aircraft antenna and your hand-held radio is connected to the antenna. It's a neat little setup that doesn't cost much and allows your regular external antenna to be used by your hand-held.

As for hand-helds, the Icom radios are good (I use an IC-A22), as is the current Sporty's unit. Whichever you choose, it's typically easier to interface to them using a PTT and their product-specific headset jacks than wiring the radio into the audio panel. I just keep the headset jacks plugged into my handheld in my flight bag and the PTT coiled up in the same pocket under the radio.

 

[jpowell13]

RAM mount

My Sportys radio resides on a RAM mount at the left edge of my panel which allows me to use the VOR/localizer/glideslope indicator hands free. I keep the headset adapter plugged into it in case my other radios fail. I plug it into the cigarette outlet during flight to keep the rechargeable battery topped off. The rubber duck antenna is held above the edge of the fuselage and seems to work pretty well in this location.

I mostly use my handheld for ATIS and for VOR checks against my panel mounted nav. It also came in handy when my PTT wiring failed on an early phase one flight. It's comforting to have the glideslope in case of an EFIS failure.

John

 

[tomkk]

... I mostly use my handheld for ATIS ...
John

I've seen others mention using the handheld for this. How do you use it for ATIS? Don't you have to unplug your headset from your panel and plug it into the handheld to use the handheld?

 

[Walt]

http://www.aircraftspruce.com/catalog/avpages/icomswitchbox.php

Personally I would like to see some testing done on this device before I would even consider installing one, increasing SWR is very likely.
I can't seem to find any specs on it either.

 

[Stroh21]

Sorry to ask, but what is SWR?

 

[WenEng]

There.

Sorry to ask, but what is SWR?

Standing-wave ratio (SWR) is a mathematical expression of the non-uniformity of an electromagnetic field (EM field) on a transmission line such as coaxial cable. Usually, SWR is defined as the ratio of the maximum radio-frequency (RF) voltage to the minimum RF voltage along the line.

No need to repeat yourself. We heard you the first time

 

[Stroh21]

Sorry about the repeat. I'm currently deployed and our internet connection isn't fantastic. The computer indicated the original post didn't go through.

 

[Canadian_JOY]

Walt - I had the same concerns about SWR. A fellow builder with access to a network analyzer had similar concerns and opted to put the antenna switchbox through its paces on the network analyzer. It faired surprisingly well. In fact it looked a whole lot like just a pair of BNC connectors in terms of insertion loss and VSWR. Yes, I was surprised by this positive result. So surprised, in fact, that I opted to keep this switchbox in place on my #2 Comm antenna coax.

 

[jpowell13]

ATIS on handheld

Tom, I usually listen to ATIS on the ramp with my handheld (without headset) before turning on the master and doing the startup checklist. There can be quite a bit of information in the ATIS recording at Baton Rouge, and I like to listen while I'm getting buckled up and removing the gust lock, etc. John