Radio

The discussion regarding the requirement to carry a radio with 8.33 kHz channel spacing rather than the current 25 kHz seems to be less hot than the one regarding mode-S transponders. Non the less the 8.33 kHz radio is required above FL 245 since 7th October 1999. This requirement will be extended to the airspace between FL195 and FL 245 on 15. March 2007 (see Swiss AIC A 013/05 SEP 01).

I do of course not plan to use my plane at that altitude, the referenced AIC does however mention that the use of 8.33 kHz below FL195 is being considered and that it is therefore recommended to install an 8.33 kHz capable radio in new aircraft or in existing aircraft if a radio is being replaced.

I have raised the question when 8.33 kHz might be required below FL195 to Skyguide, the Swiss air traffic service provider. The response has been that no date has been fixed, that some discussion is going on however, and that it might happen around 2010. As this is only three years away, my plane won't be finished until 2008 or 2009, and as the price difference between 25 kHz and 8.33 kHz radios is not too big the decision to install an 8.33 kHz capable radio seems logical to me.

24.02.2007: I just read an article today where it was stated that the German Air Traffic Control Company DFS considers making 8.33 kHz mandatory below FL195 by 2009.

A quick look at the marked showed the following radios as being available and appropriate for the purpose of a homebuilt kitplane plane:

Garmin

http://www.garmin.com

SL30

25 kHz COM/NAV

GNS430W

8.33 kHz COM/NAV/GPS

Filser

http://www.filser.de

ATR833

8.33 kHz COM

ATR833A

8.33 kHz COM Tranceiver

Becker

www.becker-avionics.com

AR 4201VHF/AM

25 kHz COM

AR 6201VHF/AM

8.33 kHz COM

ICOM

www.icomamerica.com

IC-A200

8.33 kHz COM available in TSO’d and non TSO’d version.

Summary

I eliminated most 25 kHz radios from the evaluation, as 8.33 kHz was specified as a must. I only kept some for comparison.

	Filser	Filser	Becker	Becker	Garmin	Garmin	ICOM
	ATR833	ATR833A	AR 4201	AR 6201	SL30	GNS430W	IC-A210
TSO	yes	yes	yes	yes	yes	yes	no
IFR	yes	yes	yes	yes	yes	yes	no
Channel spacing kHz	8.33	8.33	25	8.33	25	8.33	8.33 *)
Memory	100	100	99	99	16	Database	10 * 20
Jeppesen Database	yes	yes	no	no	no	yes	no
Listening on 2nd frequency	yes	yes	yes	yes	yes	yes	yes
Emergency Freq Selector					yes	yes	yes
VOR	no	no	no	no	yes	yes	no
Front mm	ø 57	160 * 42	ø 57	160 * 45	160 * 33	160 * 68	160 * 34
Size mm	65 * 65 * 190	66 * 66 * 190	62 * 62 * 210	146 * 45 * 194	158 * 33 * 267	160 * 68 * 278	160 * 34 * 271
Depth incl connector mm	220	255	230	230	290	320	295
Weight g	600	700	700	1200	1050	2900	1000
Voltage V	10,5 – 14	10,5 – 14	12.4 – 15.1	12.4 – 15.1	10 - 40	11 - 33	11.7 – 15.9
Current mA (at 13,8 V), reception	150	150	85
HF power W	6	6	5	6	8	10	8
Price without tax (MWST)	2270 $	2270 $	1325 $	?	3515 $	8800 $	1350 $
Connectors	incl	incl	169 $	?	incl	incl	incl

*) Unclear, ICOM currently specifies 25 kHz

Conclusion

We finally went for the Garmin GNS430W. It is the most expensive solution, but it has 8.33 kHz and also gives us both a certificated VOR and certificated GPS. One of the two is required for night VFR certification, and we wanted to keep that option possible. Using a portable GPS for night VFR is not permitted.