ICOM IC-A220T 8.33 software update

[CloudHound]

Just come off the phone having spoken with ICOM UK about the known issue with selecting 25 kHz frequencies and 8.33 channels at the same time.

I was told that ICOM America are working on a fix, but that it will need to go through an approval process. Not sure if that's FAA, TSO or both.

They are maintaining an e-mail list of interested buyers so I thought I'd publicise it here.

[email protected]

Our strip remains too soft to use, so I'm not pathering to fly. Once it does dry out I hope they'll have this sorted as fiddling with the menu whilst airborne doesn't feel very safe.

[Helicopterdriverguy]

What’s the problem please

[Jim59]

https://www.euroga.org/forums/maintenance-avionics/8026-icom-ic-a220-25-8-33-problem-will-need-a-firmware-change



This radio has a serious user interface implementation error. To access 25k channels you have to select a 25k mode and to access 8.33 channels you have to select the 8.33 mode. This is wrong.
An 8.33-capable radio needs to seamlessly implement 25k and 8.33k channels so that e.g. 125.000 and 125.005 are both selectable just by turning the knob (or whatever method is used to change the frequency).
One could argue that one can access a 25k channel like 125.000 using an 8.33 radio set to 125.005 and for sure that will work perfectly… until you get a frequency which uses an offset carrier system and multiple transmitters (“climax” – what an unfortunate name https://www.euroga.org/system/1/design/assets/wink.png?1410810610) to cover a wide area, and there are lots of them about (http://peter-ftp.co.uk/aviation/misc-euroga/EG_Circ_2008_P_072_en_2008-08-14%20-%20VHF%20offset%20carrier.pdf):

[CloudHound]

Jim59 has it nailed.

I upgraded from a 210 which was a great radio. The new one is equally great, it's just that no-one on the design/manufacture team appeared to fully understand the nature of 8.33 implementation.

It does appear they'll need the box back in Kent to do the change but who will pay for this has yet to be made clear.

I don't know how many radios have been sold into the UK, though for the moment buyers beware!

[TelsBoy]

I am surprised at this. I just had a load of new A24Es put my way along with an A120 for setting up & testing, and all were able to seamlessly select 25k/8.33k channels without changing the spacing, as described in that EuroGA article, so I'm surprised that the A220 doesn't.


I'm not sure that the narrower bandwidth of an 8.33 RT will present problems as in Jim's example, many airports have already converted to 8.33 equipment, I'm not sure if the en-route sites have yet but your existing radio would have to be well off-frequency (enough for it to be non-compliant) before you experienced any issues, even with offset Tx/Rx sites.

[Jim59]

The main difference between a station operating on an 8.33 channel and one on a 25 kHz frequency is the receiver bandwidth. The bandwidth of an 8.33 receiver is less than the offset of some transmitters using the same 25 kHz frequency so the 8.33 receiver might receive some transmitters (i.e. those with offset 0, some distorted with offset 2.5, badly distorted with offset 5 and nothing from those with offset 7.5).

Text below is from a NATS document.

Within the United Kingdom, the majority of VHF RTF channels provided by NATS Ltd for en-route air traffic control and those used for emergency, flight information services and VOLMET are operated from between two and four ground stations using the off-set carrier technique in accordance with the standards set down in ICAO Annex 10. The offsets employed are; ±5 kHz for a two station system, ±7.5 kHz and 0 Hz for a three station system and ±7.5 kHz and ±2.5 kHz for a four station system.

[TelsBoy]

The main difference between a station operating on an 8.33 channel and one on a 25 kHz frequency is the receiver bandwidth. The bandwidth of an 8.33 receiver is less than the offset of some transmitters using the same 25 kHz frequency so the 8.33 receiver might receive some transmitters (i.e. those with offset 0, some distorted with offset 2.5, badly distorted with offset 5 and nothing from those with offset 7.5).

Text below is from a NATS document.



I am aware of that, being a Tels man... :ok:


Typical BW on a 25k Rx is +10kHz, on 8.33k its more like +4.5k. I can't really speak for ENR comms kit as I have no experience in that area but I'm not sure if those offsets are for 25k BW Tx/Rx equipment. Offsets are there to deal with Rx/Tx at range, so unless you are a long way away from the site it shouldn't pose an issue. The offsets on 8.33k channels will presumably be smaller due to the tighter BW. Althugh like I say I haven't dealt with offset comms kit.


It will be interesting to see how this all pans out in practice with these RTs until ICOM can realease the approved update, I don't do a lot of long-distance flying so rarely use the ENR system. Plus the a/c I fly still have 25k equipment.

[Jim59]

Typical aircraft receiver bandwidths:
Bandwidth @ 25 KHZ -6-dB-bandwidth > ±8.0 kHz
Bandwidth @ 8.33 KHZ -6-dB-bandwidth > ±2.78 kHz

Having multiple transmitters on the same channel using offset carrier techniques is not possible on 8.33.

[TelsBoy]

That's in-line with the specs laid out in CAP670, though I admit in my experience I tend to test right up to the mute point rather than the -6dB step which probably gives an extra kHz or two.


As I say, I've no experience with offsets or En-Route stuff. :O

[CloudHound]

...it has to be modded by ICOM America to retain TSO. Here's the email just in:-
We can now offer you a upgrade modification for your A220T , which will allow it to tune, 25k, 8.33k ,8.33k , 8.33k , 25k simultaneously , allowing for easier on board operation.

The upgrade however must be done at our production facility in the USA to comply with TSO rules so the radio will have to be forwarded onto there.
As part of the process, your radio will have its TSO approval history revised and 8130 form re-issued in line with the factory modification.
The upgrade is free for a limited period and if you wish to take advantage of it you will need to return your radio to Icom UK so we can ship it to the USA. Please contact Chris or I so we can book your radio into our upgrade program and get it turned around as quickly as possible. We plan this to be around 15 working days, however this is an estimate and it may in the worst case be a little longer.
NB From here we can only arrange this for radios we have supplied in the UK/Southern Ireland through our UK/Southern Ireland dealer network.

Thank you for your patience and we look forward to hearing from you,

King regards
Virgil
Just come off the phone from them and it seems like they want to gather as many back to send in one go. They have 20 or so people on the contact list.

So pass the word around and let's get on with it!

[TelsBoy]

Thanks for the update CH. Good to hear ICOM are on the case. Have dealt with the ICOM UK folks a few times over the years and always found them very helpful :ok:

[Flyingmac]

I have a 210E which I'm told is the 220 without the paperwork. It's in a Permit aircraft. I have to select 8.33 via the menu. Exactly as the 220. I'm wondering if it's worth bothering about. Will Icom even re-programme it?.
I carry a Yaesu 8.33 handheld as back-up.

[CloudHound]

I think this statement from ICOM UK could be a problem for you.
NB From here we can only arrange this for radios we have supplied in the UK/Southern Ireland through our UK/Southern Ireland dealer network.
However, they're a friendly helpful bunch, why not give them a bell?

[Aeroservice]

Some info if required. The latest Icom A220T Comm Radio comes with Firmware that has a software switch that lets you select 8.33/25/Both - if you select 'Both & Save' it will dial up all frequencies no problem.
The ICOM TSO'd Version Radio (assembled in the 'States) comes with an 8130 from Kansas. Other A220 Adverts allow you to think they are suitable for panels in Aircraft, but those that need the 8130 need a 220T from Icom USA with a Factory Certification to suit.
It is the same Form and Rack standard and identical to the King KY96A/B. However, out of the Box, it has a Rack, Fitting Kit and a DSUB 25 Pin + Co-Ax Connector, with separate Pins for assembly/wiring of the DSub.
To match the King KY it needs a 'Card Edge Connector' - this was fitted to the previous Icom A200 Units that were in use for Base Stations and Vehicle Use. No Idea why they ship the A220T with a D Sub.
A great discovery though - if you buy the MBA-3 Adaptor, it will fit straight into the KY96 Rack as a card edge unit.
I was given horror stories about the Intercom. It has a built-in two Pilot Intercom as an enhancement, however, as one previous report this thread states, if you have an external Intercom (mine is a PM1000 4 place) you leave the Icom A220T Software Intercom switch out of the box, which has a default of the Internal Intercom switched off. I have been told Citronic Intercoms have an issue - something to do with the voltage on hitting the Tx Button not going completely down to zero. It needs an external relay mod for this one it seems. There may be others so please investigate yourself.
The Heli they fitted this one to had a 'Frequency Selector' switch on the Cyclic, as well as a 'Channel Change' button. These both worked perfectly. In fact, the 'Channel Change' brings up the 'History' Icon and allows you to scroll through 20 past selected frequencies. Hitting the Frequency Selector on the one in the screen, flips it to the active window. Great! No bending down!
The Radio has less power than the advertised 15W I think the King has and this is 9W. Flight checks reveal no issues whatsoever, range is as good if not better than the King and reports are 5 x 5. The OLED display is very sunlight readable and light sensitive for dimming (also software selectable).
Only issue I had was to go in and change the sidetone on software. It was set at 30% and we wound it up to 75% which was perfect in flight. Using Bose X for info. We also set the squelch to Auto but it can be overridden like the King by pressing the inner Volume button in flight for distant stations.
It's a great Radio and I recommend looking around at pricing. The difference with King is significant.
Your maintenance organisation will need to manage the mod for you but the paperwork is minimal on a one-for-one basis I am told.
Don't shoot the messenger but don't overlook it for great 8.33 solution if it suits you?
Have fun...