8.33khz options

[BoeingBoy]

Hi All,

I have to replace the King KY197 in my Archer and at the moment the options for tray mounted 8.33khz radios seem to be limited to Garmin, Trig and ICOM with the latter being the cheapest at just under £2k.

Whilst all good sets, I only need a basic 10W set capable of being the second radio to a GNS430 so I wondered if anyone has come across any other alternative suppliers or manufacturers. I am currently looking at the GTR225, the TY96 and the IC-A220T.

Any help appreciated before reaching for the credit card.

[Rod1]

What about the ATR833A? £1400 ish;

ATR 833a OLED Transceiver (http://lxavionics.co.uk/lxcart/index.php?route=product/product&path=62_85&product_id=52)

Rod1

[Jan Olieslagers]

I have installed a Trig TY91 at a cost far lower than 2000 € let alone 2000 GBP; and am very happy with it - both with the apparatus as such and the service. Most importantly, my supplier, a true-blue hardware electronics engineer, told me he is happy to sell it because Messrs. Trig actively support him in offering good service.

However I could do the installation myself (Annex 2 aeroplane) with only a final verification by someone qualified. If you need to have all the installation done by a certified workshop, that may carry its price tag - but I still find 2000 GBP very very expensive.

I can't say anything about the TY96, though - but could it really be so much pricier? Isn't it basically the same device in a different case?

[Capt Kremmen]

AFE at Kidlington have what look like some reasonable prices on both the Trig and the Icom panel radios both switchable between 8.33 and 25. I'll be taking a trip there to check the display brightness before committing.

I have another contact adjacent to Kidlington who is talking about £900 for a new set. I have no details with me. When I get back to my desk, I'll forward you contact details if you're interested. The price looks good !

[Capt Kremmen]

I forgot to mention that I'm hearing rumours that unless you use an approved installer the warranty might be invalid.

[Jan Olieslagers]

unless you use an approved installer the warranty might be invalid.

That is industry standard, and understandably, too. It is not hard to destroy any piece of electronics, least of all if it contains a transmitter. Reversing the supply voltage and transmitting with no antenna connected are guaranteed recipes, to name but those two.

As I understand things, Trig leave their dealers/resellers some leeway in judging on this kind of matter. Good on them!

[Curlytips]

Recently had this installed, and it's really good kit, but I think I bought more than I needed. It has a worldwide database of frequencies, and will identify who you are talking to, but only comes into its own when you connect to GPS source, so it knows where it is. As I'm very much a VFR kitted a/c (albeit with yoke-mounted 496), I'm not getting everything I could from it.

Despite that, it looks neat above the GTX328, and will look nicer still if I can ever afford Garmin ADS-B etc.

As the first period for claiming back against CAP1501 starts in 4 days, has anyone detected a claim form from CAA yet?

[Flyingmac]

I've fitted the Icom panel mount. Slotted straight in and worked fine after a bit of fiddling with settings. Substantially less than two grand. You need to shop around.

[Maoraigh1]

We damaged a Trig when installing it ourselves. Their support was excellent.

[TheOddOne]

As the first period for claiming back against CAP1501 starts in 4 days, has anyone detected a claim form from CAA yet?

Heard from AOPA today (we're corporate members, a good thing to be). They've been chivvying on a daily basis. Allegedly, it's still with legal who are agonising over whether or not it's legit. Give me strength.

TOO

[mothminor]

Ah, that explains the deafening silence from the ministry of silly walks.
I bought a trig at the "right" time :) but certainly not holding my breath.

[BoeingBoy]

Thanks for all the replies.

As I already have a GNS430 (upgrading to WAAS later this year) I only need a second com to remain IFR compliant. The sets mentioned all have great features (world wide data base etc) but in essence all I need is (preferably) a minimum of 10Watts power and the ability to select a frequency.

I think the ICOM will be my choice as with an adapter it will 'plug and play' into my existing KY197 rack saving on labour, and it should pan out at around £1500 with a 20% rebate from our generous benefactors.

It will be installed by a maintenance company on the aircrafts annual and signed off as part of the radio certificate.

[TheOddOne]

Hush my mouth. CAA claim form now available.

https://www.caa.co.uk/General-aviation/Aircraft-ownership-and-maintenance/8-33-kHz-funding-application/

TOO

[mothminor]

Hush my mouth. CAA claim form now available.

https://www.caa.co.uk/General-aviati...g-application/ (https://www.caa.co.uk/General-aviation/Aircraft-ownership-and-maintenance/8-33-kHz-funding-application/)

TOO


Thanks TOO, my application is in :)

[Curlytips]

I'll be sending them my "valentine" tomorrow :ok:

Regards

CT

[wigglyamp]

Thanks for all the replies.

As I already have a GNS430 (upgrading to WAAS later this year) I only need a second com to remain IFR compliant. The sets mentioned all have great features (world wide data base etc) but in essence all I need is (preferably) a minimum of 10Watts power and the ability to select a frequency.

I think the ICOM will be my choice as with an adapter it will 'plug and play' into my existing KY197 rack saving on labour, and it should pan out at around £1500 with a 20% rebate from our generous benefactors.

It will be installed by a maintenance company on the aircrafts annual and signed off as part of the radio certificate.
You don't need a second 8.33 radio to be IFR compliant if you're operating under Part NCO. The second radio can remain 25kHz ans used only on specified retained frequencies such as 121.5.

[ChickenHouse]

You don't need a second 8.33 radio to be IFR compliant if you're operating under Part NCO. The second radio can remain 25kHz ans used only on specified retained frequencies such as 121.5.
Even though Part.NCO only requires one COM for IFR, to my knowledge the fight is still open with some NAAs trying to sneak through the back door, even if this is in contrast to EU regulations. We'll see who wins.

[Curlytips]

Spookily, when I put my old handheld on *bay (ICOM A20), I had 3 different bidders from Italy. One, of course, was successful, and the Global Shipping System took care of stuff and gave me protection of payment etc. But Italy must have same rules from January, so maybe they are fighting the new rules (or could the refugee smugglers need to keep in touch with their boats?.......).

[TheOddOne]

We got £250 back on our old radio - I guess it went to the States as they're not changing and it was in really good condition.

TOO

[ChickenHouse]

Spookily, when I put my old handheld on *bay (ICOM A20), I had 3 different bidders from Italy. One, of course, was successful, and the Global Shipping System took care of stuff and gave me protection of payment etc. But Italy must have same rules from January, so maybe they are fighting the new rules (or could the refugee smugglers need to keep in touch with their boats?.......).
Syria does not have the 833 rule, or?

[pulse1]

Hush my mouth. CAA claim form now available.

https://www.caa.co.uk/General-aviati...g-application/


And two days later, there it was, gone! All you get at the moment is "File not Found". Looks like another CAA foul up.

[BoeingBoy]

Probably their way of regulating the incoming deluge of mail.

[MrAverage]

I got part way through mine but needed a serial number. Saved a PDF, just hope it still works when I get back to finishing it!

[Flyingmac]

CAA says the form has been withdrawn. It's probably a mistake by a computer.:rolleyes:

[Curlytips]

Filled in the form yesterday (using link sent out by Skywise). It wouldn't allow submission, so I saved the file as instructed, then reopened in Adobe - then had to fill it all in again! But then it would submit, and immediately got the reply back asking for ID and invoice scans, which were sent immediately. Hopefully, I'm in the queue and they haven't lost my application or are changing what they need!

Not that I'm desperate for the £600 or anything :).......

[cotterpot]

Version 2 of the claim form has been issued and is available as below:

http://publicapps.caa.co.uk/modalapplic ... il&id=7752

[pulse1]

And I managed to fill it in and got an acknowledgement. Let's see if the next step works, apparently an e mail requesting copies of the receipt and my identity. I don't have a receipt number because the Invoice was proforma.

[TheOddOne]

http://publicapps.caa.co.uk/modalapplic ... il&id=7752

This has just come up as 'file not found'

TOO

[TheOddOne]

This link from AOPA still seems to be working...

https://publicapps.caa.co.uk/modalapplication.aspx?catid=1&pagetype=65&appid=11&mode=form&id=7752

TOO

[Bluebear1872]

The PA28 Warrior I currently fly has a KY196 Radio in the Com 1 position, and KX155 TSO Nav/Com in the Com 2 position. With regard to the EASA/CAA regulations, do I have to upgrade both radios to 8.33kHz or just the one as a legal minimum. The aircraft is used to fly in IMC conditions as I have an IMC IR(R) rating.
I can't seem to find the exact regulation on line. Can anyone help and please clarify?

[Curlytips]

This is same situation as myself. You legally need one 8.33, so change the 196 to radio of your choice, and continue to use the KX155 as nav only after 1 January. You'll also need to placard the com side to say 121.5 only - as you can still use in emergency after that date. There may be some other 25 spaced frequencies that will be preserved, but realistically your new radio will be Com 1 and you'll never need the 155 voice unless your new kit fails.

I've changed my MX11 for Garmin 255a, and kept KX155 for loc/gs. Also swapped IC-A20 for a Yaesu 750L, so that I have handheld back-up (and the Yaesu has GPS too).

All the above is true if your IMC flying is like mine (using IR/R rating outside the airways). If you go IFR and into controlled airspace, you'd need full airways kit which includes 2 x 8.33, 2 x altimeter etc etc. Which is one reason I never took the IR rating.........

Suggest you do sooner than later so you can claim rebate in first tranche before they run out of advance EU payment.

[Curlytips]

Having submitted claim on first possible day, and being told probable 3 weeks before they would be in touch, CAA have kept their word. Unsurprisingly they have been so inundated with claims they expect many weeks before they can sort through waiting list - but importantly, the fact I got the email reassures me that I am in the queue........

Did you get yours?

[pulse1]

Yes, I got mine too. I won't start to panic until I hear that some are getting the dosh. Sounds like that could be a long time.

[cats_five]

Got mine as well 😀

[Curlytips]

Just received a nice mail to say that my rebate is in process (provided the invoices actually state "Paid" - which they do). CAA received over 2000 applications in first call period but state they have enough cash in kitty for this, so if compliant they will all get paid. Second call period now open.

So hopefully cash soon - but they quote "hopefully early Summer". I thought Summer had already started...........

[BoeingBoy]

The text from the CAA mail:

______________________________

This is a status update email to all applicants that have 8.33 kHz funding claims within the first tranche of funding.

The first tranche of funding includes all claims with an “E” reference number of E37641 or lower as they were received by the CAA before the tranche closed at 23:59 on 31st March 2017. Your claim is one of these.

We received over 2,000 applications in this first period and we are continuing to work our way through these to assess whether they should be recommended for payment. I am pleased to confirm that we have sufficient funding to cover all the successful claims in this first tranche, and we have now opened a second call period that will run through to 30th September 2017.

If you have not heard from us, then this is either because we have not yet completed review of your claim, or it has been assessed and is now recommended for payment.

Part of the EU funding contract is that we apply utmost due diligence and ensure the eligibility criteria have been properly met. As you can imagine, this is not a “5 minute job” to assess and review each claim form. Once all the first tranche claims have been assessed, we will make one payment to all recommended claims via BACS transfer. We are hoping to be able to do this early Summer.

There are 2 common issues that are causing delay in processing:

1. Applicants fail to provide receipt for purchases – we need to see that the goods have been paid for. Whilst an invoice is good in that it clearly details the items purchased and the cost, unless it says “paid” on it, then it is not deemed a receipt. We do need to see proof that cost has been incurred, this could be, for example; credit card receipt, card statement, bank statement, “paid with thanks”, etc.

2. If the total purchase cost of your claim(s) amount to £5,000 or more, you need to provide a copy of a bank statement that is no more than 3 months old. This must show name of bank, name of account, sort code and account number. You may choose to obscure financial transactions. Ideally include the bank statement as a supporting document to all of your claims, alternatively send it to one claim and note in the email that it covers multiple claims, quoting their “E” reference numbers.

If either of the above apply to you, then please pre-empt us asking for it and send additional supporting documents to us as a reply to your “E” reference email (note: it is that “E” reference in the subject line that ties your claim together).

Please be patient and rest assured that you are in the system.

[DirtyProp]

Recently had this installed, and it's really good kit, but I think I bought more than I needed.



If you'd consider selling it, I might have a customer....:cool:

[Curlytips]

Having gone through the fitting process etc., and having rebate on way, I feel I'm as ahead of the game as I can be. The set is future proofed, in that when I upgrade other stuff (lottery permitting), then I'll get more out of the Garmin.

And can't help feeling, that even if I got rebate on this, then sold it, and bought something less, then by then EU funds for my second application will have run out (and that's if I could even get another box before the deadline). Think I'll stick with it, but thanks!

[Curlytips]

Now coming up to 3 months since claim submitted (Valentine's Day). I know they were inundated, but has anyone had any good news yet?

[TheOddOne]

I'm not expecting payment until late Summer and we're in the first tranche.

I see in Pilot magazine that there's talk of the CAA applying for derogation. Wish I'd kept the old KX165 so I can put it back in again. I believe it's a better radio than the new Garmin 255. The new radio has too many features/buttons and the audio isn't as good, in my opinion.

TOO

[Curlytips]

TOO - yes, just read Pilot today. Not so bothered about having made the change, because I swapped out the Michel MX11 that was second box. If this means the King 155 I kept remains fully useable, I'm happy.

But I do think they should get on with the claims. It's been 60 working days since submission, and if they had 2000, then is 33 a day hard to process? And if not, that means that mine must for some reason be the last one to be processed........

Just hoping someone in the organisation follows these threads, and will take note:ugh:

[Curlytips]

Had a call from a gentleman at CAA today, who was processing my application. Small query to confirm my joint ownership (with my wife) of the aircraft, and he was happy. Said that if he didn't call again (within the next five minutes), then everything was in order and application would be passed. Phone didn't ring again, so looking forward to bank transfer :). Hopefully soon, but still not holding breath.........

[BEagle]

I see in Pilot magazine that there's talk of the CAA applying for derogation.

Incorrect! Some non-UK organisations are doing a bit of a King Canute with regard to 8.33 implementation requirements, but whether they'll have any success is very much open to doubt. It would in any case be very short-lived even if successful.

[MetOffice]

Just got our group PA28 back from its annual with a new Icom A220 fitted in place of our King box. Very modern, large clear display and good sound quality. Went for a first flight with it and quite impressed. When I landed I thought I'd try switching it into 8.33 mode - so into the setup menu select 8.33khz but now it's in set 8.33 I can't seem to get any 25khz frequencies to come up on the display, they just don't exist! Put in Cumbernauld 120.605 fine but then tried Scottish 119.875 & it wasn't there. What am I doing wrong?

[Philip Whiteman]

For the record, BEagle we were simply reporting IAOPA Europe's stance in the Notes section of the magazine

[Philip Whiteman]

...that was in the August issue. Anything we published before would also have been based on fact.

[BEagle]

Fair enough, Philip - and apologies for the previous intemperance which I will now amend.

So the comment above stating that..... "I see in Pilot magazine that there's talk of the CAA applying for derogation." was the result of someone mis-reading the magazine, I guess?

Anyway, AOPA (UK), having persuaded the UK CAA to apply successfully for 8.33 funding for UK aircraft equipage, is NOT asking the CAA for any derogation from the regulation.

For those still to do so, do NOT delay your application! The CAA still has some money left to allocate, but it can't last forever!

[Cole Burner]

The CAA still has some money left

If they relaxed their vice like grip and paid out some of the funds they have already allocated it would be good......

[BEagle]

Because each funding transfer incurs a cost which the CAA has to pay from the 8.33 pot, the plan is to minimise that by releasing the first tranche in one go in about (I gather) 4 weeks' time.

That will then mean more funds are available for the next tranche, rather than having had to be spent in admin. The CAA has made it quite clear that the maximum possible level of funding shall go to the end users and NOT get tied up in admin fees, so their plan should now ensure that the 8.33 pot will benefit as many aircraft equipage applications as possible.

[Curlytips]

Just received mail to say rebate approved and will be in bank next Monday 14 August, or within week following. That's exactly 6 months since I submitted claim (on Valentine's Day). Long time for them to tell me they love me too........:ok:

[MrAverage]

Me too on Monday!

[hegemon88]

I wonder whether there is any way to check how much of the money pot has already been allocated and if it's not too late to submit the application now?


/h88

[Curlytips]

Last messages from CAA said there was still cash available. First come, first served......

[muffin]

Just got our group PA28 back from its annual with a new Icom A220 fitted in place of our King box. Very modern, large clear display and good sound quality. Went for a first flight with it and quite impressed. When I landed I thought I'd try switching it into 8.33 mode - so into the setup menu select 8.33khz but now it's in set 8.33 I can't seem to get any 25khz frequencies to come up on the display, they just don't exist! Put in Cumbernauld 120.605 fine but then tried Scottish 119.875 & it wasn't there. What am I doing wrong?

This is apparently how the A220 works. It's design was based on the assumption that all frequencies thereafter would be 8.33 based and 25 kHz would not be required. Hence it cannot handle both schemes at once. I have one on order and just found this out yesterday. I would imagine that Icom will produce a software change that will correct this - I hope so anyway.

[BoeingBoy]

Despite having had a claim in since March and heard nothing direct (apart from the acknowledgement so have presumed all is proceeding OK) I have today received a mail generated from my G-INFO data asking if I want to make a claim?

FFS can't the CAA do anything without causing confusion and doubt!

Has anyone actually been paid yet?

[ChampChump]

The first payments were made last month. Today's e-mail seemingly went to 'everyone'.

[TheOddOne]

We got our £650 last month.
Today's e-mail seems to be a plea for everyone to come forward and claim the money; seems they haven't had the uptake they were anticipating. Are there STILL folk who think there'll be another extension?
Even if you're in a queue with an avionics shop, you can still buy the kit now and make a claim.

TOO

[CloudHound]

Muffin, MetOffice.

I too replaced my ICOM A200 with the new 220T and also discovered the problem. Spoke to their people at LAA Sywell and was reassured they had contacted the manufacturer in Japan to request a fix.

I'm very happy with the radio and, as I don't need 8.33 yet, am happy to wait for the fix.

Hmmm? Japan - speedy fix? We know a song about that don't we Colin:{

[DB6]

TheOddOne, evidently not. We bought our radio a few months ago and had the application rejected as we're still waiting to have it fitted. There is a big problem finding anyone able to do it in Scotland.

[Colibri49]

Just got our group PA28 back from its annual with a new Icom A220 fitted in place of our King box. Very modern, large clear display and good sound quality. Went for a first flight with it and quite impressed. When I landed I thought I'd try switching it into 8.33 mode - so into the setup menu select 8.33khz but now it's in set 8.33 I can't seem to get any 25khz frequencies to come up on the display, they just don't exist! Put in Cumbernauld 120.605 fine but then tried Scottish 119.875 & it wasn't there. What am I doing wrong?


Hi Metoffice. I bought my Icom A220 last November and eventually got it installed and operational in April. Subsequently there was a recall for a software update, something to do with squelch I think. It was sent back and returned in about 3 days. But it picks up interference whenever my Airmaster prop motor changes pitch and no amount of adjustment can overcome this. So I cruise with the prop set in manual control.


As regards the 8.33 vs 25 KHz mode issue, yes I soon discovered that when in 8.33 KHz mode the nearest "match" to a 25 KHz frequency doesn't work for reasons beyond my limited mental abilities, so I simply have to return to 25 KHz spacing mode. Not too difficult; just a couple of button pushes.

[Echo Romeo]

So what happens come January when 8.33 must be used, and ground stations are still on 25kz?

[Forfoxake]

So what happens come January when 8.33 must be used, and ground stations are still on 25kz?


A very good question especially since presumably Colibri's fix will not be allowed in case it swamps other nearby 8.33 frequencies.


PS Just reading and digesting the CAA guidance below. Any comments?





Technical information for Ground Stations

Conversion from 25 kHz to 8.33 kHz channel spacing

[Curlytips]

Spoke to the helpful CAA people and they pointed out that ground stations have another year to comply. So why? Apparently because they are groundbased their range is such that they won't overstep other frequencies in nearby 8.33 spacing. And supposedly they will be encouraged to change sooner as cost of 8.33 licence is cheaper than 25.

Without saying as much, they indicated they expected lots of pilots to be operating illegally for some time to come after start of Jan.

I await Jan 1st eagerly, to see just how many people/places can hear me and how many I can hear!

[Echo Romeo]

Spoke to the helpful CAA people and they pointed out that groundj

Without saying as much, they indicated they expected lots of pilots to be operating illegally for some time to come after start of Jan.

I await Jan 1st eagerly, to see just how many people/places can hear me and how many I can hear!

Always thought that's what will happen. Personally I believe that you would be able to transmit on most frequencies without, a, causing interference to overlap frequencies, or b,anyone being none the wiser.

[Forfoxake]

Just got our group PA28 back from its annual with a new Icom A220 fitted in place of our King box. Very modern, large clear display and good sound quality. Went for a first flight with it and quite impressed. When I landed I thought I'd try switching it into 8.33 mode - so into the setup menu select 8.33khz but now it's in set 8.33 I can't seem to get any 25khz frequencies to come up on the display, they just don't exist! Put in Cumbernauld 120.605 fine but then tried Scottish 119.875 & it wasn't there. What am I doing wrong?

According to my reading of CAP1573, 119.875 will be a 8.33 kHz frequency, although 119.880 will be displayed. Have you tried that?

[muffin]

An AM transmission as used on the aircraft band has a single discrete frequency for what is called the carrier. The speech information is carried in what is called sidebands on either side of this carrier frequency. These occupy space, typically 5 kHz either side. The receiver has a filter that is typically 10khz wide, so if you set your receiver to a frequency of 120.000 MHz, the filter allows the receiver to hear anything from 119.995 to 120.005. As long as the station you want is within this band, you will hear it. The same applies to the ground station, so if they are set to 120.000 they will hear anything transmitting plus or minus say 5 kHz from that frequency. Filter bandwidths for 8.33 radios will be much narrower, allowing more stations to use the same chunk of frequency space.

[Colibri49]

Just had an email informing me that the full 20% will be in my bank account on, or shortly after, Tuesday 19th September.

[Echo Romeo]

When did you submit your claim?

[arelix]

According to my reading of CAP1573, 119.875 will be a 8.33 kHz frequency, although 119.880 will be displayed. Have you tried that?

There is a lot of misunderstanding on the 8.33 issue. 119.875 is a 25 freq

25 khz freqs will still be 25khz freqs and will be selectable as before on your new 8.33/25khz radio(unless you have an IcomA220 which is a bit more difficult as explained in earlier post)

Good reading here to explain:
www.lightaircraftassociation.co.uk/2013/Magazine/May/radio.pdf

The table requires a good look to understand that your new 8.33 radio is in fact dual 8.33/25.....and your old 25 will work just fine on those freqs....which begs the question as to why we are not supposed to use them!

Oh... and CAP1573 says
"The licensing fee charged by Ofcom for an 8.33 kHz radio licence will be significantly less than the 25
kHz licence fee, due to the reduced bandwidth occupied." Yea right....... more like blackmail!

[Colibri49]

When did you submit your claim?


Goodness only knows; months ago! I believe that mine went in on day one, so if you can figure out when that was, you'll have the answer.


Okay relax, I've found it! 08th March.

[Forfoxake]

There is a lot of misunderstanding on the 8.33 issue. 119.875 is a 25 freq

25 khz freqs will still be 25khz freqs and will be selectable as before on your new 8.33/25khz radio(unless you have an IcomA220 which is a bit more difficult as explained in earlier post)

Good reading here to explain:
www.lightaircraftassociation.co.uk/2013/Magazine/May/radio.pdf (http://www.lightaircraftassociation.co.uk/2013/Magazine/May/radio.pdf)

The table requires a good look to understand that your new 8.33 radio is in fact dual 8.33/25.....and your old 25 will work just fine on those freqs....which begs the question as to why we are not supposed to use them!

Oh... and CAP1573 says
"The licensing fee charged by Ofcom for an 8.33 kHz radio licence will be significantly less than the 25
kHz licence fee, due to the reduced bandwidth occupied." Yea right....... more like blackmail!

I think the key bit in the article you cite is:

"If you accidentally select 132.005 when you should have selected 132.0
you will be on the right frequency but with a
narrower bandwidth, but the chances are that
you will be able to communicate. But if you
select 132.0 when you should be on 132.005
your radio will be in 25kHz mode and you are
likely to cause interference on several 8.33
channels and you may hear transmissions from
adjacent frequencies."

If you can communicate with a 25kHz Ground Station by selecting the nearest 8.33kHz frequency, then maybe the current ICOM A220T is set up the best way. You can continue to operate in 25kHz mode until the end of this year and then switch to 8.33kHz mode so that you do not interfere with any distant ground stations on adjacent 8.33kHz frequencies when you transmit.
If communication with a particular 25kHz ground station fails, you can temporarily switch back to 25kHz mode in the air. This will no longer be necessary when all ground stations eventually switch to 8.33kHz.

Is this summary correct, or have I missed something?

[Robin400]

8.33 radios ATC will ask you to set channel 118.405 You select CHANNEL 118.405
The transmitted frequency is 118.400

With regard to 121.5 the selected channel will be 121.505 transmitting on 121.500

The whole situation is a bit of a dogs dinner.

[Robin400]

This is a link to all 8.33 channels.

Index of /calculators (http://g3asr.co.uk/calculators/)

[Jim59]

My new 8.33 radio has a channel spacing option.
a) 8.33/25 kHz
b) 25 kHz.
The first thing I did was select option b) to disable the 8.33 feature so that when tuning it is simpler and quicker since the 8.33 channels are bypassed. A lot of money for nothing!

[Forfoxake]

Theory is all very well but what about in practice:

Just tried my Yaesu portable in 8.33kHz mode and can clearly pick up 118.800 and 119.100 on 118.805 and 119.105 respectively, although I noticed that a higher signal level is required to open the squelch on 118.800.

Obviously, I did not transmit but have previously picked up 120.605 transmissions with my 25kHz radio in the aeroplane set to 120.600 so hopefully, a 25kHz ground station would be able to pick up my transmissions on the nearest 8.33 kHz frequency. I will try that the next time I fly,

[G0ULI]

Just to try and simplify matters that have been brought up in this thread.

The new 8.33 kHz frequencies are essentially interwoven with the 25 kHz frequencies that have been used for years previously.

Unfortunately the digital frequency displays don't do the thirds rounding of frequencies that well, so the frequency on the display may be slightly off from the frequency your radio is actually tuned to.

The newer 8.33 kHz radios have narrower filters fitted in the transmit and receive circuits. This makes accurate tuning more critical if you are to be able to receive or transmit on a particular frequency.

Visually the difference is like looking at the world through a panoramic window, or through a series of smaller windows with shutters that only let you look at the view through one window at a time. The whole view is still available, its just that you have to focus on a narrower view in any particular direction than taking it all in at once.

In the case of trying to tune one of the old 25kHz frequencies, you may have to tune one channel above or below the frequency you would expect to be displayed in order to make contact. This is because your receiver has a much narrower bandwidth. You need to have the carrier frequency of the ground transmitter inside your receiver bandwidth to be able to hear the ground station.

Ground stations using 25 kHz equipment should still hear your transmissions okay because their receivers are tuned to a wider bandwidth. The issue here is that a ground station might hear you transmitting clearly, but you can't hear them because your receiver is not tuned to their carrier frequency.

Your transmissions will appear quieter and with more background noise, compared to an old 25 kHz radio. That is because your signal is not filling the entire receiving bandwidth of the ground station receiver, so you may find reduced transmitter range is a problem.

When ground stations are updated with new equipment, the quieter signal problem will disappear because now both stations will be using equipment that is closely matched in bandwidth for transmitting and receiving.

Yes, there will be some teething problems and issues and combinations of old and new equipment are used on the ground and in the air. These problems will sort themselves out as everyone moves to comply with the new standards.

Using old 25 kHz filtered equipment will cause interference to other users and you will quite probably be unaware of it. Of course you callsign will give you away, so sooner or later someone official will no doubt make you aware of the issue.

Nobody likes change and epecially the sort that requires a fair sum of money to sort out, but the new equipment does work well and will work even better once everyone has switched to the new standard.

[Robin400]

Instructions taken from a 8.33 radio manual.


Channels used with 25kHz width are entered in multiples of 25kHz: 123.500, 123.525, 123.550, 123.575, 123.600 etc. These are compatible with the old 25 kHz-only radios. To use the same frequencies with 8.33 kHz width, the frequency values entered are increased by 5kHz: 123.505, 123.530, 123.555, 123.580, 123.605 etc.

[ETOPS]

I've had direct experience of this problem. When 8.33 channels were introduced, for upper airspace in Europe, I was flying Boeing 747s. The radio tuning "Gables" heads were swapped with almost identical units that allowed the extra digit to be selected on the concentric switch which had grown from 2 to 3 levels.

Heading back over the Med early one morning Malta gave me a new channel to call Marseille but even though there were two of us looking at the "frequency" I still managed to miss-select it by one click.

The result was neither of us could here each other clearly. He kept saying "ooiscallin?" and I couldn't make proper contact as the garballing was severe.

Luckily P2 was more awake and quickly clicked over one more notch and we were able to hear ATC clearly. Thus getting both air and ground stations to "match" their frequencies is going to be the new game come Jan 1st.

[Robin400]

To keep this simple and avoid loss of comms all we have to understand is that the
(channel) we set on a 8.33 radio is not the frequency that the radio transmits on.

When ATC say " call CHANNEL xxx.xxx set the numbers normal manner.

The radio will not transmit the numbers you have displayed, that is why it is called a CHANNEL

Marine vhf has always used CHANNELS. I think the basic calling CHANNEL is 16, have not a clue
what the actual frequency is.

I posted a link which shows the set/displayed value and the frequency that the radio actually
transmits on.

[G0ULI]

Robin400

The Marine Distress Frequency Channel,16 is 156.8 MHz. Early marine band VHF radios were all crystal controlled and the frequencies and mode of transmission (frequency modulation (FM)) was chosen to prevent interference to airband transmissions and also direct communication between ships and aircraft. Aircraft use amplitude modulation or AM and the two systems are technically incompatible. There was some military reason for doing that at the time, although the reasoning is lost in the mists of time.

When digitally synthesised equipment became available, more marine channels were slotted in between the existing ones to make old and new equipment compatible. Looking at the actual frequencies against a list of channel numbers makes no sense at all as the frequencies hop about all over the place as the frequencies go up from Channel 0.

Additionally, marine radio systems are capable of full duplex transmisson and reception on some channels to enable virtually normal telephone conversations to be carried out. These channel pairings require the transmitter and receiver frequencies to be as widely spaced as possible because the transmitter and receiver sections are operating simultaneously. Tight filtering and some clever technical work arounds are needed to allow the system to work. The same full duplex system also works and is used on marine short wave frequencies but is somewhat more prone to interference. Simplex transmissions are more usually used for this reason.

As far as airband systems go, selecting the correct channel or frequency is more critical now, but otherwise the equipment functions just as it did before.

[arelix]

:ugh::ugh:
We are "overthinking" this.

We dial up the number/freq/channel given to us.

If it happens to be a "25Khz" freq then so be it.

If you are unable to dial up the number/freq/channel given...then you don't have the 8.33 option selected or you are using an "old" 25khz only.

There will still be 25khz freqs in use and you will need the 25khz selectivity for the climax offset carrier freqs, think scottish information etc with multiple transmitters all on slightly different freqs but usable with 25khz selectivity.

8.33 freqs adjacent to 25khz freqs still in use cannot be used/allocated until said 25khz freq is decommissioned.

Well that's how I understand it anyway!:)