50KHz Glideslope?

[VOR-DME]

Who knows something about 50KHz spacing for glideslope receptors?
Traditionally we have 40 GS frequencies, with 150KHz spacing from
329.15MHz to 335 MHz. But I see European ILS's requiring "50KHz
Glideslope spacing". Anyone know what receptors do this? Or why we would
want to do this? 8.33 spacing for VHF coms is easy to understand, but
are 40 ILS frequencies in a given reception area really insufficient?

[Sam Spade]

VOR-DME wrote:, but
> are 40 ILS frequencies in a given reception area really insufficient?
>

Yes.

[VOR-DME]

In article >, says...
>
>
>VOR-DME wrote:, but
>> are 40 ILS frequencies in a given reception area really insufficient?
>>
>
>Yes.

Well then - what equipment offers this 50KHz spacing.
Not the King KX155A or 165A or the Garmin 430W.

[Sam Spade]

VOR-DME wrote:
> In article >, says...
>
>>
>>VOR-DME wrote:, but
>>
>>>are 40 ILS frequencies in a given reception area really insufficient?
>>>
>>
>>Yes.
>
>
> Well then - what equipment offers this 50KHz spacing.
> Not the King KX155A or 165A or the Garmin 430W.
>
I presume the airlines that fly to Europe have that capability.

[VOR-DME]

In article >, says...
>
>
>VOR-DME wrote:
>> In article >, says...
>>
>>>
>>>VOR-DME wrote:, but
>>>
>>>>are 40 ILS frequencies in a given reception area really insufficient?
>>>>
>>>
>>>Yes.
>>
>>
>> Well then - what equipment offers this 50KHz spacing.
>> Not the King KX155A or 165A or the Garmin 430W.
>>
>I presume the airlines that fly to Europe have that capability.

Presuming is good from home, sitting around the fire.
For flying it just doesn't cut it . . .

[VOR-DME]

In article >,
says...

>
>I have not come across this, here in European pilot publications etc.
>GA would have picked this up I reckon, because we do use KX155As,
>165As, GNSx30s etc.
>
>What we are getting is PRNAV and that is a far bigger problem -
>potentially.
>
>The airlines cannot fly something that is not on an approach plate.
>
>Does anyone have a reference for a reduced ILS frequency spacing in
>Europe?

A "reference" - do you mean an example?
https://www.sia.aviation-civile.gouv.fr/aip/enligne/fr/..%5CPDF_AIPparSSection
%5CIAC%5CAD%5C2%5C0903_AD-2.LFPN.pdf

This is a very commonly used approach (VOR-DME)
I could list dozens of others requiring "50KHz Glideslope"

[VOR-DME]

In article >, says...
>
>
>In article >,
>says...
>
>>
>>I have not come across this, here in European pilot publications etc.
>>GA would have picked this up I reckon, because we do use KX155As,
>>165As, GNSx30s etc.
>>
>>What we are getting is PRNAV and that is a far bigger problem -
>>potentially.
>>
>>The airlines cannot fly something that is not on an approach plate.
>>
>>Does anyone have a reference for a reduced ILS frequency spacing in
>>Europe?
>
>A "reference" - do you mean an example?
>https://www.sia.aviation-civile.gouv.fr/aip/enligne/fr/..%5CPDF_AIPparSSection
>%5CIAC%5CAD%5C2%5C0903_AD-2.LFPN.pdf
>
>This is a very commonly used approach (VOR-DME)
>I could list dozens of others requiring "50KHz Glideslope"
>


Sorry - Make that ILS-DME

[Sam Spade]

VOR-DME wrote:
> In article >, says...
>
>>
>>VOR-DME wrote:
>>
>>>In article >, says...
>>>
>>>
>>>>VOR-DME wrote:, but
>>>>
>>>>
>>>>>are 40 ILS frequencies in a given reception area really insufficient?
>>>>>
>>>>
>>>>Yes.
>>>
>>>
>>>Well then - what equipment offers this 50KHz spacing.
>>>Not the King KX155A or 165A or the Garmin 430W.
>>>
>>
>>I presume the airlines that fly to Europe have that capability.
>
>
> Presuming is good from home, sitting around the fire.
> For flying it just doesn't cut it . . .
>
And your point is?

[Sam Spade]

VOR-DME wrote:
> In article >, says...
>
>
>>>For flying it just doesn't cut it . . .
>>>
>>
>>And your point is?
>
>
> That real questions merit real answers.
>
> I asked this question to get information for my own flying use.
> I may be reading something wrong. There could be any number of reasons why the
> matter is simpler in practice than it appears at first glance, that's why I'm
> aking.I'm disappointed not to have more in the way of informative responses,
> but perhaps these will come.
>
This isn't the best place, by far, to get good information.

You might try a business aviation forum or check the international AIPs.

[VOR-DME]

In article >, says...

>> For flying it just doesn't cut it . . .
>>
>And your point is?

That real questions merit real answers.

I asked this question to get information for my own flying use.
I may be reading something wrong. There could be any number of reasons why the
matter is simpler in practice than it appears at first glance, that's why I'm
aking.I'm disappointed not to have more in the way of informative responses,
but perhaps these will come.

[Ron Rosenfeld]

On Tue, 03 Mar 2009 21:47:22 -0800, VOR-DME > wrote:

>Who knows something about 50KHz spacing for glideslope receptors?
>Traditionally we have 40 GS frequencies, with 150KHz spacing from
>329.15MHz to 335 MHz. But I see European ILS's requiring "50KHz
>Glideslope spacing". Anyone know what receptors do this? Or why we would
>want to do this? 8.33 spacing for VHF coms is easy to understand, but
>are 40 ILS frequencies in a given reception area really insufficient?

Hmmm.

How are these new frequencies being implemented? Do you have some
documentation?

Currently, each ILS frequency is channeled to a particular GS frequency.

Given 50kHz spacing, and given that the ILS frequencies are 108.10 to
111.95 (and given that if the Freq*10 is even, it is a VOR frequency),
there are only 40 available ILS channels in that frequency range:

e.g. 108.10
108.15
108.30
108.35
...

The 150kHz spacing from 329.15-335 also results in 40 GS frequencies.

So unless there is some change in the ILS specs, it seems odd that there
should be a change in the GS specs.

Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[VOR-DME]

In article >,
says...

>
>That URL doesn't work but I have just looked up the Jeppview plate for
>ILS 25 LFPN and the ILS frequency is 110.15.
>
>There are no special notes on this plate.
>
>What happens if one sets up 110.15 on say a KX155A?

The URL worked for other contributors.
The official plate specifically includes the 50Khz limitation mentioned.

[VOR-DME]

In article >,
says...
>
>
>Update:
>
>It appears this whole topic is meaningless and the result of
>somebody's error.
>
>It turns out that all current GA nav radios support 50kHz spacing
>(therefore 40 channel glideslope). A few very old (Narco 12A with UGR2
>glideslope Rx's ?) units may still be around, but all Garmin and
>Honeywell and Narco equipment produced in the last 20 years or more is
>certainly compliant.


You should inform the appropriate authorities (French DGAC) of your
discovery. Also Garmin, Bendix King and others, who list their
specifications for glideslope spacing as 150KHz.

Do you have any documentation for your assertions?
This would be a start. . .

[-b-]

In article >,
says...
>
>
>Update:
>
>It appears this whole topic is meaningless and the result of
>somebody's error.

Fine, but who's error?

>
>It turns out that all current GA nav radios support 50kHz spacing
>(therefore 40 channel glideslope).


Did you do arithmetic in school?
I did. 40 glideslope frequencies between 329.15MHz and 335 MHz yields
150KHz spacing, just as all the manufacturers list on their spec sheets.
Divide it out, and do get back to us with your findings. . .


All Garmin and
>Honeywell and Narco equipment produced in the last 20 years or more is
>certainly compliant.

I do not really doubt this - in fact it's what I expected to find.
However on reading the specific note, and looking the item up, I cannot
find any documentation to support this. On the contrary, manufacturers'
specifications do not indicate compliance. I would be delighted if you
could point me to something to prove my reading incorrect.

[VOR-DME]

I agree with everything you say.
That's why I asked the question, because I am faced with several approach
plates which specify "Requires 50KHz Glideslope". I cannot find anything
about this in any documentation, so I have no idea what this note means.

I think what I'll do is fly a vor or loc approach at one of these and see if
the GS comes in on the KX155A. If so, I'll just guess that note is of no
importance, and relates to something very old and forgotten.



In article >,
says...

>
>Hmmm.
>
>How are these new frequencies being implemented? Do you have some
>documentation?
>
>Currently, each ILS frequency is channeled to a particular GS frequency.
>
>Given 50kHz spacing, and given that the ILS frequencies are 108.10 to
>111.95 (and given that if the Freq*10 is even, it is a VOR frequency),
>there are only 40 available ILS channels in that frequency range:
>
>e.g. 108.10
> 108.15
> 108.30
> 108.35
> ...
>
>The 150kHz spacing from 329.15-335 also results in 40 GS frequencies.
>
>So unless there is some change in the ILS specs, it seems odd that there
>should be a change in the GS specs.
>
>Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[Ron Rosenfeld]

On Thu, 02 Apr 2009 11:10:38 -0800, VOR-DME > wrote:

>I agree with everything you say.
>That's why I asked the question, because I am faced with several approach
>plates which specify "Requires 50KHz Glideslope". I cannot find anything
>about this in any documentation, so I have no idea what this note means.
>
>I think what I'll do is fly a vor or loc approach at one of these and see if
>the GS comes in on the KX155A. If so, I'll just guess that note is of no
>importance, and relates to something very old and forgotten.
>

I have finally been able to find the chart to which I believe you are
referring (ILS/DME TNO RWY 25R) and I believe you have misquoted the
requirement, and mis-understood the meaning.

The chart that I am examining on line does NOT read "Requires 50KHz
Glideslope"

Rather, the box I see reads:

"GP usable only by ACFT equipped with ILS at 50 kHz"

ou, en française:

"GP utilisable uniquement par ACFT équipé ILS à 50 kHz"

This means that the spacing on the **ILS** receiver needs to be 50 kHz.
Makes sense since the LOC frequency is 110.15.

Your KX155A should have no problem tuning this approach, and channeling the
correct GP frequency, so long as your KX155A can tune 110.15 and has a GP
receiver.

Having read that, it seems to be a strange note because, if your ILS
receiver could not tune in 50 kHz increments, you wouldn't be able to use
the LOC or LLZ approach either! In the US, I would ask our local Flight
Standards District Office for clarification if I saw a note like that. But
I would not be concerned about flying it with a KX155.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)