[ARC5] [Bulk] Re: R23 repair, dynamotor mounts, questions...AN/ARN-9

[DSP3]

Jack,

Well, that explains that.  I thought I knew about the early ILS systems 
but, it appears not.  I appreciate the explanation as it fills in 
several blanks.  My reference material only goes back to about 1947 and, 
by that time, the existing system was already in place.

Jeep - K3HVG



On 12/23/2015 12:57 PM, Jack Antonio wrote:
> On 12/23/2015 12:22 PM, DSP3 wrote:
>> These posts beg a question, or two.  I understand the 90/150 Hz VHF and
>> UHF LOC and G/S but how did this VHF-only system (ARN-9) work? Or, was
>> is horizontal guidance only??
>
> Hi Jeep
>
> It wasn't VHF-only.
>
> In the ZA and ARN-9, the localizer function was done on LF or MF.
> Hence the use of a low frequency receiver. My ZA manual references
> the RU and RAX.
>
> The glide slope was on approximately 90 Mc. It used a single beam,
> not a comparison of two signals.
>
> It apparently wasn't too successful. I have read that the localizer
> was bothered by propagation effects, and the glide slope angle was
> highly dependent on ground conditions, like dew.
>
> From my reading of the manual, it was a tricky thing to use, requiring
> quite a bit of work from the pilot prior to making the landing.
>
> No wonder it was quietly forgotten.
>
> Jack Antonio WA7DIA/4
>
>
>

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