Beam Approach Visual Indicator Ref 10Q/4 RAF
 

This One Andy ?

https://cimg3.ibsrv.net/gimg/pprune....e73050d991.png

Yes, thank you that's the instrument.
I have pictures of the reverse but cannot share yet.
Mine, or should I say, my other half`s (Christmas present from me...) looks in a used condition compared to that one. There is a little delamination on the glass and some rust etc. but it has the bulbs in position.
Cheers Andy

Hi Andy
Yes not sure if you need a minimum number of posts before being able to post pics,I guess it will be maybe 5 or 10 posts.
Without googling I cannot give any info about the system although I have a rough idea how it worked.
Hopefully somebody will come along with some useful stuff for you.

rgds LR

Ok, thanks LR.
That Aero Antique website has given me a good idea behind the theory of its use.
The million dollar question for me is if it's possible to trace the history of this specific instrument back any further ?
Iim under the impression that a good many would have been made and fitted. Perhaps in the intervening years studies and notes have been made that might give me a clue of it's past ?
Cheers Andy

Roughly, the 'beam' transmitted a radio signal consisting of dots to one side of the on course signal and dashes to the other side.
If you were right of course, you would receive dashes which meant drift left; if dots you must drift right.
As you got close to the beam, the dots and dashes would merge to become a continuous tone so you were on course.

Thank you Chevron.

Hi Andy
Some nice old 1945 Weston Aviation Instrument Adverts and company info in 'Graces Guide'

https://www.gracesguide.co.uk/Sangamo_Weston

That's a nice look into the history thanks.
Interesting to see they describe it as a Blind Approach Indicator.
This little titbit makes me think that at the time of use and the aircraft it was fitted in it's likely there wasn't any landing lights.
Cheers Andy

Can someone explain how this instrument converted the audio signal to a needle presentation?

I think in this case 'Blind Approach' just means 'Non Visual Approach' - ie in bad weather or at night to get the aircraft safely down the glideslope until hopefully eventually being able to land visually when descended to under cloudbase or visual with any Airfield/Runway Lighting/Funnel Lights/Drem Lights etc.

IFT, this might help.

https://en.wikipedia.org/wiki/Low-frequency_radio_range

You may find further details in www.airfieldresearchgroup.org.uk under RDF/Radar sites sub section 'SBA(Standard Beam Approach)'.

megan, thanks for the link. I had looked at various wiki pages, but I didn't think to look at the radio range page. I hadn't heard of the vibrating reed instrument before but this is not the same as the SBA instrument.

chevvron, can you post a link? I couldn't find the section you referred to.

Unfortunately the forum is copyright protected so links don't work and you have to dial in to get the info.

IFT, try this. On the dial pictured the two circular features are lights which light up when the aircraft passes over the relevant marker beacon during the approach, the "O" being the outer marker and the "I" the inner marker.

https://wiki2.org/en/Lorenz_beam

megan, here’s the section of the page you referenced that I’m interested in:
I am trying to find out how the indicator converts the audio A and N into what amounts to a Localizer signal.

chevvron, my problem is that I can’t find the section you quoted. Starting at the Home page, how do I drill down to the info?

!) Select 'Forum' on the header.
2) Select 'Forum Members area'. (you can sign on quite quickly if you're not already a member)
3) Page down to 'Airfield related infrastructure and associated equipment'
4) In this section select 'RDF/Radar sites'
5) From the list of threads, select page 3
6) On page 3, select 'SBA (Standard Beam Approach')
NB: If you're not already a member, it can become VERY addictive!!