Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

Mine Goes Up To 8!

Wikiposts
Search
Tech Log The very best in practical technical discussion on the web

Mine Goes Up To 8!

Thread Tools
 
Search this Thread
 
Old 20th Dec 2007, 13:38
  #1 (permalink)  
Thread Starter
 
Join Date: Dec 2002
Location: York, Pa.
Posts: 23
Likes: 0
Received 0 Likes on 0 Posts
Mine Goes Up To 8!

A question for the heavy iron jocks from a humble Saratoga driver:

I recently bought a 747 transponder control head on eBay as a toy for the kids (see link below). The funny thing (to me, at least) is that it allows digits from 0 to 8 to be selected for what I assume is each digit of the beacon code. Since transponder codes are in octal and ought to go from 0 to 7, what is going on here?

http://cgi.ebay.com/ebaymotors/ws/eB...m=230199151135
MikeGranby is offline  
Old 20th Dec 2007, 14:01
  #2 (permalink)  
 
Join Date: Jun 2002
Location: home and abroad
Posts: 582
Likes: 0
Received 0 Likes on 0 Posts
You've been had?
S76Heavy is offline  
Old 20th Dec 2007, 15:47
  #3 (permalink)  
 
Join Date: Aug 2002
Location: Switzerland, Singapore
Posts: 1,309
Received 0 Likes on 0 Posts
One guess: They used off-the-shelves parts which allowed more numbers than a transponder needs? Are you able to select the eight or is it physically inhibited?

Dani
Dani is offline  
Old 20th Dec 2007, 18:29
  #4 (permalink)  
Thread Starter
 
Join Date: Dec 2002
Location: York, Pa.
Posts: 23
Likes: 0
Received 0 Likes on 0 Posts
Here's the answer from a very kind soul at Gables...

> The G1884 series started in 1965. I started in this business in
> 1967. I don't know the whole story but back then ACT control
> panels allowed all 8's to be selected. Something to do with a
> "remote keyer" function. Apparently this function was never
> adopted and later revisions to product and newer part numbers
> only allowed 0 thru 7 selections on each digit.

So there you have it! 8888 presumably put the code under remote control from some other piece of equipment.
MikeGranby is offline  
Old 20th Dec 2007, 21:04
  #5 (permalink)  
 
Join Date: Jun 2005
Location: AEP
Age: 80
Posts: 1,420
Likes: 0
Received 0 Likes on 0 Posts
XPDR with "8" in digits...?

Don't get frustrated...
Same thing here...
xxx
I have flown airplanes with VHF COMM heads that could dial 117.xx -
And some others that could dial 136.xx as well, on the high end...
Yet the VHF COMM frequency spectrum goes from 118.0 to 135.999 mHz...
HF COMM heads that dial 2,000 to 29,999 kHz...
So, get confused with your XPDR...
Never say "it does not exist"... it very well might...!
xxx

Happy contrails
BelArgUSA is offline  
Old 21st Dec 2007, 08:58
  #6 (permalink)  
 
Join Date: Jul 1999
Location: U.K.
Posts: 269
Likes: 0
Received 0 Likes on 0 Posts
Thumbs up

And some others that could dial 136.xx as well, on the high end...
Which is just as well really otherwise you wouldn't be able to tune frequecies of 136.xx for example Redhill ATIS or Gatwick ATIS 136.52 or indeed our company frequency of 136.xx
Engine overtemp is offline  
Old 21st Dec 2007, 09:19
  #7 (permalink)  
 
Join Date: Mar 2006
Location: Southern Turkey
Age: 82
Posts: 171
Likes: 0
Received 0 Likes on 0 Posts
If you dial up 8888 you will start laying 'chemtrails' - not a lot of people know that.
rodthesod is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.