[ARC5] Mrker beacon receivers BC-357, BC-1023 and the like Sensitivity

[ac2eu at yahoo.com]

 OK, that makes sense and I learned something too!
    On Monday, October 13, 2025 at 04:47:30 PM EDT, hwhall at aol.com <hwhall at compuserve.com> wrote:  
 
 They're for "marker beacons"? Marker transmitters were arranged, three or four of them, along runway approach glide paths, for landing blind. Beamed straight upward, each marker beam beeped a tell-tale on the control panel that told a pilot where he was on the glide path: Outer Marker, Middle Marker, Inner & Barrier. At each marker he would check altitude & airspeed to ensure he was right on standard approach for the landing. The final marker indicated the runway threshold. So, the distance transmitter to receiver was not great & the receiver need not be very sensitive. It may even be intended for the receiver to be a bit deaf, so that it wouldn't detect the Marker beam until if was right over the transmitter.

Wayne
WB4OGM

On Monday, October 13, 2025 at 02:38:18 PM MDT, J Mcvey via ARC5 <arc5 at mailman.qth.net> wrote: 

Considering that s9 is around  100 microvolts. That’s pretty deaf right out of the box!
Why are built with such low sensitivity?

Sent from my undisclosed bunker location

On Monday, October 13, 2025, 2:21 PM, Revcom Electronics <revcom at wbsnet.org> wrote:
> I have a new in box BC-1023A receiver that has the manual with it, 'Technical Order No. 08-10-150' and it states the
> "normal sensitivity" for unit varies between 1500 and 2500 microvolts  at 1000cps; (30%  modulation).
> Have another one not in box.  Anyone interested on these items?
> Rod
> K0EQH
> Scott City KS                                                             
> 
> ________________________________
> From: "ARC-5 List" <arc5 at mailman.qth.net>
> To: "ARC-5 List" <arc5 at mailman.qth.net>
> Sent: Monday, October 13, 2025 12:58:06 PM
> Subject: [ARC5] Mrker beacon receivers BC-357,        BC-1023 and the like   Sensitivity
> 
> 
> I have been playing with some marker beacon receivers today.I found the sensitivity to be low.
> For example, my BC-1023 needs -13 dB signal to activate to out relays.
>  
> I can not find what the specifications for those receivers is ( was ).
> Anyone some info on that ?
>
  
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