[Milsurplus] NDB's and tank radios

[B. Smith]

Our Shut Down blunder was Loran C.
K4CHE

On 12/4/2025 5:40 PM, Charlie L. wrote:
> The rate of NDB shutdowns may be slowing or stopping.  It is still the 
> least expensive navigation aid out there, and pilots still like a 
> needle that swings around and says to fly 'thataway', as opposed to 
> discerning what his screens tell him.. Small municipal and county 
> airfields can afford an NDB with minimal expense and maintenance, 
> compared to an ILS.  The FAA is also backing off on turning off VOR 
> and TACAN equipment, a mountain top VOR near me slated for shutdown 
> has been resurrected and money spent on improvements.  Apparently the 
> military is also  finding out TACAN can not be fooled like GPS.  The 
> only difference in a standard VOR/TACAN station, VORTAC, and a VOR/DME 
> only (Distance Measuring Equipment) is the rotating antenna is turned 
> off and power reduced to 1KW out.  When the solid state second 
> generation VORTAC came online in the mid 80's, the TACAN ran at 5KW 
> out, the same as the old tube set that used a SAL89 Klystron with 12KV 
> on the cathode, but the fancy solid state system started blowing 
> amplifiers, of which three were 10 at 500 watts each, fed by a 1 to 10 
> splitter at 100 watts in, and then into  a 10:1 combiner for 5KW out, 
> but they started to burn up and it was too expensive to fix, so reduce 
> power to 1KW.  GPS still cannot be used for a precision approach 
> landing due to ground reflections, which are multiplied on an approach 
> over water, so  V/UHF ILS gear is still the norm, the latest model 
> being installed right now the ILS 420.  It has only two adjustments, 
> the rest are software.  A few years ago, an ILS could have 100 pots to 
> turn to align it and its monitors.
>
> Probably the biggest failure in the tank radios depicted in Fury, was 
> in the crystals.  The crystal used in those radios was notorious for 
> going bad, many not even making it across the pond to the ETO, just 
> going bad in transit.  I had a complete unused set for that radio in 
> the felt lined box, and checked all 100 of them, only two worked.  I 
> swapped them all to the new AF4K crystal guy for a good 160 meter 
> crystal.
>
> Charlie in NC
>
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html