[ARC5] (no subject)

[WA5CAB at cs.com]

Les,

The R-24 was also a NAV set.  But relatively scarce at least compared to 
the R-23, and the upper two COMM receivers.  However the 14 Volt R-148 is by a 
long margin the scarcest of all the AN/ARC-5 receivers.  I've only 
physically ever seen one of them.  Marty R. shipped it to me a few years ago just so 
I could say I had.  Then I sent it back to him.

One other point.  The tuning capacitors are also different between each of 
the radios.  The plug-in configuration saved time on the front end of 
filling a contract.  All of the sheet metal was interchangable.  So if the mix was 
still not settled early in a contract, work could still be started.

But you're correct.  Whoever buys it, unless he spotted all the things we 
have, is in for a surprise.

In a message dated 9/2/2010 7:29:54 PM Central Daylight Time, 
vk2bcu at operamail.com writes: 
> Hello Group:
> Yes, this is an interesting "one".  I don't know these sets well enough to 
> know if the broadcast band sets came with a "loop" antenna selector.  I 
> have a "navigation band" set (late WWII) with a "loop" antenna selector.  The 
> setup is identical to what I see in the photo.  This is consistent with 
> your observation about stencil showing 190 to 520kHz on the back panel.
> 
> Since all the IF transformers and the coil pack mount in sockets in, it's 
> would be easy to believe these sets were made in a basic configuration 
> (valves, tuning capacitor, wiring) and "configured" by simply by plugging in 
> the correct coil box and IF transformers.  At least this is how I imagined 
> the design concept at first.  I was always impressed by this concept.  Very 
> clever.  Wrong, wrong, wrong, or at least not that simple.  Different sets 
> in the same series (eg R-23 and R-26 from the ARA specification) have small 
> components that are different.   For example, the local and BFO plate 
> dropping resistors are not the same value across the range.  The lower frequency 
> sets use higher value dropping resistors than the higher frequency sets.  
> I assume this is because the oscillators "take off" more readily at the 
> lower frequency.
> 
> Anyway, I digress from the set seen on "the bay".  Who-ever buys it will 
> find one or two surprises not apparent from the photos, I'm certain.  For 
> example, the dividing plate that separates the valve compartment from the 
> tuning capacitor is missing.  This will make the set more prone to drift, 
> because of the transfer of heat.
> 
> O can't imagine why some-one would take the components from a rarer 
> broadcast band set to modify a common "navigation" set.  
> 
> Les
> 

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480