Hallicrafters S27
 

I have recently acquired a rather nice Hallicrafters S27 receiver in what appears to a fairly original unmolested condition.
I would be very interested in discovering the war time history of the set, I have attached some photo's of the set and the ID plates.
Also does any member know of a UK company that could reproduce the celluloid tuning dials as the bandspread dial is split.
Radio Daze in the USA can supply a new S meter dial but not the tuning dials at the moment.
Peter.

Re: Hallicrafters S27
 

Nice!

I wonder what the "AM Modifications" were? These were used during WWII as part of the effort to identify and locate the german 'Knickebein' navigation-beams, as well as trying to listen for radio-control signals being sent to early V2 rockets [the 'production' V2 didn't use radio-control and depended on inertial navigation].

I can understand the Air Ministry doing modifications if they were going to fly these in the like of Ansons. [The 1970s BBC series 'The Secret War' has a short clip of William Woolard(sp?) in an Anson with a S27]

The S27 I've got here has a "Pye" type coax-socket fitted to the rear panel and a screened-on front-panel identification that it's so modified.

"Modified for coaxial ????"

It's interesting too that round the 'Pye' coax socket on mine appear to be three small holes in a triangular layout - along with a hint of a circular 'shadow' on the chassis-plating, as if there was perhaps an earlier style of coax socket fitted before the Pye connector>??

Re: Hallicrafters S27
 

I am just reading The Secret War by Brian Johnson which mentions the S27 in various chapters.
The aerial connectors on mine appear to be very basic but original.
Is there any way of dating these sets, I am assuming mine is around 1940/41.

Re: Hallicrafters S27
 

I'm sure I recall a three-hole coax fitting on some versions of the CR100, though I've no idea of its designation.

Did the receivers have provision for 240VAC operation as standard, or just US market mains- perhaps the mod was a UK-suited mains transformer. Or (clutching for those straws) a wider IF bandwidth for supersonic modulation, monitored by something wider-band than the human ear?

Re: Hallicrafters S27
 

I've got one of these. With a top f of 143 Megs I think they sometimes got modified for 2 Metres!

Dave

Re: Hallicrafters S27
 

Mine has a non-standard [rather larger] mains transformer fitted: it _looks_ to be rather old (cloth-covered leadout wires...) so I imagine it could have been fitted early in the radio's life. Equally, it could have been an 'old' surplus part that was fitted later to replace a burned-out original.

The 'wide' bandwidth positiongives 50KHz bandwidth, so there wouldn't have been much need to modify it to receive above-human-hearing modulation. I'd have expected this to be done though ny fitting a separate 'IF-out' socket so whatever Blumlein or Watson-Watt wanted could be coupled up as an external unit.

Interestingly, a few photos down here:

http://www.alternatewars.com/Bomb_Lo...Bomb_Guide.htm

shows what some claim is a S27 and others a S36 (at one time during WWII on the Hallicrafters production-line the front plates were seemingly interchanged depending on what they had and how urgent the order was...) Apparently it's being used to set up the radar-altimeter that triggered the bomb at the required height.

Re: Hallicrafters S27
 

Interestingly the Stores Reference 110D/21 is for the Canadian Air Ministry, the British Air Ministry number would be in Section 10D.

Andy

Re: Hallicrafters S27
 

Andy,

I thought that section 110 referred to items not made in this country or to a UK specification
Valves area typical example. CV509 (6V6G) is listed as being manufactured by STC (UK) and RCA (USA) and has two Air Ministry numbers, 10E/349 and 110E/90. The former meeting an MOS specification and the latter to a JAN specification.
Interestingly CV510 (6V6) is to a JAN specification but is listed with both a 10E and 110E number.

All a bit confusing but then it was wartime.

Chris