The Amazing Barlow Wadley XCR-30 Radio

[Argus25]

I restored one of these radios, the main issues being replacement electrolytics and a full calibration.

These are quite remarkable radios. I'm not certain though, but I think the Wadley Loop wasn't aptly named because it is a feed forward control system. In any case I wrote an article about it to explain the loop to those unfamiliar with it and also some remarks about how to set the AGC correctly, because there is a trap to fall into using the manufacturer's recommendation:

http://worldphaco.com/uploads/THE_AM...LEY_XCR-30.pdf

[G4YVM David]

Lovely radio's. I almost had one once. Same system as a 'frog 7' if I recall correctly.

D

[Argus25]

Yes I think there are a few, like the Drake SSR-1 and another receiver by Racal.

[Radio Wrangler]

Rather a number of receivers by Racal

RA17 all versions
RA117
RA217
RA1217
to be going on with

And I think one works backwards in the MA79 drive unit.

David

[John KC0G]

Interesting stuff on the AGC. Thank you.

All of the XCR-30's of which I have been aware were the Mk. II version. Does anybody know if there was a predecessor which actually hit the streets, eg a Mk I, or a non-Mk II labelled version?

And there were several other radios which used the Wadley triple-mixing system. The Drake SSR-1, Standard C6500, Century 21, Century 21D, Lowe SRX-30 and Lowe SRX-30D all came from the same source. Then there was the Realistic (Radio Shack) DX-300 and DX-302. As David noted, the Yaesu FRG-7 also used it and it was the best known. The FRG-7 was also badged by Sears here in the U.S.A. I think that there others, but far less common.

73 John

[Argus25]

Originally Posted by John KC0G

Interesting stuff on the AGC. Thank you.

All of the XCR-30's of which I have been aware were the Mk. II version. Does anybody know if there was a predecessor which actually hit the streets, eg a Mk I, or a non-Mk II labelled version?

Thanks John.

I have only ever seen the MK2 version, though there are two versions of it, the later one uses an IC for audio out, the other transistors. Mine is the earlier transistor version. On the later IC version, looking at the schematic there is the provision for an AM-FM switch, so clearly that must have been planned, or there actually is an FM variant, but I have not seen one, maybe that is the MK3.

As well as this radio having a remarkable design and physical implementation of that, on its large single pcb, it is very hard not to be impressed by its steel case and cast front panel that is the most solid/robust arrangement of any transistor radio I have ever seen. It looks like it would do well even run over by a truck and boy is it unexpectedly heavy for its size, its like picking up a block of high density metal !

The only complaints I have heard about it is that the sensitivity is not wonderful at the low end of the band, say MW, but it relies on the Whip antenna and really I think it is just that the received noise this way is more dominant than using a ferrite rod (magnetic) antenna as most transistor radios do in that region.

On shortwave it sparkles, just with the whip and out-does most of my shortwave radios. It is important of course that it is in perfect alignment, some have been judged harshly but I'm sure the alignment was off in those cases. It also has great dial makings and when calibrated properly its easy to estimate the exact station frequency fairly closely or go to a known station frequency. There is nothing more attractive than an accurate tuning dial.

Hugo.

[Argus25]

..I put in a better picture of the radio attached.

[G6Tanuki]

They are rather nice *when* they are working properly. Apparently at the time of production South Africa was still the subject of various economic sanctions and the quality of some components was rather variable, being 'whatever we can get'.

One version, from memory, also risked static damage to the front-end transistor if you touched the whip antenna!