[Premium-Rx] Fw: Racal 177x PSU

[Michael O'Beirne]

Dear Nigel

I read your comments tonight with much interest and am grateful for your 
thoughts.

I have never seen the innards of the Redifon R1001 and so cannot comment.

I have the Marconi ICS3 here (not working yet) and I can confirm that it is 
of magnificent battleship construction, separating sensibly the DC, control 
and AF under the big diecast chassis tray from the RF which comes in on 
jumper leads via SMBs to the modules on the top side of the chassis.  Of all 
receivers under discussion, its RF performance is probably the very best (as 
was the cost), though no one would want to tune around for long with the 
click-click tuning of the decade tuning controls (though one later version 
sold I believe to the USN appears to have a microprocessed panel).

I have no issues with the 1772 other than the obvious build cost.  The 1792 
is more compact and the wiring is much better thought out, separating the RF 
from the control and AF side.  However, the cheapo connectors on the ribbon
cable do not inspire confidence, though in practice they have never given me 
trouble.

I entirely agree that the PCBs of Racal at this time were not good, not a 
patch on, say, HP's.  I have an old HP 606B sig gennie of this period and 
even the PCB in the PSU is beautifully made and gold plated.  Similarly the 
construction of the older American Norlin SR209 VHF panoramic receiver is 
more compact and better achieved using decent mil-spec Cinch connectors and 
PTFE wiring.

On thinking more deeply I can see that parts of the 1772 are indeed a 
throwback to the RA117, the most obvious being the synthesised PLL covering 
3.6 to 4.6MHz, indicating its origin as a free-running VFO (with an 
identical RA117-type film strip scale) in the original 1770 design, which 
was not progressed when it became evident that full synthesis was the way 
ahead.

However, I have always liked the super rigid diecast chassis construction 
rather than the more flexi box chassis of the Redifon R500 and R551N and 
others.

I also think that the aesthetic panel layout of the 1772 is simply 
excellent. I don't know what it is but ever since I saw a pic of one in (I 
think) Wireless World, it struck me instantly as a "must have" item. 
Indeed, virtually all Racal gear looks wonderful despite internal 
limitations.   I cannot live with ugly gear whatever its electronic merits, 
and that is one reason why I have little interest in the many Japanese black 
boxes.

73s
Michael
G8MOB

----- Original Message ----- 
From: <GandalfG8 at aol.com>
To: <premium-rx at mailman.qth.net>
Sent: Tuesday, August 10, 2010 12:13 AM
Subject: Re: [Premium-Rx] Fw: Racal 177x PSU


>
> In a message dated 09/08/2010 22:30:51 GMT Daylight Time,
> michaelob666 at ntlworld.com writes:
>
>> I  suggest that some of Nigel's comments are a little harsh.  There was
> in
>> fact quite a time span between the last of the valved gear (typically
> the
>> RA17) and the RA1772.  There were the rather poor performing  RA217
> series
>> in between, though I suspect that their problems were  more the trouble
> of
>> early transistors rather than of inherent design  defects.
>
>
> ----------------------
> Hi Michael
>
> I'm sorry but I don't think my comments were particularly harsh so  much
> as
> just being realistic.
>
> As I said earlier I don't dispute Racal's technical excellence when it
> comes to the 17xx series but there must have been something  adrift with
> their
> production engineering at that time.
>
> Although the 217/1217 series was indeed the immediate unfortunate attempt
> to produce a solid state RA17, the mindset still seems to have been well
> and truly stuck in valve age production techniques when engineering  the
> 17xx.
> That there was quite such a time span between the RA17 and 1772 only
> serves to indicate just how far the Racal head was buried in the  sand.
>
> That wiring harness might have been "a thing of beauty", just as any
> complex cableform might seem in its uninstalled, or even installed, state,
> but
> the 17XX series construction techniques were archaic in comparison  with
> other contemporary manufacturers of professional receivers.
>
> The Redifon R1001 I mentioned previously was far more typical of good
> production engineering of that period, high quality fibreglass circuit
> boards,
> chassis mounted connectors for all the control and supply wiring  with
> well
> organised fixed wiring beneath the chassis, and separate coaxial links
> topsides for all RF and signal interconnects.
> Watkins johnson was building the Quad8 and Quad8B at this same time and
> even the Marconi ICS3 hails from the same period.
>
> Racal, for whatever reason, was churning  out SRBP circuit boards on the
> 17xx series, a nice touch of domestic  radio thinking here, with that
> wonderful hinged arrangement and everything hard  wired to pins along the
> edges of
> the PCBs and all routed through one big  fat umbilical cable.
> What's really sad is not that they couldn't have foreseen the  cableform
> cooking and deteriorating but that they decided on this form of
> construction
> in the first place.
>
> And, no, I'm not given to Racal bashing, despite what it might  sound
> like:-), and in other respects I was once as great a fan of the 17xx,
> especially
> of the 1784 and variants, as anyone could be.
>
> Technically it was excellent, perhaps not too surprising given Danny's
> account of the setting up procedure:-), ergonomically it was very nice to
> use,
> but internally it was not at all well engineered and my enthusiasm waned.
>
> I accept that I'm probably out of step with much of the rest of the  radio
> world, but this does not rank as one of my favourites.
>
> regards
>
> Nigel
> GM8PZR