[Premium-Rx] Siemens E311

[Michael O'Beirne]

Dear Pierre

I have one of the few Siemens E-311s in the UK.  Mine came from a German 
Government source and is immaculate - hardly a smudge on it.  I also managed 
to get both the German and the English manuals.

However it is not a "premier Receiver", as defined by the group as having a 
microprocessor in it.  The group made a special exception for the R390A as 
it is an American "idol" of engineering excellence and that is 
understandable, though I am not a fan of the R390A for a variety of reasons.

Modifying the E311 is fraught with problems.

First it is entirely modular and it seems to be very difficult to make many 
adjustments.  The manual recommends that for many repairs or re-alignment it 
be sent back to Siemens, who would have had all the correct factory 
alignment jigs.

Second for a highly complex valved radio, it compact.  There is not much 
room for modifications.

As for the 7360 as a replacement mixer, I have heard that it is less good as 
regards intermodulation than was thought in the early 1970s.  It has the 
added problem that it is a microphonic valve and you need to fit a special 
valve base with a rubber suspension built in.  No one has made these for 20 
years or more.

Thirdly, to be effective with the 7360 you need a balanced output. 
Modifying the single-ended valve outputs (needed by the ECH81 mixers) will 
require major modification.

Fourth, one can reasonably assume that the German engineers would have 
striven to their uttmost to produce an excellent radio because that's what 
Germans do!!  At a price of 15,000DM per radio you can understand that.  In 
England in 1959, 15,000DM would have bought you 3 or 4 Mini cars or a 
reasonable house!  I joke not.

I find that the E311 in fact is a very good radio.  It has 4 stages of RF 
selectivity before the first mixer and that achieved phenominal protection 
against adjecent signals not to mention excellent IF and image rejection, 
and the front-end is pretty bombproof.  The kHz tuning is vastly nicer and 
easier to use than than on the R390A.  It tunes at about 12kHz per rev.

My major criticism is that the AGC is very harsh and "in your face".  It can 
probably be modified though I don't know of anyone who has.

My advice is to leave well alone unless there is an obvious problem.

73s
Micghael
G8MOB

----- Original Message ----- 
From: "F3WT" <ars.f3wt at wanadoo.fr>
To: <premium-rx at mailman.qth.net>
Sent: Thursday, July 21, 2011 6:46 PM
Subject: [Premium-Rx] Siemens E311


Hello ,

1°Has there been a discussion on this receiver( siemens E311 - I think one 
of if not last tube version on shortwave ) on this forum.
Is there a way to find out by retrieval/ any search action on archive-files?

2° As anybody experience with  mixer substitution by 7360 beam deflection 
tubes and its IMDR ( intermodulation dynamic range )  improvements?

Thank you for any hint.

Pierre.
F3WT.