[Premium-Rx] Watkins Johnson 8711A Repairs after 10 Years

[Steve Pappin]

Hi Raymond,

If you look at the project emphasis it would be ROI, MTTM, MTTR, and weight. 
This receiver is a quick build with highly integrated
components. Mean Time To Repair is very low, Material cost is very low, and 
Shipping weight is very low. The construction is entirely different from 
1980's radios. It is SMT with minimal tooling (bend a box). There are very 
few mechanical attachments, light weight metal, and plastics.

In the 80's they milled chassis from solid pieces, used discrete components, 
and shielded every section. Each part was designed to be serviceable. In the 
90's the emphasis became JIT and COTS (Just In Time and Commercial Off The 
Shelf). This shifted the paradigm to assemblies that could be swapped in the 
field. The failed assembly went back to the factory or into the trash. The 
manufacturer could still charge a high price for the part without employing 
highly skilled field engineers.

The paradigm today is SDR that is manufactured to high reliability telecom 
standards. The building blocks do not have a front panel. They are network 
appliances that can be installed anywhere. Mission is defined by firmware 
and hardware. These newer systems are extremely flexible. They are not 
radios in the classic sense.

There is still a need for dedicated receivers, but not as often. Since the 
new role is automated information gathering agencies are using networks to 
do the job. Demodulation is a secondary mission. It only occurs when a 
target of interest pops up. Triggers for monitoring range from language to 
modulation type to key words. The first layer of filtering is automated. 
Agencies and the military still maintain active monitoring but it is almost 
always backed up by or handed off to automated systems.

For what it's worth I like the latest DRS radios. They are robust and easy 
to configure. You can make a front panel radio. You simply add the 
functionality that you need. But, they are not cheap and user knowledge is 
key. The radios is the 80's were power on ready. The radios of today require 
several hours of study before anything useful can be done with them. 
Children who grew up with computers in the home adapt to them quickly. Most 
of the manufacturers hold training classes for their customers.

Visit the DRS website if you want to know what they are doing with latest 
generation radios (DRS is the new Watkins Johnson). You can still listen to 
legacy transmissions but there is another world beyond that.

Best Regards,
Steve


----- Original Message ----- 
From: "Raymond Boute" <raymond.boute at pandora.be>
To: "Steve Pappin" <pappy92651 at yahoo.com>; <premium-rx at mailman.qth.net>
Sent: Tuesday, July 30, 2013 12:46 AM
Subject: Re: [Premium-Rx] Watkins Johnson 8711A Repairs after 10 Years


> Dear Steve,
>
> I am not the happy (?) owner of a WJ-8711A, but your observations
> raise questions that may be relevant to other receivers as well.
>
> At 00:17 2013-07-30, Steve Pappin wrote:
>>It is not the same as a MIL-STD radio manufactured pre 1985. Why so
>>many issues? Compare the 8711A to a fully optioned radio that cost
>>$80,000 to manufacture in 1983.
>
> Would it not rather be the development cost that make/made prices high?
>
>>We are going to run out of sources for viable parts. Many of the NOS
>>parts that come in are compromised.
>
> How is the situation for the "mil-spec" receivers from the 1980's?
>
>>2) One suggestion: If you are a hobbyist buy an organ donor 8711A in
>>good cosmetic shape and use it for parts. That's what many people are
>>doing.
>
> This seems reasonable for the front panel.  However, for the other
> parts, is it not usually the same parts that go first? If so, an
> organ donor may be likely to have those parts defective as well.
>
>>6) What can I do? The best solutions if you don't have an unlimited
>>budget:
>>1) Don't use the front panel. Run the radio from the serial
>>interface to reduce wear and tear.
>
> Part of my hobby is making Rx user interfaces, with the special
> feature of having analog dials (an unexpectedly large difference in
> ease of use).  I can help by making SW for those interested (in
> return for feedback only, not money).
>    The only problem I have is with IEEE488 (GPIB): since I don't
> have a IEEE488 analyzer, if the connection doesn't work right away, I
> have to proceed by guesswork.  This limitation has to be kept in mind.
>    Perhaps an interested WJ-8711A user nearby can contact me to
> start a little project.
>
> One thing is clear: SDR has taken over.  This raises entirely new
> problems: knowlege transfer, software documentation, modification and
> experimenting, programming environment etc., but that is another subject.
>
> 73
> Raymond ON4DBV
>
>
>
>