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

[Terry O']

I interviewed a few of the engineers on the 8711 team and Steve's 
comments are accurate.

The one thing I can add is many WJ (and other) receivers are designed 
for a customer to their specifications.  The smart companies, the ones 
that survive, figure out how to design a product with this seed money 
that can be adapted for other subsequent sales.  WJ knew that radios 
with knobs were a tiny and dwindling fraction of the market.  So they 
designed a very fine set of circuit boards and enclosed it in what now 
looks like a mediocre package.

 From an engineers perspective, the 8711 is a triumph of meeting design 
constraints.  It provides robust performance in an elegant manner.  Most 
of the complaints I am reading are about things outside the design criteria.

Terry O'
http://watkins-johnson.terryo.org



On 7/30/2013 2:56 PM, Steve Pappin wrote:
> 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
>