Microwave Tuner

Complete set PTC-8700

Tuner Pictures

Controller Pictures
                                                    
 Hello all,
                                                           
 Last year, I acquired some fine equipment from a Marconi –UK plant that has been closed down. The equipment has been manufactured by the David Sarnoff research center, Princeton, NJ,USA.

Sarnoff corporation
201 Washington Road
CN 5300 Princeton
NJ 08543-5300
USA.

It concerns eight automated microwave matching tuners and their controller.

They are used for example as matching elements for microwave devices to make noise measurements or are used in conjunction with a vector network analyzer.

The following information is written on the labels of the equipment:

Manufacturer:
David Sarnoff Research Centre
Princeton, N.J.  USA
TUNERS: PMTS
PT-20         0.8 – 2.0 GHz
PT-12         2.0 – 4.0 GHz
PT-9L         4.0 – 8.0 GHz
PT-9H         8.0 – 18.0 GHz
CONTROLLER: PTC-8700 Programmable tuner controller


My aim is to get this equipment running in our RF& microwave lab .This to demonstrate our last year master of science engineering students the principles and powerful technique of microwave matching tuners.Also our local microwave club has many aspirations building low noise amplifiers and converters.

These tuners can mismatch up to an SWR of 10.Recent tuners can even mismatch up to SWR of 50 at some frequencies but are way out of my budget certainly as a radio amateur.The  recent tuners also allow to terminate other frequencies( such as harmonics) at a particular impedance for looking into IMD.

Within some months ,I get a student from Vigo university who wants to make a thesis on  it, writing software for finding lowest noise, maximum gain, best IMD,etc.
 

However, I was unable to retrieve any information on this equipment.

1) The GEC- Marconi division has closed down and throwed out all equipment and manuals.I could get no info at all.

Yes, I could buy the tuners but the reseller even didn't know what it was all about.

2) I wrote to the David Sarnoff centre only to hear they closed this microwave division that built these devices in the nineties; that all people of this division where laid off and that no info was kept.

(I got this info from an executive director now at David Sarnoff library , Phd in history, who is trying to restore info about all the achievements at David Sarnoff.)

3) The only bit of information I could find is in the recent book" Microwave Circuit Design- Using linear and nonlinear techniques"- second edition-, G.Vendeling,A.Pavio,U.Rohde-John Wiley Interscience,2005,ISBN-10 0-471-41479-4 or ISBN-13 978-0-471-41479-9,  pp918-921.

This book roughly describes the general working of these tuners as a first step using automated tuners.

4) Untill now we were able to extract some of the software from the controller and are using a logic analyzer to try to understand internal communication. However , it gets too difficult without any other information.

 This is way I am asking for your help.You guys are my only chance to get this equipment going again!

 I would be pleased if you could help me in finding : operating and service manuals, specifications, application notes, patent info, software or any kind of information on this particular equipment.

Of course I am willing to pay for costs of photocopying, shipping etc. that might come up.

I would be very obliged if you could help me to find this information.


Many thanks for your efforts in this matter.
 

 

General info on automated microwave tuners

Microwave tuners are very useful in design and research.

They are built up from a slitted coaxial line (slab line). In the slit two slugs can be moved independently  along the line and optionally towards or away from the center line. In this way , nearly all impedances on the Smith chart can be obtained.

The plungers are moved via stepper motors .Accuracy  and repeatability in positioning the plungers is very critical to achieve useful results. At higher the frequencies this becomes even more difficult.

Precise machining  puts up the costs.

However many possibilities are within reach when using tuners together with other equipment.

For example one can tune a transistor input for minimum noise while measuring the noise figure.

With the network analyzer the matching impedance for lowest noise then can be determined.

In the PMTS tuners, impedance and slug positions are related against a reference position and are stored in a table in each individual tuner.

Thus when you know the slug positions , you know the impedance and no VNA is needed anymore.

In another case, one  can tune for a predetermined  match or mismatch and measure distortion from an amplifier.(load pull) Or its stability. One also can match or mismatch the output of an amplifier at a harmonic frequency and see for the effects on for example distortion.

These are just a few examples of extending your possibilities by using tuners.

The last ten years many steps forward where made by realizing low loss tuners that can achieve very high reflection values . With multi probe tuners affecting several frequencies at the same time and with new software controlling probe positions in such ways that for example instability areas on the Smith chart are avoided while moving the probes.

Product information and many application notes can be found at the following site for example:

http://www.focus-microwaves.com/

  73's
Dr. Ing. Jan Boutsen   ON4mmW
Fax  : +32/11233621