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HP 85047A (S-param test set) with loose Port1

 

Hi,

A while ago I managed to acquire a? HP 85047A, unfortunately it has had an accident
sometime in it's life and Port1 is loose and slightly bent. I have measured the directivity
of the port and it seems to be in the right ballpark as far as performance is concerned.
However the whole sensor moves.

Opening up? the unit I see that whereas port2 is direct metal to metal contact where
the mounting screws are located, port1 has plastic washers between the two surfaces.
No matter what I try I cannot stop it moving. Anyone have any ideas?

Next week I should get an HP8753E opt 011 unit and I will then be able to see if the
Port1 sensor needs replacing or not.?

- Charles G4GUO
Dr. David Kirkby (Kirkby Microwave Ltd)
 

On 10 October 2015 at 08:56, chbrain@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:


Hi,

A while ago I managed to acquire a? HP 85047A, unfortunately it has had an accident
sometime in it's life and Port1 is loose and slightly bent. I have measured the directivity
of the port and it seems to be in the right ballpark as far as performance is concerned.
However the whole sensor moves.

Obviously being bent is not correct, but slight movement is by design. There are some accessories that fit directly onto the test sets, which have fixed spacing on the plugs. To allow for mechanical tolerances, the port 1 connector on the 85047A moves a little.


Opening up? the unit I see that whereas port2 is direct metal to metal contact where
the mounting screws are located, port1 has plastic washers between the two surfaces.
No matter what I try I cannot stop it moving. Anyone have any ideas?

Well there is a way. You take out the washers, and take about 0.2 mm off the thinner surface, but as I say, they are designed to move.?


Next week I should get an HP8753E opt 011 unit and I will then be able to see if the
Port1 sensor needs replacing or not.?

- Charles G4GUO

If you need calibration kits, contact me. You can buy our kits on eBay, but obviously it is cheaper if you don't. See link in my signature.

Dr. David Kirkby Ph.D CEng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT, UK.
Registered in England and Wales, company number 08914892.

Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please)
kkyahoo
 

?
Charles,
?
One of the ports on my 8503 S param test set moved, and yes it was the one with the plastic washers on it. It drove me mad so I simply turned the washers upside down and tightened the screws carefully.
?
73
?
Kevin
?
?

----- Original Message -----
Sent: Saturday, October 10, 2015 10:42 AM
Subject: Re: [hp_agilent_equipment] HP 85047A (S-param test set) with loose Port1

?

On 10 October 2015 at 08:56, chbrain@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:


Hi,

A while ago I managed to acquire a? HP 85047A, unfortunately it has had an accident
sometime in it's life and Port1 is loose and slightly bent. I have measured the directivity
of the port and it seems to be in the right ballpark as far as performance is concerned.
However the whole sensor moves.

Obviously being bent is not correct, but slight movement is by design. There are some accessories that fit directly onto the test sets, which have fixed spacing on the plugs. To allow for mechanical tolerances, the port 1 connector on the 85047A moves a little.


Opening up? the unit I see that whereas port2 is direct metal to metal contact where
the mounting screws are located, port1 has plastic washers between the two surfaces.
No matter what I try I cannot stop it moving. Anyone have any ideas?

Well there is a way. You take out the washers, and take about 0.2 mm off the thinner surface, but as I say, they are designed to move.?


Next week I should get an HP8753E opt 011 unit and I will then be able to see if the
Port1 sensor needs replacing or not.?

- Charles G4GUO

If you need calibration kits, contact me. You can buy our kits on eBay, but obviously it is cheaper if you don't. See link in my signature.

Dr. David Kirkby Ph.D CEng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT, UK.
Registered in England and Wales, company number 08914892.

Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please)
 

Hi,

Thanks both for the reassurance,

So it looks like it was designed to do that then.

The sensor connector is very slightly bent. I did power the unit up and using a signal generator,
power meter and a 30 dB attenuator measured the signal coming out of the? A port
with and without the load connected to port1 and there was > 30 dB difference so
I am hoping it is OK. I looked at the price of replacement units (from China) and
they are almost as much as I paid for the S-Box!

David, I have in the past looked at your Website so I may well be contacting you when
I have it working.

- Charles
 

Dave is correct.

I did not know this and checked port 1 on my 85046B and indeed it moves a bit.

Jos PA0AMX
Dr. David Kirkby (Kirkby Microwave Ltd)
 


On 10 October 2015 at 11:02, 'kkyahoo' kkyahoo@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:
?


Charles,
?
One of the ports on my 8503 S param test set moved, and yes it was the one with the plastic washers on it. It drove me mad so I simply turned the washers upside down and tightened the screws carefully.
?
73
?
Kevin

Arguably a better way is to take a file and remove about 0.2 mm from the thin end of the washers - there's a change of diameter. That will allow the bridge to tighten down, but onto a waster, rather than with a lot of air around it, as you will have. Of course your method is slightly quicker, and reversible.

Dave

 

¿ªÔÆÌåÓý

Happens on my 85046A? 3GHz unit also.
?
John G3UGY
?
?
Thanks both for the reassurance,

So it looks like it was designed to do that then.

- Charles

 

The test sets were designed this way on purpose.? There are test fixtures with a fixed spacing that are designed to mate with the front panel of the 85047, and one port had to have some slop so that slight variations in manufacturing would not prevent proper mating.? There are several other products like this with a "floating" design.

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