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Hi Bruce,

The 437B is of course only a single channel power meter, so if you want
dual upgrade from the 438A you will need to go to the E-series.
I have a 437B, and it suits my needs for a power meter. I also have a 432A,
a 435B, and almost a 436A (Its missing the A2, A3, A4 and A5 boards. So if
anybody want to donate, please let me know :)

I made two simple python scripts to read from, and write cal tables to the
437B. Much easier to enter the cal table into a text editor, than using the
arrow keys.

The biggest drawback on the 437B is the lack of number keys. All entries
are adjusted with arrow keys, But its easier to just set the frequency,
than figuring out the correct cal factor and enter that.


Regards,
Askild


On Fri, Sep 2, 2022 at 8:43 PM Bruce <bruce@...> wrote:

Dave - Thanks.

I didn't think to take a look at the 437 and I did assume that the 438
was an upgrade on the 437 - wrong I guess. I really do like my 438s
except for the inconvenience of entering the cal factor each time.

Cheers!

Bruce

Quoting Dave McGuire <mcguire@...>:

On 9/1/22 23:45, Bruce wrote:

I currently use HP 438 power meters and am considering upgrading.
Main driver fo upgrade is I'm getting sick of having to enter the
cal factor for each frequency measurement. I would like the
replacement to be a dual channel device.

I know that latter versions of HP power meters permit entering
correction tables for use with the 848X power sensors. What would
the group recommend?
Some relevant questions:
1) How hard is it to tell the PM what frequency entry to use?
2) Do any of the PMs accept an analog voltage to determine the
frequency correction (that would really be fun)
3) Any known problems to look out for

The E4417/E4418 power meters have come down in price, and are very
nice. They will also use the later series of sensor heads that
store the calibration factors in an EEPROM in the head, which are
read out by the meter and applied. You can also use the more common
84xx heads that only have the calibration factors printed on them,
not stored within them, and you enter the table manually into the
meter's NVRAM. Then you select the measurement frequency and it
will apply the calibration factor automatically, with interpolation.

The 437B cannot read the calibration factor table from the newer
sensor heads, but you can enter the table via the front panel or
GPIB. It can store ten tables for ten different sensors.

My main bench instrument now is an E4417A, which I really like.
The display is excellent; in some modes it will display LARGE digits
which you can read across a room.

For years I used a 437B, which I still have and use occasionally
in another area. Everyone complains about the display, I don't have
a problem with it myself, I just don't try to use it in the dark.
The design shares many attributes (and possibly components) with the
5384/5385 frequency counters, 3468/3478 DMMs, etc, so if you have
one of those, you know what the display is like.

I've not looked it up, but I'm willing to bet the 437B was
designed well after the 438A. While I think the 438A is a fine
design in nearly all respects, everything about it seems older than
the 437B. Older display and button styles, less-featureful firmware
(lack of sensor calibration table storage and interpolation) etc.

I've never seen a feature by which an analog input voltage can set
the correction factor.

I have every model of HP RF power meter, including the VXI and MSS
models. If you'd like specific info on behaviors/features/etc on
any of them that aren't covered by the documentation, don't hesitate
to ask.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA