I think I might have found a modern alternative...a very small surface
mount device that looks like it will do exactly what the HP doubler does
AND only $5.95 in SINGLE quantities (The AMK-2-13+)!!

http://www.minicircuits.com/products...pliers_sm.html

Doesn't get much easier than this!!

Scott
N0EDV




Jeff wrote:
If I remember correctly it uses a double balanced mixer as the frequency
doubler, and only works at high output levels from the 8640 (+10dBm), so you
would require an external attenuator to get lower levels.

The HP part No is 08754-60057.

73
Jeff
G8HUL


"Scott" wrote in message
.. .

I recently picked up an HP 8640B Opt. 323 (8640B in a can) and wonder if
anyone has information on the external frequency doubler so that it can use
it's upper frequency position (512-1024 MHz). I want to get 902 MHz out of
it to test the feed for my parabolic dish's return loss (SWR).

I can build a diode doubler to generate harmonics and then put a 1/4
wavelength of shorted-end coax across its output to select the 902 MHz
harmonic, but I'd like to be able to tune all freqs between the 512 and
1024 MHz without building a lot of shorted stubs. How does HP do it with
their doubler? Bandpass filtering? Could one bandpass filter cover that
much range?? Maybe something as simple as a low pass filter with an Fco
of 1050 MHz or so, but with this, how would I keep the fundamental freq
(256-512 MHz) out of the output??

Thanks for any leads!

--
Scott N0EDV
http://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)




--
Scott
http://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)

Scott wrote:
I think I might have found a modern alternative...a very small surface
mount device that looks like it will do exactly what the HP doubler does
AND only $5.95 in SINGLE quantities (The AMK-2-13+)!!

Not "exactly".

Guaranteed F1 in the output is only -20
dBc. Not nearly as good as a DBM.

Chuck

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In article ,
Chuck wrote:

Scott wrote:
I think I might have found a modern alternative...a very small surface
mount device that looks like it will do exactly what the HP doubler does
AND only $5.95 in SINGLE quantities (The AMK-2-13+)!!

Not "exactly".

Guaranteed F1 in the output is only -20
dBc. Not nearly as good as a DBM.

Scott-

I've read past postings that discussed Minicircuits.com and the 8640B
doubler. Why not contact them and ask if they have a better
alternative? They may be familiar with the 8640B, and have addressed
the question before.

Regarding Jeff's comment, I was of the impression that the signal was
generated at a high level prior to the attenuator, and attenuator
settings were correct for the 512-1024 band as well as the others.
Since your "8640B in a can" has the 512-1024 switch position, it should
be possible to install a home-made doubler in the same space where the
HP doubler would go, prior to the attenuator.

Fred
K4DII

Regarding Jeff's comment, I was of the impression that the signal was
generated at a high level prior to the attenuator, and attenuator
settings were correct for the 512-1024 band as well as the others.
Since your "8640B in a can" has the 512-1024 switch position, it should
be possible to install a home-made doubler in the same space where the
HP doubler would go, prior to the attenuator.

Fred
K4DII

The doubler is an external device that screws onto the front panel output
socket, there is no provision for putting it internally prior to the
attenuator. The 512-1024 switch position merely changes the displayed
frequency.

Jeff

In article ,
"Jeff" wrote:

The doubler is an external device that screws onto the front panel output
socket, there is no provision for putting it internally prior to the
attenuator. The 512-1024 switch position merely changes the displayed
frequency.

Jeff-

I understand about the HP 11690A Scott mentioned. Are you saying that
it is not possible to retrofit an 8640B with the internal doubler, or
just not possible with the military version Scott has?

I have two 8640Bs. One has the doubler option, the other doesn't. I
would like to upgrade the second one if possible.

Fred
K4DII