Article View: sci.electronics
Article #20290Re: Need 1GHz RF wattmeter
From: Larry Lippman
Date: Mon, 02 Jan 1989 04:27
Date: Mon, 02 Jan 1989 04:27
37 lines
2382 bytes
2382 bytes
In article <17960@glacier.STANFORD.EDU>, jbn@glacier.STANFORD.EDU (John B. Nagle) writes:
> Where can I get a low-cost RF wattmeter good for 1.2GHz? The power range
> required is 50mW to 5W or so at 50 ohms. Either an inline or terminating type
> wattmeter is acceptable; an SWR capability would be nice but is not essential.
> Precision required is very modest.
>
> It's easy to find wattmeters for low bands, but it's hard for UHF. Any
> ideas?
While it won't give you great resolution at power levels of 50 mW,
the cheapest off-the-shelf solution is to get some high frequency elements
for a Bird 43. You can get 1, 2.5 and 5 watt elements (P/N's 1K, 2.5K and
5K, respectively) that cover 1.1 to 1.8 GHz. These elements will also work
with a Bird 4381 or 4391.
You can go the Hewlett-Packard route. Now before you complain
about this not being "low cost", bear in mind that there is a lot of H-P
equipment in labs that you could possibly borrow. Furthermore, H-P
power meters (of the analog variety, at least) are pretty common and
inexpensive on the surplus market.
An H-P 432A or 432B power meter with 478A thermistor mount will
give you 10 mW full scale up to 10 GHz. All you need is a coaxial power
divider to bring the thermistor mount into range.
An H-P 435A or 436A with 8481H or 8482 thermocouple mount will
read directly to 3 watts.
I personally have a 435A with 8481H, would recommend that as the
best of all of the above for your application (unless you have access to
the 436A, which has a digital readout). If you really need to go to 5 W,
a power divider is trivial.
<> Larry Lippman @ Recognition Research Corp., Clarence, New York
<> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry
<> VOICE: 716/688-1231 {att|hplabs|mtune|utzoo|uunet}!/
<> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
Technical Details
Message-ID:
<2886@kitty.UUCP>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!sunybcs!kitty!larryReferences:
<17960@glacier.STANFORD.EDU>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!sunybcs!kitty!larry From: larry@kitty.UUCP (Larry Lippman) Newsgroups: sci.electronics,rec.ham-radio Subject: Re: Need 1GHz RF wattmeter Summary: Watts that you need? Keywords: wattmeter RF Message-ID: <2886@kitty.UUCP> Date: 2 Jan 89 04:27:45 GMT References: <17960@glacier.STANFORD.EDU> Organization: Recognition Research Corp., Clarence, NY Lines: 37