[NLRS] power measurement

[Ken Boston]

Hi all;

 

Just wanted to add a few more viewpoints to the ongoing power meter
discussion here at the Northern lights list;

 

I have been using bird wattmeters with the appropriate slugs, and Drake
WV-4 meters for my high power station from 50-432MHz.  the birds are
line sampling type meters, with the slugs acting like little directional
couplers, which contact fingers in the meter run to a diode detector and
on to the actual meter movement. I have a 10 watt slug which is rated
for 1.1 to 1.8 GHz (I believe) which has served well for my 903, 1296
and 2.3 gig transmitters.  The bird meters can measure the higher power
levels well by virtue of their line sampling/directional coupling
philosophy, with the correct amount of coupling serving as attenuation
for the high power levels. ( I run 500-1000 W on 6,2,and 432)  

 

Due to limitations in the line sampling section, the slug geometry and
the diode detector in the meters, the Birds are not very usable much
above 2 gig, and they are not accurate when measuring milliwatts.

 

I also have an older HP power meter, an HP432 (?) and a couple bolometer
power sensors.  As many here have already stated, these sensor heads are
not capable of much over 10-20 milliwatts.  I can borrow from my work ,
a gigatronics 8542C and 804301A sensor, good for 20 mw up to 18 gig.  I
have collected a few directional couplers, which can allow measurement
of higher power levels.  Current new price on power meters like the
Gigatronics is in the 5-7K for the meter and 1-3K for the sensors.  Used
meters of current and slightly older vintage can be had for 1-3 K (a
bargain????!!!!)

 

Bottom line, an all-in-one power meter for 1-24 gig, power rating 10
milliwatts to a KW probably does not exist. (unless there is some super
expensive top of the line meter out there that does this)  You will end
up with a collection of a decent , older power meter with some sensor
heads, power attenuators, and directional couplers that cover the bands
that you need them for.  Cruise the swapmeets, conferences and E-Bay,
and expect to spend some money.

 

I still need to find some bargain couplers for my future expansion to
3.4, 5.7 and 10 gig plans!!

 

Ken  W9GA