Watt meter comparison. The Bird 43P vs the NIST accurate Power master

[ke7trp]

I came across a Power master watt meter.  This one is the 3000 watt version.  Its NIST calibrated. 

Accuracy typically better than +/- 3% over frequency and temperature ranges, and now includes our VHF, and UHF Sensors too!   Using NIST traceable lab instruments.

I set both side by side and tested them on AM and SSB today.  Here are the results.


GK500C on 40 meter AM:
Bird 260 watt reading on carrier.
VFD meter: 262 watts.

Modulated GK500. About 80% or so on 40 meter AM:

Bird 43P.  900 watts
VFD meter 860 watts.

Icom on SSB 20 meters:
Bird 100 watts.
VFD 104 watts.

Icom on AM RF power all the way up on 20 meter:
Bird 40 watts.
VFD 44 watts.

As you can see, these meters read almost identical.   The Draw back to the bird is you need good calibrated slugs.  I have calibrated slugs.  Most dont, and use old beat down slugs so accuracy suffers.

The VFD is very very fast.  So fast, That its not really usefull on AM when speaking. The meter jumps from 500 to 600 to 800 ect over and over on the GK500.  The Bird hold up around 800 and takes its time falling down between words.

On SSB, The VFD meter is much better, as it reads the peak instantly and holds the peak there.  The Bird on SSB, is bouncing all around and needs a steady tone.

There are alot of SMUG VFD meter owners out there on the bands.  These guys will SCOFF at Bird or other analog meters and talk for hours about the NIST measurment and what it means.. Blah blah blah.  Both of these meters read almost identical in my shack.  The old bird is just as acurate.  Its going to come down to what you like..  An analog meter, Or a Digital bar Graph or digital readout. 

the BIG advantage to the VFD meters are that you get SWR and forward power at the same time.  I already have that since I use the KW matchbox with the Meter hooked up.  However, If i did not have an SWR meter like this in my tuner, I would probably really enjoy the dual readout.  For HAM radio. Both work FB.

Clark

[flintstone mop]

I'm a true blue BIRD lover. Rugged and reasonably accurate for what their designed for.
I'll bring my Bird stuff to the shop if we have an issue with the need for accuracy with a Motorola service monitor and the built-in wattmeter.
No use trying to set a poor defensless portable two-way radio to rated power if the indicating instrument is way out in left field. More than 5%!

The worst watt meter is the TeleWave
For our application, a fairly accurate instrument to indicate forward and reflected power is goodness.

Fred

[k4kyv]

There are alot of SMUG VFD meter owners out there on the bands.  These guys will SCOFF at Bird or other analog meters and talk for hours about the NIST measurment and what it means.. Blah blah blah.  Both of these meters read almost identical in my shack.  The old bird is just as acurate.  Its going to come down to what you like..  An analog meter, Or a Digital bar Graph or digital readout. 

I'll take the old thermocouple rf ammeter any time.

[ke7trp]

They have another Drawback.  RF in the room with you. Last night I fired up the T3.  I had massive feedback from computer speakers in the other room.  I keep a Field Strength meter in the shack on the table. It pegged out.  Confused, I checked over all the cables and retuned. Only after I turned the audio down could I get a carrier out. 

Put the Bird back in line, No more RF.  That Crappy RF pickup is not RF tight to the meter Head.


C

[Jim, W5JO]

 

 Specifications    Bird 43P
 

Power Range  100 mW to 10 kW using Bird® Plug-in Elements
 
 
Frequency Range  450 kHz - 2.7 GHz (depending on element)
 
 
Accuracy  CW Mode: ± 5% full scale, Peak mode: ± 8% full scale



VFD accuracy


 Accuracy typically better than +/- 3% over frequency and temperature ranges



Looks like Bird hasn't changed in years.  I had a 43 back in the 70s whose accuracy was the same and a 4411 a few years back and it was the same as the 43P in the peak mode.  But when I owned the Motorola shop the Brid was the one that would take the abuse of traveling in my car and stay within 10% each calibration period. 
 

[ke7trp]

What a horrible design this VFD is. RF is pouring out the cable to the head unit.  I stopped that by adding Ferrite beads on the cable.  After that, I did an in shack field strength test.  I tested RF levels in the corner of the room with both units. WIth the Bird there is no RF. With the VFD, There is about mid scale.  I wonder how many people out there are having RFI and TVI issues with cheap watt meters.

A bird 43 is only as good as the slugs that you use. Thats the important thing to remember.

C

[Jim, W5JO]

A bird 43 is only as good as the slugs that you use. Thats the important thing to remember.

C

The meter movement can cause trouble as well.  In fact most of the trouble with Bird meters I have seen is because the meter has been banged around. 

[ke7trp]

How can it get banged around if its sitting on my table for 10 years?

C

[ke7trp]

Tell us more about your watt meter. Who made it?  How does it work?

C

[ke7trp]

Ok. I understand all that.  Lets see pictures of your meter and who made it.

C

[ke7trp]

I think its pointless not to take videos if you have a camera  

Clark

[KM1H]

Since I wouldnt be caught dead with OWL I'll stick to the Bird 43's, I even have a pair of 75 Ohm versions with some slugs.

Picked up a couple of dozen FAA panel mounted 43 type pickup lines with a cable to a BNC on the panel for the meter at Dayton in the 90's. Been picking up meters as I can find them and have slowly been adding one panel per band from 160M to 2304 mHz; got a NIB one for $30 at Deerfield. 

Carl

[ke7trp]

What is an OWL?   

C

[K5UJ]

<<<Looks like Bird hasn't changed in years.>>>

They have changed (i.e. new products) but they keep making the 43 because they can continue to sell them and the new fancy gear is out of reach of most hams price-wise.

They probably make most of their money on the slugs.  I am content to use the 43 into a 50 ohm dummy load to measure my dead carrier.  I have watt meters at the transmatches that are good enough to measure reflected power because I don't care how much r.f.p. there is, only whether there is any or not.   I use scope and trapezoid to see if I am near 100% negative and getting round envelope peaks and linear.   I have no idea what the exact peak power is, just a guess but I'm more interested in sounding good and not being distorted and grungy.

R.

[Jim, W5JO]

How can it get banged around if its sitting on my table for 10 years?

C

If the Bird 43P was in calibration before you set it on the desk, then that is the reason it is close to the other one.  Same goes for the other one.  I believe you just acquired the VFD from another person.  If so they may have been into the coupler box and did not assemble it correctly so it is leaking RF. 

[ke7trp]

No. Its new out of the box. It has never been opened.   Its just a bad design. There should be a good choke on this line.

C

[k4kyv]

Since I wouldnt be caught dead with OWL I'll stick to the Bird 43's

I won't be caught dead ever again with coax, once I finish my  revised tuner system. I presently run a coax link between the link-coupled transmitter tanks and the tuning networks at the base of the tower, and OWL up the tower to the antenna.  When I first installed the coax, with a dummy load at the far end, I measured 100 watts at the transmitter on 75m, and 93 watts at the tower end of the coax.  After about 8 years, I now measure 100 watts at the transmitter and 75 watts at the tower end.  RF power is too expensive to waste 25% of it in a piece of coax. I plan to run OWL all the way from the shack to the tower base, as approximately a flat line to the tuning networks at the tower, with a tuned line up the tower to the antenna. When it's all done, there won't even be a place where you could insert a Bird 43.

Since I installed 40m radials under the floor joists of the shack I haven't had significant rf in the shack.  The antenna is almost 200 ft. from the house and I still get into the damned computer speakers. I think they pick up rf radiated directly from the antenna, not stray rf fields that might exist near the transmitter. The computer speakers are nearly 100 ft from the transmitter.

[ke7trp]

OH!!!   OWL.. Open wire line.  I feel like an idiot.   "OWL" did not make sense to me.

Yes. I run open wire line also.  I love it.  However, I run Coax in the shack from the Transmitter to the tuna. 

I also did not realize you guys where talking about using an ameter at the OWL.    I really need to get my hands on some of those meters.  Any idea what range to look for for a KW modulated? I want some headroom.

C

[Jim, W5JO]

No. Its new out of the box. It has never been opened.   Its just a bad design. There should be a good choke on this line.

C

If it is new have you contacted Array Solutions to see if they have had problems with the design and what they have done about it? 

[KM1H]

Different strokes for different folks.

I operate CW, SSB, and AM with a stress on DX chasing and some contesting. That means rapid QSY within a band and quick band changing. It also means no fussy narrow band antennas, no touchy tuners, and no RFI since all coaxes have large beads over them at the feedpoint and there are more beads at the output of each amp. All the amps are set up to load directly into the antennas used here even if the VSWR gets a bit high. I also use coax stubs to reduce harmonics so I dont bother nearby hams or my self when I have 2 radios running on different bands.

If I was just a casual operator seldom QSYing or hardwired to one frequency per band Id probably also use OWL and have one antenna covering several bands. That just aint my style of operating   Its called accepting diversity

Carl

[ke7trp]

I dont have time to be messing around calling the company and so forth.  With the beads, it works fine,  I am going to stick with the bird and try to find a pair of ammeters for the OWl.

C

[K1JJ]

Carl,

As you know, I also use only coax and hardline here. You mentioned the ferrite beads...  At the feedpoints of all antennas, I use coiled coax turns on a pvc form with some ferrite cores on the coax . However, I've never tried adding cores in the shack on the output of the amplifier for good measure.

How many cores and of what type and size do you recommend on a QRO amp? Do you put them inside the amp right at the load capacitor output or do you just put them on the outside of the amp at the SO-239 output connector?  

Or how about an economical way - at the Bird wattmeter that is 20' away from the amps, but will handle everything that comes through, requiring just one set of cores for all rigs?

Have you had feedline radiation problems that were cured with the in-shack cores or are you just doing it for good measure?  I guess what I'm axing is how would I know I could use some in the shack other than RF getting into the audio, RF burns off the gear...?   All seems tame at the moment.


T

[ke7trp]

Take DVM.  Hold neg in hand.  Hold POS to Chassis(back of coax connector.  Key up.

Clark.

[K1JJ]

Take DVM.  Hold neg in hand.  Hold POS to Chassis(back of coax connector.  Key up.

Clark.

heheheh... I learned how really bad those DVM POS's are when using one to measure in the vicinity of 1KW PDM power pulses.   As expected, even one of my digital meters in the rig that measures current is way off.

Analog is the only way around big fields.

So in this case, basically you're using the meter as a field strength meter looking for unbalanced RF currents. Though, all of my rigs are open in the back and will probably give a stray RF reading there...

But I'll give it a try.

T

[ke7trp]

Try it.. You can really see the RF currents.  I used wire counterpoise along base boards. Tuned em and the currents where gone.

C