Recommend a Used Bird Wattmeter 50-150 MHz?
 

Hello,

The other thread reminds me that i need a high powered, used Bird power
meter.

Up to 1000-2000 watts, 50-150 Mhz or more, VSWR too...what models can
you folks recommend? Preferably one that doesn't screw up the 50 ohms of the
dummy load too much! (check with an MFJ before and after putting the meter in)

Birds are supposed to be very accurate, or so i have heard.

Any advice or Ebay links are appreciated.


Slick

Radio913 wrote:
Hello,

The other thread reminds me that i need a high powered, used
Bird power
meter.

Up to 1000-2000 watts, 50-150 Mhz or more, VSWR too...what
models can
you folks recommend? Preferably one that doesn't screw up the 50
ohms of the
dummy load too much! (check with an MFJ before and after putting the
meter in)

Birds are supposed to be very accurate, or so i have heard.

Any advice or Ebay links are appreciated.


Slick

From http:http://www.metroactive.com/papers/me...eat-9735.html:

I missed Creech but got to hear a tape of the band's performance two
days later on a micropowered radio station broadcasting at 91.3FM out of
Los Gatos known as Radio Free Lost Gatos. The guys in Creech guest DJed,
heckled callers and played the whole of their set along with some of
their favorite bands. According to RFLG owner/manager/DJ Dr. Slick, the
station has been operating out of a house "buried in the Los Gatos
hills" for three years. "I do it for fun," Slick says. "I don't do it
because I'm an 'anarchist.' I don't go out and say, 'Kill the cops.' I'm
positive with radio."

Slick was mum on the wattage but said that 91.3 reaches all of Los Gatos
and parts of Campbell. Slick plays classic rock, jazz and "a little bit
of Bach" when not turning the controls over to guest DJs like the
members of Creech. The station can be heard Sundays and Wednesdays,
8pmÂ*3am. Meanwhile, the next Gaslighter Theater show stars Monkey, Blue
Beat Stompers, Steadyups, Lucky Strike and Pigs in Space on Friday
(Sept. 5). As always: all ages and five bucks.

From http://www.svcn.com/archives/lgwt/05...PirateCat.html

Monkey Man stepped into the world of microbroadcasting about a year ago,
with his friend Michael Magic at Free-Radio San Jose, 93.7 FM, but had
to leave the station after some of his on-air hi-jinks went too far.
After that, he started working with Dr. Slick, whose station, Free-Radio
Los Gatos, is on 91.3 FM on Sunday and Wednesday nights from 8 p.m. to
11 p.m.

"Then Dr. Slick said I should get my own station, so I went down to
Fry's and got one of those little radio kits for, like, $30." Dr. Slick
gave Monkey Man an old one-watt amplifier, and another friend, Austin
Tatious of KKUD 104.1 in Willow Glen, donated a mixing board. Pirate Cat
was on the air.

-------------

It looks like we can look forward to a bigger signal from Radio Free
Lost Gatos (or is it Free-Radio Los Gatos?). No more "all of Los Gatos
and parts of Campbell"! Or are you be building FM transmitters and
amplifiers for sale?

Roy Lewallen, W7EL

Radio913 wrote:

Hello,

The other thread reminds me that i need a high powered, used Bird power
meter.

Up to 1000-2000 watts, 50-150 Mhz or more,

You mean 88-108 MHz, don't you?

ac6xg

Roy Lewallen wrote:
. . .
It looks like we can look forward to a bigger signal from Radio Free
Lost Gatos (or is it Free-Radio Los Gatos?). No more "all of Los Gatos
and parts of Campbell"! Or are you be building FM transmitters and
amplifiers for sale?

Oops, never mind. Just answered my own question.

From http://groups.google.com:

From: Dr. Slick )
Subject: Length of Coax Affecting Incident Power to Meter?
Newsgroups: rec.radio.amateur.antenna
Date: 2003-08-11 03:25:37 PST

.. . . This is certainly not the case on our bench, which is a problem,
because i want to have an approximation of how it will perform
attached to the antenna before i ship it out to the customer. A
difference of 70 watts is not acceptable. . . .

-------------

So, out of curiosity, what does a 1 - 2 kW FM transmitter bring on the
pirate market? I'd think it would easily be enough to pay for a *new*
Bird wattmeter. But would you be able to deduct it as a business expense?

From http://www.artwanted.com/artist.cfm?ArtID=4990:

Garvin Yee

Address: 17287 Grosvenor Ct.
Monte Sereno, CA 95030
Phone: (408)395-6674

Are you still at that address? If so, could we drop by your house
"buried in the Los Gatos hills" for a demo of your handiwork in
operation, before dropping the bucks for one?

Roy Lewallen, W7EL

Come on down if you want Roy, I'd love to meet you in person too!

But you won't find any FCC violations at my place! No siree!

This will be going into a dummy load bedwarmer!

Thanks for the free plugs, i don't like to toot my own horn, i'd rather
others do it for me. i tried looking your name up too, but nothing nearly as
interesting...boring ham stuff!

Can you folks recommend a Bird model?


Slick

Dr. Slick wrote:
"Can you folks recommend a Bird model?"

Bird Electronic Corporation
30303 Aurora Road
Cleveland (Solon) Ohio 44139
(216) 248 1200
Fax (216) 248 5426
TLX 706898
Cable BIRDELEC

Contact for a catalog and copies of Bird Technical Series (Watts New
From Bird), even if you are not buying from Bird now.

There is a wealth of information available from Bird, SWR slide rule,
various wattmeter instruction books, application notes, and catalogs.
Ask for everything they can send you to help understand their products.
Their list of products is diverse.

The Model 43 has been around for about 50 years. It shares an
instruction book with Models: 4430, 4431, 4521, 4522, 4523, 4525, 4526,
and 4527. But, that is not all the models Bird has made or makes.

When you become thoroughly familiar with Bird`s instructions, you will
necessarily be familiar with how the lines that the Bird is used with
work. The literature Bird provides makes learning about transmission
lines much easier.

Best regards, Richard Harrison, KB5WZI

On 20 Sep 2003 05:08:32 GMT, (Radio913) wrote:

Can you folks recommend a Bird model?
Slick

Hi OM,

Why do you pine on for such an expensive piece of equipment when what
you admittedly need is a good load? The best Watt meter in the world
is useless without that load. Many loads come with their own built in
Watt meters, and you can build your own Watt meter for about $5 ($4.95
for the meter movement).

I can anticipate your cry for the need of calibration. A used Bird is
far from a standard in that regard - especially when you could achieve
far greater accuracy with a thermometer and a good load sitting in a
bucket of water.

But, then again, maybe there's redemption in you after all in
emulating the time honored Ham tradition of pushing a credit card
across a display case. Pretty soon the FCC will only offer a handful
of call signs (by region) like K6VISA.

73's
Richard Clark, KB7QHC

Thanks Richard,

Do you use an SO-239 connector to type "N" for the input and output
with a model 43?

Hopefully good connectors won't affect
the SWR.

Someone else also recommended model 43 too. I'll be looking...


Slick

I can anticipate your cry for the need of calibration. A used Bird is
far from a standard in that regard - especially when you could achieve
far greater accuracy with a thermometer and a good load sitting in a
bucket of water.


I've heard that the Bird Model 43 is very accurate.


But, then again, maybe there's redemption in you after all in
emulating the time honored Ham tradition of pushing a credit card
across a display case. Pretty soon the FCC will only offer a handful
of call signs (by region) like K6VISA.



Well, it's appropriate that you point this out, Richard. In the sense
that the FCC has always sold off the spectrum to the highest bidders:
Clearchannel, Time/Warner, etc.


Slick

"Richard Clark" wrote in message
...
On 20 Sep 2003 22:23:36 GMT, (Radio913) wrote:
I've heard that the Bird Model 43 is very accurate.

Hi OM,

Now you know different. Besides, NO ONE is accurate without
comparison to a known Standard.

A Bird can be made accurate, better, in fact, than the manufacturer's
claims. I doubt you would spend the money to do it the first time,
much less each time required to keep it accurate (much less more
accurate).

It makes more sense to invest in a good load and calibrate it. It is
not at all difficult, except for the cash-and-carry tech who shuns
benchwork.

73's
Richard Clark, KB7QHC


I'll bet you'd love an invitation to expand on your comments about a "good
load" and "calibrate it."

The only good load is one that presents the desired, purely resistive
impedance. Maybe you can adjust the load, but you don't make it better by
calibration.

Or perhaps you are assuming a good load, and by calibration, you are meaning
some type of thermal calibration to indicate power.

I don't use loads to measure power, I use attenuators (sufficient for the
expected power), and put a bolometer on the end of the attenuator string. Of
course, I have the luxury of other test equipment, so I can check the
attenuators, with low power, against my spectrum analyzer and signal
generators.

All that said, I still think that a Bird 43 (and yes, a good load or
attenuator string [once you get 60 dB or so on the attenuator string, an
open-end reflection is quite minor]) is the best route for a ham. A ham
typically doesn't need even the factory accuracy of a Bird, but the
versatility of forward and reverse power, with multiple power ranges and
multiple frequency ranges, is very nice. Plus, it doesn't even need
batteries, and it's small and light. (Anybody who ever lifted HP gear can
now grin.)

For the 100 MHz region, you can think about a directional coupler. Nice, but
you still need either a bolometric power meter or a calibrated spectrum
analyzer. If you don't already have those two goodies, then the Bird is the
champion choice.

Ed
WB6WSN

On Sat, 20 Sep 2003 18:41:21 -0700, "Ed Price"
wrote:

I'll bet you'd love an invitation to expand on your comments about a "good
load" and "calibrate it."

Perhaps, but very few bench techs are found here.


The only good load is one that presents the desired, purely resistive
impedance. Maybe you can adjust the load, but you don't make it better by
calibration.

Arguable. Calibration is not what you do to something, that is tuning
or adjusting. Calibration is knowledge.

Or perhaps you are assuming a good load, and by calibration, you are meaning
some type of thermal calibration to indicate power.

There are many ways to accomplish the calibration, again, there are
too few bench techs here to care.

I don't use loads to measure power, I use attenuators (sufficient for the
expected power), and put a bolometer on the end of the attenuator string.

The Bolometer is a classic load, there are many others (like a
barreter).

Of
course, I have the luxury of other test equipment, so I can check the
attenuators, with low power, against my spectrum analyzer and signal
generators.

A good method that employs the easier methods of measuring differences
rather than absolutes. However, you must eventually obtain some
standard to make the final determination.

All that said, I still think that a Bird 43 (and yes, a good load or
attenuator string [once you get 60 dB or so on the attenuator string, an
open-end reflection is quite minor]) is the best route for a ham. A ham
typically doesn't need even the factory accuracy of a Bird, but the
versatility of forward and reverse power, with multiple power ranges and
multiple frequency ranges, is very nice. Plus, it doesn't even need
batteries, and it's small and light. (Anybody who ever lifted HP gear can
now grin.)

For the 100 MHz region, you can think about a directional coupler. Nice, but
you still need either a bolometric power meter or a calibrated spectrum
analyzer. If you don't already have those two goodies, then the Bird is the
champion choice.

Ed
WB6WSN


Hi Ed,

I've never run across a need for batteries, except to light the meter.
There are better meters than a Bird. The AN/URM-120 is easily better,
and sells cheaper, has all the same qualities, but for its advantage
it also is larger and presents its readings with the meter horizontal.
If those were the only down-sides, then it is much like personal
choices in tie color.

73's
Richard Clark, KB7QHC

On 19 Sep 2003 21:59:10 GMT, (Radio913) wrote:

Hello,

The other thread reminds me that i need a high powered, used Bird power
meter.

Up to 1000-2000 watts, 50-150 Mhz or more, VSWR too...what models can
you folks recommend? Preferably one that doesn't screw up the 50 ohms of the
dummy load too much! (check with an MFJ before and after putting the meter in)

Birds are supposed to be very accurate, or so i have heard.

Any advice or Ebay links are appreciated.


Slick

I'd certainly recommend the Bird 43 -- it's worked well for me. You
can go to http://www.radiodan.com/ and look at their selection. They
have both new and used Bird meters, new and used plug-in elements,
dummy loads, etcetera. They might even be within driving distance of
you.

Bob
k5qwg

I'll bet you'd love an invitation to expand on your comments about a "good
load" and "calibrate it."

Perhaps, but very few bench techs are found here.


How about a bench engineer? How did you come to the conclusion that the
Bird plugs go bad after 3 months?

Do you have a transmitter of known Pout that you use as a standard? Of
what
power level?

Or do you use known good attenuators, and measure the error of relative
powers?



The Bolometer is a classic load, there are many others (like a
barreter).


I'm not familiar with these, tell me more.




All that said, I still think that a Bird 43 (and yes, a good load or
attenuator string [once you get 60 dB or so on the attenuator string, an
open-end reflection is quite minor]) is the best route for a ham.


Yeah, someone suggested using long lengths of RG-58 (the lossier, the
better) to improve the return loss of a no-so-50 ohm dummy load.






For the 100 MHz region, you can think about a directional coupler. Nice, but
you still need either a bolometric power meter or a calibrated spectrum
analyzer. If you don't already have those two goodies, then the Bird is the
champion choice.

Ed
WB6WSN


Hi Ed,

I've never run across a need for batteries, except to light the meter.
There are better meters than a Bird. The AN/URM-120 is easily better,
and sells cheaper, has all the same qualities, but for its advantage
it also is larger and presents its readings with the meter horizontal.


For the AN/URM-120, i found this:

"On the 25-250 and 200-1000 Mhz slugs 10, 50, 100, and 500 watts
are available."

No 1000 or 2000 watt slugs for 25-250 MHz?


Slick

On 21 Sep 2003 20:45:52 GMT, (Radio913) wrote:

How about a bench engineer? How did you come to the conclusion that the
Bird plugs go bad after 3 months?

This is the standard calibration cycle. I did not come to the
conclusion, it is commonplace schedule subscribed to by registered
laboratories performing calibrations traceable to the NIST.

The necessity is driven by experience of the industry exhibiting that
need. In other words, for 100 Birds and 100 URM-120's coming into the
lab for calibration or qualification, 70 to 90 of the Birds were out
of tolerance; and 70 to 90 of the URM-120's met spec. 10 to 30% out
of tolerance hits are not acceptable for FAA flight line work (the
Birds are much worse).

If you waited a year instead of 3 months, the Bird that was out of
whack would still be out of whack, but probably at the same level.
You could say pretty much the same for 20 years later (barring smoke
curling up at hot connectors). Repeatability is accurate only when
you've calibrated it. In other words, if I had simply noted what
Power was being read (like 60W) for an applied Power (like 100W); then
it would probably stay that way until judgement day (evidenced by
smoking connectors). If someone lost that calibration certificate,
then for those many years after, they would have been repeatedly off
by a considerable margin (and probably trying in vain to force any amp
to do what it was already doing). This is called "clueless." They
would sneer at the vendor of the amps, change their sources, and
snuggle up to their meter each evening.

Do you have a transmitter of known Pout that you use as a standard?

Of course. And a reflection free system.

Of what power level?

Full Scale and at each Cardinal point to calibrate scale linearity.
As I said, even the Bird can be calibrated to accuracies that exceed
their specification.

Or do you use known good attenuators, and measure the error of relative
powers?

Attenuators do nothing for the required input. The reference to
attenuators offered by Ed was for the detector head in a Directional
Coupled system.

The Bolometer is a classic load, there are many others (like a
barreter).
I'm not familiar with these, tell me more.

Maybe because I mis-spelled it: Barretter.

Anyway, it is a fine wire detector (that's right, just a wire). The
most accessible form, and most common item is found in a 10 mA fuse.
Another form is called a Wollaston wire. The Barretter is used in a
lot of HP Power Meters (the premium stuff). They are usually found in
pairs with one being half of a bridge with a steady bias, and the
other being the termination to a coupler connection into the
transmission line feeding the load. Only takes about +10dBm to wipe
out one of these detectors (be prepared to spend a couple hundred to
fix it too).

All that said, I still think that a Bird 43 (and yes, a good load or
attenuator string [once you get 60 dB or so on the attenuator string, an
open-end reflection is quite minor]) is the best route for a ham.

Yeah, someone suggested using long lengths of RG-58 (the lossier, the
better) to improve the return loss of a no-so-50 ohm dummy load.

That, too, is suitable. Calibration, as I pointed out, is not making
adjustments, it is gathering information. You might optimize
performance as an ancillary function of this; and to maintain
equipment in good order (plus keep customers); but if you offer no
information, then no calibration has been performed.

Calibration would also reveal that this suggestion of lossy cable was
a loser proposition if you didn't check for connector mismatch. If it
was considered trash cable, it probably has trash connectors.

For the AN/URM-120, i found this:

"On the 25-250 and 200-1000 Mhz slugs 10, 50, 100, and 500 watts
are available."

No 1000 or 2000 watt slugs for 25-250 MHz?


Slick


Hi OM,

I wouldn't know off-hand. Not really important anyway as Ed pointed
out. Directional Couplers work just as well too, plus they make the
bench more versatile than one instrument with several plug-ins. You
can use Direction Couplers for many things, the plugs-ins for only
one.

Power can be measured by calorimeters (HP made one decades ago that is
still better than any suggestions here). Or measured by a Lamp
(photometrically, as long as you are matched to its Z). Or measured
by a Lamp (by calorimetric method, as long as you are matched to its
Z). Or measured by a Thermistor (another calorimetric method). Or
measured by Thermocouple (guess what, another calorimetric method).
Or measured by substitution (using any of the above as non-matched
loads as long as both sources are fully matched). By measuring the
resistance of the load (especially carbon) as long as the power
changes the resistance to a matched condition (or by substitution if
not).

73's
Richard Clark, KB7QHC

"Radio913" wrote in message
...

SNIP

All that said, I still think that a Bird 43 (and yes, a good load or
attenuator string [once you get 60 dB or so on the attenuator string, an
open-end reflection is quite minor]) is the best route for a ham.


Yeah, someone suggested using long lengths of RG-58 (the lossier,
the
better) to improve the return loss of a no-so-50 ohm dummy load.

SNIP


Slick


Well, I wouldn't go quite that far. The "loss" of RG-58 is due to a
combination of loss in the transmission line and leakage of energy through
the relatively poor shielding. That radiated energy hanging around your test
bench is more than likely cause you new measurement errors.

Ed

Richard Clark wrote in message . ..

If you waited a year instead of 3 months, the Bird that was out of
whack would still be out of whack, but probably at the same level.
You could say pretty much the same for 20 years later (barring smoke
curling up at hot connectors). Repeatability is accurate only when
you've calibrated it.


Then it sounds like you could re-calibrate after 3 months, and not
have to worry about it for a while.


Slick