Astatic 600 swr/wattmeter ?....

[Oatmeal]

I received a email from a friend who runs the same radio and amp that I do...
He told me what his radio does with a 10w going into his amp, and what kind of a dk the amp shows on his meter and looks like my meter is showing 75 to 125 watts less than his does...kind thought this meter was off for sometime..
But didnt no how far it was off....

So, whats the chances of buying one of these meters a Radio Shack 21-534 and it been right ?.....

A 2kw scale is all Ill ever need, I dont want to be the top dog, I just enjoy talking dx on AM and SSB...

 

[TonyV225]

There good meters and last a long time Ive had 2 of mine since the mid 1990s if you are after true PEP readings then its gonna cost a bit more for a meter of that capability with a powered true peak reading circuitry in the case or shell.

Now one thing to think about is between your buddies setup and your setup whose setup is actually closer to the truth as far as output??

 

[roadrage]

As for the Bird meters, only the peak meters have the proper circuitry to detect and display true peak power. QUOTE]

Very true. I didn't want to stray off the point I was making or trying to make. I know that there is the bird meter that comes with the peak funtion and there is a kit for the bird meter that doesn't. As for the RMS refering to voltage, I am definately no expert at this. I am just stating what I read yesterday, in an article on the subject. I am not qualified to argue this point one way or the other.

But this is part of a several page definition of RMS that I just got done reading after all the responses to my previous statement, here is what I though was relevent to RMS only concerning voltage:

"It is also possible to calculate the RMS power of a signal. By analogy with RMS voltage and RMS current, RMS power is the square root of the mean of the square of the power over some specified time period. This quantity, which would be expressed in units of watts (RMS), has no physical significance. However, the term "RMS power" is sometimes used in the audio industry as a synonym for "mean power" or "average power". For a discussion of audio power measurements and their shortcomings, see Audio power."

 

[Captain Kilowatt]

One can read almost anything on the internet and as a result one must be aware of the credibility of the sources of such articles. <gotproof> That credibility must be confirmed and not simply stated or implied. IOW there is a lot of misinformation and just plain bullshit presented as facts on the internet and you are left to determine which is which.

 

[TonyV225]

One can read almost anything on the internet and as a result one must be aware of the credibility of the sources of such articles. <gotproof> That credibility must be confirmed and not simply stated or implied. IOW there is a lot of misinformation and just plain bullshit presented as facts on the internet and you are left to determine which is which.

YOU GOT THAT RIGHT!!

 

[roadrage]

One can read almost anything on the internet and as a result one must be aware of the credibility of the sources of such articles. <gotproof> That credibility must be confirmed and not simply stated or implied. IOW there is a lot of misinformation and just plain bullshit presented as facts on the internet and you are left to determine which is which.

Very true my friend, and I couldn't agree more. But the RMS definition was Wikipedia and I trust it to be fairly credible. Not that they couldn't be wrong, but I'll bet they are pretty spot on most of the time. As to the first article, I can't speak to their credibility at all. It does, however, seem to be on par with Wikipedia. My brain is beginning to smoke from all this reading though, lol. I will say that I am starting to have a better understanding of the whole idea.

 

[AudioShockwav]

But the RMS definition was Wikipedia and I trust it to be fairly credible. Not that they couldn't be wrong, but I'll bet they are pretty spot on most of the time.

Wiki is only as good as the last guy that edited`ed it, it is good for general info, but not gospel.
You can use RMS voltage and current to Calculate watts, but it is not something that you can just hook up a meter and read.



To get back to the original poster:
There is no way to tell if your Meter is going to read the same as your friends meter, even after you have the other friend "calibrate " it.
There are too many things that can be different.
Did he read on the peak or AVG scale?
Is it a Passive peak reading meter or an active peak reading meter?
Did he check his power into a dummy load?
Did he check his power into a Antenna?
If a Antenna was used, what was the SWR?
How much coax from the meter to the load/antenna did he use?
Did you check your power into a dummy load?
Antenna?
SWR?
Coax?
Was his meter built and set at the factory on a Friday when the guy "calibrating" it wanted to go home early?
Monday when he wanted to take all day and get it down to the last milliwatt?
Does his AMP have the old style 2879`s in it, or the New "red dot" 2879`s in it?

You can make yourself go crazy trying to get identical readings.
The only way to do that......open your watt meter and find the VR for the high power scale and set it so your meter reads the same as his, problem solved....sort of...unless he says that his meter reads 60 watts less when he turns the variable 1/2 way down on his amp.
Drill a hole in the watt meter and add a external control to change the reading to..............
If you are in the ballpark with his readings, no one will ever tell the difference on the other end anyway, the radios we are using are not that critical when it comes to the Signals we see on the RX meter in the radio.
Just don`t worry about it and have fun talking.


73
Jeff

 

[Captain Kilowatt]

Very true my friend, and I couldn't agree more. But the RMS definition was Wikipedia and I trust it to be fairly credible. Not that they couldn't be wrong, but I'll bet they are pretty spot on most of the time. As to the first article, I can't speak to their credibility at all. It does, however, seem to be on par with Wikipedia. My brain is beginning to smoke from all this reading though, lol. I will say that I am starting to have a better understanding of the whole idea.

Jeff touched on it above but you do know that anybody can edit information on Wikipedia don't you? I have corrected or added info on there myself before. Anyone can use the wrong terms on there and have it taken as the gospel by the masses.All it takes is for someone to post wrong info and thousands of college students suddenly get a D- on an exam.

 

[roadrage]

I'm not saying I don't believe you. I am just putting out what I've been reading on the sub. When my brain stops smoking, I'll continue researching. Im still trying to learn about this.
But I have hi-jacked this thread so I am sliding on the side. The thread can get back on topic.

73s

 

[Oatmeal]

Ok guy tell me something, should I get the meter recalibrated, or buy me another meter like the Radio Shack 21-534 meter which has a 20w, 200w, and 2kw scale.....

A meter that will handle 2kw, is all I will ever need...

 

[AudioShockwav]

By all means, If your friend will"re-calibrate it for free" then go ahead and do that.
It may or may not give you the same readings that your friend see`s with his meter.
The Radio shack meter is also a good basic meter, the same apply s that it may or may not read the same as your friends meter.
I know it seems critical right now, but as long as the radio/amp set-up is working to your satisfaction try not to worry about 75 or so watts on a meter.
I been playing radio for 30+ years and after a while you might find as I did that it is not so much what number you see on a meter as how well the whole system works together.
The only exception to this is the guys that run "Comp" set-up`s were they are using multi-amps to extremes were reflect and over drive will kill an amp quickly ..... but for the average user not so.
Have fun with you radio.


73
Jeff