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Isn't that why a bird meter is the best way of seeing true power? The slugs are calibrated for a certain freq range and effectively "ignore" harmonics.

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MoJo
www.mojoenterprises.us

If it is bleeding over at all, it isn't right....

"Isn't that why a bird meter is the best way of seeing true power?"

no, the H slug (2-30Mhz.) and the A slug (25-60Mhz.) will both respond to nominal power levels outside of their respective ranges. (not to mention the fact that the second harmonic falls well within the range of the A slug) it has to do with the manufacturers stated % of accuracy, not some imagined immunity to harmonics. you'd know that if you actually knew how to test for it and you don't see Bird making the claim because it isn't true. it's a detector circuit, not a filter.

"the cobra 29 i had WOULD DO 47W ON FREQ.!! with very little bleed to adjacent channels, if any at all. i tested it thoroughly."

then you should be able to fire right back and tell us all what the total width of both sidebands were when the transmitter was modulated since you tested it thoroughly and this parameter combined with modulation index establishes the amount of energy that would or would not contribute to adjacent channel interference when the transmitter is in operation. since the mod index is already approaching a factor of 6 (5.875 for 2W Carrier / 47WPEP) your statement already smacks of BS and total sideband width is irrelevant.

if you are sitting right next to someone who is talking on the air, you are gonna get some bleed on the same freq. put some distance between you and that person and the bleed diminishes. that even happens with bone stock radios, so what's your excuse now?

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No need to attack me there Freecell. I just asked a question to clarify something I had read on another board.

You're the one who said you cant believe all you see on the internet in another thread.

Thank you for your explanation.

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MoJo
www.mojoenterprises.us

the bold print statement wasn't an attack. the point is that it stands to reason that if you can input power at a frequency outside of the slug range and get any kind of measurement then the argument you (or whoever) posited has no merit.

believe me if it did Bird would be pushing the feature. as it stands the operating frequency range of the slugs only deals with measurement accuracy and nothing else.

in addition, the internet is no different than any other medium when it comes to separating the wheat from the chaff. the old adage is just as applicable on the net as it is anywhere else, believe nothing you hear, half of what you read and everything you see.

73,

That was why I asked the question. I had read on another board that a bird meter didn't "see" harmonics. Didn't make sense so I asked.

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MoJo
www.mojoenterprises.us

The bird meter will not see harmonics, it only detects the reflected signal from an antenna in circuit so that's why everyone uses a dummy load which is usually near 50 ohms and makes most radios show happy watts.

The use of a scope is your best bet for a true output signal reading.

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I U 212

They will if your analyzer has the capability of telling you peak wattage at a specific frequency range that you set, which the HP cell site analyzer I had access to did.

How do you do this? I'm not quite understanding what you mean. Maybe I'm just being dense...I haven't used my o-scope for measuring power output in a while and I certainly have never used it to determine power levels on harmonic freq's. I'd like to know how to do that.

mack you're babbling again.

for those of you who love repeating dribble posted on other forums i suggest you pick up a copy of something else you obviously have never read, the instruction book (pages 14 & 15) for the Bird 43 rf directional thruline wattmeter. if you actually read it then there's no way you or anyone else would be running around forums spouting off about immunity to harmonics.

anyone making that statement has no clue what they're talking about and what makes it worse is that they go plastering it everywhere on the net and make everyone else as stupid as they are.

not only is the 43 not immune to harmonics but the higher power slugs are even more prone to harmonics than the lower power slugs. the slug is a circuit and all circuits have a definitive frequency response both inside and outside of the frequency range in which they're intended to operate.

if harmonics are present at frequencies INSIDE the range of the slug then ALL harmonic energy is sum added to the resulting power measurement, as in the case of second harmonic energy occurring at 54Mhz. from a fundamental operating frequency of 27Mhz.. using the slug mentioned previously with a range of 25 - 60 Mhz..duh!

and since the butchered radio in question uses a single device in the final output stage the advantage of second harmonic cancellation is non-existent since that only occurs in a push-pull transistor configuration which requires a minimum of TWO DEVICES in the final output stage.

guys like preacherman and sparky are simply ignoring sound am transmitter fundamentals (or aren't familiar with them to begin with) in exchange for the deadkey-swing mentality and catering to the stupidity of their customer base.