Sirio Gain Master - First report

[Simon004]

There sure is a difference a 10 db increase in rf is not a 10 db increase in audio. 10 db = 10 x the rf power, 10 db in audio is 2x the loudness.

Either you are missing the point, or I am. What Booty quoted was "Robb told him a dB is a dB, in both RF and audio terms, a dB is a unit of measurement", and that is completely correct. Just because it takes a 10 fold increase in electrical power to produce a "perceivable" doubling in volume has no bearing on what a dB is, but it has every bearing on how human hearing/ears work.

 

[MrSuburban]

Either you are missing the point, or I am. What Booty quoted was "Robb told him a dB is a dB, in both RF and audio terms, a dB is a unit of measurement", and that is completely correct. Just because it takes a 10 fold increase in electrical power to produce a "perceivable" doubling in volume has no bearing on what a dB is, but it has every bearing on how human hearing/ears work.

Probably me, but I think we both said the same thin after it was all said and done.

 

[loosecannon]

the antenna is not the reason for the "louder and clearer" audio noted by some when testing antennas.
it cant be.
it comes after the radio and all the modulation "work" is already done by the time it gets to the antenna.

even if one antenna was "louder" than another, you would never notice it because of a little thing called the AGC (automatic gain control) circuit inside your receiver.

its job is to keep the audio level constant whether the signal is an S-3 or an S-7.

the question is, how well does it do its job.
i think it does its job pretty well, but its not perfect.
i would say that the perceived increases in loudness that are being noted by others are a result of the AGC not "clamping down" fast/far enough.

as for the differences in the signal strengths; since all of the antennas we are discussing are within about 2db of eachother, the differences probably have more to do with the differences in the matching systems of the antennas in question.

i would think that the IMAX's matching system is more lossy than the gain masters, which could easily account for the 3 db difference noted in these tests.

LC

 

[15minigrass]

Now that I can understand. Very well said. Thanx LC.

15.......

the antenna is not the reason for the "louder and clearer" audio noted by some when testing antennas.
it cant be.
it comes after the radio and all the modulation "work" is already done by the time it gets to the antenna.

even if one antenna was "louder" than another, you would never notice it because of a little thing called the AGC (automatic gain control) circuit inside your receiver.

its job is to keep the audio level constant whether the signal is an S-3 or an S-7.

the question is, how well does it do its job.
i think it does its job pretty well, but its not perfect.
i would say that the perceived increases in loudness that are being noted by others are a result of the AGC not "clamping down" fast/far enough.

as for the differences in the signal strengths; since all of the antennas we are discussing are within about 2db of eachother, the differences probably have more to do with the differences in the matching systems of the antennas in question.

i would think that the IMAX's matching system is more lossy than the gain masters, which could easily account for the 3 db difference noted in these tests.

LC

 

[hotrod]

bump !!!! @ cbradiomagazine after testing some good
antennas if you had to choose which one would ya get
also did ya ever see if your getting any tvi with the GM

 

[cbradiomagazine.com]

I haven't had a chance to talk to the neighbor yet. Hopefully this weekend I can do a little test.

Been busy messing around with some new radios.

I was listening to DX this evening on the GM and it really does seems to pull the signals in and have a low noise level. I'm still very impressed.

I forget to mention earlier that I did run into the same issue when assembling where the connector piece coming out of the base section had gotten crimped a bit over the edge in shipping. I do think that is something that needs to be addressed but it didn't seem to effect the antenna negatively.

The bandwidth is pretty awesome - I flipped from 11 meters up to 10 meters this evening and SWR is an afterthought.