Deviation/Multipath Meter

[Notnilc]

Hello Audiokarma Guru’s,
Can anyone tell me the theory behind the Deviation/Multipath meter on my Kenwood KT8300? I’m pretty sure I understand the Multipath feature for tuning the antenna. But why is there static when the deviation needle is bouncing to the music at about 100, all the while the signal strength is at its highest, and the tuning meter is dead center? I find that if I move the tuning dial slightly out of tune the reception is crystal clear, but the deviation meter is at zero, the signal is weaker, and the tuning meter is not on center.

 

[Punker X]

Deviation is the modulation level of the FM. Pretty much like a VU meter on an Amp. Most modern commercial stations are over modulate no and will be at 100 or over.

 

[Notnilc]

Deviation is the modulation level of the FM. Pretty much like a VU meter on an Amp. Most modern commercial stations are over modulate no and will be at 100 or over.

Thanks is for the response. So why does the FM sound better and more clear when I dial the tuner just out of tune and deviation is at 0? The fuzz or hiss goes away but the signal is weaker and the tuning meter is just off center.

 

[chazix]

I find that if I move the tuning dial slightly out of tune the reception is crystal clear, but the deviation meter is at zero, the signal is weaker, and the tuning meter is not on center.

This points to a need for an alignment.

 

[KentTeffeteller]

Deviation is the modulation level of the FM. Pretty much like a VU meter on an Amp. Most modern commercial stations are over modulate no and will be at 100 or over.

I agree the poster's Kenwood tuner needs an alignment. His having to detune the station is definitely a symptom. I also dislike today's modern brickwall compressed audio, and over processing audio twice over (modern broadcast processors are usually abused in the name of competitive loudness wars).

 

[Notnilc]

This points to a need for an alignment.

Thanks for the tip. However, I spoke with some audio engineers at Chrysler and they have stated that I need a better antenna, and they also confirmed my suspicion that de-tuning has resulted in mono playback, which is why the stereo hiss is not present.

 

[Notnilc]

Thanks for the tip. However, I spoke with some audio engineers at Chrysler and they have stated that I need a better antenna, and they also confirmed my suspicion that de-tuning has resulted in mono playback, which is why the stereo hiss is not present.

The

Thanks for the tip. However, I spoke with some audio engineers at Chrysler and they have stated that I need a better antenna, and they also confirmed my suspicion that de-tuning has resulted in mono playback, which is why the stereo hiss is not present.

Also, the tuner was recently aligned

 

[gadget73]

If the signal strength peaks when the tuning meter is centered, that says the IF strip and detector match. usually alignment problems will show a signal peak with the tuning meter off-center.

signal to noise is considerably worse in stereo mode. Just an artifact of how it functions. If manually switching it to mono makes it quiet, then I'd be inclined to agree with a better antenna possibly fixing or at least helping the situation. Using the narrow IF bandwidth may also help, though that will narrow up the stereo effect considerably.

 

[rcs16]

Some things to check
Disconnect the antenna, muting off, tune to a spot where all you hear is white noise thru the speakers.
The tuning meter should be in the dead center, for both wide and narrow IF filter positions, if not adjust VRg4 pot for center when in Wide and VRg12 for Narrow
First step in the adjustment procedure, p7 service manual.

Deviation muting action should happen near equal distanced on both sides, from tuning meter center while tuned to a strong signal.

Move your antenna around, tilt it even, see if that changes the noise issue. The Stellar Labs 30-2460 small yagi is worth trying if you can get it out side preferred. Brian B has a simple method to increase its gain a bit, see 88-108MHz site
http://ham-radio.com/k6sti/stellar.htm

 

[Notnilc]

If the signal strength peaks when the tuning meter is centered, that says the IF strip and detector match. usually alignment problems will show a signal peak with the tuning meter off-center.

signal to noise is considerably worse in stereo mode. Just an artifact of how it functions. If manually switching it to mono makes it quiet, then I'd be inclined to agree with a better antenna possibly fixing or at least helping the situation. Using the narrow IF bandwidth may also help, though that will narrow up the stereo effect considerably.

Thanks. I agree with your response. I added a better antenna today and there’s a noticeable difference, but it’s still not pulling the same reception as my upstairs stereo.

 

[Notnilc]

Some things to check
Disconnect the antenna, muting off, tune to a spot where all you hear is white noise thru the speakers.
The tuning meter should be in the dead center, for both wide and narrow IF filter positions, if not adjust VRg4 pot for center when in Wide and VRg12 for Narrow
First step in the adjustment procedure, p7 service manual.

Deviation muting action should happen near equal distanced on both sides, from tuning meter center while tuned to a strong signal.

Move your antenna around, tilt it even, see if that changes the noise issue. The Stellar Labs 30-2460 small yagi is worth trying if you can get it out side preferred. Brian B has a simple method to increase its gain a bit, see 88-108MHz site
http://ham-radio.com/k6sti/stellar.htm

Thanks for the troubleshooting tips. I’m definitely going to purchase a better antenna.

 

[Bob@FM]

Thanks. I agree with your response. I added a better antenna today and there’s a noticeable difference, but it’s still not pulling the same reception as my upstairs stereo.

Try the KT-8300 upstairs - same antenna, same location as the one that works better. When you put the FM antenna higher, even only 10 ft higher from ground, it does wonders for reception.
Bob