Phase mod vs. FM in Yaesu HTs
 

Hi, I have a Yaesu/Vertex VX-150 & VX-6R. Was looking at the manuals the
other day and noticed the different emission types. Essentially the 150
uses Phase modulation (G3E) and the 6R uses FM (F3E).

Will there be any appreciable difference in the performance of these radios
because of this?

I have noticed that, using an interchangeable antenna, the 6R has a greater
range than the 150, even though they're both supposedly putting out 5 watts.
Could the different emission types be the cause of this?

Phase mod vs. FM in Yaesu HTs
 

The modulation type won't cause this as you wouldn't be able to tell
the difference in a reciever. Phase Modulation and FM Modulation with
75 uS pre-emphasis sound exactly the same. 75uSeconds is the time
constant of the RC network in the FM microphone audio circuit.

It's likely a difference in the receiver sections or antennas.

Stuart
WB6RXG

On Thu, 10 Nov 2005 01:40:12 GMT, "Falky foo"
wrote:

Hi, I have a Yaesu/Vertex VX-150 & VX-6R. Was looking at the manuals the
other day and noticed the different emission types. Essentially the 150
uses Phase modulation (G3E) and the 6R uses FM (F3E).

Will there be any appreciable difference in the performance of these radios
because of this?

I have noticed that, using an interchangeable antenna, the 6R has a greater
range than the 150, even though they're both supposedly putting out 5 watts.
Could the different emission types be the cause of this?

Phase mod vs. FM in Yaesu HTs
 

Thanks! Any idea why the different radios use different modulations?



WB6RXG wrote in message ...
The modulation type won't cause this as you wouldn't be able to tell
the difference in a reciever. Phase Modulation and FM Modulation with
75 uS pre-emphasis sound exactly the same. 75uSeconds is the time
constant of the RC network in the FM microphone audio circuit.

It's likely a difference in the receiver sections or antennas.

Stuart
WB6RXG

On Thu, 10 Nov 2005 01:40:12 GMT, "Falky foo"
wrote:

Hi, I have a Yaesu/Vertex VX-150 & VX-6R. Was looking at the manuals the
other day and noticed the different emission types. Essentially the 150
uses Phase modulation (G3E) and the 6R uses FM (F3E).

Will there be any appreciable difference in the performance of these
radios
because of this?

I have noticed that, using an interchangeable antenna, the 6R has a
greater
range than the 150, even though they're both supposedly putting out 5
watts.
Could the different emission types be the cause of this?

Phase mod vs. FM in Yaesu HTs
 

I don't know but I would suspect it is simply design considerations by
the design engineers.

WB6RXG

On Fri, 11 Nov 2005 00:50:45 GMT, "Falky foo"
wrote:

Thanks! Any idea why the different radios use different modulations?



WB6RXG wrote in message ...
The modulation type won't cause this as you wouldn't be able to tell
the difference in a reciever. Phase Modulation and FM Modulation with
75 uS pre-emphasis sound exactly the same. 75uSeconds is the time
constant of the RC network in the FM microphone audio circuit.

It's likely a difference in the receiver sections or antennas.

Stuart
WB6RXG

On Thu, 10 Nov 2005 01:40:12 GMT, "Falky foo"
wrote:

Hi, I have a Yaesu/Vertex VX-150 & VX-6R. Was looking at the manuals the
other day and noticed the different emission types. Essentially the 150
uses Phase modulation (G3E) and the 6R uses FM (F3E).

Will there be any appreciable difference in the performance of these
radios
because of this?

I have noticed that, using an interchangeable antenna, the 6R has a
greater
range than the 150, even though they're both supposedly putting out 5
watts.
Could the different emission types be the cause of this?

Phase mod vs. FM in Yaesu HTs
 

Perhaps this will help compare FM to Phase modulation
as I remember it in collge
http://www.musicdsp.org/showone.php?id=160


--
CL -- I doubt, therefore I might be !






WB6RXG wrote in message ...
I don't know but I would suspect it is simply design considerations by
the design engineers.

WB6RXG

On Fri, 11 Nov 2005 00:50:45 GMT, "Falky foo"
wrote:

Thanks! Any idea why the different radios use different modulations?



WB6RXG wrote in message ...
The modulation type won't cause this as you wouldn't be able to tell
the difference in a reciever. Phase Modulation and FM Modulation with
75 uS pre-emphasis sound exactly the same. 75uSeconds is the time
constant of the RC network in the FM microphone audio circuit.

It's likely a difference in the receiver sections or antennas.

Stuart
WB6RXG

On Thu, 10 Nov 2005 01:40:12 GMT, "Falky foo"
wrote:

Hi, I have a Yaesu/Vertex VX-150 & VX-6R. Was looking at the manuals
the
other day and noticed the different emission types. Essentially the
150
uses Phase modulation (G3E) and the 6R uses FM (F3E).

Will there be any appreciable difference in the performance of these
radios
because of this?

I have noticed that, using an interchangeable antenna, the 6R has a
greater
range than the 150, even though they're both supposedly putting out 5
watts.
Could the different emission types be the cause of this?

Phase mod vs. FM in Yaesu HTs
 

On Fri, 11 Nov 2005 00:50:45 +0000, Falky foo wrote:

Thanks! Any idea why the different radios use different modulations?

Phase modulation is simpler to implement, thus cheaper to build.

--
Korbin Dallas
The name was changed to protect the guilty.

Phase mod vs. FM in Yaesu HTs
 

On Thu, 10 Nov 2005 01:40:12 +0000, Falky foo wrote:

Hi, I have a Yaesu/Vertex VX-150 & VX-6R. Was looking at the manuals the
other day and noticed the different emission types. Essentially the 150
uses Phase modulation (G3E) and the 6R uses FM (F3E).

Will there be any appreciable difference in the performance of these radios
because of this?

I have noticed that, using an interchangeable antenna, the 6R has a greater
range than the 150, even though they're both supposedly putting out 5 watts.
Could the different emission types be the cause of this?

When you say Range what exactly are you talking about?
Range is a combination of transmit power, receiver sensitivity and
propagation path.

Do you know what power the radios are putting out
Did you measure there output?
Do you know the receiver Sensitivity for these particular radios?

Published specs are for comparison only, actual production radios will
differ from published specs by significant amounts.

--
Korbin Dallas
The name was changed to protect the guilty.

Phase mod vs. FM in Yaesu HTs
 

Didn't do detailed analysis.. just realized that the VX-6 was hitting
repeaters better than the VX-150, even when using the same antenna.
Wondered if that difference was because of the different modulation types.


When you say Range what exactly are you talking about?
Range is a combination of transmit power, receiver sensitivity and
propagation path.

Do you know what power the radios are putting out
Did you measure there output?
Do you know the receiver Sensitivity for these particular radios?

Published specs are for comparison only, actual production radios will
differ from published specs by significant amounts.

--
Korbin Dallas
The name was changed to protect the guilty.

Phase mod vs. FM in Yaesu HTs
 

Transmitter Range graph

http://www.artscipub.com/simpleton/simp.range.html
--
CL -- I doubt, therefore I might be !






"Falky foo" wrote in message
. com...
Didn't do detailed analysis.. just realized that the VX-6 was hitting
repeaters better than the VX-150, even when using the same antenna.
Wondered if that difference was because of the different modulation types.


When you say Range what exactly are you talking about?
Range is a combination of transmit power, receiver sensitivity and
propagation path.

Do you know what power the radios are putting out
Did you measure there output?
Do you know the receiver Sensitivity for these particular radios?

Published specs are for comparison only, actual production radios will
differ from published specs by significant amounts.

--
Korbin Dallas
The name was changed to protect the guilty.

Phase mod vs. FM in Yaesu HTs
 

Other things enter into the equasion: includeing how WIDE the signal
is-- Most repeaters have recieve filters that accept modulation to:
+- 4.9 KHZ (and that ONLY if you are relatively close to the input
frequency) over +- 800 HZ can accentuate clipping of your signal-
if you exceed +- 5 KHz, you will lose some audio, due to "clipping",
and it gets worse , if you are off frequency ! "tis a case of TOO MUCH
audio being WORSE than too little! Essentially, Phase modulation
is the same as Frequency modulation, and there should be little diff.
between the 2, as far as the recievers are concerned. The "Modulation
Index" is the limiting factor- Keep in mind that a Commercial FM station
(150 KHz +- deviation) , has also , many subcarriers in the signal, that
you don't hear (like background music for stores, sterio piolets, stock
market data, ect) ALL in their carrier- you can detect those with
filters at the appropriate freq, and BANDWIDTH. and, there are outfits
that sell adapters for fm recievers to decode them (but you wont hear
the normal broadcast, thru them!) Television stations do similar things
with their audio, and video! These are called SUB CARRIERS. In sum
total, IF your modulation index exceeds the bandwidth of your reciever
,the audio will be limited (or eleminated)! But that doesn't mean that
your audio isn't there, only that the reciever refuses to accept your
overmodulation-- dont try to speak LOUDER, try whispering, and see if
you get a response! Jim NN7K




Falky foo wrote:
Didn't do detailed analysis.. just realized that the VX-6 was hitting
repeaters better than the VX-150, even when using the same antenna.
Wondered if that difference was because of the different modulation types.

Phase mod vs. FM in Yaesu HTs
 

Actually, the typical FM rcvr can handle up to +/-7kHz deviation unless it
has had new filters added for narrowbanding, etc.....this is due to the
filters not having a sharp cut off at the 5 khz point....My GE MSTR II rcvrs
can accept up to 7 kHz dev signals on strong signals..on weak signals, the
wider deviation starts to confuse the squelch ckt and thus the rcvr starts
to squelch..but the rcvr is designed for 5 kHz deviation...and this is
normal of FM filters...

FM broadcast stations are +/- 75 kHz...not 150 kHz! The max b/w of a FM
broadcast signal is 200 kHz.....(which is normal channel spacing also)
including the subcarriers..
and Modulation Index is Dev/highest freq of modulation....but MI IS not the
limiting factor in a rcvr...It is overall deviation and bandwidth (B/W is
equal to 2x (dev PLUS Mod freq). You can have a 3 kHz dev with 1 kHz tone
and the MI is 3....increase to 5 khz dev with a 1 kHz tone and the MI DROPS
to 1.6...thus MI is NOT the issue....the overall BW in the above examples
would be 8kHz and 12 kHz respectively.

Yes, FM vs PM if done right is not noticeable on the air...unless the PM has
not been corrected or the FM does not have preemphasis...
PM is easier to implement on xtal radios and is much more stable in older
designs....FM is better in PLL radios..also FM allows Digital modes (DCS,
etc) where as PM cannot handle it (DC offsets dont work with PM).

Chris
WB5ITT

"Jim - NN7K" wrote in message
om...
Other things enter into the equasion: includeing how WIDE the signal
is-- Most repeaters have recieve filters that accept modulation to:
+- 4.9 KHZ (and that ONLY if you are relatively close to the input
frequency) over +- 800 HZ can accentuate clipping of your signal-
if you exceed +- 5 KHz, you will lose some audio, due to "clipping", and
it gets worse , if you are off frequency ! "tis a case of TOO MUCH
audio being WORSE than too little! Essentially, Phase modulation
is the same as Frequency modulation, and there should be little diff.
between the 2, as far as the recievers are concerned. The "Modulation
Index" is the limiting factor- Keep in mind that a Commercial FM station
(150 KHz +- deviation) , has also , many subcarriers in the signal, that
you don't hear (like background music for stores, sterio piolets, stock
market data, ect) ALL in their carrier- you can detect those with
filters at the appropriate freq, and BANDWIDTH. and, there are outfits
that sell adapters for fm recievers to decode them (but you wont hear
the normal broadcast, thru them!) Television stations do similar things
with their audio, and video! These are called SUB CARRIERS. In sum
total, IF your modulation index exceeds the bandwidth of your reciever
,the audio will be limited (or eleminated)! But that doesn't mean that
your audio isn't there, only that the reciever refuses to accept your
overmodulation-- dont try to speak LOUDER, try whispering, and see if
you get a response! Jim NN7K




Falky foo wrote:
Didn't do detailed analysis.. just realized that the VX-6 was hitting
repeaters better than the VX-150, even when using the same antenna.
Wondered if that difference was because of the different modulation
types.

Phase mod vs. FM in Yaesu HTs
 

Now- what did I say ?? Syntax? what does +/- 75 Khz add up to?? 200
Khz?? NO , it adds up to a 150 KHz channel bandwidth ( +/- 75 KHz),
with 200 KHZ Channels!! But, I digress: on WEAK signals, clipping
of signals, at least in the Motorolas that I am used to, will start
(clipping, chopping, DISTORTING, the signal, once you exceed +/- 5
KHz)! The point I try to make is, unlike human experience, TOO MUCH
can be far worse than too little, when comes to LOUDENESS into a
microphone (at least on FM)! Its kind of like the worlds cheapest
hearing aid-- a button that states "YELL, I'M DEAF" ! It may work in the
real world, but, when applied to radio, t'aint necessarily so! And, in
trying to keep from technological overkill, try to keep it in SIMPLE
terms, as MOST folks here don't have Engineering Degrees! The point
is, that the modulation type (Phase, or Frequency) isn't necessarilly
what is causing the difference, at a given power level on radios, but
the deviation component (at a given power level) can have drastic
implications on a (Repeated, or Directly) recieved signal, Vs. a
carrier,or very narrowly modulated signal ! Jim NN7K (Retired U.P.,
and S.P. Radioman, and Communications Dept Electronic Technician)



CWB wrote:
Actually, the typical FM rcvr can handle up to +/-7kHz deviation unless it
has had new filters added for narrowbanding, etc.....this is due to the
filters not having a sharp cut off at the 5 khz point....My GE MSTR II rcvrs
can accept up to 7 kHz dev signals on strong signals..on weak signals, the
wider deviation starts to confuse the squelch ckt and thus the rcvr starts
to squelch..but the rcvr is designed for 5 kHz deviation...and this is
normal of FM filters...

FM broadcast stations are +/- 75 kHz...not 150 kHz! The max b/w of a FM
broadcast signal is 200 kHz.....(which is normal channel spacing also)
including the subcarriers..
and Modulation Index is Dev/highest freq of modulation....but MI IS not the
limiting factor in a rcvr...It is overall deviation and bandwidth (B/W is
equal to 2x (dev PLUS Mod freq). You can have a 3 kHz dev with 1 kHz tone
and the MI is 3....increase to 5 khz dev with a 1 kHz tone and the MI DROPS
to 1.6...thus MI is NOT the issue....the overall BW in the above examples
would be 8kHz and 12 kHz respectively.

Yes, FM vs PM if done right is not noticeable on the air...unless the PM has
not been corrected or the FM does not have preemphasis...
PM is easier to implement on xtal radios and is much more stable in older
designs....FM is better in PLL radios..also FM allows Digital modes (DCS,
etc) where as PM cannot handle it (DC offsets dont work with PM).

Chris
WB5ITT

"Jim - NN7K" wrote in message
om...

Other things enter into the equasion: includeing how WIDE the signal
is-- Most repeaters have recieve filters that accept modulation to:
+- 4.9 KHZ (and that ONLY if you are relatively close to the input
frequency) over +- 800 HZ can accentuate clipping of your signal-
if you exceed +- 5 KHz, you will lose some audio, due to "clipping", and
it gets worse , if you are off frequency ! "tis a case of TOO MUCH
audio being WORSE than too little! Essentially, Phase modulation
is the same as Frequency modulation, and there should be little diff.
between the 2, as far as the recievers are concerned. The "Modulation
Index" is the limiting factor- Keep in mind that a Commercial FM station
(150 KHz +- deviation) , has also , many subcarriers in the signal, that
you don't hear (like background music for stores, sterio piolets, stock
market data, ect) ALL in their carrier- you can detect those with
filters at the appropriate freq, and BANDWIDTH. and, there are outfits
that sell adapters for fm recievers to decode them (but you wont hear
the normal broadcast, thru them!) Television stations do similar things
with their audio, and video! These are called SUB CARRIERS. In sum
total, IF your modulation index exceeds the bandwidth of your reciever
,the audio will be limited (or eleminated)! But that doesn't mean that
your audio isn't there, only that the reciever refuses to accept your
overmodulation-- dont try to speak LOUDER, try whispering, and see if
you get a response! Jim NN7K




Falky foo wrote:

Didn't do detailed analysis.. just realized that the VX-6 was hitting
repeaters better than the VX-150, even when using the same antenna.
Wondered if that difference was because of the different modulation
types.