On 8/2/2014 7:48 PM, wrote:
Jerry Stuckle wrote:
On 8/2/2014 5:53 PM, Rob wrote:
Lostgallifreyan wrote:
Jerry Stuckle wrote in news:lrio4f$fs4$1@dont-
email.me:

Nope. I'm talking about what is commonly used here. But there are some
people from the U.K. who think they are experts on everything.


To be fair to him, I'm in the UK and he may well have aimed that point at me,
knowing this from the message header or some earlier post of mine. I'm
also interesed in how the US conventions differ from ours.

I think you should be careful not to mistake Jerry's conventions
for US conventions. It looks a lot like Jerry makes many assumptions
that are not based on signal theory or common practice, but mainly on
his own experience as a cable fitter.


Cabling is not the only thing I do - nor the only thing I have done in
the past. It is just one of the things my company does.

But like other trolls, you think you know everything, when you actually
know nothing.

So much for the anonymous troll who uses a fake email and probably
doesn't even have a call sign.


And here he goes off into his usual "stupid troll" rant with yet a person
who had the umitigated audacity to imply Jerry Stuckle does not know
everything about everything.

You ignorant peasants just don't understand; Jerry Stuckle has done
everything, knows everything and is NEVER, EVER wrong about anything.

To even hint otherwise is blasphemy and you shall be severely reprimanded
and totally disparaged as you well deserve.



And here's one of the other anonymous trolls without a call sign on this
newsgroup. If I didn't know some REAL hams in the U.K., I would have a
VERY DIM VIEW of the people there. You, "Rob", Gareth and a couple of
others - all cut from the same form.

But trolls can't stand the truth, can you?

Once again, you can have the last word - as trolls need

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

On 8/2/2014 8:50 PM, Jerry Stuckle wrote:
On 8/2/2014 7:48 PM, wrote:
Jerry Stuckle wrote:
On 8/2/2014 5:53 PM, Rob wrote:
Lostgallifreyan wrote:
Jerry Stuckle wrote in news:lrio4f$fs4$1@dont-
email.me:

Nope. I'm talking about what is commonly used here. But there are some
people from the U.K. who think they are experts on everything.


To be fair to him, I'm in the UK and he may well have aimed that point at me,
knowing this from the message header or some earlier post of mine. I'm
also interesed in how the US conventions differ from ours.

I think you should be careful not to mistake Jerry's conventions
for US conventions. It looks a lot like Jerry makes many assumptions
that are not based on signal theory or common practice, but mainly on
his own experience as a cable fitter.


Cabling is not the only thing I do - nor the only thing I have done in
the past. It is just one of the things my company does.

But like other trolls, you think you know everything, when you actually
know nothing.

So much for the anonymous troll who uses a fake email and probably
doesn't even have a call sign.


And here he goes off into his usual "stupid troll" rant with yet a person
who had the umitigated audacity to imply Jerry Stuckle does not know
everything about everything.

You ignorant peasants just don't understand; Jerry Stuckle has done
everything, knows everything and is NEVER, EVER wrong about anything.

To even hint otherwise is blasphemy and you shall be severely reprimanded
and totally disparaged as you well deserve.



And here's one of the other anonymous trolls without a call sign on this
newsgroup. If I didn't know some REAL hams in the U.K., I would have a
VERY DIM VIEW of the people there. You, "Rob", Gareth and a couple of
others - all cut from the same form.

But trolls can't stand the truth, can you?

Once again, you can have the last word - as trolls need


Actually, that statement is unfair - to Gareth. At least he isn't
afraid to let people know who he is. So Gareth, I apologize for mixing
you in with the anonymous trolls. You're better than that.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

amdx wrote in :

I probably missed something in this thread, but where are you going to
get an FM transmitter that isn't designed to work with FM radios?


A CB no-longer-wants-to-be? Ok, facetious answer, but there's a point to
this, they do exist. For all I know, if the microtransmitters have slightly
narrower bandwidth deliberately to reduce encroachment on other signals (wise
maybe, given that many of these devices may be built and used), then the loss
of SNR and quality for music listening may be acceptable for some, but not to
me. I wouldn't use one if they haven't got good quality sound. If intended
for use in a car, there's much less likely a demand that they should.

Rob wrote in :

Deviation is something different than bandwidth. To receive an FM signal,
as a rule of thumb you require a receiver with a bandwith of about
twice the deviation plus twice the maximal audio frequency. So to receive
a signal with 15kHz audio and 75kHz deviation, you require a bandwitdh
of about 180kHz.

This is not "to make things less critical". It is a requirement because
of the characteristics of FM modulation, where sideband frequencies are
determined by a Bessel function.

The ratio between deviation and maximal audio frequency, the modulation
index, determines the signal/noise ratio after demodulation for a strong
signal.

That's useful. It ties in with things I have read about phase modulation
synthesis. At risk of opening a wild (but fun) bit of off-topic, I wonder if
given a reference carrier at precise fixed frequency, a phase modulation
technique might allow advantages to signal transmission that FM lacks.

On 8/2/2014 9:55 PM, Lostgallifreyan wrote:
Rob wrote in :

Deviation is something different than bandwidth. To receive an FM signal,
as a rule of thumb you require a receiver with a bandwith of about
twice the deviation plus twice the maximal audio frequency. So to receive
a signal with 15kHz audio and 75kHz deviation, you require a bandwitdh
of about 180kHz.

This is not "to make things less critical". It is a requirement because
of the characteristics of FM modulation, where sideband frequencies are
determined by a Bessel function.

The ratio between deviation and maximal audio frequency, the modulation
index, determines the signal/noise ratio after demodulation for a strong
signal.

That's useful. It ties in with things I have read about phase modulation
synthesis. At risk of opening a wild (but fun) bit of off-topic, I wonder if
given a reference carrier at precise fixed frequency, a phase modulation
technique might allow advantages to signal transmission that FM lacks.


Not really. All phase modulation does is integrate the modulating
signal and use that to shift the phase of the carrier (which also
requires a frequency change to effect the phase change). The resulting
signal is exactly the same as if the carrier were directly frequency
modulated. The only difference is how you got there.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

Jerry Stuckle wrote in
:

That's useful. It ties in with things I have read about phase
modulation synthesis. At risk of opening a wild (but fun) bit of
off-topic, I wonder if given a reference carrier at precise fixed
frequency, a phase modulation technique might allow advantages to
signal transmission that FM lacks.


Not really. All phase modulation does is integrate the modulating
signal and use that to shift the phase of the carrier (which also
requires a frequency change to effect the phase change). The resulting
signal is exactly the same as if the carrier were directly frequency
modulated. The only difference is how you got there.


Ok. What made me wonder is that I read (in the context of phase modulation
for musical audio synthesis) that true FM methods can cause a frequency drift
that is avoided completely by using phase modulation. I wondered if that fact
might (at some other cost) be useful in signal transmission at RF.

On 8/2/2014 10:52 PM, Lostgallifreyan wrote:
Jerry Stuckle wrote in
:

That's useful. It ties in with things I have read about phase
modulation synthesis. At risk of opening a wild (but fun) bit of
off-topic, I wonder if given a reference carrier at precise fixed
frequency, a phase modulation technique might allow advantages to
signal transmission that FM lacks.


Not really. All phase modulation does is integrate the modulating
signal and use that to shift the phase of the carrier (which also
requires a frequency change to effect the phase change). The resulting
signal is exactly the same as if the carrier were directly frequency
modulated. The only difference is how you got there.


Ok. What made me wonder is that I read (in the context of phase modulation
for musical audio synthesis) that true FM methods can cause a frequency drift
that is avoided completely by using phase modulation. I wondered if that fact
might (at some other cost) be useful in signal transmission at RF.


Yes and no... Without knowing the context, I would guess the frequency
drift they refer to is caused by a DC bias to the modulator from the
incoming signal itself with FM modulation. This would assume the
incoming signal is DC coupled, which I would guess it might be in music
synthesizers (don't know - never worked with one).

Using phase modulation, if there were a DC bias on the signal, it would
just old the phase at a constant angle - and since frequency shift is
based on the change in the phase angle of the signal (and vice versa, of
course), the signal would have zero deviation.

It's something I've never encountered in radios, but then you don't
normally see radios DC coupling the audio signal to the modulator. But
I will admit most of the FM transmitters I've worked with (both
commercial FM and VHF/UHF business and ham bands) have been phase
modulated.

The only time I remember getting deeply into direct FM was back in the
early to mid 70's when I was working on a frequency synthesizer of 2
meters (this was back when crystal rigs were still common). It's pretty
easy to get FM out of such a circuit since frequency is directly
controlled by voltage - all you need to do is feed the modulating signal
into the VCO feedback loop. It ended up working pretty well, and I
didn't have any problem with frequency drift (but then with a VCO any
drift automatically solves itself).

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

Jerry Stuckle wrote:
On 8/2/2014 8:50 PM, Jerry Stuckle wrote:
On 8/2/2014 7:48 PM, wrote:
Jerry Stuckle wrote:
On 8/2/2014 5:53 PM, Rob wrote:
Lostgallifreyan wrote:
Jerry Stuckle wrote in news:lrio4f$fs4$1@dont-
email.me:

Nope. I'm talking about what is commonly used here. But there are some
people from the U.K. who think they are experts on everything.


To be fair to him, I'm in the UK and he may well have aimed that point at me,
knowing this from the message header or some earlier post of mine. I'm
also interesed in how the US conventions differ from ours.

I think you should be careful not to mistake Jerry's conventions
for US conventions. It looks a lot like Jerry makes many assumptions
that are not based on signal theory or common practice, but mainly on
his own experience as a cable fitter.


Cabling is not the only thing I do - nor the only thing I have done in
the past. It is just one of the things my company does.

But like other trolls, you think you know everything, when you actually
know nothing.

So much for the anonymous troll who uses a fake email and probably
doesn't even have a call sign.


And here he goes off into his usual "stupid troll" rant with yet a person
who had the umitigated audacity to imply Jerry Stuckle does not know
everything about everything.

You ignorant peasants just don't understand; Jerry Stuckle has done
everything, knows everything and is NEVER, EVER wrong about anything.

To even hint otherwise is blasphemy and you shall be severely reprimanded
and totally disparaged as you well deserve.



And here's one of the other anonymous trolls without a call sign on this
newsgroup. If I didn't know some REAL hams in the U.K., I would have a
VERY DIM VIEW of the people there. You, "Rob", Gareth and a couple of
others - all cut from the same form.

But trolls can't stand the truth, can you?

Once again, you can have the last word - as trolls need


Actually, that statement is unfair - to Gareth. At least he isn't
afraid to let people know who he is. So Gareth, I apologize for mixing
you in with the anonymous trolls. You're better than that.

I beg your pardon, my liege, but it was my understanding I was to have
the last word. Obviously I was in error.

I was also quite suprised to find I am British, but if your worship says
I am British, I must be British as your worship is never wrong.


--
Jim Pennino

In message , Jeff writes






Jerry does not seem to take on board that this is an international
group, not a group of ex-US cable technicians who slovenly misuse dBm
to mean dBmV, when the rest of the world uses dBm correctly to mean dB
relative to a milliwatt.

I think only a small minority of US cable TV people would misuse dBm
when they really mean dBmV. I worked in the industry all my life, 20
years of which were for an American company - and I never found this to
be a common practice.



--
Ian

On 8/3/2014 5:18 AM, Jeff wrote:
And here's one of the other anonymous trolls without a call sign on this
newsgroup. If I didn't know some REAL hams in the U.K., I would have a
VERY DIM VIEW of the people there. You, "Rob", Gareth and a couple of
others - all cut from the same form.

But trolls can't stand the truth, can you?

Once again, you can have the last word - as trolls need


I do find that rant very amusing; particularly that fact that Jerry
misses completely how similar he and Gareth are!!

As soon as they are challenged on a subject, rather than carry on a sane
argument they both resort first to impugning someone's knowledge and
qualifications (without any grounds or knowledge of the person) and then
to name calling.
It is a startling resemblance.

Jeff




No, it's just calling unsubstantiated claims by anonymous trolls what
they are - pure bull manure! Especially when they repeatedly show a
complete lack of the knowledge they claim they should have.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================