VHFRadioBuff wrote:
: Hello all. I have a question. How come with some commercial radios, Tone
: Squelch only works when the mic clip is grounded, so when you remove the mic
: from the clip, it opens the receive to everything?

: I recently bought a Standard UHF radio for GMRS use and it has this, so my wife
: can listen for me without hearing other junk, but when she removes the mic
: (that I had to ground), she hears everything on the freq!

She is supposed to .. before transmitting .. how else would she (or
anyone) know if there is someone else using the frequency?

Ham radio is different .. if a repeater needs a tone for access it is to
keep distant users of a similar (or same) frequency repeater from
accessing your local repeater unintentially. It is not to keep different
users of the same repeater from hearing each other.

Many different users can access a GMRS repeater. To keep from hearing
unwanted converstations those in your "group" agree to use a specific
tone. So you only hear 'calls' from your group. But the repeater may
already be in use when your group tries to make contact. Listening without
a tone is the only way to be sure you are not interfering with another,
ongoing conversation.

To put it another way .. assuming that your HAM repeater passes tones.
Would you set up a tone with a fellow ham for use on a non-tone required
repeater? If you did, then you would not hear any other traffic on the
repater except your firend. If you didn't listen without a tone first,
before transmitting, you'll eventually end up stepping on an existing
conversation on the repeater ... and making folks really, mad at you!

Richard in Boston, MA, USA

Howdy Andy.....Reread what Ralph described to you carefully and, when
you
think about it, you'll see that he's described exactly the same
reasoning
amateur repeaters use PL tones, with the same benefits and consequences
if their use is misunderstood (a user who, using the correct PL tones,
and is accessing a repeater may be interferred with by another station
transmitting on the same frequency but not using PL tones or who may be
using a different PL tone...of course the difference in signal strengths
received by the repeater will determine the degree of interference).

Maybe some amateur repeaters are transmitting a PL tone....if so I
didn't realize that, and persons in the coverage area could be open to
interference if for some reason they attempted to share the frequency
using a different tone or no tone (and vice versa).

Quite a few repeaters here in SCV-land do put a tone on their output
(almost always the same one they use for their primary receiver).
There are a couple of reasons for having tone-squelch turned on, on a
mobile rig using these repeaters:

- There's quite a lot of QRM on certain 2-meter repeater output
frequencies - commonest cause seems to be leakage from improperly-
installed cable TV systems in homes and apartments. It's often
strong enough to unmute a rig driving through the area of the QRM
emitter, unless tone-squelch is used or carrier-squelch is cranked
*way* up.

- We occasionally get tropospheric "skip" from repeaters on the same
frequencies, 100 miles or more away, which use different
(usually county-based) PL tones.

The best bet, as
we all (should) know, is to listen first, ensure the frequency is clear,
then transmit.

Definitely agreed!

My own mobile and HT rigs will show the incoming signal strength, or a
BUSY indication, even if the tone squelch is suppressing the audio...
so "look before transmit" works pretty well with these rigs ;-)
Unfortunately this isn't possible with all rigs, or in an eyes-are-
busy-elsewhere situation.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Howdy Andy.....Reread what Ralph described to you carefully and, when
you
think about it, you'll see that he's described exactly the same
reasoning
amateur repeaters use PL tones, with the same benefits and consequences
if their use is misunderstood (a user who, using the correct PL tones,
and is accessing a repeater may be interferred with by another station
transmitting on the same frequency but not using PL tones or who may be
using a different PL tone...of course the difference in signal strengths
received by the repeater will determine the degree of interference).

Maybe some amateur repeaters are transmitting a PL tone....if so I
didn't realize that, and persons in the coverage area could be open to
interference if for some reason they attempted to share the frequency
using a different tone or no tone (and vice versa).

Quite a few repeaters here in SCV-land do put a tone on their output
(almost always the same one they use for their primary receiver).
There are a couple of reasons for having tone-squelch turned on, on a
mobile rig using these repeaters:

- There's quite a lot of QRM on certain 2-meter repeater output
frequencies - commonest cause seems to be leakage from improperly-
installed cable TV systems in homes and apartments. It's often
strong enough to unmute a rig driving through the area of the QRM
emitter, unless tone-squelch is used or carrier-squelch is cranked
*way* up.

- We occasionally get tropospheric "skip" from repeaters on the same
frequencies, 100 miles or more away, which use different
(usually county-based) PL tones.

The best bet, as
we all (should) know, is to listen first, ensure the frequency is clear,
then transmit.

Definitely agreed!

My own mobile and HT rigs will show the incoming signal strength, or a
BUSY indication, even if the tone squelch is suppressing the audio...
so "look before transmit" works pretty well with these rigs ;-)
Unfortunately this isn't possible with all rigs, or in an eyes-are-
busy-elsewhere situation.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Ham radio is opposite of most comercial thinking. On a local ham repeater
most hams want ot be able to hear all that is going on on the repeater so
that if anyone puts out a call he can be answered by anyone for a casual
chat. GMRS users are usually only interisted in the other parties they want
to talk to and not hear all the chatter on the frequency. That is why the
hook switch blocks out the gmrs and also releases the tone decoder when off
hook.

I am a volunteer EMT on a first aid squad and I never understood why they made
it so when the mic was picked up, you'd hear everything. We don't want to hear
everything when we pick the mic up. We wanna hear the other EMS units from our
area, not some dispatch center 60 miles north of us. With the squelch open like
that, sometimes it makes it difficult for us to communicate. With the squelch
closed, there's no problem.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
73! de Andy KC2SSB - WPYI880 (GMRS)
Beachwood, NJ USA! Grid FM29vw
http://vhfradiobuff.tripod.com

Ham radio is opposite of most comercial thinking. On a local ham repeater
most hams want ot be able to hear all that is going on on the repeater so
that if anyone puts out a call he can be answered by anyone for a casual
chat. GMRS users are usually only interisted in the other parties they want
to talk to and not hear all the chatter on the frequency. That is why the
hook switch blocks out the gmrs and also releases the tone decoder when off
hook.

I am a volunteer EMT on a first aid squad and I never understood why they made
it so when the mic was picked up, you'd hear everything. We don't want to hear
everything when we pick the mic up. We wanna hear the other EMS units from our
area, not some dispatch center 60 miles north of us. With the squelch open like
that, sometimes it makes it difficult for us to communicate. With the squelch
closed, there's no problem.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
73! de Andy KC2SSB - WPYI880 (GMRS)
Beachwood, NJ USA! Grid FM29vw
http://vhfradiobuff.tripod.com

Maybe some amateur repeaters are transmitting a PL tone....if so I
didn't realize that, and persons in the coverage area could be open to
interference if for some reason they attempted to share the frequency
using a different tone or no tone (and vice versa). The best bet, as
we all (should) know, is to listen first, ensure the frequency is clear,
then transmit.

The 2 repeaters that I mentioned both allow you to set your radio for tone
DEcode so that you will only hear that repeater. Both of them have other
repeaters coming in when there's the slightest enhancement. Fortunately for us,
our mics don't need to be grounded so the decode function is always there,
squelching out those other repeaters that are coming in and allowing us to
share the frequency.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
73! de Andy KC2SSB - WPYI880 (GMRS)
Beachwood, NJ USA! Grid FM29vw
http://vhfradiobuff.tripod.com

Maybe some amateur repeaters are transmitting a PL tone....if so I
didn't realize that, and persons in the coverage area could be open to
interference if for some reason they attempted to share the frequency
using a different tone or no tone (and vice versa). The best bet, as
we all (should) know, is to listen first, ensure the frequency is clear,
then transmit.

The 2 repeaters that I mentioned both allow you to set your radio for tone
DEcode so that you will only hear that repeater. Both of them have other
repeaters coming in when there's the slightest enhancement. Fortunately for us,
our mics don't need to be grounded so the decode function is always there,
squelching out those other repeaters that are coming in and allowing us to
share the frequency.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
73! de Andy KC2SSB - WPYI880 (GMRS)
Beachwood, NJ USA! Grid FM29vw
http://vhfradiobuff.tripod.com

She is supposed to .. before transmitting .. how else would she (or
anyone) know if there is someone else using the frequency?

The whole purpose of setting up the radios with PL encode and decode is so you
don't hear the other users of the frequency. Once the mic is off the hook, it
makes that feature moot. Years ago, our volunteer ambulance shared a frequency
with a bus company. We'd take the mic off the hook to call dispatch and we'd
hear things like "Linda! You forgot to pick up little Jonny this morning. His
mother is very mad." Of course they were using a PL encode/decode, but
apparently it didn't open when they lifted their mics, so they never heard us.

Ham radio is different .. if a repeater needs a tone for access it is to
keep distant users of a similar (or same) frequency repeater from
accessing your local repeater unintentially. It is not to keep different
users of the same repeater from hearing each other.

We're talking on simplex GMRS freqs, not repeaters. There aren't any local
repeaters for us.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
73! de Andy KC2SSB - WPYI880 (GMRS)
Beachwood, NJ USA! Grid FM29vw
http://vhfradiobuff.tripod.com

She is supposed to .. before transmitting .. how else would she (or
anyone) know if there is someone else using the frequency?

The whole purpose of setting up the radios with PL encode and decode is so you
don't hear the other users of the frequency. Once the mic is off the hook, it
makes that feature moot. Years ago, our volunteer ambulance shared a frequency
with a bus company. We'd take the mic off the hook to call dispatch and we'd
hear things like "Linda! You forgot to pick up little Jonny this morning. His
mother is very mad." Of course they were using a PL encode/decode, but
apparently it didn't open when they lifted their mics, so they never heard us.

Ham radio is different .. if a repeater needs a tone for access it is to
keep distant users of a similar (or same) frequency repeater from
accessing your local repeater unintentially. It is not to keep different
users of the same repeater from hearing each other.

We're talking on simplex GMRS freqs, not repeaters. There aren't any local
repeaters for us.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
73! de Andy KC2SSB - WPYI880 (GMRS)
Beachwood, NJ USA! Grid FM29vw
http://vhfradiobuff.tripod.com

On 24 Nov 2003 05:03:35 GMT, pamme (VHFRadioBuff) wrote:

Ham radio is opposite of most comercial thinking. On a local ham repeater
most hams want ot be able to hear all that is going on on the repeater so
that if anyone puts out a call he can be answered by anyone for a casual
chat. GMRS users are usually only interisted in the other parties they want
to talk to and not hear all the chatter on the frequency. That is why the
hook switch blocks out the gmrs and also releases the tone decoder when off
hook.

I am a volunteer EMT on a first aid squad and I never understood why they made
it so when the mic was picked up, you'd hear everything. We don't want to hear
everything when we pick the mic up. We wanna hear the other EMS units from our
area, not some dispatch center 60 miles north of us. With the squelch open like
that, sometimes it makes it difficult for us to communicate. With the squelch
closed, there's no problem.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
73! de Andy KC2SSB - WPYI880 (GMRS)
Beachwood, NJ USA! Grid FM29vw
http://vhfradiobuff.tripod.com

The reason you hear everything when you pick the mike up is because you are
supposed to listen to everything before transmitting so you can avoid
interfering with other traffic that may already be using the channel.

Dave Head
K8DH