Shure wireless handheld microphone. Spec can be found here if it can be of any help
http://www.shure.com/pdf/discontinued/L-Series.pdf

Microphone transmit at 180.4MHZ. It was made in 1990. It uses a 20.05MHZ crystal by MTRON
as far as I can tell like the one uses in Radio Control car, but about half the size. Can the
frequency be changed to something like 218.5MHZ by just changing the crystal?
If so, what frequency should I use?

Thanks for any info you can give.

wrote in message news:yvw6g.8938$ZL6.1511@trndny04...
Shure wireless handheld microphone. Spec can be found here if it can be of
any help
http://www.shure.com/pdf/discontinued/L-Series.pdf

Microphone transmit at 180.4MHZ. It was made in 1990. It uses a 20.05MHZ
crystal by MTRON
as far as I can tell like the one uses in Radio Control car, but about
half the size. Can the
frequency be changed to something like 218.5MHZ by just changing the
crystal?
If so, what frequency should I use?

Thanks for any info you can give.


180.4 divided by 20.05, is near as dammit 9, so the crystal oscillator stage
is probably running through two tripler stages ( these are just 'dirty'
amplifiers with appropriate tuned circuits in their collectors or drains, to
pick off the third and then ninth harmonics. ) First stage may well be the
oscillator itself.

In theory, all you need to do is sub the crystal for one at 1/9th the
frequency of the desired output, so for 218.5, you would need a crystal at
24.277 MHz. The oscillator will probably be ok with this comparitively small
change of frequency, but the tuned circuits in the multiplier stages will
need to be adjusted. The first tripler stage will probably be in range, but
the second will be nearly 40 megs off tune, so you may have difficulty
getting it there without altering values in the tuned circuit. Also, if
there is a following RF PA stage, this may well require retuning also,
depending on whether any tuned circuits are just broadband tanks, or
harmonic filters.

Finally, crystals can have many different specifications in their cut
scheme, and load capacitances, depending on whether they are designed for
series or parallel resonance, or overtone use. Crystal cutters understand
what is required if you can let them have a copy of the oscillator
schematic. At this sort of frequency, it will probably be a series crystal
with 30pf loading.

Also be aware that the band that you are proposing moving the mic to, is not
in general, a license-free band for this sort of use, so depending on where
you are in the world, you would probably be contravening telecoms
regulations, and could render yourself liable to prosecution, if you cause
interference to other legitimate band users.

Arfa

wrote:
Shure wireless handheld microphone. Spec can be found here if it can be of any help
http://www.shure.com/pdf/discontinued/L-Series.pdf

Microphone transmit at 180.4MHZ. It was made in 1990. It uses a 20.05MHZ crystal by MTRON
as far as I can tell like the one uses in Radio Control car, but about half the size. Can the
frequency be changed to something like 218.5MHZ by just changing the crystal?
If so, what frequency should I use?

Thanks for any info you can give.

#1, Its not just one crystal, its two. Transmitter and receiver.
And unless you have a communications test set, i would advise against
it. If your determined to do it, send it back to shure to have it done
at the factory. Of course, its probably not worth it. Better to
sell it on Ebay or such and find a used one with frequencies that are
better suited to your uses. VHF wireless are on there way out. WHo knows
what frequencies will be clear in the future. Basically in the USA, VHF
is from around 169 to 215 MHz or so. You need to know what TV channels
are in use in your area now.

Bob

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

"Bob Urz" wrote in message
...


wrote:
Shure wireless handheld microphone. Spec can be found here if it can be
of any help http://www.shure.com/pdf/discontinued/L-Series.pdf

Microphone transmit at 180.4MHZ. It was made in 1990. It uses a 20.05MHZ
crystal by MTRON
as far as I can tell like the one uses in Radio Control car, but about
half the size. Can the frequency be changed to something like 218.5MHZ by
just changing the crystal?
If so, what frequency should I use? Thanks for any info you can give.

#1, Its not just one crystal, its two. Transmitter and receiver.
And unless you have a communications test set, i would advise against it.
If your determined to do it, send it back to shure to have it done
at the factory. Of course, its probably not worth it. Better to
sell it on Ebay or such and find a used one with frequencies that are
better suited to your uses. VHF wireless are on there way out. WHo knows
what frequencies will be clear in the future. Basically in the USA, VHF
is from around 169 to 215 MHz or so. You need to know what TV channels
are in use in your area now.

Bob

One thing to be accutely aware of is the fact that the "L" series is for use
by Broadcast Stations only. The microphone (transmitter) HAS to be licensed
under part 74 (Broadcast), and only TV/Radio station are eligible. If you
are playing with this in your house, it's probably not a real risk. If it's
at a public location, you need to use something that either doesn't require
a license, or something that you can (and did) license. It's not as if the
FCC is going to hunt you down. They now offer "snitch rewards", which gives
motivation to individuals to look for unlicensed users. I know of a couple
of underpaid local broadcast engineers that have played the game and won.


COPY FEDERAL COMMUNICATIONS
COMMISSION
WASHINGTON, D.C. 20554

GRANT OF EQUIPMENT
AUTHORIZATION COPY
Type Acceptance

Shure Incorporated
5800 W. Touhy Ave
Niles, IL 60714-4608
United States Date of Grant: 07/24/1989

Application Dated: 02/13/1989

Attention: Dillard Gilmore , Senior Engineer, Global Compliance

NOT TRANSFERABLE
EQUIPMENT AUTHORIZATION is hereby issued to the named GRANTEE, and is
VALID ONLY for the equipment identified hereon for use under the
Commission's Rules and Regulations listed below.


FCC IDENTIFIER: DD4L2

Name of Grantee: Shure Incorporated

Equipment Class: Licensed Broadcast Station Transmitter
Notes:

Grant Notes FCC Rule Parts Frequency
Range (MHZ) Output
Watts Frequency
Tolerance Emission
Designator
M4 74.861 174.0 - 216.0 0.05 0.005 % 60K0F3E


M4: Operation of this unit is limited to use at stations licensed for
use under Part 74 of FCC Rules.

Mail To:
None Specified,
MET Electrical Testing Co.
916 W Patapsco Avenue
Baltimore, MD 21230




8904278315022250

Bob wrote:

"Bob Urz" wrote in message
...


wrote:

Shure wireless handheld microphone. Spec can be found here if it can be
of any help http://www.shure.com/pdf/discontinued/L-Series.pdf

Microphone transmit at 180.4MHZ. It was made in 1990. It uses a 20.05MHZ
crystal by MTRON
as far as I can tell like the one uses in Radio Control car, but about
half the size. Can the frequency be changed to something like 218.5MHZ by
just changing the crystal?
If so, what frequency should I use? Thanks for any info you can give.

#1, Its not just one crystal, its two. Transmitter and receiver.

And unless you have a communications test set, i would advise against it.
If your determined to do it, send it back to shure to have it done
at the factory. Of course, its probably not worth it. Better to
sell it on Ebay or such and find a used one with frequencies that are
better suited to your uses. VHF wireless are on there way out. WHo knows
what frequencies will be clear in the future. Basically in the USA, VHF
is from around 169 to 215 MHz or so. You need to know what TV channels
are in use in your area now.

Bob


One thing to be accutely aware of is the fact that the "L" series is for use
by Broadcast Stations only.

Really? there are thousands of those units still out there in churches,
schools and such across the country. Even though they are suppose to
file license applications, my guess is there is less than 5% compliance
across the USA. The FCC could bust most of the churches in the country
if they were stupid enough to do so.

Bob

The microphone (transmitter) HAS to be licensed
under part 74 (Broadcast), and only TV/Radio station are eligible. If you
are playing with this in your house, it's probably not a real risk. If it's
at a public location, you need to use something that either doesn't require
a license, or something that you can (and did) license. It's not as if the
FCC is going to hunt you down. They now offer "snitch rewards", which gives
motivation to individuals to look for unlicensed users. I know of a couple
of underpaid local broadcast engineers that have played the game and won.


COPY FEDERAL COMMUNICATIONS
COMMISSION
WASHINGTON, D.C. 20554

GRANT OF EQUIPMENT
AUTHORIZATION COPY
Type Acceptance

Shure Incorporated
5800 W. Touhy Ave
Niles, IL 60714-4608
United States Date of Grant: 07/24/1989

Application Dated: 02/13/1989

Attention: Dillard Gilmore , Senior Engineer, Global Compliance

NOT TRANSFERABLE
EQUIPMENT AUTHORIZATION is hereby issued to the named GRANTEE, and is
VALID ONLY for the equipment identified hereon for use under the
Commission's Rules and Regulations listed below.


FCC IDENTIFIER: DD4L2

Name of Grantee: Shure Incorporated

Equipment Class: Licensed Broadcast Station Transmitter
Notes:

Grant Notes FCC Rule Parts Frequency
Range (MHZ) Output
Watts Frequency
Tolerance Emission
Designator
M4 74.861 174.0 - 216.0 0.05 0.005 % 60K0F3E


M4: Operation of this unit is limited to use at stations licensed for
use under Part 74 of FCC Rules.

Mail To:
None Specified,
MET Electrical Testing Co.
916 W Patapsco Avenue
Baltimore, MD 21230




8904278315022250




----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

"Arfa Daily" wrote in message
...

wrote in message news:yvw6g.8938$ZL6.1511@trndny04...
Shure wireless handheld microphone. Spec can be found here if it can be
of
any help
http://www.shure.com/pdf/discontinued/L-Series.pdf

Microphone transmit at 180.4MHZ. It was made in 1990. It uses a 20.05MHZ
crystal by MTRON
as far as I can tell like the one uses in Radio Control car, but about
half the size. Can the
frequency be changed to something like 218.5MHZ by just changing the
crystal?
If so, what frequency should I use?

Thanks for any info you can give.


180.4 divided by 20.05, is near as dammit 9, so the crystal oscillator
stage
is probably running through two tripler stages ( these are just 'dirty'
amplifiers with appropriate tuned circuits in their collectors or drains,
to
pick off the third and then ninth harmonics. ) First stage may well be the
oscillator itself.

In theory, all you need to do is sub the crystal for one at 1/9th the
frequency of the desired output, so for 218.5, you would need a crystal at
24.277 MHz. The oscillator will probably be ok with this comparitively
small
change of frequency, but the tuned circuits in the multiplier stages will
need to be adjusted. The first tripler stage will probably be in range,
but
the second will be nearly 40 megs off tune, so you may have difficulty
getting it there without altering values in the tuned circuit. Also, if
there is a following RF PA stage, this may well require retuning also,
depending on whether any tuned circuits are just broadband tanks, or
harmonic filters.

Finally, crystals can have many different specifications in their cut
scheme, and load capacitances, depending on whether they are designed for
series or parallel resonance, or overtone use. Crystal cutters understand
what is required if you can let them have a copy of the oscillator
schematic. At this sort of frequency, it will probably be a series crystal
with 30pf loading.

Also be aware that the band that you are proposing moving the mic to, is
not
in general, a license-free band for this sort of use, so depending on
where
you are in the world, you would probably be contravening telecoms
regulations, and could render yourself liable to prosecution, if you cause
interference to other legitimate band users.

Arfa



Thank you all for the info and suggestions.

One more question. If I change the receiver's frequency to match the mic
instead, would it require any retuning? The receiver's spec list a frequency
range of 180MHZ to 250MHZ.

Thanks.

"Quoc Anh" wrote in message news:BsL6g.60$re6.34@trndny04...
"Arfa Daily" wrote in message
...

wrote in message news:yvw6g.8938$ZL6.1511@trndny04...
Shure wireless handheld microphone. Spec can be found here if it can be
of
any help
http://www.shure.com/pdf/discontinued/L-Series.pdf

Microphone transmit at 180.4MHZ. It was made in 1990. It uses a
20.05MHZ
crystal by MTRON
as far as I can tell like the one uses in Radio Control car, but about
half the size. Can the
frequency be changed to something like 218.5MHZ by just changing the
crystal?
If so, what frequency should I use?

Thanks for any info you can give.


180.4 divided by 20.05, is near as dammit 9, so the crystal oscillator
stage
is probably running through two tripler stages ( these are just 'dirty'
amplifiers with appropriate tuned circuits in their collectors or drains,
to
pick off the third and then ninth harmonics. ) First stage may well be
the
oscillator itself.

In theory, all you need to do is sub the crystal for one at 1/9th the
frequency of the desired output, so for 218.5, you would need a crystal
at
24.277 MHz. The oscillator will probably be ok with this comparitively
small
change of frequency, but the tuned circuits in the multiplier stages will
need to be adjusted. The first tripler stage will probably be in range,
but
the second will be nearly 40 megs off tune, so you may have difficulty
getting it there without altering values in the tuned circuit. Also, if
there is a following RF PA stage, this may well require retuning also,
depending on whether any tuned circuits are just broadband tanks, or
harmonic filters.

Finally, crystals can have many different specifications in their cut
scheme, and load capacitances, depending on whether they are designed for
series or parallel resonance, or overtone use. Crystal cutters understand
what is required if you can let them have a copy of the oscillator
schematic. At this sort of frequency, it will probably be a series
crystal
with 30pf loading.

Also be aware that the band that you are proposing moving the mic to, is
not
in general, a license-free band for this sort of use, so depending on
where
you are in the world, you would probably be contravening telecoms
regulations, and could render yourself liable to prosecution, if you
cause
interference to other legitimate band users.

Arfa



Thank you all for the info and suggestions.

One more question. If I change the receiver's frequency to match the mic
instead, would it require any retuning? The receiver's spec list a
frequency
range of 180MHZ to 250MHZ.

Thanks.


If the receiver tunes across that range, then it just does. No tuning other
than setting it to the frequency that your radio mic is outputting on, will
be required.

Arfa

That would be an awfully wideband VHF receiver. The frequency spec
just means that the circuit is designed for that range. It
doesn't necessarily mean that you won't have to change coils
and capacitors, or retune.

Arfa Daily wrote:

If the receiver tunes across that range, then it just does. No tuning other
than setting it to the frequency that your radio mic is outputting on, will
be required.

Arfa

"Mike Berger" wrote in message
...
That would be an awfully wideband VHF receiver. The frequency spec
just means that the circuit is designed for that range. It
doesn't necessarily mean that you won't have to change coils
and capacitors, or retune.

Arfa Daily wrote:

If the receiver tunes across that range, then it just does. No tuning
other than setting it to the frequency that your radio mic is outputting
on, will be required.

Arfa
It depends on how you read it I suppose. I was assuming that he had a
tuneable receiver - some kind of VHF scanner or programmable handheld or
something, which is why I said that if it tunes that range, then it just
does. How it does this is of no consequence to the user. I have an Icom 706.
It tunes from topband to 2 metres with a couple of button pushes - I don't
have to go inside to retune coils, or change caps. My TV set tunes from
470MHz to almost 900MHz virtually continuously ( small break between bands
IV and V ). My satellite receiver tunes from 920MHz to 2050MHz, so I don't
think that 70MHz is an " awfully wideband " receiver.

Of course, if it is a fixed single frequency or channelised and rock-bound
receiver that's merely *capable* of operating over that frequency range,
then yes, you are probably right, unless it's synthesised, in that you would
have to replace the L.O. crystal. I would not necessarily expect to have to
retune the front end or change coils and caps though, if it is specced for
that frequency range. It may actually have a real barn door antenna circuit.
However, I agree that if it was mine, and the front end was tunable, I would
probably peak it up for best performance on the specific frequency.

Arfa