VHF reception on the cheap
 

hey there,
im pretty keen to start recieving severe weather warnings via marine
vhf. just wondering if theres any electronic hacks involving modifying
an am/fm radio? im handy with a soldering iron, so im not afraid to get
stuck into it.
cheers,
cameron

VHF reception on the cheap
 

hey there,
im pretty keen to start recieving severe weather warnings via marine
vhf. just wondering if theres any electronic hacks involving modifying
an am/fm radio? im handy with a soldering iron, so im not afraid to get
stuck into it.

I'm sure it's possible, but it's not uncomplicated.

The NOAA weather radio frequencies are in the 162 MHz region (162.400
through 162.550). It would be necessary to figure out a way to
re-tune a standard FM radio (probably changing both the front-end
bandpass tuning and the local-oscillator tuning) to extend the radio's
tuning range upwards from its normal limit of around 108 - 110 MHz.

Perhaps more complex is the fact that the NOAA channels use
narrow-band FM modulation - the channels are only 25 kHz apart, and so
the carrier deviation is probably limited to +/- 12 kHz or so. That's
far less than a standard commercial FM station, as these are usually
200 kHz apart and use a much wider carrier deviation.

The difference in modulation has at least three implications. One is
that you'll have to adjust a standard FM radio's tuning knob _very_
carefully to get the NOAA channel centered in its bandpass, and the FM
automatic-frequency-control circuit may interfere with you. A second
is that you'll probably find two or more NOAA transmitters sitting
within the receiver's bandpass - you won't be able to tune into one
and eliminate adjacent-channel interference from the other(s). A
third is that even if you do get the signal down to a single channel,
the audio output level will probably be very low due to the narrow
deviation of the carrier.

It'd probably be cheaper and easier to find an inexpensive
AM/FM/weather radio which has this feature built in, or perhaps to
find a specialized kit.

--
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!

VHF reception on the cheap
 

On Fri, 17 Feb 2006 00:37:25 -0000, (Dave Platt)
wrote:

hey there,
im pretty keen to start recieving severe weather warnings via marine
vhf. just wondering if theres any electronic hacks involving modifying
an am/fm radio? im handy with a soldering iron, so im not afraid to get
stuck into it.

I'm sure it's possible, but it's not uncomplicated.

The NOAA weather radio frequencies are in the 162 MHz region (162.400
through 162.550). It would be necessary to figure out a way to
re-tune a standard FM radio (probably changing both the front-end
bandpass tuning and the local-oscillator tuning) to extend the radio's
tuning range upwards from its normal limit of around 108 - 110 MHz.

Perhaps more complex is the fact that the NOAA channels use
narrow-band FM modulation - the channels are only 25 kHz apart, and so
the carrier deviation is probably limited to +/- 12 kHz or so. That's
far less than a standard commercial FM station, as these are usually
200 kHz apart and use a much wider carrier deviation.

The difference in modulation has at least three implications. One is
that you'll have to adjust a standard FM radio's tuning knob _very_
carefully to get the NOAA channel centered in its bandpass, and the FM
automatic-frequency-control circuit may interfere with you. A second
is that you'll probably find two or more NOAA transmitters sitting
within the receiver's bandpass - you won't be able to tune into one
and eliminate adjacent-channel interference from the other(s). A
third is that even if you do get the signal down to a single channel,
the audio output level will probably be very low due to the narrow
deviation of the carrier.

It'd probably be cheaper and easier to find an inexpensive
AM/FM/weather radio which has this feature built in, or perhaps to
find a specialized kit.

I agree with Dave, and decided to look at Ramsey kits; not the
cadillac of the kit's that have been available over the years but
workable. They have a VHF receiver that is listed as a 2 meter
amateur receiver but is tunable to any 5 mHz section between 130 and
180 mHz so it should work. Cost is under $50 - of course you can also
find pre-built weather radios for less but then you miss the fun of
assembling the kit.
http://www.ramseyelectronics.com/cgi...&key=FR-SERIES

VHF reception on the cheap
 

hi,

try a used uniden bearcat scanner, tons of them
at pawn shops and ebay or also new.

marty

VHF reception on the cheap
 

In article ,

They have a VHF receiver that is listed as a 2 meter
amateur receiver but is tunable to any 5 mHz section between 130 and
180 mHz so it should work. Cost is under $50 - of course you can also
find pre-built weather radios for less but then you miss the fun of
assembling the kit.

Several models of Sony Walkman have WB reception, including a $30 model.
The problem with them is thy use the same bandwidth as they do for FM
broadcast reception, but will work if NOAA signal is strong.

--
Larry Weil
Lake Wobegone, NH