Has anyone pulled a VHF Rx to enable the Wx APT transmissions at 137.1MHz? If so, how easy is the conversion?

If not, a downconverter to enable the Wx signals to be received on a VHF wideband broadcast receiver.

Can anyone point me in the direction any cirecuits, kits or any mixer circuits or any other info regarding this project. Complete systems from Timestep, ICS and Hamtronics etc are reather expensive. :-)

Best regards David 73 de G6UXD/MM

Yes. Its possible, and easy to do. The oscillator and RF coils are removed, and rewound with less turns. Usually they have 4 turns, replace with three. By squeezing them together, the frequency can be lowered slightly to help tracking. The band pass RF filter also needs raising in frequency. The IF filters are WAY too wide, but with a good aerial the satellite tuned will predominate. I have one here that works great. Good luck, and have fun.

On Feb 5, 8:09*pm, lenseman wrote:
Has anyone pulled a VHF Rx to enable the Wx APT transmissions at
137.1MHz? *If so, how easy is the conversion?

If not, a downconverter to enable the Wx signals to be received on a
VHF wideband broadcast receiver.

Can anyone point me in the direction any cirecuits, kits or any mixer
circuits or any other info regarding this project. *Complete systems
from Timestep, ICS and Hamtronics etc are reather expensive. :-)

Best regards *David 73 de G6UXD/MM

--
lenseman

I got into this years ago and modified a Radio Shack Weather Cube
radio. I don't remember the specifics but it wasn't difficult. I think
all you need to rx the weather sats is a radio and a PC with a sound
card. Free software is available.

Jimmie

In article ,
lenseman wrote:

Has anyone pulled a VHF Rx to enable the Wx APT transmissions at
137.1MHz? If so, how easy is the conversion?

If not, a downconverter to enable the Wx signals to be received on a
VHF wideband broadcast receiver.

David-

If the FM receiver has high-side injection for the broadcast band, you
may be able to pull the local oscillator a bit higher, and receive the
137 MHz signal using low-side injection. I think the receiver's RF
amplifier stages would need to be retuned as well. A counter would be
helpful to be sure you are receiving the right signal.

I think it would be easier to build a crystal controlled converter to
translate the 137 MHz signal to the FM receiver's IF frequency.

Fred

On Feb 6, 11:39*am, JIMMIE wrote:
On Feb 5, 8:09*pm, lenseman wrote:

Has anyone pulled a VHF Rx to enable the Wx APT transmissions at
137.1MHz? *If so, how easy is the conversion?

If not, a downconverter to enable the Wx signals to be received on a
VHF wideband broadcast receiver.

Can anyone point me in the direction any cirecuits, kits or any mixer
circuits or any other info regarding this project. *Complete systems
from Timestep, ICS and Hamtronics etc are reather expensive. :-)

Best regards *David 73 de G6UXD/MM

--
lenseman

I got into this years ago and modified a Radio Shack Weather Cube
radio. I don't remember the specifics but it wasn't difficult. I think
all you need to rx the weather sats is a radio and a PC with a sound
card. Free software is available.

Jimmie

Never tried it but I think the receiver being wide band may be a
problem. There are a few ICs out that are basically radios on a chip.
It takes very view added parts to get them working. I cant think of a
part# now but I am sure someone will.

Jimmie

What would be the point.... the FM radio already can convert the 137megs to 10.7 megs with just modified coils! Why complicate something simple? A signal generator would be more useful than a freq counter to get it on frequency. The beauty of it is it will also receive aircraft .... the FM discriminator on cheap FM radios will also happily demodulate AM. I have done this, it works well, and takes just 30 minutes.