First, I apologize if this is not the right spot for a post like this.

I work for a small LPFM station. We have no money, but we have an
opportunity to rebroadcast our signal and extend our coverage area. Here
is the problem: I need to be able to tune in the composite signal from
the LPFM and feed the composite directly into a transmitter.

Did I mention we have no money? I cannot afford the few hundred dollars
to the $2,000 it takes to purchase a radio receiver. How in the world
could I take a standard radio receiver, skip all the signal processing,
and simply take the composite signal to a BNC connector?

Does anyone have any ideas?

Thanks in advance for any ideas.

On Feb 5, 3:50 pm, HardwareMonkey
wrote:
First, I apologize if this is not the right spot for a post like this.

I work for a small LPFM station. We have no money, but we have an
opportunity to rebroadcast our signal and extend our coverage area. Here
is the problem: I need to be able to tune in the composite signal from
the LPFM and feed the composite directly into a transmitter.

Did I mention we have no money? I cannot afford the few hundred dollars
to the $2,000 it takes to purchase a radio receiver. How in the world
could I take a standard radio receiver, skip all the signal processing,
and simply take the composite signal to a BNC connector?

Does anyone have any ideas?

Thanks in advance for any ideas.

If you have any technical knowledge or know someone who does this can
be done with any decent receiver. You have to find the discrimator
coil or the input to the stereo decoder IC. This is generally the same
electrical point. You can either tap that point with a high input
impedance wideband amplifier or simply disconnect the input to the
decoder IC and feed this to an adjustable amplifier such as a video
distribution amplifier. Video DA's seem to work great for this purpose
as they have wide bandwidth DC to 6Mhz. I have done this a few times
and a scope is very helpful in determining loss through the ampifier.
Use a dead carrier with pilot 19Khz and measure a reference before any
work is done. Then when a connection is made to the input of an
amplifier check the level again. If the level to the input has dropped
you may have impedance issues that will cause you problems. Let me
know how this works for you or if you have any further questions.

What you are saying makes sense conceptually. But finding the decoder
circuit seems a little rough. How would one recognize this?

Secondly, I never considered the signal loss that the receiver itself
would have. I think that I could simply boost the signal at the exciter
(it already has some form of adjustable gain IIRC). Any reason that
would not work? Obviously, I would need to look at the overall
modulation... which I do not have the capability of doing... but that is
a separate issue.

Fred Francis wrote:
If you have any technical knowledge or know someone who does this can
be done with any decent receiver. You have to find the discrimator
coil or the input to the stereo decoder IC. This is generally the same
electrical point. You can either tap that point with a high input
impedance wideband amplifier or simply disconnect the input to the
decoder IC and feed this to an adjustable amplifier such as a video
distribution amplifier. Video DA's seem to work great for this purpose
as they have wide bandwidth DC to 6Mhz. I have done this a few times
and a scope is very helpful in determining loss through the ampifier.
Use a dead carrier with pilot 19Khz and measure a reference before any
work is done. Then when a connection is made to the input of an
amplifier check the level again. If the level to the input has dropped
you may have impedance issues that will cause you problems. Let me
know how this works for you or if you have any further questions.

On Feb 5, 6:15 pm, HardwareMonkey
wrote:
What you are saying makes sense conceptually. But finding the decoder
circuit seems a little rough. How would one recognize this?

The decoder IC can be located non technically by using an NTE or ECG
demiconductor reference guide available for free at most NTE or ECG
parts distributors. Look up th epart number for each IC and the
description. One the decoder IC is found the pinout for that IC can
also be found in the book giving you most of the info you need. The
loss I am referring to is not from the receiver but rather in the
circuit modifications made to it. If not done properly you will lose
pilot level due to impedance mismatch causing you problems in
remodulating the transmitter.

If you can come with some money I will do this for you. Let me know
what type of receiver you are using and we will work form there. I can
also provide you with a premodified receiver if you would rather go
that route.