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Hello Guys
Hello Guys
I was Hoping to have some insight on this issue. I just bought a new Transmitter for my station. It is on FM and I was wanting to Simulcast my other Station that is also on another FM frequency Well When I hooked the 3.5 M Audio Cable into my Nearby Radio it sounded real muddy and the Further up I went With the Volume the More I heard the Beat of the audio playing over my new tx. I did try to simulcast other stations on my frequency and I heard no beating in the audio chain during those times. This only seems to occur with my own signal. This does not occur on my main frequency. What are the causes of this and how can I improve my audio. Your help is always appreciated!
Total posts : 45366Sounds kind of like the rf from your transmitter is maybe travelling back along your audio lines and getting picked up somewhere earlier in the audio chain. If so, then the feedback could result in oscillation in the audio ranges and sound like a beat.
In a perfect world, that’d only happen with an AM transmitter, not an FM. But many FM transmitters have some degree of an AM component to their RF output, and audio amplifiers can make excellent AM recievers for strong nearby signals.
I’d try a ferrite bead over the audio cable before your transmitter. If that doesn’t do it, maybe also between any sources that have a magnetic pickup like tape players and some turntables. If you don’t have any ferrite beads onhand (they can be scavenged off lots of things including an old computer monitor cable) you might try moving the audio cables and/or coax and see if that makes any difference in the beat.
Another thing that can cause some odd effects is if you’re using coax and it doesn’t go straight away from the antenna for a few feet before being curved. Don’t know if that might apply with your station, since I don’t know much about your setup at this point.
Yet another possibility is if the sound board/sources or even the nearby receiver are *real* close to the transmitter and something isn’t shielded properly/enough.
Daniel
Total posts : 45366If I follow what you are doing, you are taking a signal from transmitter 1 from a receiver and feeding this received audio into transmitter 2. If this is not the case, then what follows doesn’t apply.
It could be that the 19 kHz stereo pilot from transmitter 1 is being passed through your simulcast receiver to the audio input of transmitter 2 and it is mixing with the transmitter 2 pilot causing a beat note. You might try another receiver in the simulcast chain. Otherwise an audio low pass filter would be needed on the input of the second transmitter to eliminate the pilot from the received audio.
Neil
Total posts : 45366Thanks for your responses Guys
I do believe It could possibly be a number of the above mentioned .. My receiver was real close to the transmitter and I do have coax running to an antenna a few feet away. I may try this scenario again later… but for now I just hooked this puppy up to my laptop and created another station on another frequency… and now all is well:) I do love to experiment with transmitters though… There’s no telling what I will come up with next!
Later
Jim
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