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A few things I see here. You don't say anything about having a band pass cavity. Also, have you tried ferrites on the coax for all three ports of the duplexer? As for the audio lines, you need some wire like in used in broadcast, where there is at least two wires within a shield that has a bare wire in that shield. Then you only ground the end with the lowest signal. RG-174 is probably not going to be your friend with this problem. Have you made use of a service monitor to compare some levels???
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Mick - W7CAT ----- Original Message -----
From: "Chris Baldwin via groups.io" To: [email protected] Sent: Saturday, May 10, 2025 06:07:22 PM Subject: [repeater-builder] Broadcast audio on repeater receive audio This one is playing hell with my sanity.from 95.7FM coming in along with the repeater receiver audio. I can dial it down to zero using the controller's audio input pot, so I'd assume it's coming in on the RX audio line. The audio level of the broadcast audio is significantly lower than the repeat audio, so the repeater is still usable, it's just... Highly annoying. the shield, one end of the shield, the other end of the shield, nothing. Tried some ferrites (the ones that come with the Quantar and AstroTAC equipment), no luck. Tried them everywhere. AC lines, audio lines, control lines, no change. 174 is grounded, the audio level of the broadcast FM increases. wiring on the back side of it that's picking this up. shielding and ferrites. I don't believe that RF is getting into the controller itself directly, it's obviously coming in on the RX audio line. there isn't so much exposed wiring, nor a need for an outboard PL encoder/decoder which could be part of this (but I tried ferrites on all of its cabling as well. league. -- Untitled Document |
