Bridgecom repeater?

Discussion in 'Ham Radio Discussions' started by WA2NAN, Sep 20, 2019.

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  1. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    There are several possibilities:

    First of all, not every mobile is going to have a strong enough signal to hold the squelch open.

    If you are using CTCSS to activate the repeater, there is no need to even set the squelch. So long as the tone is there, and the received signal is readable, the transmitter will be activated. When the tone goes away, the receiver audio should immediately drop out and no audio, including "squelch noise", should be repeated. The "COR" is obviously set to 4-seconds which should be fine.

    It is possible that there is "desense" caused by the duplexer. Are you using the same duplexer as with the General Electric repeater? If so, you really need to verify that the tuning has not changed. If another duplexer, then it may have not been properly tuned. If the repeater came with a new duplexer, there is a very good chance that the tuning has been altered in shipping.

    By some chance, is the repeater really for +/- 5 kHz deviation or is it for +/- 2.5 kHz deviation. If for +/- 2.5 kHz deviation you will definitely have a problem with "chopping out".

    I misread that the transmitter stays on. Was thinking that the transmitter was also cutting out.

    Glen, K9STH
     
    NL7W likes this.
  2. WA2NAN

    WA2NAN Ham Member QRZ Page

    I've heard from some others on email who say they have the same problem with their Bridgecom. Question is, with an outboard controller that has active squelch and ctcss built in bypass the internal squelch and cure the problem?
    Wa2nan
     
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Did you consult with Bridgecom?

    The last commercially made "ham radio" repeater I owned was a long time ago, made by Spectrum Communications in PA. That was actually a really good "machine" with a lot of features and blinkly lights and had rather amazing audio frequency reproduction, so the output sounded exactly like the input signal -- which some more expensive LMR repeaters could not do. But I think they're gone. Too bad, as their repeaters really were well designed. That had a squelch circuit that would allow a signal to become so noisy you really couldn't understand it at all before it dropped out.

    But of course repeater "performance" is largely based on TX/RX isolation and lack of desensitizing. My test for that was always "a very weak signal, just barely breaking squelch" received while turning the TX on and off. There should be no difference at all. If there is any difference, the repeater can be improved.
     
  4. WA2NAN

    WA2NAN Ham Member QRZ Page

    Hi,
    Yes I contacted Bridgecom and they sent me a video showing a scope with -122 dbm threshold on a squelch setting of (1) which is the lowest. That doesn't address the way the squelch snaps shut as soon as the signal flutters for an instant. We have no desence problem. Feeding a tone into the receiver without the transmitter on and reducing the signal shows that a still readable signal gets dropped by the squelch curcuit too soon... TheI tech support tries to make you think all is well and you don't know what your talking about....I hope their attitude changes...
     
  5. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    Many modern FM receivers are close to full quieting at 0.2-microvolts which -122 dBm is very close to that sensitivity (dBm chart at http://wa8lmf.net/miscinfo/dBm-to-Microvolts.pdf ). Being "old school" where FM is concerned, I still think in microvolts rather than -dBm.

    If it were me, and if it is possible, I would return the repeater, get my money back, and look elsewhere for another repeater. If that is not possible, is there a way that the receiver can have the squelch disabled (runs fully open at all times) and then an inexpensive CTCSS decoder be installed to actually key the transmitter? Unlike the old reed type CTCSS decoders (which have been passe' since the early to mid 1980s) modern, solid-state CTCSS decoders are, basically, "instantaneous" and open as soon as the tone is detected and will remain open even when the tone level is virtually lost in the noise.

    When CTCSS is used to activate a repeater, "standard squelch" really needs to be turned off because having both turned on causes all sorts of problems. Also, "standard", or "carrier" (another name for exactly the same thing), squelch really needs the ability to be set from wide open (receiver audio present all the time) to fully squelched, and beyond, for any number of reasons.

    Glen, K9STH
     
  6. WA2NAN

    WA2NAN Ham Member QRZ Page

    Hello All,
    I recently posted a complaint about the sharp squelch cutoff on my new Bridgecom bcr-50v vhf repeater. If the incoming signal fades slightly and momentarily, a still very readable signal will be chopped by the squelch. I'm used to signals that drop to the noise level before squelching out. I've heard from a few more owners having the same problem. Some here recommended using an outboard controller an tone board with active squelch as a cure. Bridgecom tech support is pretty useless, won't talk about it but sent two emails saying make a video of the problem and they never heard of this before. So far about 10 users have emailed me with the same problem and being ignored by tech support. Question is, will using the outboard controller disable the internal squelch and cure the chopping problem? Tnx...Kerry-wa2nan
    kerry@northnet.org
     
  7. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    An external controller will still be affected by the squelch circuit in the repeater receiver unless the audio is taken directly from the detector and amplified externally to the receiver before being applied to the transmitter. Basically, you have to, somehow, disable the receiver's squelch circuit or bypass it entirely.

    The circuit will have to be modified in one way or another.

    Glen, K9STH
     
  8. KA9JLM

    KA9JLM Ham Member QRZ Page

    You should test it with tone squelch disabled.

    You may need a delayed squelch to keep the repeater receiver open when a tone is not decoded.
     
  9. KA9JLM

    KA9JLM Ham Member QRZ Page

    Hang time.
     
  10. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    It has adjustable hang time. The OP already said they have it set at 4 seconds, which is actually quite a long hang time.

    Not the issue.
     

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