Buzzing Vertex vxr-7000

[VETCOMMS]

I recently had the internal Sinclair duplexer tuned at a Motorola dealer.   I noticed after reinstalling the repeater would do one of two things. 

It would not respond when an HT or a mobile radio was keyed up with the appropriate tones.  If I turned the repeater off and back on again the repeater would work for a while but when left idle for a while with no keying of the repeater it would again,  not respond when an HT or mobile radio was keyed up. 

The other thing it did was a buzzing sound I'd never heard before I had the duplexer tuned.   I'm not sure if I can upload a video but will attempt to. 

 

 

[SteveShannon]

33 minutes ago, VETCOMMS said:

I recently had the internal Sinclair duplexer tuned at a Motorola dealer.   I noticed after reinstalling the repeater would do one of two things. 

It would not respond when an HT or a mobile radio was keyed up with the appropriate tones.  If I turned the repeater off and back on again the repeater would work for a while but when left idle for a while with no keying of the repeater it would again,  not respond when an HT or mobile radio was keyed up. 

The other thing it did was a buzzing sound I'd never heard before I had the duplexer tuned.   I'm not sure if I can upload a video but will attempt to. 

 

 

Turn off all tones on the repeater and try again. 

[VETCOMMS]

On 10/9/2024 at 9:29 PM, SteveShannon said:

Turn off all tones on the repeater and try again. 

I cleared the tones on the repeater and on my HT and when I transmit the HT the busy light on the repeater lights up but I cannot hear my voice in the repeater and no squelch tail or courtesy blip was heard.   

[VETCOMMS]

Would desense cause this after a flat pack duplexer was tuned?

[SteveShannon]

1 minute ago, VETCOMMS said:

Would desense cause this after a flat pack duplexer was tuned?

Not if done correctly. The entire purpose for the duplexer is to ensure that the transmitter’s signal has no effect on the receiver.

[WRUE951]

I had similar problem when i ordered a Duplexer from a 'popular' radio sales outlet.   I actually got two different Duplexers shipped to me that were bad or not tuned right.. The radio outlet worked with me, fed X out replacements and the 3rd one hit a homerun..  It worked..    Take the duplexer out and transmit receive on simplex using same tones.  If it works then, you gots a bad duplexer  

[VETCOMMS]

Can someone please confirm I'm not doing something wrong.  As you read at the beginning this repeater was doing a weird buzzing sound so I took it to a Motorola dealer and he tuned it on their Aeroflex service monitor.  The tech said "it's running at 80 dbm which is really good."  I don't know what that means.  He said they found that the jumper running from the flat pack duplexer inside the repeater to the antenna connection on the outside of the repeater had a short in it.  He said there was not much resistance but it had a "dead short."  He said the repeater was putting out 28 watts after the duplexer.

I got the repeater home, hooked it up, tried with with several different tones on tx and rx side, tried no courtesy blip, tried setting one channel with no tones on either TX or RX.  I can hear my voice in the speaker on the repeater but it does not transmit.  I hooked my SWR meter up to the coax and it is not transmitting.   

As I type this I'm thinking they didn't put the antenna connection on the back of the repeater on the part that is not hooked up to the duplexer.  Seems like I did that when I first got this repeater.   *edit* - I looked through the vent on the bottom of the repeater and the antenna is hooked up to the correct part of the duplexer.    If it's not that, does anyone have any other ideas why it would receive and not transmit?

[SteveShannon]

5 hours ago, VETCOMMS said:

Can someone please confirm I'm not doing something wrong.  As you read at the beginning this repeater was doing a weird buzzing sound so I took it to a Motorola dealer and he tuned it on their Aeroflex service monitor.  The tech said "it's running at 80 dbm which is really good."  I don't know what that means.  He said they found that the jumper running from the flat pack duplexer inside the repeater to the antenna connection on the outside of the repeater had a short in it.  He said there was not much resistance but it had a "dead short."  He said the repeater was putting out 28 watts after the duplexer.

I got the repeater home, hooked it up, tried with with several different tones on tx and rx side, tried no courtesy blip, tried setting one channel with no tones on either TX or RX.  I can hear my voice in the speaker on the repeater but it does not transmit.  I hooked my SWR meter up to the coax and it is not transmitting.   

As I type this I'm thinking they didn't put the antenna connection on the back of the repeater on the part that is not hooked up to the duplexer.  Seems like I did that when I first got this repeater.   *edit* - I looked through the vent on the bottom of the repeater and the antenna is hooked up to the correct part of the duplexer.    If it's not that, does anyone have any other ideas why it would receive and not transmit?

Go right back to that dealer. He might be able to clear this up quickly. 

[gortex2]

How do you know its not transmitting ? What antenna system are you using ? What is your test procedure and what subscriber are you uising ? 

[VETCOMMS]

53 minutes ago, gortex2 said:

How do you know its not transmitting ? What antenna system are you using ? What is your test procedure and what subscriber are you uising ? 

I think it's not transmitting because when I put my cheap Chinese swr meter in line and use my HT to tx to the repeater,  the swr meter does not do anything.   All zeros on the display.   I have it on a little mag mount in the garage while I'm testing but it will be connected to a 6' omni when done. 

Not sure what you mean by subscriber.

[gortex2]

So first thing you need to do is get it on a antenna outside of your test room. Hook it up to an outside antenna. Your most likely desensing not only the radio but the repeater as well. Subscriber aka portable radio. 

[VETCOMMS]

7 hours ago, gortex2 said:

So first thing you need to do is get it on a antenna outside of your test room. Hook it up to an outside antenna. Your most likely desensing not only the radio but the repeater as well. Subscriber aka portable radio. 

I'm such a rookie.  Figured out the problem.  I didn't push the repeater button in on the Vertex so it was running in base mode.  Putting out 33.8 watts with an SWR of 1.5 and transmit % of 95.98% on the temporary antenna.  It's tuned for 462.625 and meter shows 462.623.

Thanks for the help!