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146.97 Update

Posted by Harrison W1HAF on July 3, 2015 at 10:55 AM

Hi All,

Here is an update to let you know what is happening with the 146.97 repeater. It appears that we have located the source of our interference which is being caused by a commercial video link for the Town of Waterford. There is a Motorola wifi type microwave video link between two sites located at the Fargo Road site. When the system was powered off the interference went away. I notified the Town of Waterford authorities of our findings and asked if they could have this checked. I told them that we would be more than happy to assist in resolving this interference issue. I had noticed it before we changed repeaters and we thought that this may be the cause. We now know that this is definitely the cause.

We also may have a problem with our 30 year old Station Master antenna. It appears that we are hearing crackling noises on the input even if the received station has a solid signal into the repeater. This may be a sign of a bad antenna. There are three dissimilar metals at the base of the antenna that may corrode. The antenna has taken a beating on top of the tower over the years. This may cause loose or broken solder joints inside the radome of the antenna. We had a problem with desense on the repeater causing the repeater to lock up when it transmitted PL. I took the PL off the transmit side so now the repeater will not lock up. It had just enough reflected power along with transmitting the PL to cause the receiver to stay open and keep the repeater on. If you reprogrammed your radios in full PL enc/dec you should reprogram them to just encode tone not ctcss for now.

Joe, K1IKE, and I will be conducting a few further tests at the site. I suggest that we consider replacing this antenna if we would like to get the full performance of our repeater back. We are currently researching several options for a commercial grade replacement antenna. We will have to present this to the club for a vote. Considering our primary reason for being a club is to provide reliable repeater coverage I would suggest that we replace the antenna with the best possible option that we can afford.

It would be nice to have this project wrapped up during the next month before we start Hurricane season. If we have to call a special meeting for a vote maybe we can have it at the site so everyone can see the equipment in person. We also need to remove the old equipment and bring it to the L&M Hospital site for storage. I am currently working on getting us access to the Hospital site again. I will keep you informed.

Harrison W1HAF

Update July 15, 2015.

K1IKE,Joe, and I went to the site on Wednesday 7/15/15 and conducted further testing on the hardline and antenna. Joe has test equipment that can sweep the hardline and antenna and look for shorts or problems. After conducting further tests it appears that the hardline and antenna tested out fine. It appears that all the problems are still being caused by the wifi type video link setup that the town is using as a repaeter site to send video from one site to another. When the link was shut down the interfrence disappeared. When we turned it back on the interfrence on the input comes right back. The repeater and dupluxers also tested fine. Therefore, I contacted the Town of Watererford and asked that they please contact the contractor who installed this system so that we can work with them and resolve this issue. I hope to have a resolution in the coming weeks.



Harrison W1HAF

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