Physical Radio Systems of the WVRA
last update 04/27/2008
146.865 repeater
PL 114.8 (2A)
This system is a split site repeater that is also linked full time to the 147.135 repeater. The transmit half of the system (146.865 PL 114.8 2A) is located at Mosinee Hill near Wausau and Rib Mountain. The transmitter is a M216 Motorola Radius 45 watt mobile radio with the power turned down to approximately 1 watt. This runs through an attenuator network and is input to a GE Mastr II 100 watt continuous duty power amp.. It then and TX/RX circulator and second harmonic filter and then through 2 TX/RX bandpass cavities to the 7/8" hardline. The hardline runs up the tower to a level of 90ft. The total run of hardline is approx 140ft. the hardline is connected to a Celwave PD340 6db gain antenna. This transmitter is connected to a UHF Motorola Radius M120 mobile radio. This link radio listens for the link that is being transmitted from the FOX55 tower in the town of Hewitt, northeast of Wausau.
The 146.265 (PL 114.8) receiver is located at the Fox 55 tower located northeast of Wausau in the town of Hewitt. The receiver is a Motorola Radius M208. The radio is run through a Micor 2M receive preamp and then goes into a Wacom duplexer. The other side of the duplexer goes to the 145.610 WIN Link node radio. The output of the duplexer is fed into the VHF port of a PCTEL/Maxrad VHF/UHF diplexer. The output of the diplexer is connected to 7/8" hardline that is then run up the tower to a level of 375ft. The total run of hardline is approx 575ft. The antenna is a Diamond X500HNA on a Pyrod 6ft side arm bracket.
The 146.265 receive radio is hooked into a signal quality (SQM) card in a Motorola Spectra TAC voter along with the satellite receivers on 147.735. The output of the voter is sent to a S-Com 7K controller which goes to the 147.135 transmitter. The output of the voter also goes to a Motorola Maxtrac 100 transmitter which transmits the signal to Mosinee Hill to be rebroadcast on the 146.865 transmitter.
2/20/07 - Noticed that when the 146.865 transmitter gets hot, it intermittently will not transmit. It seems that if you leave the system unkeyed for about 10 seconds, the transmit will come back. I have only heard this problem once, but Jerry mentioned that he thought it happened once before during the reports on the Wednesday evening net.
4/15/07 - Today, the 146.865 transmitter was upgraded to a 100 watt transmitter. There was also a circulator added to the antenna system along with the 2 TX/RX bandpass cavities. After the circulator and 2 cavities, there is 60 watts out to the antenna. It was noticed before the work began that the transmitter was down to 17 watts out to the antenna. This may explain why some people mentioned that sometimes it seemed that the transmitter dropped off of the air and others said it went noisy. With the upgrade to 100 watts, the power out of the transmitter was turned down to approx 8 watts and this will hopefully remedy the problem of the transmitter dropping in power. If it doesn't, we will need to replace the driver PA. The PA added to the system is a VHF GE MastrII 100 watt continuous duty PA. This PA feeds into the TX/RX circulator and then into the 2 TX/RX bandpass cavities. The new PA is feed from the Motorola Radius M216 transceiver that is turned down to approximately to 8 watts and is feed into a 50 ohm transmit pad network. The output of the network is feed into the input of the GE MastrII PA.
4/18/07 - The problem with the 146.865 transmitter is still there. Isn't it great that nothing acts up when you are at the site to work on it. I will try to get back up to the site Friday or Saturday to swap out the intermediate PA and see if that cures the problem.
4/19/07 - Swapped out the intermediate PA today and retuned the transmitter. However, later today I noticed that it is still dropping out.
4/20/07 - Had a chance to look at the 146.865 transmitter while it was acting up this afternoon when Matt N9NMH and Mike KB9DED were using the system. Looks like the link receiver from Hewitt (FOX55) is OK. It appears that the problem is somewhere in the 146.865 transmit radio. I should hopefully be able to swap out the radio sometime this weekend (4/21-22) between my work schedule.
4/22/07 - Had a chance to spend more time trouble shooting the intermittent transmit problem today and found that the 50 ohm attenuator pad has an intermittent problem. I removed it and jumpered around the the 100 watt PA, so we are running on low power until I can fix the network. That should hopefully be early in the week. I hope to have it completed so that we can use it for the MS walk on the weekend of 4/28-29/07.
4/23/07 - Reinstalled the repaired attenuator network and tested. Appears that everything is up and running again. Turned the power out of the transceiver down to 5 watts to go into the attenuator network to give about 230mW into the PA.
4/28/07 - Heard through the grapevine that there was a problem again with the 146.865 transmitter during the Wednesday night swap net. I removed one of the attenuators in the network and turned the transmit power on the transceiver down to approx 1 watt. I am hoping that the problem is a heating issue within the attenuator network.
5/4/07 - Heard from Dennis W9PBB that the 865 transmitter cut out during the CW net on Wednesday night. Swapped out the attenuator network with a different one. This one is only rated for 1/2 watt, but hopefully it will stand up alright with the fan blowing on it. If this one fails, we'll have to look into getting a higher power one.
5/16/07 - Heard the 146.865 transmitter failed during the nets tonight. I will order a replacement attenuator for it this time.
6/2/07 - Heard the 146.865 and 147.135 transmitters cutting out. Problem is in the voter and turned up after adjustments were made to the voter last weekend.
6/23/07 - Got out to the Fox 55 tower and repaired the problem of the transmitters cutting out. The problem was in the voter.
6/24/07 - Got up to Mosinee Hill to replace the bad attenuator. I also installed a bank of fans in the cabinet to help with cooling. The building on Mosinee Hill is not heated or air conditioned.
7/3/07 - Interesting problem today, both the 147.135 and 146.865 transmitters were off the air. I noticed the problem shortly before 5pm. I went out to the Hewitt tower and found both the Astron SL11 power supplies that power the link receivers were only putting out about 4 volts. I turned off one radio attached to each supply and the voltage came up to 13 volts. I turned the radios back on and the voltage stayed at 13. After some further trouble shooting, I found out that we had a short power outage at the site and when the power came back on, the power supplies go into shut down. This only happens when the AC power is lost or the power is turned off and then returned while all the link receive radios are powered up. In this state, this also caused the voter interface to not work. I powered down all unnecessary radios and will bring out a different power supply to power all the link receivers. Thanks to everyone that called to inform me of the problem.
7/7/07 - Installed a replacement power supply for the link receive radios. Wired the voter interface to a separate Astron SL11 power supply.
7/8/07 - 146.865 transmitter was cutting out during the weather net today. Went to the site while it was acting up and found that the temperature in the building was 105F and it was warmer in the cabinet. The transmit radio was going in to shutdown due to the heat. I removed the radio so that it can be checked over. I also had to fix the exhaust fan in the building.
7/11/07 - I was able to make the modification to the radio over the last couple of days and re-installed the transmitter. I tested the radio on the bench by keying the radio up for 10 minutes while having a heat gun blowing on the PA. After letting it cool down, I also keyed the radio up for 25 minutes. The output power stayed very stable near 1 watt. Remember that this radio drives the 100 watt PA.
7/18/07 - During the net, I heard the UHF link to Mosinee Hill from the Hewitt tower drop off the air a couple of times. This sounds similar to the problem we were experiencing with the the 146.865 transmitter dropping off of the air due to the heat. I hope to get to the site on the 19th to pick up the link radio and check it over. It may need the same modification that I did on the 146.865 transmitter. The 146.865 transmitter seemed to work without failing during the net except for the times that we lost the UHF link.
7/19/07 - Removed the UHF link transmitter at the Hewitt site (transmits to the 146.865 at Mosinee Hill) to check it over and make the modification. I hope to have it back up by the end of the weekend.
7/22/07 - Reinstalled UHF link transmitter at Hewitt for the link to Mosinee Hill. The radio checked out OK, so I made the same modification to the TX power control circuit that was made to the 146.865 VHF transmitter.
10/12/07 - Installed a UHF corner reflector at the Fox55 tower for the link to Mosinee Hill.
10/15/07 - The transmitter had been kerchunking since Sunday so I checked the power out to make sure that nothing was wrong. Looks OK - about 60 watts out to the hardline.
11/13/07 - The transmitters on 146.865 and 147.135 were kerchunking again. It was still acting up when I got out to the Fox55 tower and found that the status tone detector on the Signal Quality Module (SQM) for Bevent was out of tune. I retuned the detector circuit and all is working fine now.
1/25/08 - Lost power to most of Rib Mountain including the tower on Mosinee Hill that this repeater is located at. The generator ran perfect and we had no loss of service on this transmitter or the 147.735 satellite receiver and link.
3/12/08 - Noticed that the 146.865 transmitter isn't working. Will look at in the next couple of days.
3/14/08 - Went to look at the 146.865 transmitter and found that the fuse was blown on the power supply. This also shut down the satellite receiver and both link radios. Saw the old generator sitting in the parking lot, maybe the fuse blew when they were switching the generators. The roof is also leaking very bad in the building. I put a board over part of the top of the cabinet to try to keep the water from getting in to it.
4/26/08 - If you've been listening over the last couple of
days, you would have heard that there were times that the transmit audio was OK
and times when it was very low. I tracked it down to the Abbotsford site
and UHF link receive radio at Hewitt. There were actually 2 problems.
The link receiver has low receive audio out to the voter and the satellite site
at the Abbotsford tower has low audio coming to Hewitt. It is unknown as
to whether the problem at Abbotsford is the link transmitter or the 2M receiver.
For now, the Abbotsford site has been removed from the voter and the link
receive radio has been removed for repair. I hope to get to the Abbotsford
tower in the next couple of weeks.