VE3GBT Repeater

[Tom VA3TS]

The GBT repeater has been returned to its location, however there is an issue with Environment Canada's equipment which has a detrimental effect our ours. Environment Canada has been notified and we are awaiting a response. The effect is to desense our receivers which will make it difficult to operate the equipment. But the link is in service and the repeater itself may be useable in Paisley itself. The saga continues and eventually we should see a satisfactory conclusion.

best regards  Tom TS and Bernie BQM

[Tom VA3TS]

Would anyone have a TDR Timer Domain reflectometer or equivalent like a VNA that can be used to detect faults in antenna feedlines. If you have such a beast let me know.... 73

[Dave_VE3WI]

Hi Tom

My RigExpert analyzer will do TDR.  I've only done it once but would be happy to give it a try.  It needs the Z0 and VF of the cable.

73
Dave

[Tom VA3TS]

Thanks for the offer Dave, Richard had one at the site recently but there was some issue with the TDR portion so if you can get that going it would be great. The zo would be 50 ohms but we need a small ladder to get up a bit to see if the cable has any writing on it.

Below is an swr sweep that Richard performed.
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attached is the SWR plot for the Paisley coax line.  I did a spread from 135 Mhz to 165 Mhz to include the Environment Canada weather radio.  It appears that for the VE3GBT frequency of 146.730, the SWR is approximately 3.0:1 and it gets worse for the Environment Canada WX radio frequency is slightly higher.  Not ideal for sure.

As you know I didn't get a screenshot of the TDR scan to send along, but it appeared to show excessive reflective pulses during the test of the hardline and it appears in the first 40-50 feet.  It seemed as though the reflection of power in the first section of hardline before the spice outside is in poor condition, almost rendering the test inconclusive.  More testing would need to be done if further data is required.



Richard 
VE3OZW

[Tom VA3TS]

The old GBT repeater is out of service and replaced with our updated MTR2000 equipment. The feedline is still an issue however the upgrade of repeaters has been completed and works. Our next steps are to comeup with some hard data on the old feedline and hopefully we can enlist the efforts of all the stakeholders to get this resolved. Some pictures below

[Tom VA3TS]

Paisley Repeater Feedline VE3GBT

Approximately 5 years ago the antenna feedline on the 300 foot tower near Paisley came loose during high winds. The tower owner, had a company come in and resecured the feedline to prevent further damage. However, the damage had been done and the performance has degraded consistently over the last few years to the point where high swr is now the rule and not the exception.

We use this feedline along with Environment Canada who operate their weather radio transmitter on 162.455 and have enjoyed a positive relationship with them in the recent past. This relationship is paying off in dividends now, due to EnvCanada's desire to replace this feedline and who has asked if we as a club would like to participate in the replacement. The tower owner does not have the will to do this themselves but will not stand in the way of it being replaced by others.

Your club assisted EnvCanada with the testing and subsequent determination that the feedline could not be repaired and the best recourse would be to replace the cable. This is a 7/8 inch heliax cable.

EnvCanada had asked for a quote to replace the cable from Spectrum telecom and has received same. I won't go into details here but the information will be at the September club meeting for those who wish to peruse it. Suffice it to say that the costs are in the order of $xxx which included materials and installation/labour for 3 days work.

In order to guarantee our (the clubs) access to the site and feedline, we have offered to EnvCanada, assistance with this expense to the amount of $xx which includes any taxes.

Our radio club has been the recipient over many years by organizations which permitted our use of their facilities. This includes Bell Canada, Rogers and Explore, to which we are grateful. For all the years that our club repeaters have been hosted by others, we have yet to have any ongoing expense for hydro to run our gear or payment for tower access. When we moved VE3OSR to the Rogers site, Rogers installed our UHF link feedline and antenna at very little cost to us other than the cost of the feedline and antenna itself, many thanks.

We are excited to be close to a solution to this 5 year issue at Paisley and look forward to the VE3GBT repeater delivering the same excellent coverage it once had.

Finally, whatever help you can offer is appreciated with our thanks.

Tom St.Amand VA3TS
President GBARC