June 18, 2005

New Antennas Connected


I'm pleased to report that at about 3pm today the new and higher antennas for both the 444.725mhz and 52.92mhz repeaters were connected to the system and appear to be functioning properly.

The SWR on the 440 antenna is indicating a close to optimum match with little, if any, reflected power. The six meter antenna shows a 1.8:1 match with the repeater transmitting into it. Both repeaters appear to be putting roughly 50-60w into the transmission line (though the metering is not a benchmark for accuracy).

There is no perceptible desense. No interference from the nearby FM broadcast transmitters, or other odd noises have been noted. All appears good.

The grounding and lightning protection devices have been installed. Due to the new cable routing, the six meter output power sampler has been removed from the circuit pending longer
leads for the sample voltages.

73 KF8KK

June 17, 2005

Repeater Antenna Raising


I'm overjoyed to report that today the new antennas for the 444.725 and 52.92 repeaters were raised to the 330'-340' point on the tower.

Thanks to the hard work and expertise of Glen Walker, Del WB8DEL, Keith WA8ZWJ, Mike N7LMJ and myself, todays work went smoothly and appears to be functioning as it should.

The antennas are oriented properly and affixed at the southeast leg of the tower. The 440 antenna is arranged to provide 9db of gain towards the east and downtown Traverse City. This is an 'offset-omni' arrangement with a very wide lobe of gain.

The six meter antenna is oriented towards the south and Evart.

There is a tower shadow that effects the areas near Glen Haven. It appears to manifest between the main intersection in downtown Glen Arbor at it's eastern edge, and the Glen Haven maritime museum at the western edge. Adding to the tower shadow is a rather large and ominous terrain feature that would be hard to pass a signal over regardless of tower shadow.

As of this date the repeaters have not been connected to the new antennas.

More to come, 73 KF8KK

June 07, 2005

Summer Alignment Notes


Today was the day for the summer frequency alignment and audio tweaking at the main repeater site. Sadly, it was spurred on by the 'dirty pot' in the 222mhz receiver manifesting itself again. The volume control on the IC37A transceiver was exercised and hopefully the audio loss through it has been exorcised.

Additionally, the audio levels from 449.725 and 52.42 receivers was checked and set. Sadly the existing logic problem with the 6mtr voter board made adjusting the 6m side a bit tedious. I expect to change out the 6m voter with another board with my improvements incorporated at some time later this month.

The 444.725 transmitter was found to be 1.7khz low in freq, and the 52.92 transmitter was almost 1khz low. I brought both of these to about .25khz low. The temperature at the time was in the low to mid 80's outside--- typical summer weather. The VHF remote base was right on frequency when checked on 144.92. the 52.42 receiver had been adjusted about a week ago and was not checked again, neither was the two 449.725 receivers-- which will be needed to be checked on the next visit (oops-- I knew I forgot something).

Sadly, today it was noted that the 52.42 receiver at W8TVC was picking up a fair amount of what I would call 'AM Noise'. This had manifested about a month ago and never noticed since then, but it was back today. It was NOT on the UHF link between the TVC site and Empire, nor was it on the 449rx there, but it was on the six meter receiver only.

That's the latest... 73 KF8KK

June 05, 2005

Packet TNC reset

Sadly, late in the evening on Saturday the wI0OK digipeater got stupid (mid connection to the wI0OK-1 mailbox) and returned to 'factory fresh' parameters.

On arrival at the repeater site the TNC was looking fine and appeared functional but the callsign had reverted to 'nocall' and all the localized parameters were reset to factory defaults.

Oh well--- let's hope this doesn't become habit forming.

73 KF8KK

Six Meter Receiver Tuning


Today turned out to be the day to take the 52.42 receiver at the W8TVC site and move it up to the proper frequency from about 2khz low. Thankfully, swapping out a 10pf capacitor for a 5pf was all that was needed to bring the Mitrek channel element within tuning range of the desired frequency.

While at the site I also did some snooping into the intermittant desense problem that seems to be affecting the 145.27 repeater. While there was nothing that stood out as definately bad, it did seem that one of the cables (between the Polyphaser and duplexer Tee) might be suspect. I will have to return with a 4' length of superflex heliax (N male - PL259) and give that a try.

73 KF8KK