Well, not quite. It isn’t Klondike Alaska, rather the other world famous location; Klondyke Waikato. And what a great location to have a radio antenna. With the surrounding pine plantation having been harvested, the views also aren’t too bad. In the thumbnail1 showing the track leading back down to the road, you might just see the top of Mt Egmont. But enough of the geography, we were on a mission.

Amongst the several Amateur repeaters operating from Klondyke, one is a National System node. As well as providing coverage to greater Auckland and Waikato areas, the node has links to the North (Brynderwyn), East (Kaimai) and South (Egmont). For those of you wondering about the use of the name Egmont for a location; the system was built before the name was changed, and all the equipment references for that link relate to Egmont. But I digress… For some time, the link from Klondyke to Egmont was very noisy, so on 17/7/25, ZL1BQE, ZL1BK and ZL1DL made a site visit.

The day was drizzly and at the repeater location, visibility could only be rated as poor. It was difficult to see to top of the antenna tower. But never mind, the issue was most likely in the electronics and so it was an “inside job”. Harry measured the tx ouput for the link to Egmont and it was down ( slightly ) to considerably less than 0.5 watt. The tx module was removed to the service bench and when connected to appropriate test equipment, Harry announced “I think it could be this” and set about adjusting two coil slugs. The rf power rapidly increased to around 13w – enough to be happy with. You get the impression that Harry had performed this adjustment before…

The rack at Klondyke with 6625, National System, 50 MHz, DStar and PRS repeaters.
The rear of the rack with a few “hangers on” while some antennas are temporarily reallocated. Feeds to the antennas exit the building at the top left of the picture.

With the power level for the Egmont link back to good, the tx module was re-inserted in the rack and tested. It was observed at the time that the tx LED on the module was dimly glowing when tx was not on. Still, the module transmitted when requested and the tx LED glowed normally at the appropriate time. And after a couple of minutes of power on, the tx LED illumination, in standby, dimmed further. So all good. We packed up and left.

Just as we arrived back at Keith’s QTH, we overheard a conversation on the National System, enthusiastically observing that the Egmont link was working well again – apart from some sort of side tone on the transmission from Klondyke to Egmont…

24/7/25 Klondyke Revisited

After some pondering about the errant tx LED behaviour trying to tell us something, Dave looked at the circuit for the tx module and it would seem that the LED’s behaviour might be a result of bad capacitors. There was a chance that the circuit (9v linear regulator that is enabled on tx) that the LED was connected to, was oscillating when it’s function in life was very definitely not an oscillator. This could be the source of the “side tone” heard on the link. Interestingly, some years ago, ZL3CK replaced capacitors in the modules. Unfortunately though, at some later stage, it transpires that there was a problem with the Klondyke / Egmont [K/E] transmitter module and it was swapped out – for one that hadn’t been recapped! You couldn’t make this sort of stuff up…

So on a much brighter day, Keith, Harry and Dave returned to Klondyke and again put the K/E tx module on the bench. This time, monitoring the transmitted audio, a terrible noise was evident. A quick look at the 9v regulated supply showed a nasty oscillation of about 1v pp. A 10µF cap was quickly tacked across one of the regulator caps and no more noise ( and no more partly illuminated tx LED, in standby ). At that, the 10µF caps on the exciter PCB were replaced with non-electrolytic, solid types. Interestingly, all of the removed caps had a capacitance reading within tolerance – around 10µF, but they all had seriously high ESR; around 10 ohms (could be even higher, but 10 ohms is the max available range on the ESR meter used)!

Keith opening up the errant module – ready for surgery
No sub mm SMD technology here – parts you can actually replace with relative ease!

After a final bench test, the module was re-racked, tested and we were away.

And… a few more pics…

Handy Tower
Even more handy accommodation for when the weather isn’t sunny and calm
Not so handy pic but strangely interesting [ED: find another photographer for next time…]
  1. For those who can’t see Egmont in the thumbnail – here’s a better opportunity with a larger version of the pic (click on the pics for a larger view): ↩︎
The top of Egmont is visible in the orange circle

And if you cant see it – here it is.. (contrast adjusted!)

If you still can’t see it, check out your local opticians for a “2 pairs for $299” deal 😎