Tag - band pass filters

Band Pass Filter Update

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Construction of the band pass filters continued today, progress has been slow recently as i needed some more parts (M3 10mm bolts and some M3 nuts), I also had the problem of finding some appropriate coax to use for the internal connections. As luck would have it i have a couple of barely working Wifi antennas that have some nice long leads of very thin coax, it turns out that the coax is RG-174, perfect for my short internal connections on the BPF’s.

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5B4AGN Band Pass Filters – Construction Started

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I started construction of the first of two automatic band pass filters tonight. These will be used in the M0XXT contest station in conjunction with high power stub filters to allow us to run a proper Multi-Single or Multi-Two station.

These are similar to the Dunestar 600 devices, however they use the W3NQN filter design so the performance is superior to the Dunestar’s. They were designed by Bob Henderson 5B4AGN, who had some professional boards and cases made up.

They employ a very clever motherboard system, so the filters can be removed/replaced easily.

The photo is of the first, nearly complete motherboard

Band Pass Filters Update

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Progress on the band pass filters is progressing nicely, the second motherboard is almost complete and winding of the coils for the first set of filters has begun. Hopefully I should be starting on tuning the filters shortly.

Here is a quick pic of the L1 winding for 40m