So I have started to collect all the little pieces required for my 3.8 Meter dish project. First on the list due only to its availability and wanting to work inside when its only 10 degrees F here in CT is the Septum Feed.
I have built this feed in the past from KL6M's excellent plans (http://kl6m.com/23cm/23CM-SEPTUM-FEED.pdf) but sold it off with all the other gear I had accumulated before my recent move. Recently along with my old dish I was able to get my hands another septum feed however I quickly realized it was going to need quite a bit of work to bring it up to standard..... Rather then buy all new parts for 75$ from Online Metals I figures I would salvage what I could.
First off I noticed that the measurements didn't work out to the KL6M plans..
The tuning adjustments were in the wrong spot and the septum dimensions were way off. I corrected this by rotating the back-plate 90 degrees and re drilling the tuning adjuster holes and septum screw holes.The old holes were then filled with epoxy and a new coat of paint applied.
I also realized that I needed to replace all the tuning hardware as well as the feed connectors and probes with new construction.... I was able to salvage one SMA connector that I found to be an Amphenol unit.... Saved me 8$!
The new hardware was made from 1/4 inch brass round stock, brass 1/4 x 20 hardware and 20 mm round discs as the plans call for. I was able to use the Rockwell lathe and bandsaw at work to machine the parts.
New Parts...
Dry Fit...
Old kitchen tile used to prevent damage to the bench. I used a little flux, solder and a propane torch to heat the parts.
All soldered up and pretty close to centered.
Cleaned up with sandpaper wrapped around a dowel.
My new septum material arrived from online metals. The markout is pretty simple if you follow KL6M's instructions closely. I made the determination that the original septum that came with this feed was of unknown design and to thin. The width of the septum, according to the plans, has little effect on performance and a HUGE effect on how easily it is to drill. 1/4 inch aluminum plate makes it very easy.
This is a picture of the waveguide that was salvaged from the old feed. I filled any mounting holes with epoxy, cleaned up any corrosion and threw a coat of primer on the outside for protection.
I have built this feed in the past from KL6M's excellent plans (http://kl6m.com/23cm/23CM-SEPTUM-FEED.pdf) but sold it off with all the other gear I had accumulated before my recent move. Recently along with my old dish I was able to get my hands another septum feed however I quickly realized it was going to need quite a bit of work to bring it up to standard..... Rather then buy all new parts for 75$ from Online Metals I figures I would salvage what I could.
First off I noticed that the measurements didn't work out to the KL6M plans..
I also realized that I needed to replace all the tuning hardware as well as the feed connectors and probes with new construction.... I was able to salvage one SMA connector that I found to be an Amphenol unit.... Saved me 8$!
The new hardware was made from 1/4 inch brass round stock, brass 1/4 x 20 hardware and 20 mm round discs as the plans call for. I was able to use the Rockwell lathe and bandsaw at work to machine the parts.
This is a picture of the waveguide that was salvaged from the old feed. I filled any mounting holes with epoxy, cleaned up any corrosion and threw a coat of primer on the outside for protection.
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