Power supply: Updated schematic

I’ve updated the schematic for the power supply. Made a few corrections and rearranged a few things.

Still haven’t figured out why the outputs are behaving like they’re shorted out. Putting a my DMM across the output terminals gives me about 148Ω, which seemed on the low side to me.

Power supply schematic 20170716
Power supply schematic 20170716

A quick check of the SCR shows that it seems to be ok. I think I’ll check the pass transistors next. Looks like they should be easy enough to remove for a quick test. I should probably check the big filter caps too, although I wouldn’t expect those to be bad.

In the process of troubleshooting, I’ve removed the 6 pin connector and large capacitor (1.4 mF) associated with it. I’m planning on replacing them with Powerpole connectors. Three of them will fit nicely in the space occupied by the 6 pin connector. Just need to figure out how to secure them in place.

CARS President-elect

So I’m now the President-elect of the Charleston Amateur Radio Society.

The nominating committee put forth their selections for the club officers at the June meeting, and at the last meeting this past Monday, people at the meeting voted for them. Since nobody else stepped forward to throw their hat into the ring, the officers selected by the nominating committee were all elected by acclamation. Of the officer positions, the only new person was the President (me).

I’ll start my new job with the August meeting. It’s a bit of a higher profile position than I’m used to taking, but I’m looking forward to serving the club as President as the club heads towards its 50th anniversary in a few years.


Lowcountry Contest Club Mesh Networking Symposium

Update: I received a correction for the date of the symposium. It will be on Wednesday June 14. RSVP by June 11.

Did you know there was a Lowcountry Contest Club? I didn’t know there was a Lowcountry Contest Club. Apparently they’ve been around a while.

Anyway, word came to me that they’re holding a Mesh Networking Symposium June 1014 at the Fleet Reserve Association in Goose Creek.

The Low Country Contest Club (LCCC) will be holding a symposium on MESH networks for amateur radio at the Wednesday, June 10, meeting of the LCCC at the Fleet Reserve Association in Goose Creek, SC at 1800.  We generally arrive at 1800, order food/drink if desired at appx. 1830, and start the symposium shortly thereafter.  Note that there is no “meeting,” just the symposium. Directions, etc. are at the bottom of this email.

Terry, N4TLF, and I have been working for some time on establishing a 2.4GHz link between our houses, so we could further investigate the use of MESH networks in amateur radio.  We have finally managed to establish the link, and are currently working on ways to improve it, and also make the link available to others.

To make a MESH network really useful we need more participants.  To that end we are inviting interested members of TARC and CARS to attend the June meeting of the LCCC, and will have (for lack of a better word) a symposium on MESH networks that will address
equipment, software, and problems involved in making a useful MESH network in the Charleston metropolitan area.  We should have an example of a MESH network set up in the FRA building, and a demonstration of at least one possible application.

If you know of a ham that is interested please bring them with you.  They do not have to be a member of any club; only interest is required!

This is a growing part of amateur radio.  We think you will find it interesting, and hope that this will help to get a MESH network established here in the local area.

I assume they mean Saturday June 10 and that Wednesday is just a typo.

The symposium date is June 14. RSVP by June 11 if you want to attend.

Ham radio mesh networking is becoming a pretty popular thing these days with projects like Broadband Hamnet and AREDN using COTS wifi equipment and custom firmware. For hurricane and storm prone areas like the Lowcountry, having an infrastructure independent communication network based on a mesh network over the ham bands could be a very useful thing.

I’ll be out of town at Southeast Linuxfest when the symposium is happening, but if you’re interested in going, RSVP to W4MEL at <w4mel at arrl.org>

Coax to the shack

Spent the afternoon today getting the coax from the entrance panel through the conduit and into the shack. On the first attempt the string I was pulling the coax with broke, so we had to pull some more string. One of the contractors that worked on the house told us a while back that if the string ever broke, tie a new string to a plastic grocery bag, stuff it into the conduit and use a vacuum at the other end to suck it through. Worked like a charm.

With the new string run, managed to get both of the lengths of coax (RG-8X I believe) I had used at the old house through the conduit. One is 75′ and the other is 100′ along with a few extra strings in case we want to pull some more coax. Based on what was left of the 75′ coax hanging outside the entrance panel, it looks like the run between the panel and the shack is around 60-65′. That means there’s a good bit of coax coiled up in the entrance panel right now.

Entrance panel coax
Entrance panel coax

Still a fair bit to do at the entrance panel. I have to decide if I want to trim it (which would mean I’d have to learn how to terminate coax) or leave it coiled up inside the box. Lightning arrestor needs to be mounted, and I’ll have to work out a grounding scheme. Then I need to figure out how to hold the antenna up in the air.

At the shack end, there’s enough sticking out that should make it easy to work with.

Coax in the shack
Coax in the shack

I think I’m going to drill a couple of holes in the wall plate for some short SO-239 bulkhead connectors. Then it will be short jumper cables from the radio to the wall.

One step closer to getting the shack back on the air.

Cable entrance panel finally installed

It took a while longer to get to than I originally planned, but I finally got around to installing the coax entry panel to the side of the house. I even managed to do it without mangling the siding around the box too badly.

Entry panel installed
Entry panel installed

Almost looks like it was originally part of the house.

Next task is to caulk around the mounting box and the entry panel to seal everything up, then pull the coax through the conduit.

Entry panel installed
Entry panel installed