Miscellaneous babble – Page 2

The new Top Bands

US amateur radio operators will soon have access to small slivers of the 630 m and 2200 m bands as secondary users. The 630 meter allocation goes from 472-479 kHz (a little bit below the US AM broadcast band, 530 – 1700 kHz) while the 2200 meter allocation goes from 135.7-137.8 kHz (not a heck of a lot).

Although the new allocation was announced several months ago, now access to the bands is only a form submission and 30 days away.

Before being allowed to operate, hams will be required to notify the Utilities Technology Council. Notification can be done online, and involves submitting name, contact info, call sign, lat/long of your antenna location(s) and the bands you’re planning on operating on. If you don’t hear anything back within 30 days, you’re supposedly good to go.

Even if you have no immediate plans to operate on the new bands, you might still want to notify the UTC in case you decide to operate there later. If there’s no objection to your notification, and a utility later wants to deploy or modify a PLC system near you, they’ll have to use a frequency range other than one you’ve indicated on your notification.

If an electric utility seeks to deploy a new or modified PLC system on a transmission line that is within one kilometer of a previously coordinated amateur station, the electric utility must employ a frequency in the 9-490 kHz range that has not been included in the amateur station’s notification, as ARRL suggests. If the previously coordinated amateur station no longer operates in the band, the electric utility may deploy a PLC system in that band.

Now, how to build an antenna for 2200 m…

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.

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.

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.

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.

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.

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.