I've been playing with the TenTec 1056 receiver to optimize its performance measuring solar noise. One of its features as a communications receiver is the fairly narrow and adjustable bandpass filter. The manual doesn't say, but it appears to have about a 1KHz bandwidth. This is really too tight for picking up broadband noise from the sun.

The guys at Fringe Dwellers recommend adding a switch to allow you to bypass the bandpass filter stage altogether. This goes a little too far the other way for my suburban location. The Radio Jove receiver has a multi-pole filter with a 3.5 KHz bandwidth. I decided to follow their lead. I put a simple RC filter in place and so far it seems to be working well.

Here's how it is hooked up. Remove the "Mute" jumper and put an SPDT switch across it with the common to the right end. Across R12 (3.3K), put a series combination of a 1K resistor with a 0.047uF cap. The resistor goes to the right, the other end of R12 is ground. The node where the resistor joins the cap connects to the other end of the bypass switch. Voila, a simple RC filter.

Now to record data for a couple of days and see how my results compare to others.

Cheers,

Keith

We are all set up for Astronomy day here at the Robert Ferguson Observatory. We are getting a good crowd for Solar observing which will last until 4:00 PM. Then after a break for a meeting and dinner, we'll be back to show the night sky. I brought my Orion 8" dob, several others will be here with small scopes, and all of the large scopes in the observatory will be operating. We also have not 1, but 4 lecturers who will be giving a variety of talks starting at 8:00 PM.

Although there are no sunspots today, the sun appears to be active in the decametric radio spectrum. Dean has picked up several noise bursts on the Radio Jove receiver.

Wherever you are, there should be some club doing public astronomy today. If not, at least go out and look at the moon and Venus tonight just after sunset.

Dark Skies!

Keith

I have some rudimentary plots available from Radio-SkyPipe on-line now. You can see the data here. The prominent red track is from the 24.8KHz Gyrator II receiver monitoring NLK at Jim Creek, Wa. The flat orange track near the bottom is from the 20.1MHz receiver. I'm still working on that one. I hope to have something on the other channel soon too.

I've also taken info from some of my posts here and started to create some "permanent" pages on my solar monitor project. This Linkwill take you there. So far, it just covers the system mainframe and bar graph modules. Over the next few weeks I'll add pages for each receiver/sensor too.

Cheers,

Keith

I've had my Orion XT8 Classic Dobsonian Telescope for years and I love it. Last year at the Golden State Star Party we were "treated" to a thunderstorm the first night. I managed to stay pretty dry, but the base of my telescope got wet. Particle Board does not like to get wet.

About a week later, it was starting to come apart. Luckily, I had a half sheet of 3/4" hardwood plywood left over from a kitchen remodel we did a couple of years ago. I took the original base apart and used the pieces as templates to cut new ones from the plywood. I reused as much of the original hardware as possible. I changed the connections between the pieces to some steel knock-down furniture fasteners. These are the kind where the screw that holds two boards together threads into the side a special pin that goes in a second hole drilled at right angles to the screw hole. They work really well and don't rely on screw threads biting into the edge of the plywood. Here's a picture of the complete base:



One problem I had was that the azimuth movement was sticky. It was just teflon pads riding on the multiple coats of polyurethane. The original was high pressure laminate on the friction surface. Telescope Builder folklore held that "Ebony Star" laminate in combination with the teflon pads gave the best results. Luckily, Scope Stuff sells pre-cut rings of the stuff complete with a set of pads. The prices look a little high at first, but they do include shipping, which can be expensive on an awkward part like this.

Laminate is generally installed with contact cement. My quandary was how to apply the cement to the base without making a mess. Here's how I did it.



First, I centered the ring on the bottom of the rocker box with a couple of pieces of masking tape. Then, I started covering the laminate with tape, making sure to leave plenty of tape off the sides, and not worrying about completely covering the laminate itself.



When I had it all taped, I made a registration mark on the tape and then took an X-Acto knife to carefully cut around both edges of the laminate leaving a perfectly masked ring.



The contact cement goes on with a little brush in the bottle, so I didn't need to mask any more like I would with a spray adhesive. I put two coats on the base because of the shiny surface, and one coat on the back side of the laminate. When they were ready to go (Read the instructions) I put a bunch of cable ties laying flat across the glued area on the base to keep the ring from sticking all at once. When I had the ring lined up nicely, I pulled the cable ties out one-by-one and pressed the ring into place.



I also replaced the original teflon pads on the ground board with the new ones that came with the laminate ring. Now my telescope swings around nicely. Just the right combination of drag and ease of movement.

I'm planning to give it a really good workout this coming weekend (24-Apr-2010) for Astronomy Day at the Robert Ferguson Observatory.

Clear Dark Skies to All!

Keith

I finally got a relatively rain-free Saturday to install the T2FD antenna up on the roof of the garage. To prep as much as possible, I finished up the bases for the three vertical supports. Here's a picture of one of them:



These started out as standard 2" PVC "T" fittings which I cut to fit the ridge of the garage roof. You can see the template I used to mark the key points on the fittings before cutting. I went a little steep on the angle so that they would tend to rest on the ends and not rock in the middle. I just clamped them in a woodworking vise and cut with a hacksaw.

I also pre-cut the ropes to make the installation go faster since the forecast was for some showers randomly through the day.



Here's the antenna installed on the roof. You can just about make out the wires in the photo. The ropes at each end are tied to eye bolts that are screwed into the trim boards on the gable ends of the roof. The eye bolts are screwed in at a slight angle so the ropes won't rub on the edge of the roof. I'll probably need to adjust the ropes once everything settles in.

The finished antenna seems to be working great. I have the 20.1 MHz receiver hooked to it and collecting data on Radio Sky-Pipe. I need to work through the image save/FTP upload process so I can get some recordings posted on the site.

Then I'll be working on finalizing the 111 MHz receiver and modifying my WWVB receiver to give me signal strength measurements.

Cheers,

Keith