NG9D

Friday, November 29, 2013

Schematic Diagram for Joe's Reflex Regen Receiver Project!

You may have seen how well Joe's Reflex Regen Receiver plays at www.YouTube.com/NG9D. Here is the schematic diagram in higher resolution!
73, Lynn
NG9D

Tuesday, January 4, 2011

Packaging a T1056 Receiver Kit

Here are a few photos of project enclosures made for the Ten Tec amateur radio receiver kits, model T1056. A Radio Shack enclosure is used, with an aluminum front panel and plastic cabinet.

Basically, the process involves soldering components onto the printed circuit board and then measuring the completed board before laying out the hole pattern and drilling the front panel. No drilling is required on the plastic case. The height of holes for controls depends on the stand-off supports you use. The supports are also available at Radio Shack.

If you keep the control potentiometers soldered directly to the PC board, then the holes are all aligned and the spacing is set by the printed circuit board. Or, instead of soldering the pots to the board you can use jumper wires to locate the controls wherever you want on your panel. I decided to keep all the pots soldered directly to the board, except for the main tuning controls.

Measure twice before drilling. Mark the panel and use a sharp center-punch on each hole centerline. The center-punch helps keep the drill bit in the correct location when cutting the holes. After center-punching, I drilled small pilot holes before drilling the final larger holes.

After all the drilling is done, make a trial fit-up of all switches, jacks, indicator light and control panel to cabinet. After you are satisfied that all the parts fit properly, then disassemble completely. Wash the panel with liquid soap to remove any dirt or oil.

Completely rinse and dry (I use a hair drier).

Only after the panel is completely clean and dry, then finish with two light coats of spray paint. Allow the panel to air-dry overnight (or longer) before handling to avoid fingerprints.

After the panel is dry, then you can mount the speaker to the panel using two-part epoxy adhesive.

After the speaker is installed, reassemble all the parts. You can then attach pressure adhesive rubber feet to the cabinet. The rubber feet give the radio a solid support and prevent it from sliding around your operating table when you adjust the controls. The yellow radio works on the 40 meter ham band.

You can also paint the plastic cabinet. Be sure to wash and dry it before painting. Allow the cabinet to completely dry before assembling. Attach the rubber feet to the cabinet after the paint is thoroughly dry. The gray radio is a 20m receiver.

There are other packaging options. Ten Tec sells several all-aluminum cabinets that also make nice enclosures.

73 de NG9D

Monday, August 23, 2010

Camping (and Ham Radio)

We certainly enjoyed camping this weekend at Starved Rock State Park!

The limited space doublet antenna with the homebrew parallel wire transmission line worked well on 80 thru 17 meters.

The 50 foot (15m) long doublet was supported at the center with 3 pieces of 5 ft long TV mast. And the ends of the antenna were supported with 12 foot long, telescoping aluminum painters poles.

73 de NG9D

Sunday, August 15, 2010

Simple QRP Doublet Antenna

Here is the antenna and feed line I made this weekend. It is designed to be used with an ATU for portable QRP use on 20, 30 and 40 meters. DO NOT USE THIS ANTENNA NEAR OVERHEAD POWER LINES. The doublet and feed line are made from two pieces of wire, each 75 feet long. 25 feet of each wire forms the radiator, and 50 feet of each wire forms the feed line.

There are no mechanical or soldered connections between the feed line and antenna since each side is one continuous piece of wire. At the center of the doublet, I used a couple wraps of plastic electrical tape to hold the insulated wires together.

The parallel feed line is simply the insulated wire taped together at 2'-6" intervals and runs down the mast. There is 50 feet of feed line. If I want to make the doublet longer, all I need to do is un tape the center of it and re-tape it at the selected length. For example, I could make the doublet 100 feet long and the remaining parallel feed line would then be 25 feet long. No cutting or soldering of the wire.

The wire is the 20 gage underground dog fence wire. The insulation is UV resistant HDPE. Since the PFR-3 has a tuner, I figured it would load on all three bands, which it did. I got a good match (dark SWR LED) on all bands and made a couple good contacts, on 40 and 30m.

No, the feed line conductors do not use spacers and there is not an intentional air gap between them, and so it likely does have some slightly greater attenuation than a traditional open-wire feed line due to the dielectric properties of the HDPE insulation and closely spaced conductors. But as far as I could tell from reading, the maximum attenuation would be no more than say 4db per 100 feet on 14 MHz, and less on 10 or 7MHz. Since the feed line is 50 feet long, the maximum signal penalty would be about -2db (maybe -1db on 40m) and so a useable signal to noise ratio can easily be maintained at the receiver/transmitter.

The first contact on 40 meters using this antenna was with NW3DC, Washington, D.C. (610 miles). My first contact using this antenna on 30 meters was W4JFR/Jim in Troy, Alabama, a distance of 690 miles from my statiion.

The impedance of the feed line might be on the order of 100 to 150 ohms, but with the tuner being able to match the line, apparently most of the RF is going to the antenna. I was going to make the feed line twisted, but then realized I would have more flexibility with the incrementally taped feed line, and I couldn't think of a reason that local/random "imperfections" of the line would make any practical difference.

The support is a piece of PVC with a short metal extension at the top and is about 18 feet tall. The ends of the antenna droop down to tree branches within reach from ground. With 50 feet of feed line, I had to route all the excess on the handrail of the deck and would trim it to length for a permanent installation, but in the spirit of experimentation I will keep it this size for now so I can add and subtract length to the doublet for fun.

Boards Done

The yard game is finished. Now back to ham radio antenna construction!

Wednesday, August 11, 2010

Fun Yard Game

I am building a "surprise" gift for a friend's birthday. It is a game called bean bag toss, or bags and boards... or simply "bags". I have finished building the boards and painting with acrylic semi-gloss paint. Now comes the fun part, painting the Blackhawks Logo!