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Friday, August 16, 2019

NASA Image of the Day: Hubble’s Portrait of Star’s Gaseous Glow

August 16, 2019 - Although it looks more like an entity seen through a microscope than a telescope, this rounded object, named NGC 2022, is certainly not algae or tiny, blobby jellyfish. Instead, it is a vast orb of gas in space, cast off by an aging star. via NASA https://ift.tt/33DMs3i

Thursday, August 15, 2019

NASA Image of the Day: NASA and SpaceX: Dragon Crew Extraction Rehearsal

August 15, 2019 - On August 13, 2019, NASA astronauts Doug Hurley, left, and Bob Behnken continue to work with teams from NASA and SpaceX to rehearse crew extraction from SpaceX’s Crew Dragon. via NASA https://ift.tt/2z2gPSN

Monday, August 12, 2019

HDTV Antenna Project - Finished!

My bow tie HDTV Antenna!

A few days ago I posted about working on an HDTV antenna project I'd seen on the internet and wanted to try it. Finally, I decided to get going with it after scrounging for the parts needed. 

I found some parts around the house and picked up an item or two from local stores. Some of the parts are not as easy to come by these days.

Here's the parts I used:
  • 1 2x4 Piece of wood
  • 4 wire coat hangers 
  • 8 #10 x 1" screws 
  • 8 washers
  • #10 gauge wire (Purchased from Rural King)
  • 1 matching transformer/coax connection (Purchased from Radio Shack)
  • 6" of cable TV coax 
Most of this stuff is lying around the house, but the transformer (also known as a "balun" is by far the hardest part to locate these days. I found some on Amazon that are en route, but yesterday I went to nearby West Town Mall and there is a hole-in-the-wall Radio Shack that surprisingly had it available. It was the most expensive piece to purchase. While the part from Amazon was $3, Radio Shack had it for $11! I didn't want to pay that much but after checking Hoem Depot and Walmart and turning up empty, I wanted to finish this project by the end of the weekend and needed it, so I went ahead and paid for it. I asked for 3' of TV cable coax and they were going to sell it to me for $16! I politely declined and found some after a brief search in my broom closet.

I used the instructions found here for a reference guide. 

Re-positioned to pick up
even more channels
I found a leftover 2 X 4 in my backyard and cleaned it up. After measuring and drilling the holes that would hold the coat hanger wires, I then measured and cut one side of a wire coat hanger to the required 14" length. I marked the necessary length using the curve of the lower part of the hanger to become the base of the "V" shape so very little bending would be needed to get the hangar in the necessary form. I then used the piece that was cut from the first hangar as a "template" for the remaining hangars.

While cutting one of the hangars, it was extremely brittle and when I attempted to bend the base of the "V" it snapped. The other side of the hanger behaved the same way. It was the same type of hangar as the others but for some reason was way more brittle. Fortunately another hanger was available. All of the hangers were coated in plastic, so I took a lighter and used it to burn through the center, exposing the metal to make the necessary contact. 

The exposed metal of the hangar was connected to the screw once it was set, and the #10 wire was cut through with wire strippers in order to expose the wire and make contact with the screws as well. I tried to solder the balun but the prongs were not making a good connection, so I clipped them off and stripped the wire 1/4" and was able to easily solder to the middle of the wire. The washers were used to help keep all of the parts together where they were connected at the base of the "V"s.

It took about an hour to piece all of the parts together and align. I stapled the prongs of the matching transformer to reduce stress on the soldered connection.

The Old Rabbit Ears
I opted to not use a metal backing for the reflector as I felt that it wasn't needed at this time. I may test it out later but don't think it will improve the performance.  

The End Result

After plugging the 6' coax in to the antenna I then took it upstairs to the living room TV. Prior to this antenna, I had a set of good ole' fashioned rabbit ears for the antenna. While it worked for what I needed, I would have to occasionally need to re-position the antenna and use the tuners on the rabbit ears in order to get better reception. I had about 25 channels the rabbit ears received with adjustments needed if I changed channels on several stations. I even used a "signal booster" to try and get additional channels to no avail.

Full Disclosure: I live about 5 miles from Sharp's Ridge, where most of the transmitters for the local channels reside, so tuning in to the "big three" are not difficult, even on rabbit ear antennas. However, two stations in particular (The Fox and CW affiliates) are located elsewhere and are often harder to tune in. The Fox station could be picked up by the rabbit ears after some fine tuning, however the CW affiliate was not received no matter what I attempted.

Rabbit Ears reception
As soon as I plugged in the new antenna, all of the channels were crystal clear (no pixelation or dithering that can occur on a DTV signal) and no fine tuning was needed.

I performed a re-scan of all the channels I could pick up and was amazed that I had 6 new stations on the list. The CW affiliate (4 stations) and a low-power religious channel with 2 stations (HD/SD) were now on the list.

HDTV Project reception
The best thing was I didn't have to get up and retune any of the channels! The reception was perfect. I moved around the living room and no change was noticeable on the TV.

After I scanned for new channels, I decided to check a couple of things out on the old rabbit ears. I had a "signal booster" that was plugged in to the AC and was supposedly designed to boost the reception of any antenna, SD or HD. I didn't really notice a difference in reception but kept them plugged in. After plugging the rabbit ears back in I went back to 29 stations received. When I removed the "signal booster", it actually increased to 31 stations! When I plugged my HD antenna through the "booster" It reduced the number of stations scanned to 33. The damned thing was an attenuator in disguise!!! I will probably throw that in the garbage. I doubt it's good enough for Goodwill at this point...

Signal booster, residing
on a throne of lies!
While Knoxville is not a "major" television market, it does offer many stations over-the-air for those wishing to "cut the cord" and reduce their cable costs. I cut the cord over 4 years ago and have not missed it. Many of the channels I can get through over-the-air TV or online via streaming. I do have services like Hulu, Netflix, and Amazon Prime as well as Sling TV, but I'm still paying less than half what I was paying with cable TV, and that was without the "Premium Channels" like HBO/Showtime. An antenna such as this helps with television selection.

Overall, not bad for less than $20 of parts purchased, parts lying around, and an hour's worth of time to piece it all together. Even if you had to purchase all of the equipment, you're looking at $25 at the most. Compared to the price of many commercial antennas, this has impressed me the most. I will recommend going to a hamfest or other electronics parts store for the coax connector to the antenna. That will cut the cost even further.

When I get the $3 coax connector I purchased from Amazon (due to arrive next month, presumably from China) I will construct another one of these and use it for my mother's TV so that she can enjoy more over-the-air channels as well.

Wednesday, August 7, 2019

He's turned to the Dark Side!!!

In nearby Carter County, a warrant has been issued for Luke Sky Walker.

Reports are he was last seen with a cargo smuggler and Bigfoot, both famous for making the Kessel Run in less than 12 parsecs...

He's been in trouble with the law before, and got the attention of the REAL Luke Skywalker himself:

Tuesday, August 6, 2019

DIY HDTV antenna

I have begun a project to build an HDTV antenna using a 2x4, wire coat hangers, and nuts and bolts from wherever I can find in the house.

I'm scrounging around for copper wire (buying from the store is EXPENSIVE!) and hoping to have all the necessary parts later this week. 

Part of the project requires a BALUN for antenna impedance matching. 20 years ago they were a dime a dozen and everywhere. Now, not so much.

While the project calls for a metal screen on the back to act as a reflector, I'm not going to add one at this time. I want to see how this performs before tweaking it further.

Stay tuned! Get it???