Updated TV Antenna Thoughts

[lakngulf]

Finally made it back up to the farm to raise the antenna. Was able to get a "tooth" from the FEL tooth bar under the antenna pipe and eased it up about 5 feet. Placed a 2x4 under the pipe to hold it in place.
RESULT: Boom I was able to pick up WBRC FOX 6 from Bham.
The next two days we have BRUTAL winds, up to 30 mph gusts. The station started dropping a bit and Pixalating. But just receiving the station was more than I had before. Thought about raising the antenna more but decided to work on exact direction first.
According to the website we discussed above, Fox 6 and several other channels are at North 11 degrees from my antenna location. I downloaded an Compass App on my phone and placed another 2x4 pointing directly at North 11 degrees. Then I rotated the antenna to line with the 2x4.
Still had lots of wind, but great results. Now I have the screwdriver holding at this location.

 

[MossRoad]

Good job!

Does your TV have a signal strength meter buried in the menu somewhere? A couple of mine to. I've used that to rotat the antenna to the strongest reading with good results. Just make an initial reading. Then move the antenna clockwise an inch, record the reading, inch, reading, etc... until it goes a lot lower. Then go back to the original position and repeat counter-clockwise. You'll soon get a good indication of the highest reading. Works great.

 

[k0ua]

I was missing out on the term ERP. Went and read up a bit. Makes more sense now. I was confusing transmitter power with ERP. Man, I'm rusty.

Yep ERP (Effective Radiated Power) is another way of saying total system gain or loss. Start with the transmitter power, add in the loss of the feed-line, and add in the gain of the antenna. All feedlines have loss, The feed-lines used in high powered TV transmitters don't have a lot, but they have some, so you must figure in that loss. So less power hits the antenna than leaves the transmitter, but the TV transmitting antenna will have lots of gain. Lets say 13 dB of gain. Lets say the feed-line has 3dB of loss (or expressed another way is -3dB of gain). So overall system gain is 10dB. (13dB -3dB) if you are with me so far, lets say the actual transmitter is putting out 100,000 watts of power. So the ERP is 1,000,000 watts. Or said another way 1 megawatt.

Keep in mind 10 times the power may not do as much at the far end as you would think. It is significant but maybe not as much as some would think.

Also the path loss from the transmitter site to the receiver site can be calculated from a path loss formula, and the receiving antenna gain can be measured or looked up (good luck with the finding that figure from the manufacture though) and you can calculate the signal level dripping out of the feed-line at the TV receiver.

 

[k0ua]

To the original poster, you can't argue with success.

To California, the VHF channels refract (bend towards the earth) a bit better than UHF channels. There are many many factors that effect this.

 

[MossRoad]

Yep ERP (Effective Radiated Power) is another way of saying total system gain or loss. Start with the transmitter power, add in the loss of the feed-line, and add in the gain of the antenna. All feedlines have loss, The feed-lines used in high powered TV transmitters don't have a lot, but they have some, so you must figure in that loss. So less power hits the antenna than leaves the transmitter, but the TV transmitting antenna will have lots of gain. Lets say 13 dB of gain. Lets say the feed-line has 3dB of loss (or expressed another way is -3dB of gain). So overall system gain is 10dB. (13dB -3dB) if you are with me so far, lets say the actual transmitter is putting out 100,000 watts of power. So the ERP is 1,000,000 watts. Or said another way 1 megawatt.

Keep in mind 10 times the power may not do as much at the far end as you would think. It is significant but maybe not as much as some would think.

Also the path loss from the transmitter site to the receiver site can be calculated from a path loss formula, and the receiving antenna gain can be measured or looked up (good luck with the finding that figure from the manufacture though) and you can calculate the signal level dripping out of the feed-line at the TV receiver.

Yeah, I'm with you all the way. Good refresher course!

I have a friend that used to be the engineer at my old employer's TV and radio stations. He got retired about 15 years ago and I got retired last June. We were always meaning to give each other tours of our facilities and we ran out of time before we each got kicked out! Time flies!

 

[lakngulf]

Good job!

Does your TV have a signal strength meter buried in the menu somewhere? A couple of mine to. I've used that to rotat the antenna to the strongest reading with good results. Just make an initial reading. Then move the antenna clockwise an inch, record the reading, inch, reading, etc... until it goes a lot lower. Then go back to the original position and repeat counter-clockwise. You'll soon get a good indication of the highest reading. Works great.

I will check on that. Thanks for suggestion. I have been to menu to scan and there are lots of options so it might just be there.
When a station number displays in top right some have a 720 or so number and some have 1000 or greater. What is that?

 

[MossRoad]

I will check on that. Thanks for suggestion. I have been to menu to scan and there are lots of options so it might just be there.
When a station number displays in top right some have a 720 or so number and some have 1000 or greater. What is that?

That's the resolution of the picture. Here's a link that explains it.
HDTV resolutions - 1080p / 1080i / 720p / 480p / 480i

In a nutshell, it how many pixels are displayed across the screen. The higher the number, the better the quality of the picture.