Skin Effect of an Antenna?

[gary350]

I am rebuilding my TV antenna after 5 years in the weather, screws, washers, connectors, are rusted. It use to work great it received 44 channels crystal clear 40 miles away. I have been having a little trouble with the antenna not picking up a good signal on channel 4 this week. I have 2 identical antennas one aimed at magnetic 308 degrees Nashville and one aimed at magnet 359 degrees Lebanon for 6 extra TV stations in a different town, both antennas give me 50 TV channels.

I have 200 feet of #10 copper I wont need to buy wire and soldering all connections instead of screws with clamps and flat washers like factory antennas. Since we are dealing with very small voltage and small current I wonder if less wire resistance and less skin effect will make a better antenna?

 

[ronsimpson]

I have 2 identical antennas

How do you mix the two signals together?

trouble with the antenna not picking up a good signal on channel 4

I think this small antenna does not have good gain at channel 4. (low frequency)

 

[MikeMl]

That antenna is not designed to receive "over-the-air" Channel 4 (66-72MHz). It works only for UHF channels (above 470MHz)

Biggest problem with outside antennas is mixing dissimilar metals. Use only stainless steel hardware with aluminum elements. Coat interfaces with **broken link removed**

 

[4pyros]

I am replacing the small #20 wire with #14 copper

Was the small #20 stranded
Is the #14 solid
Skin effect will have a large impact on your interconnect wires
You want more skin for less resistance at higher frequencies.

 

[gary350]

TVFool.com shows channel 4 is real channel 10 the signal is 44 db. real frequency is 193.25 MHz.

Channel 8 is real channel 8 with 47 db and 181.25 MHz I have not trouble with this channel.

Channel 5 with 38 db is real channel 50 that is 691.75 MHZ it comes in crystal clear.

Both antennas have a balum with 18" coax to T combiner and 50 ft of coax to the TV.

Each TV has its own antenna. One antenna is Nashville the other antenna is Lebanon.

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http://www.antennahacks.com/comparisons/cm4228_vs_db8_vs_hd8800.htm

 

[nsaspook]

I would also check the coax connections/cables for water intrusion. Most of the RG-59 type cables have a foam dielectric that breaks down over the years unless perfectly sealed and will wick moisture slowly down the coax causing internal corrosion and sometimes strange selective RF losses.

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[dr pepper]

Skin effect is an issue with things like switching transformers where currents are high, or a transmitter.
The coax's characteristic impedance is the most important spec, and the construction of the centre conductor and centre core insulation.
Coax degrades over time so use new stuff.
Grid dipoles like yours are commonly used in areas where reflections are an issue, such as metal buildings or if the aerial is close to the ground.

 

[Nigel Goodwin]

TVFool.com shows channel 4 is real channel 10 the signal is 44 db. real frequency is 193.25 MHz.

Channel 8 is real channel 8 with 47 db and 181.25 MHz I have not trouble with this channel.

Channel 5 with 38 db is real channel 50 that is 691.75 MHZ it comes in crystal clear.

Those aerials are low gain UHF ones, used for analogue TV in areas of high ghosting - not really suitable for long distance reception or for VHF reception.

Using proper high gain aerials, for the correct frequencies, would dramatically improve your reception.

 

[gary350]

I built this TV antenna 5 years ago. It gives me 44 channels from Nashville and 6 channels from Lebanon. Weather messed it up so I rewired it last week. It has a range of 65 miles crystal clear OTA HDTV free. I use 2 chain link top rails as the 20 foot tower. All I need to do now is stand it up then run the coax to the TV. Now both TV antennas are the new improved version. The larger reflector increased signal. Space from bow ties to reflector screen was 5" now it is 6" with the added PVC pipe. I can Increase or Decrease signal by changing the screen bow tie spacing from 5" to 12" it is like tuning the antenna. Stations with a weak signal can be tuned to a much stronger signal by moving the screen out to 10". This antenna peaks at mid range and drops off a little on low and high end but signal strength on the field strength meter is 75% to 95% all the time. A 4 bay bow tie antenna works good but not in rain and bad weather but this 8 bay bow tie antenna pulls in a good strong signal it is not bothered at all by flash flood rains, snow, fog or anything. The 50 foot tall tree forest behind the house is no problem either.

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[4pyros]

I built this TV antenna 5 years ago. It gives me 44 channels from Nashville and 6 channels from Lebanon. Weather messed it up so I rewired it last week. It has a range of 65 miles crystal clear OTA HDTV free. I use 2 chain link top rails as the 20 foot tower. All I need to do now is stand it up then run the coax to the TV. Now both TV antennas are the new improved version. The larger reflector increased signal. Space from bow ties to reflector screen was 5" now it is 6" with the added PVC pipe. I can Increase or Decrease signal by changing the screen bow tie spacing from 5" to 12" it is like tuning the antenna. Stations with a weak signal can be tuned to a much stronger signal by moving the screen out to 10". This antenna peaks at mid range and drops off a little on low and high end but signal strength on the field strength meter is 75% to 95% all the time. A 4 bay bow tie antenna works good but not in rain and bad weather but this 8 bay bow tie antenna pulls in a good strong signal it is not bothered at all by flash flood rains, snow, fog or anything. The 50 foot tall tree forest behind the house is no problem either.

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Nice work!