Weird thing happening

[mattyb8562]

Hi everyone,

I built a bi directional 4 bay antenna with no reflector last year and have been happily pulling all 6 of my local channels total of 20 with the sub channels. I spent several weekends finding the best spot on my roof and pointed at every tower in a 150 mile ratios hoping to pull in a couple more channels without success. I rescan every couple weeks just to see if anything new pops up. A couple of nights ago I scanned again during a severe lightning storm and got 14 more channels 52 including all the sub channels. The farthest one is 138 miles away. Some are weak and drop out allot some are fairly strong and seem to be here to stay. So total I have scanned in 66 ota channels. I know some people are going to say I'm full of crap heck I would to I wasn't seeing it with my own eyes but it true and I have no idea why. I haven't made any changes to the antenna in a year or so. I guess my next move will be to add a reflector and a motor and see if I can lock on to some of the harder to get ones. Any thoughts on this?

[John Candle]

As the other question askers do , Do This --> http://forum.tvfool.com/showthread.php?t=4 , make a radar plot with the correct address and what the antenna height is.

[mattyb8562]

Originally Posted by John Candle

As the other question askers do , Do This --> http://forum.tvfool.com/showthread.php?t=4 , make a radar plot with the correct address and what the antenna height is.

I didn't think it was important....my bad. I wasn't really asking any specific question just was fishing for some opinions. I'll post the radar plot and additional info in the morning. Thanks for the reply.

[GroundUrMast]

You're describing atmospheric ducting, 'skip'. A phenomena resulting from layers of the atmosphere becoming ionized (electrically charged). When the conditions are right, the atmosphere can act as a duct or pipe, making a temporary path for radio waves over quite a distance.

Many TV sets and tuners don't allow you to manually tune, making it difficult to 'hunt' for weak signals. Now that your tuner has 'seen' them it is letting you tune to them... even if the signal is too weak to be reliable.

I hope you have taken reasonable precautions regarding grounding... it sounds like thunder storms may be common in your area. A properly grounded system would be far more likey to survive a nearby lightning strike than a one not properly grounded.

As JC has suggested, it would be interesting to see your TVFR.

[mattyb8562]

I was thinking it had to do with the recent storms we have had. Yes I live in the south we are very pron to severe storms. My antenna is grounded. Grounding is not optional in this neck of the woods.

Here is my plot...

http://www.tvfool.com/?option=com_wr...3e47b23559e991

I set the antenna height to 100ft on the plot just to show all the channels I am getting. It is actually about 30ft above the ground and 20ft below the tree line.

These are the channels I have scanned in real channels 28, 35, 32, 43, 8, 29, 11, 12, 13, 14, 39, 36, 24, 16, 22, 45, 51, 28, 30, 26, 31, 33, Channels not showing on the plot 33-1, 43-1 43-2 43-3 (WBBQ), 49-1. 3-1 and 21-1 are on the same rf channel 28 and swap out occasionally.

These channels were all watchable when they were scanned in. Now most are hit and mis some are dead and by no means reliable. It actually has made my home channels less reliable I'm guessing do to interference from the other signals fighting for the rf channel or virtual channel. Thanks for the in put guys.

[mattyb8562]

This is interesting. According to this Troposheric ducting forecast page i found the night I rescanned I had very good conditions for ducting. According to the color chart on the map I was in the intense area surrounded by very intense and very strong. here is the map http://www.dxinfocentre.com/tr_map/archive/3eam.jpg


http://www.dxinfocentre.com/tropo.html

[John Candle]

Yes I see with the radar report that your location has many channels that are at , finger tip reach .