tv antenna

   / tv antenna #121  
People devote their entire lives to the study of antennas and transmission lines. Like any other science, there is nothing simple about it.

WOW really, didn't know that. I didn't have that much time, only had one month to get an antenna working, would of finished 3 weeks ahead of schedule if I would of stayed with the first smaller antenna instead of mess around with 2 bigger ones, now I have a big $240.00 antenna hanging upstairs in the garage. But atleast I get the channels I wanted, maybe when I get a minute, might do an auto scan for tv channels see what I get.
 
   / tv antenna #122  
People devote their entire lives to the study of antennas and transmission lines. Like any other science, there is nothing simple about it.
True. I admire those specialists.


From the casual consumer point of view - choosing an antenna is like blundering around in the dark. It takes a lot of reading to find honest, informed, relevant comparisons between available models. (as illustrated in this thread!).

Then installing an antenna, choosing a mount location and attaining optimum height - is about like figuring the proper tail for a kite. Try this, try that, wonder if you are approaching or departing from optimum.

Several hundred $ of test gear would probably improve the odds of determining optimum location but who has that, aside from maybe dedicated ham radio hobbyists. I don't think the homeowner can rent such gear, or would know how to use it, for his once in a decade antenna replacement.

The last straw was buying a current-generation TV and discovering it can't remember selected channels when you rotate the antenna and do a second channel search. My Channelmaster digital converter and every TV I've had in the past could do that, I assumed any TV could.

I've been playing around with fringe FM and then TV reception for several decades but the conversion to digital TV was the end of any success. I'm stuck with college-campus PBS (nearly all cooking shows and free international news from Japan, Germany etc) plus a few channels of telenovellas, shopping, or old I Love Lucy episodes hosting overwhelming ads.

Bah. 55 miles north of a world-class city (SF) and no national network channels beyond PBS-lite and Univision. Before the digital conversion, a 30 ft mast and rotator was sufficient to see San Francisco and also the Walnut Grove antenna cluster over in the Valley that serves Sacramento/Stockton. Now - nothing.
 
   / tv antenna #123  
That FM trap must be the only reason why my bigger antennas didn't work, I thought an antenna was an antenna just stick it up in the air and that's it.


No, no , no. The antenna needs to be a channel 7-51 to reduce overloading from FM signals and a FM trap to null the FM signals that do make it down the coax from the antenna.
FM broadcast signals will completely pooch an otherwise first class tv antenna system.
 
   / tv antenna #124  
Lets go over a few basic concepts as simple as I can make it.

What is an antenna? (remember I am going to make it very basic.) it is a chunk of wire or other metal (aluminum often) that collects Radio Frequency (henceforth RF) energy and sends it down some kind of transmission line (many different types, but coax is common) These signals pop out at the other end as very small amounts of electrical energy. Your receiver is designed to match the transmission line and accept this energy into its first input stage. Think of this as the receptionist desk at at office building. See I told you I was going to make this simple..

BUT.. here is where some problems come in.. RF energy from all sorts of transmitters on the earth MAY be pumping energy into our antenna. True, on VHF and UHF and higher frequencies, a lot of transmitters on earth (and outer space for that matter) may or may not be able to reach our antenna due to the way that radio signals travel over the earth, and the upper frequencies often don't propagate (travel) so very far. Sometimes :) Notice I use a lot of weasel words, like sometimes.. Because sure as I state something for a fact there is something else that make that fact not always true.

But anyway. even on VHF and up there is still a heck of a lot of energy hitting our antenna. Now the antenna itself acts in a limited way due to the sizes we make the antenna, to reduce some of the signals we are not interested in putting into our receiver . So some frequency' (channels if you like that better) will require different sizes of antennas to be what we call resonant. Resonant means the natural frequency that this antenna offers the least amount of "resistance" to passing on to the receiver.. Remember I am making this as simple as I can. So when some says you need an antenna optimized for a certain group of channels, it will allow those signals to be "picked up" easily and may offer some rejection to some other frequencies that we are not interested in.

Now back to that receptionist at the front desk.. Our receiver's "front end" which may be an amplifier stage or maybe just a mixer. But in any case, our little receptionist can only handle so much RF hitting her desk all at the same time. If you hit her with too much, she goes into "overload" and cant cope with all of this and just lays down and produces garbage for the next stage in the receiver. We call this non linear operation. But you can imagine the receptionist laying back in her chair with her tongue hanging out and screaming.

Now a little bit about FM radio signals. Like TV signals, they are darn strong, Lots of high powered transmitters on real tall towers to have coverage to mobile antennas that are little bitty to fit on mobiles. So sometimes these FM transmitters whose signals we pickup on or TV antennas as unwanted signals. We need some way to keep these "big signals" from coming down our transmission lines and overloading our little first stage receptionist.

An FM trap is a type of resonant circuit that blocks these signals from coming to our receptionist desk and making her tongue hang out and do all that screaming. So if our receptionist is happy with the amount of RF energy coming in and can stay in a linear mode of operation Then she can pass good information on to the next stage to keep weeding out all these signals and paring it down to the one signal we want to hear/see and decode it and present it to the end user. Thats our eyes and ears.

OK, so I have hit the high points... any questions?:)
 
   / tv antenna #125  
KOua, That's a lot of intake for someone in my pay grade, seeing how I'm from another country, lets recap and see if I got it or am I going backwards

Antennacraft HBU55> (UHF Range: 60+ Miles (Ch. 14 - 69) (VHF High Range: 100 Miles (Ch. 7 - 13)<<This on my garage now, and it works. and points towards Portland-ish.

Winegard HD 8200U> (Range: 65 miles, it pulls in channels 2 to 69).<<Next I tried this, didn't work, but was able to take it back to Homedepot, Yea!

Antennacratf HD1850> (UHF Range: 60+ Miles (Ch. 14 - 69) (VHF Low Range: 100+ Miles (Ch. 2 - 6) (VHF High Range: 100+ Miles (Ch. 7 - 13)<<I tried this one and didn't work and still have it, Boo hoo...

Winegard HD 7084P) (Lo band VHF/Hi band VHF/UHF/HD/FM, RANGE 60 TO 80 MILES +Range: <<No channels listed, odd-ish. But it's on my house from last year and it works, points towards Bangor and both antennas are on a Channel Master pre-amp 7777

This only took 1 hour to look all this up as simple as I know how, so guys and gals, Riddle me this, in laymen's terms WHY<is it this FM Trap thing or not???????????
 
   / tv antenna #126  
Without hooking up your coax to a portable field strength meter it is hard for me to tell 1500 miles away why your installation did not work.. previously I mentioned double checking and or substitution of any baluns and coax and its connections. Coax can be checked with an ohm meter and and aligator clip on the far end to check continuity. Baluns not so easy.. best just substitute. Also double check antenna connections and deployment of its elements. When I was doing TV antenna installations professionally (many many years ago) we had the portable field strength meter and it was very very handy to figure things out and also to get antennas pointed correctly. Just hook a short piece of coax up to the meter from the antenna and watch the meter as you rotated the antenna by hand and lock it down when satisfied.
Also are we sure your splitter/combiner is passing signals? have you tried hooking your tv up to just the antenna that does not work and pointing it around to determing how things are working.?

Amazon.com: Solid Signal Digiair Pro ATSC TV Antenna Signal Meter Spectrum Analyzer (DIGIAIR-PRO-ATSC): Electronics
 
   / tv antenna #127  
Bah. 55 miles north of a world-class city (SF) and no national network channels beyond PBS-lite and Univision. Before the digital conversion, a 30 ft mast and rotator was sufficient to see San Francisco and also the Walnut Grove antenna cluster over in the Valley that serves Sacramento/Stockton. Now - nothing.

We took a hit too...

Had a great Monterey Station that often carried the blacked out pro sports televised games... gone in a poof!

On a separate note... sure sounds like a war zone tonight here in Oakland... even with a total and 100% zero tolerance outright ban on sale, possession or use of Fire Works... not to mention the vegetation is tinder dry...
 
   / tv antenna #128  
We took a hit too...

Had a great Monterey Station that often carried the blacked out pro sports televised games... gone in a poof!

On a separate note... sure sounds like a war zone tonight here in Oakland... even with a total and 100% zero tolerance outright ban on sale, possession or use of Fire Works... not to mention the vegetation is tinder dry...

Sounds like a war zone here too. I went out earlier and added to the noise with my .44 magnum and a .45acp auto. i like to sling lead along with the noise.:D vegetation and ground is very wet after some good rain finally.
 
   / tv antenna #129  
   / tv antenna #130  
I want it! But at $300+ for (hopefully) one time use ... I'll never buy one.

Is there any cheaper Harbor Freight - quality similar device available, or some sort of kit with its signal interpreted on your phone?

If not there needs to be one... hmmm just an RF deck and a bluetooth connection to your phone running an app. Good idea..
 

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