# multidirectional



## satcrazy (Mar 16, 2011)

Just read a post in the general sat discussion where this person used a antenna in the attic, and a multi directional seawatch 20" marine antenna.[ seperate from the other, I believe] Picking up 40 or more channels at night.

This is new to me. Can a marine antenna be that good? Why not use these for more OTA viewing?

My antenna is also in the attic [ 3rd floor] and is just OK. It is positioned to pick up 75% of what is local. I have to move it to pick up the others, but then I lose the first 75%.

Anybody know about these multidirectionals?


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## RBA (Apr 14, 2013)

You can buy omnidirectional antennas from about $20. Problem is quality and multiple signals can lead to interference with other channels. Marine antennas are usually designed for a saltwater environment better construction and more expensive.


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## gov (Jan 11, 2013)

In my area (between two DMAs 180 degrees apart) 2 bedspring 4-bay antennas (connected via HF splitter/combiner) works pretty well except for one VHF ATSC channel (phoeey!) 

YRMV.

:righton:


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## KyL416 (Nov 11, 2005)

Yeah with the shrinking of the TV band from 2 - 69 to 2 - 51 it's very possible to have signals on the same or adjacent channel coming from different directions.

Put your address into TVFool.com to see if any of the channels you watch regularly are flagged with the cochannel and adjacent warning icon. Your location near the great lakes might make it even worse since the lakes are known to carry signals from a long distance.


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## SayWhat? (Jun 7, 2009)

satcrazy said:


> Just read a post in the general sat discussion where this person used a antenna in the attic, and a multi directional seawatch 20" marine antenna.[ seperate from the other, I believe] Picking up 40 or more channels at night.
> 
> Can a marine antenna be that good? Why not use these for more OTA viewing?


It really shouldn't be about 'marine' or not. It's about the frequency range and what channels the area TV stations are using. Any VHF-HI/UHF antenna should work unless the stations are using the upper channels: Then you would need something capable of getting 800Mhz.

https://en.wikipedia.org/wiki/North_American_broadcast_television_frequencies


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## gov (Jan 11, 2013)

I've also noted with the 2 antenna arrays I like using, if I disconnect one antenna, it is surprising (to me anyhow) that one antenna will frequently catch 2/3 (or so) of the channels the other antenna is 'supposed' to receive. With the 2 DMAs so close to 180 degrees apart, a considerable number of items in the landscape can be a reflector and put signals back on the other antenna. In the bad old NTSC days, that meant wicked ghosting (even with 2 antennas) but ATSC if presented with reflections, apparently, if one is consistently a few dBs stronger than the rest, it all still works just fine.


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## kenglish (Oct 2, 2004)

Looking at the website info, the Seawatch antenna has to be operated on 12-volts DC (which you might expect on a small boat).
It also looks like it would be a UHF-only antenna, due to the size.
Omni-directional antennas are always going to be a "hit or miss" situation, since they are so subject to multi-path distortion, as well as having no way to "focus" in the direction of the transmitters and away from nearby interference. What works today, may be bad tomorrow.

If all your channels are in the same general direction, just go with a standard VHF+UHF antenna (the "old-fashioned" looking ones).
If they are in different directions, and you only have one TV to connect to it, use a rotor. Sometimes, even having two TVs and two rotors might be easier, cheaper and more reliable.
The Seawatch line looks to be about $120 to $180 each.

(As an aside....there was once a standard for a Smart-antenna and the interface for it inside the tuner or TV. It was about the size of those "flying-saucer" antennas, but included some dipole attachments that stuck out all around. Those could be controlled by the TV's own tuner. I don't know why they didn't also make a version that had four separate outputs, which would have been ideal for attic or balcony.)


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## grunes (Nov 13, 2013)

I think the O.P. was referring to my posts. Yes, the attic antenna was the omni-directional Marine antenna. And no, 30 or 40 channels isn't all that good here (College Park, MD, close to Washington, DC, a major urban area) - TVfool.com lists a lot of channels I don't get, and I was counting sub-channels of the same broadcast station (e.g., 4-1, 4-2, 4-3...), most of which TVfool leaves out. I presume I would get more channels if the antenna was not in the attic and was higher up, or if I used a directional antenna. I think the maximum range of that antenna is less than 45 miles - not nearly as good as a good directional antenna.

I used that antenna because I already had it, so the test cost me nothing. What it showed me was that I can get all the major broadcast networks, even with a less-than-optimal antenna. If you don't live in a major metropolitan area, or are surrounded by tall buildings, perhaps that won't be true for you.

It is easier to deal with an omni-directional antenna. E.g., you don't need a lot of fancy circuitry that rotates the antenna on schedule to use a video recorder. 

Marine antennas have two advantages, for which you must pay a lot extra - corrosion resistance, and an internal ground plane. As best as I can figure out neither will increase the initial number of channels received, though I suppose that if you get corrosion, that could reduce the number of channels received. 

For attic use, I suspect there will be little corrosion, so corrosion resistance doesn't matter. If you are worried about corrosion, an electrician tells me to make your electrical connection more weather-proof by twisting the wires together if connecting two wires, using ILSCO De-Ox paste (not Ideal Noalox - it's for aluminum wires) on the connector and/or wires, surround the connected ends with shrink wrap tubing (and heat shrink it), tap screw-on connections with a hammer after tightening, re-tighten 24 hours later, and make sure you double-nut all screw-on connectors so they don't come loose. If you are really worried, surround your antenna with a radome.

For your house, you've got a real ground plane, so you don't need an internal ground plane. And someone on this board claimed ground planes aren't useful for most TV channels, though I don't know enough to confirm that. 

So most people don't bother getting a marine antenna if they don't have a boat, or live right next to salt water.


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## satcrazy (Mar 16, 2011)

Thanks for the replies.

Yup, Canada is right across the lake, and my father had a large old fashioned antenna [ no cable then] with a CM rotator. We used to pick up several [ Canadian] during the day and more at night. Toronto was ahead of it's time then.

I can't go on the roof here, so I have to settle for attic . When I did homework for digital transition, I kept reading a UHF antenna was what was the best, so I got a cheaper R Shack model.

Is there any chance I would ever be able to pick up canada again without a roof mount? I guess it would have to rotate, since the tv stations are south of me, and canada is north. If it gets too pricey , I'll have to wait until I need to cut the cord.

I'm not sure what antenna would work, or if I should just give up on the idea.


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## KyL416 (Nov 11, 2005)

Put your address into TVFool.com to see what comes up.

I'm not sure where in Northwest PA you are, but I put in Erie as a quick check, the NBC affiliate is on VHF 12. There's some Buffalo, Toronto and Cleveland stations on VHF that might be available to you too. With a specific address you'll get a much better idea.

There's also a lot of co-channel interference in the area coming across the lakes which might make it hard to pull in distant stations with anything but a directional antenna. The lakes give a great boost though, so it might be possible to get them in the attic if there are no major obstructions between you and the lakes.


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## grunes (Nov 13, 2013)

kenglish said:


> Looking at the website info, the Seawatch antenna has to be operated on 12-volts DC (which you might expect on a small boat).
> It also looks like it would be a UHF-only antenna, due to the size.


BTW I tested mine without the pre-amp, which, as I recall, had gone bad years ago. I think it came with a 120VAC adaptor. Besides, the cable was only 25' long, and wasn't split, and some of my channels come in quite strong. As best I understand it, with most antenna amplifiers, if any channels come in strong, a pre-amp won't do any good, because the AGC is wide-band, so I didn't replace it.

It works with UHF, VHF channels, though I don't know if it was designed for both. It was a Shakespeare Seawatch 2030. I think Shakespeare Seawatch antennas are made by Winegard, which sells non-marine antennas too.

The Shakespeare website doesn't seem to be working well right now - links to documentation don't work. Maybe they are out of business?

The O.P. says he/she can't go up on the roof.

Another alternative is to mount a mast to the side of your home. I'm not sure you really want an outdoor antenna in the middle of your roof anyway; the electrician told me it is safer to let lightning strike currents follow a straight line to ground, and that there are National Electric code rules regarding that.

You don't have to cut the cord for a test. Duct tape whatever antenna you've got to the top of a ladder next to your house, in nice weather, when lightning is unlikely. Then run a decent coax cable, as short as you can make work, to your TV, and aim it where TVfool.com says the stations you want are located.


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## satcrazy (Mar 16, 2011)

KyL416 said:


> Put your address into TVFool.com to see what comes up.
> 
> I'm not sure where in Northwest PA you are, but I put in Erie as a quick check, the NBC affiliate is on VHF 12. There's some Buffalo, Toronto and Cleveland stations on VHF that might be available to you too. With a specific address you'll get a much better idea.
> 
> There's also a lot of co-channel interference in the area coming across the lakes which might make it hard to pull in distant stations with anything but a directional antenna. The lakes give a great boost though, so it might be possible to get them in the attic if there are no major obstructions between you and the lakes.


Yes, Erie. I will look at tv fool. Thanks.



grunes said:


> BTW I tested mine without the pre-amp, which, as I recall, had gone bad years ago. I think it came with a 120VAC adaptor. Besides, the cable was only 25' long, and wasn't split, and some of my channels come in quite strong. As best I understand it, with most antenna amplifiers, if any channels come in strong, a pre-amp won't do any good, because the AGC is wide-band, so I didn't replace it.
> 
> It works with UHF, VHF channels, though I don't know if it was designed for both. It was a Shakespeare Seawatch 2030. I think Shakespeare Seawatch antennas are made by Winegard, which sells non-marine antennas too.
> 
> ...


Duct Tape,LOL I have plenty.
thanks..


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