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Old 19-Mar-2017, 1:28 PM   #1
Billiam
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4 bay antenna question

In my current home I have been using a Super G 1483 8 bay. Works well. But it is probably overkill for my situation and better suited to receiving Deep Fringe signals. This is probably the case for any 8 bay as long as I use the preamp.

http://www.tvfool.com/?option=com_wr...e6a4c725d89c82

I'm receiving every channel down to Ch. 26. Happy with that. Using a RCA pre amp I am getting pretty good signals of about 20 db snr readings on the TV SS meter.

I'd like to use a 4 bay instead because then I will be able to add a Delhi VIP 302 VHF antenna to use for Dxing and FM. Will mount both antennas on a rotor. Have limited space and can't really use a Yagi style antenna or large UNF/VHF either. Have those sitting in the cellar when the day comes that I have a larger property and house. If I have to mount them on the chimney and remove them from the current location I definitely have to use small antennas due to tree limb issues and because chimney's can't really handle large antennas.

According to the repack info I am seeing most of the Dayton channels I want to receive (all in red on the report) will be in the 30 to 36 channel range. With that in mind, and using a preamp which 4 bay has the best reception of channels in that range? Ch. 45 likely won't come in right now but maybe after it changes to Ch. 36 in a few years I will have a shot at it.

And, would I be better off trying a different preamp than the RCA? It is not overloading at all but I think I've read there are other preamps available that offer a little more gain in strong signal areas while not prone to overload.

Any suggestions?
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Old 19-Mar-2017, 2:56 PM   #2
rabbit73
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I don't think you can do any better. You need the narrower beamwidth of the 8-bay antenna to separate the weak signals from the strong local signals that are only about 12 degrees away in azimuth.
Quote:
most of the Dayton channels I want to receive (all in red on the report) will be in the 30 to 36 channel range. With that in mind, and using a preamp which 4 bay has the best reception of channels in that range?
Antennas Direct DB4e.
Quote:
And, would I be better off trying a different preamp than the RCA? It is not overloading at all
I'm surprised that it isn't overloading; according to your report, the preamp AND your tuner should be overloading. Maybe the trees are making the signals weaker.
Quote:
I think I've read there are other preamps available that offer a little more gain in strong signal areas while not prone to overload.
Those two factors are mutually exclusive. You can have more resistance to overload with less gain or you can have more gain with less resistance to overload, but you can't have more gain with more resistance to overload.

The Antennas Direct Juice preamp has more resistance to overload.

According to your report, WCPO has a signal power of -12.0 dBm and WRGT has a signal power of -91.6 dBm, for a signal dynamic range of 79.6 dB. To that, you must add the minimum required SNR of 16 dB for the weakest signals, which gives a SFDR (Spurious Free Dynamic Range) of 95.6 dB, which is impossible. The best preamp with gain has a SFDR of 81.7 dB. The Mini Circuits ZHL1010 has a SFDR of 92.2 dB, but it only has a gain of 10.4 dB.

If you think your idea will work, why don't you try it?
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Last edited by rabbit73; 19-Mar-2017 at 3:11 PM.
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Old 19-Mar-2017, 4:41 PM   #3
Tower Guy
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Where is the repack info for Dayton available?
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Old 19-Mar-2017, 6:44 PM   #4
Billiam
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Quote:
Originally Posted by Tower Guy View Post
Where is the repack info for Dayton available?
Saw it posted on the AVS.com Cincinnati HDTV OTA board. Page 498 I believe.
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Old 19-Mar-2017, 6:53 PM   #5
Billiam
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I also have a U4000 from Antennacraft. Worked pretty well and in fact I was able to receive 2, 7 and 22 from Dayton reliably with it. Only problem was I needed to move the antenna up or down a foot to receive either 2 or 7 adequately. However, that was when the antenna was in a previous location. After moving the setup 10 feet further east and installing the Super G 1483 suddenly I gained Ch. 26 and also reliable reception of 2 and 7 without having to move the antenna up or down a foot. Makes me think if I stacked a couple of 4 bays it would do what I need it to. Or a rotor which I will need for DX purposes and to likely get 2 or 7 reliably will solve the issue.

I probably should do a test with the U4000 at the current spot before buying another 4 bay. While the U4000 is now my travel antenna at least I could get an idea if I will need to stack 4 bays at the current spot or can get by with a single 4 bay. May still try something like the CM 4248 or buy a U8000 which still seems to be available online at a couple of places.

I read the CM 4248 has a bit more gain in the 30 plus channel range vs. the DB8. DB8e will be too and heavy for me to mount at my location due to the constraints of locating the antenna where I can get the Dayton signals. If I didn't need a rotor I would give it a shot. Best to stick with a 4 bay or the CM 4248 or U8000 both of which weigh at least a couple lbs. less than the DB8e.


Quote:
Originally Posted by rabbit73 View Post
I don't think you can do any better. You need the narrower beamwidth of the 8-bay antenna to separate the weak signals from the strong local signals that are only about 12 degrees away in azimuth.
Antennas Direct DB4e.
I'm surprised that it isn't overloading; according to your report, the preamp AND your tuner should be overloading. Maybe the trees are making the signals weaker.
Those two factors are mutually exclusive. You can have more resistance to overload with less gain or you can have more gain with less resistance to overload, but you can't have more gain with more resistance to overload.

The Antennas Direct Juice preamp has more resistance to overload.

According to your report, WCPO has a signal power of -12.0 dBm and WRGT has a signal power of -91.6 dBm, for a signal dynamic range of 79.6 dB. To that, you must add the minimum required SNR of 16 dB for the weakest signals, which gives a SFDR (Spurious Free Dynamic Range) of 95.6 dB, which is impossible. The best preamp with gain has a SFDR of 81.7 dB. The Mini Circuits ZHL1010 has a SFDR of 92.2 dB, but it only has a gain of 10.4 dB.

If you think your idea will work, why don't you try it?
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Old 19-Mar-2017, 9:16 PM   #6
Billiam
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Rabbit73. What is your opinion of the Winegard LN-100 pre amp? Looks like it has a very low noise floor and sufficient gain to work at my location.
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Old 19-Mar-2017, 11:51 PM   #7
ADTech
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The LNA100 is not a preamp, it is a line amp.
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Old 20-Mar-2017, 1:01 AM   #8
Billiam
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Quote:
Originally Posted by ADTech View Post
The LNA100 is not a preamp, it is a line amp.
Never used one of these before. My guess is that is best suited for multiple TV's then.
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Old 20-Mar-2017, 2:16 AM   #9
ADTech
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It's best used for indoor antennas.
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Old 20-Mar-2017, 11:50 AM   #10
Billiam
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Thanks AD Tech.
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Old 20-Mar-2017, 4:58 PM   #11
rickbb
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Quote:
Originally Posted by Billiam View Post
Never used one of these before. My guess is that is best suited for multiple TV's then.
I use one at the end of a long run, (100+ feet), and just before a splitter. Made a useless reception end point work just like being at the antenna.
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Old 20-Mar-2017, 6:24 PM   #12
ADTech
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Quote:
Originally Posted by rickbb View Post
I use one at the end of a long run, (100+ feet), and just before a splitter. Made a useless reception end point work just like being at the antenna.
Yep, that describes its application as a line amp that happens to be indoors. Best performance will be achieved with the amp as close to the antenna as is possible, that prevents otherwise avoidable increase in system noise figure.
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