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Old 2008-10-04, 01:41 PM   #406
stampeder
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Exclamation I would not do it

Quote:
Originally Posted by dandaling
Not attempting a debate on the subject but 300ohm and Stampeder should try it out before dropping an idea like this.
That's assuming we haven't tried stuff like that before, like when I mistakenly installed an attenuator instead of a filter at a lady's house back in the early 1970s... boy was she livid when her favourite shows were all grainy and snowy.

I can't speak for 300ohm, but in my case I know what works and what doesn't. In your case you find that the results are great, and that's fine. As I always say, I'm delighted when someone gets reception that satisfies their needs.

But, I won't advocated things that are known to be problematic for deteriorating the signal.
Quote:
Originally Posted by roger1818
it will add the noise of the two amplifiers to your system
Roger you are correct about it being a noise and internal reflection issue. I also agree with 300ohm that combining 2 preamped signals is in effect pairing not just the normal peaks and nulls of the antennas but actually their amplified peaks and nulls. In this case, it worked.
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Old 2008-10-06, 09:41 AM   #407
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Tentsu,
I will probably change up my configuration a bit but currently I get (with no pre-amp and just a dist amp):
2-1 (70 to 80%)
4-1 (80%)
7-1 ( 60%)
23-1 (90%)
17-1 (90%)
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Old 2008-10-09, 12:21 AM   #408
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I've built a wooden framed SBGH to try and test here in my area. The results were fantastic! It's on my roof right now, but that's not a long term option. My goal was to test it out on the roof and install a permanent one in the attic. To do that, I'll most likely follow 300 ohm's tube plans. From there I need to figure out how to properly amplify and distribute it to three different rooms on three different floors.

What I'm wondering is....

1. What amplifiers seem to be working well with SBGH's? I was thinking about a 7777 or 7778, but I wanted to check here to find out which would be the best reviewed.

2. Should I skip the pre-amp and just feed it into a distribution amp in the attic before any of the downleads to the 3 rooms? If so, does anyone have one running with an SBGH?

Any help would be greatly appretiated.
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Old 2008-10-09, 02:13 AM   #409
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Default Amplification is based on math

dialed_in, its not a matter of which preamp or amp "works best" in someone's opinion or experience on their own specific system, it is based on math in regards to the specific details of your own system regardless of whether the antenna is an SBGH or not.

First, you need to test your system without any amplification. Only then will you know if you need any or not. Install your unamplified system as planned and then let us know what happens.

If your results are not very strong, consult with us in the Reception Results thread for your area and let us help you decide on a course of action since it might be a case of something else being at issue.

If it turns out that you do require an amp of some sorts you would need to calculate how much loss your system is incurring from splitters, coax length, etc. and get a preamp that overcomes that loss. Each split costs about 3 or 4 dB of signal, and 100 feet of RG6 coax costs about 6 or 7 dB. If, for example, your system was costing you about 12dB of signal you'd want to have a preamp capable of at least 13dB boost while contributing only a very low noise level.

Don't buy a sledge hammer to put a tack in the wall.
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Old 2008-10-19, 05:49 PM   #410
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I just hooked up my CM 4228 to my Panasonic TH-42PZ77U and the signal strength on the only digital channels it is receiving (8-1 and 12-1) is in the high 40s. Is it appropriate to add a preamp/amp?

The CM 4228 is still just on my deck but will be moving to the roof which will add about 12' to the height. I'm running 25' of RG6 to a indoor splitter with 3' of RG6 going to an analog TV (awaiting a Zenith DTT901 converter) and 50' going to the Panasonic.
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Old 2008-10-19, 09:32 PM   #411
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Your maximum length of RG6 is about 90 feet, which will cost you about 5dB, so I'd say you might need to have one.

Right now with the antenna down on the deck if you put a preamp onto it and test it the reception is not very strong at this point so you'd just be amplifying noise and junk.
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Old 2008-10-20, 08:25 PM   #412
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According to my vintage Channel Master catalogue, the 0064C preamp has 17dB gain on VHF, 16dB on UHF.

Last edited by stampeder; 2008-10-20 at 11:30 PM. Reason: ALL CAPS posts are forbidden
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Old 2008-10-27, 11:56 AM   #413
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Does the Channel Master 0064C pre-amp require an A/C or D/C power supply?
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Old 2008-10-27, 01:36 PM   #414
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It comes with a power injector unit paired with the preamp unit. Are you missing the power injector?
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Old 2008-10-27, 11:08 PM   #415
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Yes. I'm missing the power injector. I know it's a paired system. What voltage does this pre-amp use?

I salvaged a 40' tower with rotor and pre-amp. Luckily I had a rotor control. The salvage site was a new owner who knew nothing about the existing system and was not interested in letting me look around. A previous pre-amp I checked out (for a neighbor) had an A/C power injector.

I already have a CM 0264DSB (with a D/C power injector) connected to my CM 3020 antenna. I've decoupled the VHF from the UHF.
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Old 2008-10-28, 01:55 AM   #416
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The CM0064 had a model CM0747 AC power injector (transformer) that output 18VDC to the preamp. You can find them from many sources, but just make sure its the proper one for the Spartan2 model line.
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Old 2008-10-28, 08:42 AM   #417
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Default Substitute A/C Power Injector

After talking to Stark Electronics on the phone, all the information I had posted is incorrect and I have deleted it.

The CM0747 is a D/C Power Injector.

Last edited by systems2000; 2008-10-28 at 09:09 AM.
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Old 2008-10-28, 08:51 AM   #418
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Does the information you have show the noise figure for the 0064C?
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Old 2008-10-28, 02:06 PM   #419
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I wish I knew what the noise level is - the guy in Post #119 never got his answer either.
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Old 2008-10-28, 09:09 PM   #420
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The representative at Stark Electronics recommended trying the Winegard 15.3 A/C power injector, although he did point out that the 0064C was probably more than 10 years old and that circuit fatigue would be a good reason to just get a new one.
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