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Does a more respected, more expensive preamp make a difference?
- Thread starter Dylan Jake Jake
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Get the KT-200-COAX preamp. It's pretty much the best one out there. I've been using one for years, and have tried others, and nothing beats it so far. Including the latest TELEVES preamps. KT-200 TV Booster
The noise figure of the KT-200 is very good, the gain is a bit high and they don't publish some of the most important specs like IP1 (1dB compression) and IP3. Those determine how the amplifier will play in a high RF environment and if it will produce IMD. Looking at its current consumption of 70ma and it works from 7 to 14V, its probably got 5V or even 3V devices inside. You can sort of determine its IP1 and IP3 ratings from the voltage and current it uses and its probably not capable of more than about 10dBm output power and an IP3 of maybe 30-33dBm which is not very high.
I live in RF hell and have never found an off the shelf TV preamp that works here. Most actually make the picture worse due to the amplifier getting spanked by nearby high power transmitters and the amplifier spews out a spectrum of noise and ghost signals that cover up off air TV signals. Testing using an omni directional antenna here for things other than TV, I've measured -20dBm of signal off the antenna and that put into an amplifier with hundreds or thousands of signals and 24dB gain and a low IP1 and IP3 like the KT-200 is a recipe for disaster.
Bottom line is what works for one person in their neighborhood may not work for you and your neighborhood with high power FM transmitters, paging systems, cell phone towers, etc.
I'm not sure of the KT-200. Performance looks real nice. High gain in preamps is important if you live way out in the sticks like I do where you don't have any strong signals in the area. Just like an SDR preamp, many TV preamps boost across the whole range of VHF/UHF. Especially those inline bullet amps like Radio Shack sold.
Better ones will have notch and bandpass filtering. But still have a fixed (or variable if you have such a model) gain.
If you're using common high quality coax and you had the opportunity to check sig. strength close to the antenna and end up losing a whole lot at the termination to the TV. Me? I'd consider just biting the bullet and getting some good low loss commercial 75 ohm coax and good connectors....and make one run of it. Extra connectors, splices to make up for length only adds to signal loss. In a low signal area the best RG-6 you can get isn't going to help if it has a high dB loss. And the extra shielding just helps keep RF noise isolated. I don't have any, so I don't notice the difference at all really between what the cable company left me and quad shielded. But that's me.
Yeah. Overload on strong transmitters has been a problem for a long time. External inline channel specific filters are available to attenuate those signals in these cases. I don't have to worry about that in my area. Not at all.
I just caught an Antenna Man review of of the Televes T-Force preamp. Brilliant! Somebody has actually thought of an AGC integrated into the thing. And the ability to use 2 antennas, both UHF/VHF. Not like others where one port will be for VHF and the other for UHF. That's cool.
BUT. What makes me wonder is if you get strong station overload and the AGC kicks in and lowers gain, what happens to the gain on weaker stations further away? I mean, all signals are passed down the coax and the preamp doesn't know what station your TV is tuned to. That part sounds kinda' sketchy. So I guess putting a notch attenuator for the strong station BEFORE the preamp at the antenna would work. I don't know.
Better ones will have notch and bandpass filtering. But still have a fixed (or variable if you have such a model) gain.
If you're using common high quality coax and you had the opportunity to check sig. strength close to the antenna and end up losing a whole lot at the termination to the TV. Me? I'd consider just biting the bullet and getting some good low loss commercial 75 ohm coax and good connectors....and make one run of it. Extra connectors, splices to make up for length only adds to signal loss. In a low signal area the best RG-6 you can get isn't going to help if it has a high dB loss. And the extra shielding just helps keep RF noise isolated. I don't have any, so I don't notice the difference at all really between what the cable company left me and quad shielded. But that's me.
Yeah. Overload on strong transmitters has been a problem for a long time. External inline channel specific filters are available to attenuate those signals in these cases. I don't have to worry about that in my area. Not at all.
I just caught an Antenna Man review of of the Televes T-Force preamp. Brilliant! Somebody has actually thought of an AGC integrated into the thing. And the ability to use 2 antennas, both UHF/VHF. Not like others where one port will be for VHF and the other for UHF. That's cool.
BUT. What makes me wonder is if you get strong station overload and the AGC kicks in and lowers gain, what happens to the gain on weaker stations further away? I mean, all signals are passed down the coax and the preamp doesn't know what station your TV is tuned to. That part sounds kinda' sketchy. So I guess putting a notch attenuator for the strong station BEFORE the preamp at the antenna would work. I don't know.
I bought, and tried just last week the Televes preamp based on Antenna Man's review. It's junk compared to the KT-200-Coax. It has a 4-6db NOISE (NOT .4, but FOUR to SIX db), and my lowest power stations pixelate with it.
I removed it, and put the KT-200 back in place. I can't recommend the Televes.
I've experimented with approx a half dozen different amps/pre-amps and have had the best luck, at my location, with a mast mounted Channel Master 7777 Pre-Amp. A recent scan locked 87 channels. As others have mentioned, results may vary depending on several factors including location, proximity to high tension lines, elevation, terrain, etc. The only way to know for certain is to try it. The one certainty is that mast mounted is better than in house because it eliminates boosting any interference the lead-in may pick up.
I've also tried MANY different preamps. The Channel Master is a good one, but it's far too much power for my area. It actually wipes out a bunch of my stations. It worked fantastic when we lived in the other house in the middle of the woods, when my mast was only about 25' up. Once I added enough mast to get it at 40', signal wipe out due to higher incoming signals levels at that height. I was amazed, it was like the stations were no longer there, they were just gone.
I literally have a garage full of preamps here with a few costing over $1k and do a lot of testing but mostly for wide band VHF/UHF radio work. I generally use a spectrum analyzer to see before and after the preamp checking for IMD and other artifacts. The KT-200 has an FM trap and that will go a long way towards reducing IMD, but I don't need to buy one to know roughly how it will perform. I have preamps with similar noise figure and gain and slightly higher IP1/IP3 and they fall apart here on a wide band omni antenna.
The only thing that has survived here so far is a low gain (10dB) one with a 1dB compression point around 1 watt and a whopping IP3 level of 46dBm but its noise figure is rather high at 3.5dB. That one will amplify without raising the noise floor or crate ghost signals due to internally generated IMD. This particular preamp draws over 500ma at 12V and that kind of hints at its high signal handling capability.
The KT-200 looks better than many other preamps out there in the noise figure category but I wish they would publish more specs so people can make a better decision when shopping. I also wish it had higher signal handling capability. Again, what works at one house may not work so good at another.
Email the guy who builds these. he's very responsive. He also has plenty of other preamps to try. If you don't believe me on the KT-200, check Avsforum, and you'll see how they test out with people who have all the equipment. HDTV Technical
I had the exact issue with signal glitching every few seconds. In my case, the KT-200 solved the problem. 6 year old thread, but might be of interest starting at post #23:
CM-7777 Using 12Vdc Power Supply
The Kitztech is a very good amp (I swear by them and own two!) but, as fred555 notes, it is not waterproof. You will need to put it in a waterproof enclosure. - Trip
www.satelliteguys.us
Hello, Dylan Jake Jake; welcome to the forum.
It is difficult to say if it would make a difference.
We can give you general advice about preamps, but we would need more information about your situation to give you specific advice about your reception problem.
At the very least, we would need to know what antenna you are using, what channels you want, and a signal report for your location.
You can do a signal report at this site. (I use coordinates from Google maps):
RabbitEars.Info
I tried many and a year or so ago, I bought one of the locally made ones. It looks like their webpage is down, and it was a old Ham making them, but I must say it is the best am I have ever used. My signals come from all directions, and have that covered with a VHF high log and a UHF Yagi combined in a compromising azimuth, but was never able to get our local ABC WLOS out of Asheville NC. I bit the bullet and ordered one of these, mild amp at I believe 15 Db. Solved all my problems and get WLOS fine now. The TRUTH AMP ©™ - UHF VHF HDTV Digital TV Antenna Signal Booster Amplifier for sale online
Here it link to my antenna map
RabbitEars.Info
RabbitEars, where you can learn all about local, over-the-air TV channels.
www.rabbitears.info
WRTV is the main channel that I wouldn't even really say I struggle with, just have maybe slight pixels on a weathery day.
I use the winegard platinum series hd7694p with the PBD preamp.
The towers I care about that carry Indianapolis ABC, NBC, Fox are all 56-60 miles away. Any recommendations if a better preamp would help?
During the day ABC and FOX come in at 2 out of 4 bars of signal (somewhere between 50-60% signal strength). I'm worried when the leaves on trees grow back during the summer the signal will get worse and cause issues again like before fall and winter hit.
In your case the problem is not just amplifying weak signals, it is amplifying them without overload from WTIU. WTIU is roughly 60 dB stronger than the Indy stations that you are trying to watch. Fortunately WTIU is in a different direction that Indy, so the actual difference in signal strength is probably in the 40-50 dB range, which is still significant.
Most manufacturers no longer publish overload data on their preamps, so it’s a matter of trial and error to see what works best.
Most manufacturers no longer publish overload data on their preamps, so it’s a matter of trial and error to see what works best.
Are you saying WTIU can interfere with my signals from Indy? I don't care about WTIU, that channel has garbage on it.
It makes me wonder if my preamp is actually overamplifying the signals? Because VHF signals are generally in the 70-80% signal range, the UHF channels are the ones that I struggle with. The PBD amp boosts VHF by 16db and UHF by 25db. My VHF channels are fine, UHF are a bit sketchy... am I on to something? My coxiable cable run is about 110 feet. Although the CBS tower only 30 miles away is 90-100% signal. I find it odd pointing my antenna not directly at the tower somehow gives me better signal than directly pointing my antenna at the tower. CBS 4 WTTV for example, I get better signal pointing straight north instead of at the tower north east. Which I think is a clear indicator that my signal is too strong when pointed directly at the tower, or no? My antenna is currently pointed basically straight north. I seem to get worse signal on all the channels when I point my antenna directly at the Indy towers.
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I'm thinking of buying and trying either the
Channel Master CM-7778V3 Titan 2 Medium Gain TV Antenna Preamplifier [Version 3]
orChannel Master CM-7777V3 Titan 2 High Gain TV Antenna Preamplifier [Version 3]
any thoughts on which you would think is best bet for my situation given all the details I gave?
