![]() There are good amplifier designs and cheap amplifier designs, and you get what you pay for.Īmplifiers ingest weak TV signals and make them stronger. Amplifiers can do a lot of good, but they can also create problems for TV reception. Everyone knows what an amplifier is, but there’s plenty of misunderstanding about how TV amplifiers work and when to use them. ![]() A weak wheather channel are good for VHF and on UHF you could use a constant transmitting control channel.For this month’s post, we’re going to focus on TV antenna amplifiers. To evaluate all this you'll need a steady signal, preferable a weak one with lots of noise. A simple filter that also will attenuate some on other frequencies are a stub filter and are easy to cut You the very easy see if the filter is effective or you can tune any filter to the exact frequency. It's easy to set up to be able to look at the frequency spectrum and see where any offending strong transmitters are. One thing that everyone should have are a cheap tv usb dongle for $10. If the end result isn't much better than without an amplifier then there is probably a frequency that needs a special filter. If there is a noticable differense towards a better reception when the fm filter are put between amp and antenna then the amplifier is suffering from desencing and the fm filter needs to be remained between antenna and amplifier, or go for a better amplifier. They are cheap and effective and first trying them between scanner and amplifier will make their pass thru attenuation negligibel. When dealing with amplifiers I would suggest to first try them out at the scanner, with the variable attenuater in between. You can get away with some wide band preamps if your out in the sticks but you won't know if it will work until you try it. Otherwise if I use most models of Mini-Circuits, cable TV amps, etc, my reception gets worse due to the general high levels of RF in the area I live. ![]() Most of those work fantastic bringing weak signals out of the noise but most of these were designed to have narrow band pass filters in front of them to only allow a tiny slice of the band to pass through feeding repeater receivers. I have a bunch of Angle Linear preamps but they range from maybe 10MHz wide to 100MHz wide and are band specific. I have one particular wide band 1-1000MHz preamp made by a MU-DEL who makes receive front end equipment for Govt customers, and that is one of the few that amplify ok, without raising the noise floor very much and I can actually hear weak signals a little better. If I was only looking at the strong signals I would think the preamp is working great, but its really not. Adding most preamps kills off the weak signals and they get buried in the noise, where slightly stronger signals are now fuzzy and noisy sounding and the strong signals are much stronger on the S meter but now I have an S3 to S5 noise floor where before I had zero. This is because most preamps I use here are being overloaded to some extent and the thousands of signals passing through it is creating thousands of IMD signals that are adding to the noise floor.įor example, if I'm receiving VHF air band on an Icom R-7100, a receiver that is not known for overloading easily, I can hear distant weak aircraft signals to a certain extent with a noise floor of about zero. ![]() Sure the S meter reads more with the preamp but the noise floor goes up more and out of proportion to the signals I want to receive. Where I live nearly all wide band preamps I've tried make reception worse on many bands. Two USB dongles, on two different ST2 antennas, both with LNA-580 preamps at the base. I have lots of DC Blocks and they're cheaper than my preamps, so I normally use one. I didn't attach this initially, but it shows a way to feed DC up the coax with a DC block BEFORE the preamp.ĭepending on the Bias-Eee you use, you may not need it. There's some additional information in this thread. I use PVC pipe and fittings to make a housing for them. Mini-Circuits ZQL-1900MLN for 500 MHz and up including aircraft ASD-B RF Bay LNA-580 for everything below 600 MHz You can see the housing below one of them. You didn't mention the range(s) you want to cover or the price range you have in mind.īut, this is the setup I use for six of my antennas that have a preamp mounted right at the base of them.Īlso, it's a good idea to have some way to control the signal level.
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