GRE Super Amplifier

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KMG54

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What might do you better than a amp, is a FM trap. Do you have any strong FM broadcasts in the area?
 

IdleMonitor

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What might do you better than a amp, is a FM trap. Do you have any strong FM broadcasts in the area?
The radio station in town here doesn't really interfere in any comms I listen to, however the local weatheradio tower is in a direct line of site of me and is only a few km's away. It however does cause some interference just not on anything I listen to.
 

KMG54

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Newark electronics have cheap FM traps that I use to block brodcast stuff. For the weather tower I use a Par filter. I am guessing your weather is in the 162 MHZ range up there also.
 

KMG54

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Only reason I am suggesting it is FM broadcast stations probably love your discone and could be overloading the front end. And your amp may be fine and increasing the FM.
 

IdleMonitor

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Newark electronics have cheap FM traps that I use to block brodcast stuff. For the weather tower I use a Par filter. I am guessing your weather is in the 162 MHZ range up there also.
Yes it is. It doesn't affect anything I actually listen to regularly but if I do a search on frequencies then I notice the interference more so the vhf.

The area I'm trying to focus on to pull in a better signal is in the 800 mhz of a system that's about 60-80 kms away.
 

IdleMonitor

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I'll note that the FM broadcast main tower is at the same location as the weatheradio tower. The transmission frequency in the 900 mhz from studio to the broadcast tower doesn't interfere at all nor does the FM broadcast frequency.
 

Ubbe

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Scanners have poor receivers with high noise figures. Almost any external amplier will increase a scanner sensitivity due to its lower noise figure. If a scanner have a 5dB NF noise figure it will be added to the lowest signal possible to receive, lets say -125dBm and the 5dB will change that to -120dBm as the lowest signal possible to receive. Add an amplifier with 0,5dB NF that amplifies the signal at least 4,5dB and the scanner will receive a -124,5dBm signal. That's a 4,5dB gain without needing to switch to a higher gain antenna or low loss coax. Put that amplifier at the antenna and the coax loss will be irrelevant and the antennas different impedancies at different frequencies will instead be constant to the coax and the coax loss will instead be converted to additional gain to the initial lowest signal possible to receive value.

It's always a good idea to add a low noise amplifier and then add an attenuator to keep the total gain low enough to not overdrive the scanner. Scanners have often bad filters so that FM broadcast filters and pager filters for 155Mhz and for other frequencies with strong signals might be needed, if the total gain are too much for the scanner. Even cheap $10 sat inline amps with 3dB NF improve the sensitivity of all my scanners when connected directly to their antenna input thru a variable attenuator to set the total gain to a suitable low value.

/Ubbe
 

vagrant

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I have one of those GRE amps. I use it inline with a notch filter to the frequency range I want to RX. If I turn it near half way it wipes things out. It just raises the noise floor too much. (Of course, the noise around me is not the same for you)

I have to keep the dial set at less than half. Also, without the notch filter, it almost wipes everything out unless I turn all the way down or off. Basically, I have experienced the same result you are with that RX amp. It simply overloads various wide band RX equipment, or at least my receivers that cost less than $1000.

I actually have two of those, they both operate/have the same result. Hmmm...now that I think about it, I have never used it down low on HF frequencies so I am unsure the results there; however, as to VHF and UHF forget it...unless you employ a notch filter or a narrow tuned antenna.
 

sibbley

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I have 2 super amps I picked up early 2018 on Ebay, brand new in the original boxes for $50 each. I do use them to bring in digital signals. I can run them with the dial full bore, however only on digital signals. If I try analog, I need to turn the dial almost all the way down, it simply overloads. However, digital (DMR/NXDN) come in quite well with little to no overloading, Uniden/Whistler alike. Only filters used are what ever the Stridsberg passive multicouplers may include. As always, YMMV...
 
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