GRE scanners should include their own Preamp circuit

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Gilligan

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I have been scanning for upwards of 15 years. I bought the GRE handheld preamp for about 50 bucks a year or so ago and found it wasn't much use in a metropolitan city like OKC. But spending the summer in rural Montana, in a valley of only 100K people, I find that my reception is very limited without the preamp. Opening it up and examining the circuitry inside this little box shows that it's basically a 2" x 1" circuit board and a 9V battery. There's an on/off switch, an LED, and a knob to adjust gain from 0-20 db.

Here's what I'd like to see. I'd like to see the next GRE scanner have this circuit (their own GRE preamp) built in. As small as it is and for the difference it makes, it's a necessity outside a metro area. And when you're paying upwards of $500 for a scanner, this little ciruit works magic for reception. You'd have to try it to see the difference it makes. At least it could be a special option when you order the newest model, to add the preamp for an extra 25-50 bucks.

The whole circuit is so small that you could eliminate both BNC connectors (since it's internally inline w/ the antenna), make the on/off (bypass) switch a setting in the scanner (like the attenuator), and make the gain adjustable w/ either a setting in the radio or (not as likely) w/ a small knob on top of the radio. You could tie it to the squelch knob (personally I hate having squelch as a knob at all - who ever uses it anyway?) but the menu option is better.

The biggest annoyance of using this preamp externally is the bulkiness on top of the radio and having to constantly connect and disconnect it to the radio w/ the antenna. It is entirely possibly to move the whole circuit inside the scanner and use the batteries inside to power it if the user chooses to.

So who thinks it would be a good idea for the next GRE scanner to have an internal preamp?
 

icom1020

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I suspect the obvious question #1 would be, would I want to pay an additional $100 for what may or may not work for me when the threshold for paying more bucks for higher end scanners is already tight for consumers and retailers.
2, would it be worth the expense for the mfg to include this as a selling point if the majority of owners are not in an area prone to intermod? I personally wouldn't mind it but would probably wait a year or 2 to see how well the extra component would suss out in the radio.
 

troymail

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I'd like to think I know what this pre-amp does (but not necessarily).

My PSR500 is very prone to interference in my area any I use the ATTentuator function alot more than I'd ever expect to.... Wouldn't this pre-amp be the opposite of turning on the ATTenuator? If so, for the area I'm in 99% of the time, I'd never use the pre-amp circuit.

On the other hand, I could see being in places where it might come in handy - but not necessarily enough to warrant paying more than $25 more for the radio with the pre-amp built in.

Come to think of it - given my extensive use of the attenuator - maybe the PSR500 already has the pre-amp in it...???
 

Gilligan

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Good question. Does the PSR500 already have a preamp circuit built in?

Another thought. It wouldn't be an extra $100, maybe an extra $25. But really, it was probably more mark-up than anything else, because the circuit itself can't cost but a few dollars to make. I bet the other $45 was markup and the cost of the case and connectors, etc.
 

k8tmk

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The best place for a preamp is right at the antenna where the signal is the strongest. Lead-in cables add some attenuation to the signal and weaker signals will get noisier. When you use a preamp near the receiver, you will also be amplifying noise.

Randy, K8TMK
 

Gilligan

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The best place for a preamp is right at the antenna where the signal is the strongest. Lead-in cables add some attenuation to the signal and weaker signals will get noisier. When you use a preamp near the receiver, you will also be amplifying noise.
It is entirely possbible to put the circuit inline at the antenna of a handheld scanner inside the radio and make the on/off circuitry embedded in the software. The circuitry itself could be just before the BNC jack on top.
 

WayneH

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It's strange that the scanner's receiver isn't sensitive as-is for you. Mine is damn hot and if there are any sensitivity issues it's because of RFI or the noise floor. I've put my 500 against my XTL5000 on a VHF P25 channel with a fringe signal and the 500 definitely kept up.

I think the preamp in big cities will be useless. Sometimes I have to attenuate with pads (since the ATT is 20DB too much) to help with reception when I'm up high or in places that get pelted with broadcast RF. I'd much rather see the receiver built more solid against interference.
 

Mike_G_D

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Attenuation values

Wayne,

I am in major agreement with you here! BTW - just out of curiosity, what values do you typically use in terms of the pads you use with your 500 when in dense RF areas? I'm thinking 6dB to 10dB since I would think that 3dB wouldn't do much...but? Just curious.

-Mike
 

n4jri

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It's strange that the scanner's receiver isn't sensitive as-is for you. Mine is damn hot and if there are any sensitivity issues it's because of RFI or the noise floor. I've put my 500 against my XTL5000 on a VHF P25 channel with a fringe signal and the 500 definitely kept up.

I think the preamp in big cities will be useless. Sometimes I have to attenuate with pads (since the ATT is 20DB too much) to help with reception when I'm up high or in places that get pelted with broadcast RF. I'd much rather see the receiver built more solid against interference.
Maybe this guy has a deaf radio. My first one was. At any rate, a set up with more different programmable steps of preamping/attenuation may be a good wishlist item for the next model.

73/Allen (N4JRI)
 

WayneH

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Wayne,

I am in major agreement with you here! BTW - just out of curiosity, what values do you typically use in terms of the pads you use with your 500 when in dense RF areas? I'm thinking 6dB to 10dB since I would think that 3dB wouldn't do much...but? Just curious.
Typically about 5-6 depending on which ones haven't rolled under the seat yet. It's usually just enough to not totally kill the fringe stuff when searching. I think 10 would be as high as I go. Though sometimes if I'm up high enough the built-in attenuator definitely does help but forget about searching.
 

Mike_G_D

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Pads n' such like...

Thanks Wayne!!

That's kinda what I figured. I will think about making a purchase from Mini-Circuits (probably easiest for me right now - been out of the industry for awhile).

I am thinking up a list of technical questions that I may PM you about just sos ya know.

-Mike
 
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