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Scantenna Question

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planeguy_jerm

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I know this question has been asked here before I just couldn't find it. I just ordered a psr-500 (I am really excited) I also order a scantenna to go with it. The antenna comes with a 75 ohms 50' cable. The psr-500 owners manual says to only use 50 ohms cable to connect to the scanner. Do I need to by a special filter or a special cable, or is it safe to use the cable that comes with the antenna. (I don't want to ruin my new scanner, when it comes.)
 

Airdorn

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I've had a scantenna for 4 years now with that 50' of cable that comes with it, and I get GREAT reception. Awesome antenna.

It just so happens I'm replacing the cable with some LMR-400 this weekend. :)

Airdorn
 

mrdinks

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I was wondering the same thing, I have already run LMR. If the scanner and cable is 50 ohm will there be any downside connecting a 75 ohm antenna?
 

ka5lqj

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50 ohm vs 75 ohm......

Good Morning, "Mr.", All,

As long as you aren't transmitting or even if you are, there is just a slight difference in the 50 to 75 ohm coax. On a receiver, this is not that big a deal. However, if you are using it to transmit on, with a transistorized or surface-mount IC transmitter, the vertical standing wave ratio (the difference in "match" between the radio, coax, and antenna, is probably too great to use. On a tube-type transceiver, it's about 1.5 : 1 and acceptable. New transcievers don't tollerate that much of a mis-match.

Now, since you are using it for a scanner receiver, there's not that much noticable difference. Here on my scanner antennas from the antennas to the receiver, I use quad-shielded, RG-6, up to 150 mhz. Above that, I use TV, RG-11 Underground for less loss at longer lengths and heights. IF I had access to 1/2" to 3/4" hardline, I'd use it for UHF antennas, with adapters to use the last 6' being TV RG-11.

IF you can find the RG-6 from a supplier for Cable TV coax, get the one that has the "messenger wire", a covered aluminum wire that enables you to string long spans with the aluminum wire for support. This is usually used as a "drop wire" from the pole to the house. Leave enough "wire" to secure it to the antenna mount to hold the vertical wire straight, leave a "drip loop" near the antenna and use stand-offs to keep it away from the metal support pole. Then, make another "drip loop", at a "ground block" and bring the coax in the house.

When I get it finished, I'm adding a "primer" on antennas. coax and etc for "tips". I don't consider myself an "eggspurt" by any means. Just what I've learned over 50 years of Radio/Electronics, LOL!

If you have "questions", I can be emailed or "e-mauled" (flamed) at:

KA5(dot)LQJ(at)gmail(dot)com. <== to keep SPAM bots away, LOL!

Respectfully submitted,
73 (Best Regard)

Don/KA5-LQJ
 

scanrock

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I was just on the Grove Website and asked the same ? I was always under the impression
that you have to use RG8 or LMR 400 , 50ohms I'm a little confused also why does the
scantenna use F connectors ? The LMR400 I have been using for 7 years is showing signs of corrosion and must be replaced is cheaper wire better? Grove also supplies RG6 with the Diamond Discone you would think that should be 50ohm.
 
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I read somewhere that, all other factors being equal, using a 50 ohm antenna and 50 ohm radio connection, switching to a 75 ohm feedline will cause less than a 10th of an S-unit difference in the received signal. That is imperceptible to the human ear.
 

hoser147

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I'm a little confused also why does the
scantenna use F connectors ?
It is probably the cheapest route for the companies to go you can buy RG6 in various lengths at Walmart with F connectors. You can always change the connectors to the one you want with little effort.............Hoser
 

Airdorn

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Hoser:

Where's a good place for that 'bicycle flag' fiberglass rod, you think?

Also, that scantenna f-connector is just for its little matching transformer. Seems like you could remove that and put a 300 ohm -> 50ohm transformer (balun or whatever) on it and it'd prolly have a BNC connection.
 

btritch

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Paragould/Greene County AR
cable

What's a good cable to use with a scantenna antenna? I'm supposed to get an antenna on Tuesday..I'm planning to wind proof it real good using the 6' bicycle flag, But I am using standard RG 58 cable with it PL 259 connectors on it. What I need to know is what is a good cable to use to get the best and most reception on it without much gain loss for max performance? Where can this be found at? Also, How can I split it for two scanners? "T" connector? Please help!
 

W4KRR

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Coconut Creek, FL
btritch said:
What's a good cable to use with a scantenna antenna? I'm supposed to get an antenna on Tuesday..I'm planning to wind proof it real good using the 6' bicycle flag, But I am using standard RG 58 cable with it PL 259 connectors on it. What I need to know is what is a good cable to use to get the best and most reception on it without much gain loss for max performance? Where can this be found at? Also, How can I split it for two scanners? "T" connector? Please help!
RG-6U coax should be fine. Time Microwave LMR-400 is better, but will cost you a bit more. I wouldn't use RG-58, it has too much loss.

I would NOT use a "T" connector to split the coax to use with two scanners. There are some who will tell you that they do this and it works fine, but it can have very unpredictable results. Companies like Stridsberg Engineering and Electroline make splitters made just for this purpose.

Stridsberg Engineering splitters:
http://www.stridsberg.com/

Electroline splitters can be found on eBay, that's where I got mine. They're used mainly for TV applications, but they work fine for scanners also.
 

btritch

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Different Areas.

I'm talking about using something to split it to two different parts of the house. My end of the house has the be closest and best because I'm the one that wants to hear the farthest away.. the other part of the house is a long ways BUT I'll just use the cable that's already being used there because they just want to hear locally in town anyway so that won't be a problem. I am using 75 ohm RG 58 Cable with BNC connectors on both ends. 75 feet to one room and 100 to the other and to split it off the antenna I'm using a cable with a PL259 connector on the antenna and splits two ways with PL259's on it. It's a cable usually used to hook two CB antenna's to one reciever but it's all I had at the time.. I need something to split two ways one of being the best..The other being not so important.. But I am using cable with both cables right now..Should I use just RG58? What should I use to split it off with? Is 75 & 100 feet runs too long?
 
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