still reception problems

[babyreb]

new antenna new coax added height still better results with a rs 800mgh rubber duck.
any sugestions antenna is a radio shack discone rg 8 coax .would extra caox that is wound up have a effect

 

[LarrySC]

Never loop coax into a coil. Signals will load up and stop in a coil. Spread out coax or cut and replace connector. Post more info on ant and scanner.

 

[Al42]

And on antenna height and distance to what you're trying to hear.

Hey, Larry, you ruined your record. That post was right on.

 

[babyreb]

Never loop coax into a coil. Signals will load up and stop in a coil. Spread out coax or cut and replace connector. Post more info on ant and scanner.

now should i go higher i have at least 7 plus ft extra of coax now i start at 9ft above ground on a vent tube and have 15 ft of mast above that so true height is about 24 or so ft from ground i hade better results from my rg58 coax. now would a ground help . primary is 800mg iam using a pro 96. some of lower bands seem to better. now is the antenna on top have use other than to transmit

 

[Al42]

Let's take one thing at a time. Your antenna is 24 feet above ground. What kind of cable? How far away is the 800 MHz signal you're trying to hear? How high is its antenna?

 

[babyreb]

Let's take one thing at a time. Your antenna is 24 feet above ground. What kind of cable? How far away is the 800 MHz signal you're trying to hear? How high is its antenna?

yes antenna height about 24 ft a guess. most msp towers are 10 to 20 air miles but 30 and 40 mile towers are worse than with rubber duck my extra coiled coax sond like most my problem . but i could get those 30 plus mile towers with rg58 coax iam useing rg8 50 ohm scanner shop said would best for my buck besides high price coax

 

[Al42]

RG8 has less loss than RG58. (8db/100feet@850 MHz for RG8, 14db/100feet@850 MHz for RG58. That's not less than twice the loss, it's 4 times the loss.)

Your horizon at 24 feet is about 5.8 miles. In order for you to have a decent shot at a tower 30 miles away, it would have to have a 24 mile horizon - or a height of about 400 feet. Doable, but not that many towers are that high.

As Larry said, DO NOT coil the coax. At 850 MHz, a turn or two is all you need to keep the signal from getting to your scanner. Worst case, stretch it out in one big "U". Best bet, if you're not going to raise the antenna, is to cut the coax to the length you need plus a couple of feet to allow you to move things around.

 

[babyreb]

RG8 has less loss than RG58. (8db/100feet@850 MHz for RG8, 14db/100feet@850 MHz for RG58. That's not less than twice the loss, it's 4 times the loss.)

Your horizon at 24 feet is about 5.8 miles. In order for you to have a decent shot at a tower 30 miles away, it would have to have a 24 mile horizon - or a height of about 400 feet. Doable, but not that many towers are that high.

As Larry said, DO NOT coil the coax. At 850 MHz, a turn or two is all you need to keep the signal from getting to your scanner. Worst case, stretch it out in one big "U". Best bet, if you're not going to raise the antenna, is to cut the coax to the length you need plus a couple of feet to allow you to move things around.

ok i will try that but i can reach those towers in the back yard on my handheld sometimes better with a rubber duckbit i do beleave it is the coiling up my coax i think another 5ft of mast and shorten my coax ? sound good????? and thank u guy m sterling hgts mi

 

[Al42]

Sometimes the signal gets refracted, but you can't count on that. Straight "unbent" 850 MHz signal goes in a straight line from the transmit antenna to your antenna. If part of that path is through the ground, the signal will penetrate a couple of feet - and that's it. IOW, if you can just see the tip of the transmitting antenna from your antenna (even if you have to use a telescope) it'll work. If the tip of the transmitting antenna is just under the horizon (not an inch under - just under) it will probably work. If it's any lower than that it will work when you get refraction (from weather, usually), but not without the signal getting refracted.

 

[kb2vxa]

Hey Larry,

"Signals will load up and stop in a coil."

It's better to tie a knot in it, RF is like water in a garden hose. Now if you put a sharp kink in it and hold it real tight and then let it go you'll get signals all over your face like the Little Rascals did to Granny. Have a little fun with your friends, kink thier coax when they're not looking.

Oh Al, pointing a Yagi downward at just the right angle is a great way to work the antipode. Don't tell them, let them figure out what the antipode is.

 

[Foosywoosy1919]

A discone is completely the wrong way to go if you want to monitor a Trunked system.. A hunk of metal the size of your thumb on a cord would work better. The higher in MHz you go, the physically smaller the wave is. A discone is a huge antenna, and you only really need a two or three inch antenna to work on the TRS System.. Get a mag mount and a RS 800MHz antenna and put it on your roof. That may work alittle better!

 

[RISC777]

opposite feet, kb2vxa
my discone picks up 4 EDACS, 10 TRS departments, and 10 or more conventionals

 

[Al42]

A discone is completely the wrong way to go if you want to monitor a Trunked system.

The antenna has nothing to do with whether the system is conventional or trunked.

The higher in MHz you go, the physically smaller the wave is. A discone is a huge antenna

A low frequency discone is. An 800 MHz discone is pretty small. A 300 MHz discone is a little larger, but it tops out at over 900 MHz, so it'll work at 850.