Wide Band Antenna

Started by M. Hamed in sci.electronics.basics5 years ago 14 replies

Is there such a things as an antenna that will get me everything from HF to VHF with reasonable strength? I have a BNC telescope antenna that...

Is there such a things as an antenna that will get me everything from HF to VHF with reasonable strength? I have a BNC telescope antenna that seems to get FM broadcast and higher but very little once you start going below 100 MHz.


Antenna Lightning Protection

Started by W. eWatson in sci.electronics.basics6 years ago 18 replies

I have a mast, rotor and yagi TV antenna on my roof. The antenna is probably 15' feet above the roof. It has 12 or so large elements, and a...

I have a mast, rotor and yagi TV antenna on my roof. The antenna is probably 15' feet above the roof. It has 12 or so large elements, and a similar amount of smaller elements. There are three guy wires. It was struck by lightning about eight years ago, and took out the rotor control in the house. There was no apparent damage to the antenna it is not in use, disconnected from the TV, but ...


Re-activating a Roof-top TV Antenna

Started by Joe in sci.electronics.basics11 years ago 3 replies

I would like to help a relative "re-activate" a roof-top TV antenna on a single storey house in southern California. From the ground, it...

I would like to help a relative "re-activate" a roof-top TV antenna on a single storey house in southern California. From the ground, it looks to be physically in good shape, each of four corners has 4 guy wires holding the mast, which looks to be something close to 20 feet tall. I need a how-to to get the antenna in shape. It currently has its feed cable dangling on the mast, not...


300 ohm to 75 ohm impedance matching "transformer"

Started by Joe in sci.electronics.basics12 years ago 3 replies

I bought a 300 to 75 ohm "matching transformer" to hook up to a home built TV antenna. The matching transformer looks exactly like the one on...

I bought a 300 to 75 ohm "matching transformer" to hook up to a home built TV antenna. The matching transformer looks exactly like the one on this URL: http://www.solidsignal.com/prod_display.asp?PROD=WMXFMRPT I have a couple of questions: Can these matching transformers be used in either direction? That is, my antenna will get the 300 ohm end, and the TV antenna input will get the ...


Crystal Radio Questions

Started by Joe in sci.electronics.basics10 years ago 10 replies

I'm winding a coil for a crystal radio. The original plan says to wind the antenna coil on top of the tuning coil, whereas another version...

I'm winding a coil for a crystal radio. The original plan says to wind the antenna coil on top of the tuning coil, whereas another version says to wind the antenna coil *adjacent* to the tuning coil, separated by about 1/4 inch. If I wind both versions of the antenna coil on the form, will one winding interfere with the other? That is, I would only hook up one antenna coil at a time, so ...


Lubricate coax connection

Started by AK in sci.electronics.basics6 months ago 7 replies

It's hard to unscrew the coaxial cable from the antenna. Is there something that can make that easier and minimize corrosion? I think there...

It's hard to unscrew the coaxial cable from the antenna. Is there something that can make that easier and minimize corrosion? I think there is corrosion occurring on the aluminum "arms" of the antenna as well. https://imgur.com/ntxK7ou


Antenna impedance

Started by riccardo manfrin in sci.electronics.basics6 years ago 19 replies

With reference to this schematic: http://www.pyroelectro.com/projects/pyro_rf_transmitter_27mhz/img/schematic.png I'd like to know if there is...

With reference to this schematic: http://www.pyroelectro.com/projects/pyro_rf_transmitter_27mhz/img/schematic.png I'd like to know if there is a general rule of thumb for determining the antenna impedance Z(w) and therefore the matching inductance L3. Also, I'd like to know what is the meaning behind the choice of the "12 inches of AWG 28" (cause 12inches do not seem to me like any fraction...


long antenna

Started by RichD in sci.electronics.basics4 years ago 4 replies

During my workout yesterday, I attached a 3 meter extension to the earphone cord of my radio, as I wanted to place it at a distance. The cord...

During my workout yesterday, I attached a 3 meter extension to the earphone cord of my radio, as I wanted to place it at a distance. The cord is the antenna. I was indoors, where the reception is usually crummy. I figured the longer line should improve performance, right? No! The reception was barely decipherable. Can anyone explain the physics here? -- Rich


radio antenna ?

Started by mowhoong in sci.electronics.basics7 years ago 7 replies

My country has only one radio broadcast station with different channel playing music,news,etc. Why is it that I need to readjust my radio antenna...

My country has only one radio broadcast station with different channel playing music,news,etc. Why is it that I need to readjust my radio antenna ( Direction ) when I listen to the different station or channel ? Can any members explain to me , Thank you . Best Regards


High Gain Antennas

Started by Phil Allison in sci.electronics.basics9 years ago 3 replies

** Hi all, inspired by a series of posts on the subject of antenna gain - I did a little Googling. My quest was to find the highest gain...

** Hi all, inspired by a series of posts on the subject of antenna gain - I did a little Googling. My quest was to find the highest gain antenna ever uilt - I guessed it might be a large parabolic dish as used by NASA etc. But what is the actual * gain * in dBi ?? There is a famous 305 metre diameter dish in a place called Arecibo in Puerto Rico - it is reckoned to have a gain...


TUTORIAL - Example 2, Using Femm to Calculate Component Values of Simple buried Stripline configured like a coax to use in LTspice/PSpice

Started by RobertMacy in sci.electronics.basics5 years ago

These anlayse work at 2.5GHz in FR4 type PCB material for those of us who want to drive ?? or an antenna = Bluetooth, Wifi, zigbee, or GPS...

These anlayse work at 2.5GHz in FR4 type PCB material for those of us who want to drive ?? or an antenna = Bluetooth, Wifi, zigbee, or GPS antenna module and want to see how much a 'longer than desirable coax' run detriorates the NF of the Receiver. The skin effect is in there, but I did NOT want to make this a 'broadband model' Skin effect issimply at 2.5GHz. Boradband Model is res...


Litz wire for AM ferrite Rod Antenna?

Started by Bill Bowden in sci.electronics.basics13 years ago 28 replies

How much improvement can I expect using Litz wire to wind a AM ferrite Rod antenna as opposed to using solid copper wire? Is it worth the...

How much improvement can I expect using Litz wire to wind a AM ferrite Rod antenna as opposed to using solid copper wire? Is it worth the trouble to obtain Litz wire, or can I expect almost the same response at say 1 MHz using regular solid enamaled copper wire? -Bill


1 Micron Antenna for Solar Power

Started by Bret Cahill in sci.electronics.basics4 years ago 5 replies

I always wondered why you couldn't do this: http://nextbigfuture.com/2015/09/solar-cells-will-be-made-obsolete-by-3d.html

I always wondered why you couldn't do this: http://nextbigfuture.com/2015/09/solar-cells-will-be-made-obsolete-by-3d.html


Paparazzi drones

Started by Roger Dewhurst in sci.electronics.basics5 years ago 11 replies

I suspect that little more than a dish antenna and a spark plug is required to over-ride the radio control of these things. The use of these will...

I suspect that little more than a dish antenna and a spark plug is required to over-ride the radio control of these things. The use of these will piss off nearby TV users but not as much as a shotgun will piss off the police. Comment please.


When we listen to the radio ?

Started by mowhoong in sci.electronics.basics8 years ago 1 reply

I would greatly appreciate if someone can explain to me the need to angle the radio antenna at 45 degree for FM and 90 degree for AM or SW...

I would greatly appreciate if someone can explain to me the need to angle the radio antenna at 45 degree for FM and 90 degree for AM or SW mode. Thank you .


AC current relay

Started by Anonymous in sci.electronics.basics8 years ago 15 replies

I want to switch on some receptacles when another one is drawing current. I want my remote controlled TV to turn on the equipment ancillary...

I want to switch on some receptacles when another one is drawing current. I want my remote controlled TV to turn on the equipment ancillary to the television - converter box, antenna rotor, speaker amp. Ideally something that can sense down to 1 amp or so then energize the other outlets, and uses minimal current itself. These things used to be fairly common to switch off the other comp...


1N5819s? Or just a couple of 1N4001s?

Started by Dave in sci.electronics.basics6 years ago 4 replies

I have been wanting to make use of a pair of 1N5819s to protect an RF amplifier I am building from static discharge, should someone touch the...

I have been wanting to make use of a pair of 1N5819s to protect an RF amplifier I am building from static discharge, should someone touch the antenna, but haven't been able to obtain any of these just yet. I DO have some 1N4001s however, and am honestly wondering what advantages the 1N5819s would have over the the more readily available 1N4001s (which are already sitting on my workbench....


equation: dBm to mW/cm^2

Started by Winston in sci.electronics.basics8 years ago 26 replies

I have a 1 GHz 1/4 W whip driving a detector that outputs RF level data as a D.C. reading that is easily convertible to dBm. However I need the...

I have a 1 GHz 1/4 W whip driving a detector that outputs RF level data as a D.C. reading that is easily convertible to dBm. However I need the reading presented in mW / cm^2 I understand that my antenna has a gain of 1 dBi. In this chart http://www.geopathfinder.com/Conversion Chart.pdf ..I see that 0 dBm (for example) is equal to 0.0121 mW / cm^2 The chart refers to an equation sou...


I need an Arnold Schwarzenegger plug

Started by Anonymous in sci.electronics.basics8 years ago 15 replies

I'm installing an antenna system for my tv. Using a coax splitter, it says in the instructions that if there are any unused connectors on...

I'm installing an antenna system for my tv. Using a coax splitter, it says in the instructions that if there are any unused connectors on the splitter, I need to install a Terminator. I guess that means I need to get a plug from Arnold Schwarzenegger. Does he sell them on rbay, or do I need to meet him in person to get one?


GFCI/lightening

Started by default in sci.electronics.basics5 months ago 2 replies

I had a lightning strike hit an antenna mast and it took out a lot of electronics in my house. It actually popped circuit breakers in the house...

I had a lightning strike hit an antenna mast and it took out a lot of electronics in my house. It actually popped circuit breakers in the house along with taking out the TV, modem, KVR switch, low voltage LED lighting, and several power supplies. The interesting thing was the circuit for the Ground Fault outlet that feeds my outdoor workbench was kaput, but didn't show any signs of being ...