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So if I was going to make a big antenna say 15ft tall and use an itrip to run it. Would it be able to support that big of an antenna. If not what would I do so it could. Seems like I might need some sort of amplifier and help on where to get one would be great.

Topic by thejrb    |  last reply

HDTV antenna?

How do I make a simple effective HDTV aerial

Question by John Der Stepanian    |  last reply

Tetrahedron Antenna

Hello I have a question about an idea I have for an antenna that always points to the sky antenna no matter how it lands; this is for a high altitude balloon. My idea was to make an antenna the shape of a tetrahedron, so that one antenna always points up. Does  having 4 antennas diminish the signal from the transmitter at all? Thank you

Topic by sdtacoma    |  last reply

TV antenna

Is it possible to make a tv antenna from an old router? I have an old router and a tv antenna. I am trying to do this because my stupid cable provider won't pick up a second CBS. Then my TV tower fell about 5 years ago. Last month I found this station. It's 79.2 miles away. My little indoor TV antenna pick it up at NIGHT, on CLEAR skies only. (Not in the day) and I have to hold the antenna. I know routers would be didgital (if that has anything to do with it). My tv does have the digital tuner. On digital I can't pick it up, but i do somewhat on analog.

Topic by popit    |  last reply

Grounding an Antenna

I'm thinkin of puttin up a high antenna. Due to my location with a mountain between me and broadcast towers, reception can be sketchy.  One concern is that of lightning strikes.  But if the antenna is grounded, wont that also ground out the microvoltage radio signals? How do I get microvolt signal without risk of megavolts burning the house down? I've done a wee little bit of google research, but haven't seen this question addressed.

Topic by Toga_Dan    |  last reply

wifi antennas

Can i use the wokfi antenna hack with a laptop that already has internal wifi?

Topic by spanishfly    |  last reply

Antenna issues- loss of signal with a DIY antenna Answered

Recently, I have made an HDTV antenna using a video from youtube ( and some inspiration from Instructables that I have read. The issue i'm having is that I am slowly losing my signal. I noticed the rust build-up on the end of the fins of it and I have cleaned them up, but it didn't help. Another issue is that I can't seem to pick up a local channel, yet on clear nights I pick up channels from 100 miles away. ( I live in Winchester, Ky and I pick up Cincinatti channels) Anyone have any ideas? Maybe re-work the metal parts with a different type of metal? Maybe a few ideas on different designs?

Question by PapaHex    |  last reply

Antenna for a mobile home

I would like to make an antenna that really works for my mobile home. Does anyone have any ideas. I have seen the ones that use pvc tubing but there is something inside I think.

Topic by didee    |  last reply

RFID antenna question. Answered

How sensitive is RFID functionality to the length of its antenna? Specifically, if I had an RFID like this one, cut the antenna and then resoldered it, would the loss in antenna length (I'm guessing about half an inch) affect the workings of the device?

Question by Kiteman    |  last reply

FM radio antennas

Are there any ideas out there for building an FM antenna booster that can be used with the usual whip antenna that comes built into most radios these days. Most of the radios are made in such a way that it is difficult to get at the internal wiring, so the booster would have to be an external unit.

Topic by youri    |  last reply

best antenna for me ?

I have a TP-link TL-WN722N wifi adapter ... it came with a detachable 4dbi antenna but its range is not good i want to use some wifi which are far from me with my current adapter the signal i get is very weak so i think by replacing antenna i can increase its range :) i searched a little bit no google & website & i liked this :) i think i can make it :) is there is any better option than this ? i want a long range antenna

Question by aayushsoni007    |  last reply

dish turned into an antenna

Can anyone help me mod a dish/direct tv satellite and make it an antenna going to the converterbox? i bought this p-o-s antenna for $50 and voila... i got 8 friggin channels.... and i live in an open space no trees whatsoever and 2~3 miles away from the tv station.... i have a dish and a direct tv satellite i also bought one of those converter boxes.. its just rediculus to buy another antenna if anyone knows how to mod the old ones anyways...

Topic by dondef  

Tesla coil antenna?

With the cold and bad weather out there I started again to tinker with my old UHF radio.Trying to build a nice antenna to put on the roof of the hous and such things...While looking up on the various antenna designs I could not help it and followed a few links with antenna designs and specs for all sorts of frequencies.There are things like horizontal or vertical transmission waves or even circular ones.But also some of the basics can be quite different, like whip antennas, dipoles or coiled ones.The later we often see in these keyfob transmitters and receivers for door bells and similar low range, low cost options.Some really old ham radio links got me to the topic or electrically shortening and lenghtening antennas.Things like coils in a whip or added capacitors to match the antenna to frequency and transmitter.A tesla coil usually produces a lot of RF interference, not just on the main frequency it operates on.And from research and physics we learned that for really great distances you need really low frequencies.Like for example the very low bands used for submarine communication around the globe.Here antennas on land can be several km long...The inventor had a few ideas in terms of wireless electricity and communication but I wonder if there is more to it...Despite the broadband EMF a tesla coil produces it is also a really narrow beam antenna.Basically the radiation cone is orientated straight up instead of the usual horizontal patterns we use for communication.The topload again provides a spherical radiation pattern.I am wondering about how a tesla coil would operate as a directional antenna if the topload is replaced with a whip style antenna of a lenght that matches the wavelength...The hip would again provide a more or less spherical beam but the coil underneath would "puch" a directional from underneath.In the classic design the topload is meant to prevent arcing while providing a capacitor so the whole thing is resonant.At lower power arcing is no problem anyways, but what effect in terms of capacitance would a whip style antenna have?Classic pherical or donut style toploads provide little to no gain in terms of antenna properties.If you would use a sphere as an antenna for your CB radio then it would be perfect for very short distance but utterly useless for open range communication.We all know the fun of placing a flourescent light near a tesla coil to show "wireless electricity".Sadly this is more an effect caused by the high frequencies be able to produce the glow in the gas filling.Trying to make an incandescent lighbulb glow is far trickier.Several experiments show that two properly tuned tesla coils can work as transmitter and receiver.But to my knowledge no one ever tried this type of experiment with an antenna on the tesla coil...

Topic by Downunder35m  

satellite patch antenna

Hello, who know the way of making a flat or patch satellite antenna? I want to find a DIY Instructables about this topic. Any ideas?

Topic by sloth  

antenna for wireless connection?

I would like to improve the signal from our modem.  (serviced by centurylink)

Question by MizDaizy    |  last reply

Tv antenna combiner

Does anyone know how to make a tv antenna combiner? The ones available for purchase do not work with my application.I have two digital antennas, one on the eave of the house and one on the gable. The one on the eave picks up 23 channels, the one on the gable picks up 30 DIFFERENT channels (mostly, some overlap) . I would like to be able to connect both antennas to my tv to get the maximum channels. Currently I have to go out and switch antenna cable at the box to watch the channel with the best program. Both antennas require 5V dc. I have tried multiple "combiners" from local sources and again they do not work, at best I get the mid range frequencies which is about 15 channels. Yes I could drill holes in the walls and put more cable in and us an A/B switch but not only is that a lot of work and costly, its no fun and I cant use my soldering iron :-)Thanks David

Question by race25  

UHF CB radio antennas or scanner antennas anyone?

For a while now I am back to experimenting with various antenna designs for my UHF radio.Started as something entirely different but who cares LOLAnyways, we usually have either a standard whip antenna or a vertical dipole design for mobile use, like on your car.This is a very good design for both types of antennas, mostly due to the short wavelenght compared to the "old" 2m or 27mHz CB radios.Fun fact for at least AU in this regard is that back in the day everyone jumped onto UHF to get away from the overfilled chatter on 27MHz, now the old 2m band is basically dead except for marine use.One thing I really miss on UHF though is distance!Line of sight communication sounds fine at first but then you really have to realise the limits once out and about.As a result we often have to choose between a high gain antenna or a stubby for going into the mountains or being in a convoy.Only way out seems to be the golden middle by opting for one of the 4.5 - 6-5DBI antennas.Neither solution really satisfies me though :(To get around the limitations and have some fun again when sitting high on a mountain I compared various commercial antennas I had.You know, pick someone with a weak signal coming in and hope he hears you and has some time for a chat.Turned out there is not really that much difference in terms of receiving a signal.Quite huge differences though when it comes to the other side being able to hear you!So I jumped onto a basic SWR meter and actually checked my so called factory tuned antennas - all but one were way off the charts here.At least if you are like me and like optimised instead of compromised antenna systems.A Standing Wave Reflection ratio of 1:2 or even 1:2.5 is seen as very acceptable thing on UHF for some weird reason.Back in my glory days no one I knew would have accepted anything above 1:1.3 for his 27MHz system, be it mobil or a station at home.Sure enough, repeating my long distance tests a few days later with tuned antennas resulted in far better results.An antenna for long distance calls or emergencies?!The easiest way to get more distance on UHF is obviously getting the antenna as high as possible.From a nice mountain top you have it way easier than in any urban areas for example.Explains why so many of the long and sturdy antennas are just simple dipoles on a long pole.If you ever checked the feedback for these double quad TV antennas you realise they are literally in the same frequency range.Similar story for all the Yagi antennas for our TV sets that you find on so many roofs these days.Only problem with them is that they usually don't give a damn about transmitting qualities.And of course that they are usually providing around 300Ohm instead of the 50Ohm our radio expects.A TV needs 75Ohm and a balun is used to provide a isolation as well as a matching for the TV.Needless to say I could not accept this ;)My first design was made from aluminium foil glued onto some printed and stiched pages for a double quad.1MHz bandwidth is quite narrow, so the basic square design with about 13.8cm for the sides of the squares was easy.To my surprise by just adding standard RG58 cable this design was very close to 50Ohm already, I had around 60.A few glue sessions later I was able to match it to 52Ohm - close enough for test.Did not want to risk anything with my expensive Icom so I used my cheap Baofeng handheld for the initial tests.Indoor mind you...To me disappointment I seemed to be unable to pick up anything.So let the sanner run and waited...After being bored enough I decided to pick, starting with the antenna and when I moved it the handheld suddenly had a clear signal.Desperate as I was I grabbed the radio and waited for the chat to continue - nothing again...Then it finally hit me: The double quad is quite directional....Sure enough by just turning it slowly I was able to pick up chatter on various channels.Once brave enough to risk it I even got confirmation that people about 10km away could hear me just fine.Time to scale it up a notch...Next design already had the directional problem included as a design feature.I added a director in the front and a reflector in the back.The endless hours of glueing and cutting were replaced by using 12mm wide copper tape and sturdier cardboard.A test with my car on a little "mountain" and the antenna on 2m pole mounted to roof rack gave me, for the first time ever, conversations with people that were over 30km away.I am currently trying to make the entire thing omnidirectional.The omni quad....If you take two double quad antennas and mount them at a 90° angle you end up with very nice 2-lobe pattern, 4 lobes if you don't use a reflector.Problem here though is that these designs really mess with your antenna matching.Not to mention that using it while driving only works at quite low speeds.One day I will do the final design in stainless steel wire though...Anyways, using the directional properties to get an omnidirection radiation pattern meant using 4 seperate antennas with a reflector for each of them.Still left a few dark spots at short range but otherwise really nice for long distance if you don't want to constantly turn your antenna.Getting 4 antennas down to 50Ohm on the connection to the cable was painful to say the least.The problem of taking care of distances to be in the sweet spot for the 477MHz range also meant the design ended up to be quite bulky.One of my lightbulb moments providing good ideas caused me to use one reflector with a double quad either side.Worked almost fine but again provided totally different values to somehow match if it ever should transmit a signal without damaging the transmitter.Obvious conclusion was to buy a new roll of copper tape and to try to get four single antennas into one "housing" without stacking them.Bad idea here was to cross the antennas :(Better idea was to make 4 pyramids out of carboard and aluminium foil.Sadly this resulted in a failure because the 4 sides of the pyramid reflect the signal not flat bt at their corresponding angles.Had to make it really big and use 90° angles, resulting in the signal being reflected like light in these cat-eye reflectors on your bike.After wasting a few days to create the real thing it turned out to not really work properly for the reception already.Even close range signals came in really distorted.I guess the double reflection meant the phase is shifting and cancelling out what the antenna gets.My last desing idea for testing will be with a different approach.Instead of 1/4 Lambda elements I will use small 1/64 Lambda elements.Only about 2cm long means that matching is pain in the behind but if the purpose is just receiving it should be fine.The reflector will be four flat sides like a box with antennas in front of the sides and the cables joined in the center.If you like to fiddle with antennas and don't mind trying a weird looking base antenna on your roof I might be willing to write up a short Instructable based on my designs - let me know in the comments....By the way: it is quite easy to desing this for the common 2.4GHz Wifi bands ;)

Topic by Downunder35m    |  last reply

Using Satellite dish or tv antenna as wi-fi antenna.

Is there way to use satellite dish or TV antenna from top of my building connecting it to computer, and use it as Wi-Fi antenna. On my wall I have a jack like this: which jack should i plug my cable(probably SAT) to connect it with network adapter. I know it sounds weird but I think its possible. What's your opinion?

Question by dvix-xx    |  last reply

Making sure antenna is working

I have a FT950 connected through a coaxial cable to a Buddipole antenna setup as a 40 Meter Dipole. I have a brother in Arizona and I heard him on a 40 meter frequency a couple of days ago but he could not here me at all when I was transmitting. How do I know the antenna is woring and actually transmitting the signal ? I have a Antenna analyser but quite frankly don't know how to use it to see if the antenna is actually sending the signal Can anyone help and advise me how to hook up and use the Analyser ? PJM21b

Topic by PJM21B  

USB WiFi Antenna Mod

I am working on adding a helical antenna to a cheap USB WiFi adapter.  My question is where do I connect the antenna to existing circuit.  I've attached a closeup picture with three likely points.  My three main questions are: 1) Where to connect the external antenna 2) Do I disconnect the rest of the onboard antenna (my gut says yes) or just add in the new 3) What impedance will the external antenna need to match?  I assume the components between points C&B; and B&A; are for some kind of impedance matching.

Topic by telfon    |  last reply

wire a antenna to open or close?

Wire a car antenna to open or close using a digital timer and 12 volt battery charged by solar panel.  The antenna opens with +/- and closes with reverse power -/+.

Question by latate    |  last reply

Change the fixed antenna on a router

I'd like to change the 2db antenna that is fixed on my Netgear WGR613V with a bigger one to improve wifi range. 1) I'd like to know if if's possible and what connector I should choose to solder. I understand there are SMA, TNC, etc...? I made the mistake of buying a NEWLink 7dBi Omni Directional Reverse SMA Antenna and I don't know if I'll be able to use it. thks in advance Cheers. G

Question by Gaetan321    |  last reply

am antenna connection problem?

My tuner has seperate places to connect am and fm antennas.  The am connection is intended for 2 wires. I just bought an am antenna and discovered that it  has a plug end, not a bare wire end. Is there some sort of adapter/connector I can use?   I don't want to strip the wire. I think I need the equivalent of a reverse banana plug - instead of wire in, plug out - I need plug in, wires out. Any help / suggestions appreciated.

Question by re-tired    |  last reply

DIY USB WIFI antenna

Ok so basicly at my school they have two different WIFI spots one is near the classrooms that I work in and is WEP protected and only for teachers and the other one is in another building and is not WEP protected and I can only get that signal if I am in that building. So what I want to do is make my own WIFI antenna so that I can get the unprotected signal while in my classroom. I want to make a USB wifi antenna pretty much.

Topic by jackillac92    |  last reply

DIY Car Stereo Antenna?

Want to know if anyone has turned their roof rack into am/fm radio antenna or knows how? Not how to mount an antenna on a roof rack!!! I have a Jeep Liberty (2005), w\ (self) custom made aluminum roof rack. And I have 35ft of flexible/braided grounding strap to make internal run from roof-rack through and internally down to jeep frame if/as needed. **Concept Notes**  Outside rectangle frame is 1-1/2" (O.D.). I will rubber-coat all straight tube section then apply appropriate wire on to rubber and re-coat with rubber coating. I was then looking to slide slightly over-sized (I.D.) carbon fiber tubing over that. Ground and antenna wire will run through inside of rack turn down stanchion where bolts to roof. Rubber grommet to further insulate & protect wires. I want super reception AM & FM, little to no visible footprint, 1. What wire or such for antenna is best/appropriate? 2. Proper lay out antenna wire? ie., wrapped around primary insulated tubing or laid out length-wise.

Question by nickynite63    |  last reply

Hooking up an FM antenna?

I recently got a new power amplifier/tuner from my dad's buddy. On the back, where you hook up the antennas, there are 4 terminals: 2 for FM and 2 For AM. One on the AM side is for the antenna, and the other is ground. This make sense to me, because an AM loop antenna has two wires which need to be hooked up. On the FM side though, it also has a terminal for ground... From what I understand, FM antennas are composed of a single "wire", like those coming out of radios or the ones on cars. What's the ground on the FM side for?

Question by tylervitale  

Re: dipole HD antenna?

 I noticed in Home Depot 4' x 8' sheets of metal lathe used for putting stucco on housing exteriors.  It was cellular with each cell being an elongated hexagon approx 5/8 inches in length.  The long sides of each cell had been bent at 20-30 degrees (guess) to provide a cavity based substructure for the stucco.  My thoughts went to the fractal antenna posted by williamruckman  on Jan 3, 2009.  An interior attic roof would provide an invisible and safe location similar to the entry point for a dish cable.  The lathe could be shaped virtually without limitation for tuning.  Thoughts??  VR?

Question by von rad    |  last reply

Exterior Wifi Super Antenna

I need to build a dish for a friend so he can get WiFi from about 200 meters. I have several dishes to work with my problem is the antenna will be at least 30 feet from the computer. I will use this linksys usb  i would like input on the idea of a usb to cat 5 to stretch the usb cable? should i power the linksys from a powered hub ? the build will be posted on instructables when done and i will give credit due. my parabolic gets about a 14 db increase from a WiFi usb thumb it just puts the thumb into the sweet spot of the dish and is not for the outdoors. I an open to any and all suggestions tomorrow i will post what my db are from the site .

Topic by bikerbob2005  

Long Range Wifi Antenna

Can anyone recommend a good instructable to boost the reception range for my computer's wifi device? I know there are tons of them on here already, I just need to know which ones might have the longest range. Another thing is what design would be best. The kind involving a parabolic dish/mesh to direct signals to a usb dongle. One that is more of an omni direction antenna. One that makes use of one of the old sattelite tv dishes sitting in the garage. Requesting advice, comrades.

Topic by Kozar    |  last reply

how to make digital antenna ?

Stainless wire to make digital antenna info please.

Question by teav56    |  last reply

inductivily coupled wifi antennas

Is inductive coupling between antennas and my wifi card/computer possible? If so, how (I don't want to tamper with my laptops innards).

Topic by bubbahead    |  last reply

Different antennas on one mast

I have a standard vhf/uhf/fm antenna on my roof. I live about 45 miles + from the towers. I also would like to get in HD Radio and decent fm stations. Therefore, I bought an Antennacraft FM6 yagi antenna for the roof. Can I place this antenna on the same mast as the tv antenna? If placed too close would this cause interference for either? Any advice would be appreciated. Thanks!

Topic by stacym456    |  last reply

How to create RFID antenna

Can you please guide me as how to create RFID Antenna and how it can be integrated with RFID reader ?

Topic by arumansoft    |  last reply

Which is the FM transmitter antenna ? Answered

When I wanted to expand my FM transmitter broadcast range I found a White and Red and Black wires please specify me which is the antenna one .

Question by achraf52    |  last reply

Basic outdoor fm antennae? Answered

I need to make a basic fm antennae for my reciever inside my mancave,  It's a steel shed converted and inside reception drives me crazy.  I do have basic poles and some wire types in my arsenal.  Someone PLEASE HELP.  I need my music to keep my sanity if you can relate.

Question by gday85208    |  last reply

Rotating Antennae Wiring Question? Answered

Ok, something I've been thinking about for awhile.  Say you have an antennae/radar dish/etc that rotates 360°. Naturally, you have wires running up to the antennae connecting it to the rest of your circuit/broadcasting/receiving device. How do you prevent the wires from wrapping around the antennae and causing it to stop or causing the wires to break? I suppose you could reverse the antennae every so often to prevent this, but there must be a better way. Also, I figured you could have some sort of connection that rotated around, but it seemed that a rotating connection could be problematic if debris or something got in the way. It also doesn't seem like a very solid way to connect the two devices together.  Not actually building something here, just a curiosity. Thanks!   

Question by transistorguy    |  last reply

How to turn "off" internal antenna while using External antennae?

Greetings! I am beginning a project to put a home-made >18db  yagi on my CLEAR modem; in desiring to keep original functionality while adding ability for external attenna access, the installation of a PCB or case mount BNC suggests a need to turn "off" the internal antenna when the external is connected. is this do-able? if so, may I ask for assistance in understanding how please? Thank you. CAH

Question by Ceyarrecks    |  last reply

How do you determine the length of an antenna and the size of a fractal antenna? Answered

In an instructable, the formula for calculating antenna length was given as "length in meters =300 / frequency in MHz".  The example given was for a Bluetooth antenna with a frequency of 2450MHz.  The antenna length was calculated as 300/2450 = 0.1225m = 12cm.  The author then divided it by 4 to make a "quarter wave" antenna length of 30mm.  Why divide it by 4 and what is the benefit of a "quarter wave" antenna.  What is the effect of the conductor leading to the antenna?  If the 30mm antenna is soldered to a 4mm lead, does that result in a 34mm antenna?  For a fractal antenna, should the 30mm length of wire be folded into a fractal shape or should the total fractal antenna be 30mm in width?  I have read somewhere that one of the benefits of a fractal antenna is that they are able to receive signals of different wave lengths.

Question by fcampbell    |  last reply

how can i attach an antenna (or a cable as antenna) to this cordless phone base?

Theres ANT1, ANT1_SHORT and ANT1_SGND. I thought maybe solder a cable into ANT1 only and it should work. I need to extend my phones range by a couple of meters (it says 50mts but it doesnt even gets to the 5 mts. probably due to the walls) thanks! i did find this schematics: in my search. Its the TG220 one. I probably would just solder and try it but i fear i might damage it as i got no replacements

Question by JohnnyG22    |  last reply

Can you make a wifi antenna?? Answered

OK, so here is my idea, I want to make a wifi antenna from scratch and then ad a booster to it to improve my old laptop's range. Is it possible to build your own antenna or do you need a base antenna or connector?

Question by JM1999    |  last reply

Is there a way to estimate how long an antenna is?

If I built a radio transmitter and then attached it to an antenna of unknown length, is there a way to calculate the length of it using transmissions? Or, as a separate question, if I had an antenna of known length and then increased or decreased the length, would there be a way to estimate the new length from transmission properties (basically without physically measuring the antenna? Assume the antenna is a straight line.

Question by kakashibatosi    |  last reply

which wifi antenna setup is better?

Hi, I currently have an antenna in form of 12" dish and alfa 1w usb nic with 5db eboit antenna in the middle and I get signal from 1km range but I will be moving to an half island and there is internet about 1.5 km away. is the fallowing antenna any better then my setup? can you compare. thank you fellow wifi geeks.. Al

Question by celalboz    |  last reply

RF antenna wiring (Possible error)?

For our truck scale, we have small remotes to automatically record the weights. The remotes just do not have the range that they should be getting (Sometimes we have to actually touch the antennas with the remotes). Before I ask my questions, let me explain how they are wired up. There are 16 remotes going to 16 channels in the controller box, The first set of 8 are on one receiver/antenna and the second set is just a copy of the first set. The antennas are just a small whip type antenna connected to the center conductor of the coax, there are then 4 more of those wires pointing down, these ones are connected to the shielding on the coax. There is a 75ft RG6 coax cable running to each of those antennas, This cable runs into the scale shack and connects to the f-type jacks on the controller box. Inside the box, there is a short piece of shielded wire going from the coax jack into the rf receiver. Here is where it gets weird, The center conductor AND the shield both are attached to a single screw terminal on the rf receiver. If my thinking is correct then this basically turning the coax cable itself into the antenna, Am I correct? Why would it be installed like this, Was it a bad installer? How should this be done for optimum performance? Thanks, Kade

Question by FarmerKJS    |  last reply

What is the best TV antenna for me?

I live in a bottom, surrounded by hills and trees, in a fringe reception area. My digital TV reception stinks to put it mildly. What is the best kind of antenna to get, where can I get it, how high should I mount it, what is the best way to mount it etc. ? I live in a small wood house with a chimney, and a tin roof. By the way, I am not cheap, just broke and don't make a lot of money, so the cheaper the better. Thanks?

Question by kikdvd    |  last reply

Antenna length for a frequency modulated signal.

I  am given to understand that the length of an antenna is proportional to the wavelength of the signal that is fed to it (a quarter wavelength, for example). In the case of a signal modulated by amplitude, the frequency (and therefore wavelength) of the carrier wave remains unchanged. However, in the case of a signal modulated by frequency, the signal fed to the antenna will vary in frequency (and, therefore, wavelength). My query is this : how would one go about calculating the length of an antenna for a frequency modulated signal? Its frequency is not constant, so to construct an antenna of say, a quarter of the wavelength, would be impossible. I thank you in advance for your assistance. AlexHalford

Question by alexhalford    |  last reply

Car Stereo Antenna for In-Home use? Answered

I'm decent with working with modifying electronics, but I don't have much experience with antennae, reception, or any of that good stuff. I have plenty of experience with soldering, both wire connections, and motherboard components, so that's not a problem.. I already have my stereo wired to my computer's psu, with the pci-e power, and already have everything hooked up as of a year ago.. Aux In, Usb, and Sd all work fine, but I can't use the FM radio function, due to my lack of an antenna.. I've heard of bending a coat hanger, and shoving it in, and I don't like that shotty work, and I used to have an extension, or an adapter, (Not sure exactly what it was), but It got mediocre reception, and I gave it to a friend that I hooked up a stereo indoors for.. I can find such an adapter cheap, but I want something that will get AWESOME signal.. I know most components that require lengths of wire drop voltage, or signal over distance, such as power cables, Cat5 cables, so on and so forth.. So what can I use, modify, or make to get the reception I want, on a budget? I don't want a crappy fix.. I just want something affordable, reliable, and something that won't look too horrible. I have the stereo mounted to my desk, so not much will be exposed, depending on the length of said antenna, Thanks in advance!!

Question by FordKid17    |  last reply

CB radio antenna question(s)....

I have a UHF CB radio in the car that is now quite outdated.Waiting for a 80CH replacement to arrive so the old one can be used as a fixed station in the house.Recently I made a new straight whip for the car as the fibreglass one snapped off.Now the problem I am facing is a total between reality and computer simulation.Here is what I did:Started with a straight steel wire on the elevated mounting - this spring mount is supposed to provide a ground plane as it was originally for a ground independent antenna.Simple math tells that a 1/2 Lambda whip should be around 33cm long, so I started with 40 and used my truted SWR meter.As it turned out my antenna was too short !?Tried again with a longer wire and got a good SWR reading of 1.09 with a total whip lenght of 49cm.As the elevated mount basically turns the entire antenna assembly into a vertical dipol I decided to simulate the thing in Mmangal.Should be straight forward, diameter and length of the ground rod, wire length and diameter for the actual whip.But with the same dimensions I have working fine on the car Mmangal tell me my antenna is totally out of whack.Calculated SWR is well over the 15 and the antenna is not anywhere near resonant in the 470MHz band.Mmangal is mainly for lower frequencies but shouldn't it work for the 70cm band as well?If I design the antenna as a classic ground plane with 3 or 4 radiating elements sloped at 42° I still get nowhere with my whip length.Since my SWR meter is correct and the antenna working really well I am wondering where my problem with Mmangal might be?Anyone here using it for 470MHz or with some insight on how to get the correct values for a vertical dipol antenna with a rod for ground and wire for the whip?

Question by Downunder35m