What antenna configuration do i use?

[AngWay]

So i have been struggling to figure the answer out to this question for a while now. I bought the RTL-SDR kit and i don't know how to configure the antenna, videos on youtube have conflicting answers i see one person say use it one way and then another person in a different video says to use it another way. I will add some pictures here showing what i mean, in the first pic the antenna is vertical , and the second pic it's horizontal, and the third pic is a bunny ears type config. The stuff i am listening to is between 150 and 450 mhz. also i thought about sealing this antenna up and putting it on the roof of my house, can it be used that way? would it work? it's a dipole antenna maybe you all are familar with it, it comes with the RTL-SDR bundle kit on amazon.
Thanks to everyone who responds

 

[jtwalker]

My opinion, toss it in the trash.

 

[paulears]

The toss it in the trash, can oddly be quite valid in certain circumstances. What you have to do, is consider the physics and then balance that against practical things. Firstly, its an antenna designed as a workable compromise. A dipole is not an issue, but telescopic ones need adjustment if what you want to listen to is anything other than strong. So if you do the maths, you might arrive at a length for a particular frequency, and it will work a bit above and below it. If you use it pulled out so the two elements are in a plane, 180 degrees apart, then that is the dipole standard mode, and it will also be resonant at 3 times the frequency. If you perk the elements into a v shape, then its not really a dipole any more but one of the dozens of different antenna standard designs. It might give you some directivity, or for wideband use, the ability to null out annoying strong signals that spoil reception. It is always a compromise. However, they are indoor designs, poorly suited for base station use. They‘re fragile, difficult to mount on poles or walls, and usually mean you need to waterproof a joint outside. If you want an outside antenna, buy or make one that is strong and waterproof. Use decent cable and it will last years. One crash from a seagull will bend the flimsy telescopics, plus they will rust and perform very badly.

what you have is a quick to setup, compromise antenna. With your intended use, it could work. If the transmitter is local and strong, it will be fine. If your source is a bit further away, it may never hear it. Antennas need to be suitable for the frequencies desired, reliable, in the clear and usually high up, or a random bit of wire might work just as well. Buy a dipole meant for radio FM reception, cut the tubing to the right length and stick it outside on a proper mount with decent cable. Pretty cheap. In metric, take 300, divide by the wanted frequency and you have the wavelength. Divide by four to get the rough length of each tube on a centre fed dipole. Thats a simplified bit of maths but is fine for receive.

 

[AngWay]

The toss it in the trash, can oddly be quite valid in certain circumstances. What you have to do, is consider the physics and then balance that against practical things. Firstly, its an antenna designed as a workable compromise. A dipole is not an issue, but telescopic ones need adjustment if what you want to listen to is anything other than strong. So if you do the maths, you might arrive at a length for a particular frequency, and it will work a bit above and below it. If you use it pulled out so the two elements are in a plane, 180 degrees apart, then that is the dipole standard mode, and it will also be resonant at 3 times the frequency. If you perk the elements into a v shape, then its not really a dipole any more but one of the dozens of different antenna standard designs. It might give you some directivity, or for wideband use, the ability to null out annoying strong signals that spoil reception. It is always a compromise. However, they are indoor designs, poorly suited for base station use. They‘re fragile, difficult to mount on poles or walls, and usually mean you need to waterproof a joint outside. If you want an outside antenna, buy or make one that is strong and waterproof. Use decent cable and it will last years. One crash from a seagull will bend the flimsy telescopics, plus they will rust and perform very badly.

what you have is a quick to setup, compromise antenna. With your intended use, it could work. If the transmitter is local and strong, it will be fine. If your source is a bit further away, it may never hear it. Antennas need to be suitable for the frequencies desired, reliable, in the clear and usually high up, or a random bit of wire might work just as well. Buy a dipole meant for radio FM reception, cut the tubing to the right length and stick it outside on a proper mount with decent cable. Pretty cheap. In metric, take 300, divide by the wanted frequency and you have the wavelength. Divide by four to get the rough length of each tube on a centre fed dipole. Thats a simplified bit of maths but is fine for receive.

so i should buy a dipole or a discone my frequencies i listen to are from 150 to 450 mhz

 

[mmckenna]

frequencies i listen to are from 150 to 450 mhz

Are you listening to the -entire- range between 150 and 450MHz, or just the 150-174 and 450-470MHz LMR range?

If it's just the public safety/LMR stuff, then a base dual band antenna with some gain designed for LMR use (as opposed to the amateur radio dual band antennas) will run circles around a discone.

Discone antennas have zero gain and perform poorly compared to a band specific antenna that has some gain. The only benefit to a discone antenna is it's exceedingly broad bandwidth. Unless you are listening to the entire range between 150-450 (including all the TV bands, UHF aviation, 220MHz, military, etc. then I'd skip the discone.

 

[popnokick]

Yes, the antenna that you have is not going to be as effective as this inexpensive indoor antenna that you can put together in about 15 minutes with less than $20 in hardware store parts. Scroll down the page to the all-wire version (unless you want to make the copper pipe version). Hang it vertically on the highest floor of your building, preferably in / near a window -
Homebrewed Off-Center Fed Dipole - The RadioReference Wiki

 

[paulears]

What people are saying is that honestly, we don't know your circumstances. If your area of interest was say, marine band and the stuff up in the 440-450 ish area then a dipole would probably be a great antenna, and cheap. You could use something like the diamond style antennas - these work pretty well with a bit of gain at 144-8Mhz, but are OK-ish at marine. They accidentally cover some of the UHF air band not too shabbily, but they're not very wonderful at VHF air. If you want good results (though not exceptional) everywhere, then a discone would be great. You've kept the details of what you want to do quite secret, so none of us will say Buy an XYZ, because we get the feeling you have not told all?

 

[AngWay]

What people are saying is that honestly, we don't know your circumstances. If your area of interest was say, marine band and the stuff up in the 440-450 ish area then a dipole would probably be a great antenna, and cheap. You could use something like the diamond style antennas - these work pretty well with a bit of gain at 144-8Mhz, but are OK-ish at marine. They accidentally cover some of the UHF air band not too shabbily, but they're not very wonderful at VHF air. If you want good results (though not exceptional) everywhere, then a discone would be great. You've kept the details of what you want to do quite secret, so none of us will say Buy an XYZ, because we get the feeling you have not told all?

Ok what i listen to is 151.6700, 155.2375, 152.6825, 161.800, 453.6620, 462.1350 it's mostly police and ems stuff. i am looking at this Antenna what do you think? it says it's made for those freqs.

 

[prcguy]

Ok what i listen to is 151.6700, 155.2375, 152.6825, 161.800, 453.6620, 462.1350 it's mostly police and ems stuff. i am looking at this Antenna what do you think? it says it's made for those freqs.

Ooh, not a good representation of a Discone. More like a ground plane that went wrong. For about the same $$ you should be able to get a Tram type Discone which is a real Discone.

 

[paulears]

Yep - I concur. That's a poorly designed sort of discone. 4 lower elements do NOT make a cone at all!.

 

[AngWay]

Ooh, not a good representation of a Discone. More like a ground plane that went wrong. For about the same $$ you should be able to get a Tram type Discone which is a real Discone.

So this Antenna is the better one? i thought that since the other one was designed for those specific freqs that it would be better, so no? And what kind of cheaper antenna would you say is best for these freqs 151.6700, 155.2375, 152.6825, 161.800, 453.6620, 462.1350 ?

 

[prcguy]

So this Antenna is the better one? i thought that since the other one was designed for those specific freqs that it would be better, so no? And what kind of cheaper antenna would you say is best for these freqs 151.6700, 155.2375, 152.6825, 161.800, 453.6620, 462.1350 ?

The Tram Discone should give consistent performance from the VHF air band down to 118MHz up through your 462MHz frequencies and probably to 512MHz. Discones that cover the lower frequencies I mentioned are not so good in the 700/800/900range because the radiation pattern points up above the horizon loosing some gain. If all your interested in is the 151-155MHz and 453-463MHz range then a dual band collinear type ground plane may work a little better, the kind that has a whip about 3ft long with a coil in the middle and a mount with three or four ground radials about 18" long each.

Maybe something like this antenna

Dual Band VHF/UHF 150-160 & 450-470 MHz 5/8 Wave High Gain Antenna

5/8 Wave Antenna, 150-160 & 450-470 MHz, Base loaded Dual Band High gain antenna Gain (dB) 3/6. Base loaded Dual Band High gain antenna. 75 Watts, Whip Length

theantennafarm.com

On this ground plane mount

Tram 1465 - Mobile Antenna To Base Convertors

Mobile to Base Station Adapter Kit. Use with NMO style HF, VHF and UHF antennas. Includes bracket, clamps, radials and mounting bracket. Frequency Range 0 -

theantennafarm.com

 

[AngWay]

The Tram Discone should give consistent performance from the VHF air band down to 118MHz up through your 462MHz frequencies and probably to 512MHz. Discones that cover the lower frequencies I mentioned are not so good in the 700/800/900range because the radiation pattern points up above the horizon loosing some gain. If all your interested in is the 151-155MHz and 453-463MHz range then a dual band collinear type ground plane may work a little better, the kind that has a whip about 3ft long with a coil in the middle and a mount with three or four ground radials about 18" long each.

Maybe something like this antenna

Dual Band VHF/UHF 150-160 & 450-470 MHz 5/8 Wave High Gain Antenna

5/8 Wave Antenna, 150-160 & 450-470 MHz, Base loaded Dual Band High gain antenna Gain (dB) 3/6. Base loaded Dual Band High gain antenna. 75 Watts, Whip Length

theantennafarm.com

On this ground plane mount

Tram 1465 - Mobile Antenna To Base Convertors

Mobile to Base Station Adapter Kit. Use with NMO style HF, VHF and UHF antennas. Includes bracket, clamps, radials and mounting bracket. Frequency Range 0 -

theantennafarm.com

That looks totally differnt than the tram discone i sent but i'll take your word for it u seem to know alot more than me. i'm getting ready to pull the trigger on a antenna and that's the one i should go with and i won't have any problems with it? btw what about a J pole antenna?

 

[prcguy]

That looks totally differnt than the tram discone i sent but i'll take your word for it u seem to know alot more than me. i'm getting ready to pull the trigger on a antenna and that's the one i should go with and i won't have any problems with it? btw what about a J pole antenna?

If the 151-155MHz and 453-463MHz range is all you will ever need going far into the future, then the Tram mobile antenna and ground plane mount will work a little better than a Discone across those specific ranges and maybe a few MHz more on UHF but that's it. Otherwise a Discone works ok over a very wide frequency range including 118-136MHz VHF air, 144-148MHz amateur, 148 to 151MHz fed stuff, 151-174MHz business, commercial, public service, marine and more fed stuff. Plus the 225-400MHz UHF air band, 406-420MHz fed, 420-450MHz amateur, 450-512MHz business, commercial, public service, etc. A Discone works over a very wide frequency range and works well for most people.

Make sure your comfortable with you future needs and get what covers the stuff you want to hear. There are some antennas that will receive a little to a lot better than a Discone but you give up super wide frequency range doing that and the ones that work a lot better start to cost a lot more $$.

A J-pole is a tuned frequency resonant antenna and not my favorite. They do come in a dual band version that might work across the VHF and UHF frequencies you mentioned and possibly a little bit better than a Discone, but they are not wide band and they have their specific problems.

 

[AngWay]

If the 151-155MHz and 453-463MHz range is all you will ever need going far into the future, then the Tram mobile antenna and ground plane mount will work a little better than a Discone across those specific ranges and maybe a few MHz more on UHF but that's it. Otherwise a Discone works ok over a very wide frequency range including 118-136MHz VHF air, 144-148MHz amateur, 148 to 151MHz fed stuff, 151-174MHz business, commercial, public service, marine and more fed stuff. Plus the 225-400MHz UHF air band, 406-420MHz fed, 420-450MHz amateur, 450-512MHz business, commercial, public service, etc. A Discone works over a very wide frequency range and works well for most people.

Make sure your comfortable with you future needs and get what covers the stuff you want to hear. There are some antennas that will receive a little to a lot better than a Discone but you give up super wide frequency range doing that and the ones that work a lot better start to cost a lot more $$.

A J-pole is a tuned frequency resonant antenna and not my favorite. They do come in a dual band version that might work across the VHF and UHF frequencies you mentioned and possibly a little bit better than a Discone, but they are not wide band and they have their specific problems.

Ok i think I'm gonna go with This all i listen to is those i said but i do want to hear other stuff when i want. btw i have ordered a antenna switch as well and running two coax cables so i can put up two antennas and just switch between what i want. i think that will be the best way so i can cover it all. i have a J pole that will be the second antenna....

.a huge problem i have been having is when i'm listening to the 150 range i have bad overload or something it only happens on that band and there are only 4 main control channels there but they are to strong and my feed goes bazerk when listening, i'll add some pics showing what i mean, i have tried playing with the gain but nothing works, i do have a fm filter installed but it doesn't help. if u have any ideas on that i'm open ears. This happens every minute or so it really messes up everything. i have posted about it before here and on reddit but nobody really knows.

 

[AngWay]

If the 151-155MHz and 453-463MHz range is all you will ever need going far into the future, then the Tram mobile antenna and ground plane mount will work a little better than a Discone across those specific ranges and maybe a few MHz more on UHF but that's it. Otherwise a Discone works ok over a very wide frequency range including 118-136MHz VHF air, 144-148MHz amateur, 148 to 151MHz fed stuff, 151-174MHz business, commercial, public service, marine and more fed stuff. Plus the 225-400MHz UHF air band, 406-420MHz fed, 420-450MHz amateur, 450-512MHz business, commercial, public service, etc. A Discone works over a very wide frequency range and works well for most people.

Make sure your comfortable with you future needs and get what covers the stuff you want to hear. There are some antennas that will receive a little to a lot better than a Discone but you give up super wide frequency range doing that and the ones that work a lot better start to cost a lot more $$.

A J-pole is a tuned frequency resonant antenna and not my favorite. They do come in a dual band version that might work across the VHF and UHF frequencies you mentioned and possibly a little bit better than a Discone, but they are not wide band and they have their specific problems.

The discone with the whip at the top what makes that different than the one without it. Like what would you need the whip for?

 

[merlin]

That Tram is about your best bet if you can get it above your roof line.
As for your overload, it happens and a couple solutions are:
1 Reduce your gain in your dongle configuration, Turn off AGC and slide the gain to about mid point.
This could still be too much, but the idea is reduce the gain until the desired signal just drops a bit. (Best S/N ratio)
2 If you still have an overload, you may need an attenuator, say 6 to 10 Db after the antenna.
Using an FM broadcast trap and/or any bandpass filtering will help a lot also.
Note, that discone is very broadband, you should get good performance from 100 MHz to above 900 MHz
Use a quality RG6 or LMR coax to 50 foot.

 

[merlin]

The discone with the whip at the top what makes that different than the one without it. Like what would you need the whip for?

The whip is added for frequencies below 100 MHz and I found they are poor at best. Not needed for your application.

 

[prcguy]

The discone with the whip at the top what makes that different than the one without it. Like what would you need the whip for?

Most Discones with a whip have the whip tuned to about 50MHz to help it work on lower frequencies. The loading coil in those whips helps decouple the whip from the Discone a bit on higher freqs to avoid problems. The Centerfire Discone you pointed to just has a VHF whip on top making it a VHF ground plane and not really a Discone any more. I prefer no whip on top and if I need lower frequencies I'll add a low freq antenna and combine it with the Discone.

 

[AngWay]

That Tram is about your best bet if you can get it above your roof line.
As for your overload, it happens and a couple solutions are:
1 Reduce your gain in your dongle configuration, Turn off AGC and slide the gain to about mid point.
This could still be too much, but the idea is reduce the gain until the desired signal just drops a bit. (Best S/N ratio)
2 If you still have an overload, you may need an attenuator, say 6 to 10 Db after the antenna.
Using an FM broadcast trap and/or any bandpass filtering will help a lot also.
Note, that discone is very broadband, you should get good performance from 100 MHz to above 900 MHz
Use a quality RG6 or LMR coax to 50 foot.

I have tried that with the gain i have also tried removing my LNA and that doesn't help either i have a FM filter on it already . what is a attenuator? is it something i can put at the antenna like the fm filter?.

Also if i run 40 foot of RG6 and go into a splitter can i use RG58 pigtails to connect my dongles to the splitter or will that defeat the purpoose of the RG6?