What is a good wide-band receiver antenna today?

[KD9KSO]

Decades ago I had a RadioShack discone on the roof for general coverage. I later added a Yagi beam and pointed it at KSTL. It picked up great. From 20 miles away I could pick up Clearance Delivery and the tower controllers.

Currently, I'm using my tri-band ham antenna to receive for the scanners, but switching back and forth is a pain and I can't talk on the radio and listen to long range on the scanners.

I don't really know what is good these days for outdoor scanner antennas. I'd like some gain, so I'm not considering a discone. I'm pretty far out and mostly just receive local transmissions on the Diamond RH77CA's I use on the hand-helds when the ham antenna is in use. I'm also using a home built 1/4 wave ground plane.

I am mostly interested in CIV/MIL aviation, and public service. I have separate antennas for below 30Mhz. No 7, 8, or 900Mhz, no digital, and no trunking.

So what is popular these days for omni-directional receive antennas for conventional VHF/UHF?

 

[Freemor]

I use a Tram 1411 Discone antenna for my SDR. It does an excellent job from MW to about 1Ghz. I use it for everything from SWL to tracking planes with ADSB on 1090Mhz.

 

[John_S]

My Comet GP-6 and the diy off center fed dipole that gets mentioned here are both winners at my station.

 

[Enforcer52]

The best omni-directional multi-band that I have found for my use in a rural area is the Omni X. The discones just didn't cut it on 800mhz. It's on the expensive side but well worth it.

OmniX Scanner Base Antenna

Specs Gain: 3 VHF 4 UHF dBi Pattern: Omni-directional Wavelength: 1/2 Elements: 3 Tuned: 118-137, 148-175 & 225-900 MHz Band: UHF & VHF Connector: N Female Cable: RG8X Cable Length: 16 Inches Height: 45" Width: 30" Weight: 2 lb Features Multi Band-Wide Coverage: The uniquely...

dpdproductions.com

 

[KD9KSO]

Thanks for the link. This might be the one.

 

[John_S]

I gave that Omni X a try and at first it seemed good...until I tried building the DIY OCF dipole. The DIY antenna is better on VHF High and Low.

 

[hazrat8990]

From the looks of the OmniX, it seems to just be an expensive, oddly shaped fan dipole. There may be some magic device hidden inside the pipe at the feed point, but I have my doubts.

 

[prcguy]

From the looks of the OmniX, it seems to just be an expensive, oddly shaped fan dipole. There may be some magic device hidden inside the pipe at the feed point, but I have my doubts.

It appears to be a two element inverted V fan dipole for VHF in parallel with a fat dipole for UHF. Could you make one that will work the same? Sure. Can you make one for less than what the Omni X cost? Sure, if you don’t count labor. Or you’re willing to work for $1 an hour.

I think it might take me a good 4 to 6 hours to make one from scratch estimating the lengths of the original, starting a little longer and trimming to resonance if I had all the materials in front of me, which I probably already have in my garage. But Im really good at this and have lots of experience.

For anyone else you have to locate the materials, prep and cut them, prep the coax with connector and lugs after you fish it through a hole in the pipe, make an insulated spacer to hold the coax centered inside the pipe and have test equipment ready. Oh, and if you make a mistake and elements come out too short start over. Or just buy one from DPD.

 

[John_S]

The construction of this antenna is actually quite simple...take two slightly off center fed dipoles and flip one of them. Arrange them 90 degrees apart. There's no phasing or any other type coils or matching network. And it wasn't cheap either. Not complaining but for my usage, the DIY antenna was way better.

 

[hazrat8990]

It appears to be a two element inverted V fan dipole for VHF in parallel with a fat dipole for UHF. Could you make one that will work the same? Sure. Can you make one for less than what the Omni X cost? Sure, if you don’t count labor. Or you’re willing to work for $1 an hour.

I think it might take me a good 4 to 6 hours to make one from scratch estimating the lengths of the original, starting a little longer and trimming to resonance if I had all the materials in front of me, which I probably already have in my garage. But Im really good at this and have lots of experience.

For anyone else you have to locate the materials, prep and cut them, prep the coax with connector and lugs after you fish it through a hole in the pipe, make an insulated spacer to hold the coax centered inside the pipe and have test equipment ready. Oh, and if you make a mistake and elements come out too short start over. Or just buy one from DPD.

A person could literally make this for free if they were to use scrap pieces from an old lawn chair and an aluminum broom handle. The only thing that might need to be sourced, is a piece of PVC. As far as tuning, there are plenty of online calculators that will get you close enough. If you were to try to use it for transmit, then tuning would be necessary.

 

[John_S]

It could be home built....but after my experience I wouldn't bother. Need 1/4" solid aluminum rod, some 1 1/8" aluminum tubing, and some stainless hardware to hold it together...along with plastic insulators. Simple construction but not a simple diy project once you examine it.

 

[prcguy]

A person could literally make this for free if they were to use scrap pieces from an old lawn chair and an aluminum broom handle. The only thing that might need to be sourced, is a piece of PVC. As far as tuning, there are plenty of online calculators that will get you close enough. If you were to try to use it for transmit, then tuning would be necessary.

There are 3 separate dipoles to contend with that interact and no online calculator will estimate things close enough. Have you ever designed and built a complex antenna from scratch then accurately tested it against another antenna?

 

[hazrat8990]

There are 3 separate dipoles to contend with that interact and no online calculator will estimate things close enough. Have you ever designed and built a complex antenna from scratch then accurately tested it against another antenna?

It is literally just a fan dipole, nothing more. The only difference is that all of the elements are using tubing instead of wire, and they are arranged in a manner that would give only the highest band true vertical polarization, and the others close to vertical.

 

[rivardj]

It is literally just a fan dipole, nothing more. The only difference is that all of the elements are using tubing instead of wire, and they are arranged in a manner that would give only the highest band true vertical polarization, and the others close to vertical.

Ok cowboy, whatever you say.

 

[prcguy]

It is literally just a fan dipole, nothing more. The only difference is that all of the elements are using tubing instead of wire, and they are arranged in a manner that would give only the highest band true vertical polarization, and the others close to vertical.

So I guess DPD should drop their price to around $20 based on this info?

 

[John_S]

I wouldn't give more than $100 after seeing it.

 

[hazrat8990]

So I guess DPD should drop their price to around $20 based on this info?

I'm not saying that at all. It appears to be a quality product that is put together nicely. They are a business, and are entitled to make a profit. The price is a bit steep IMHO, but as long as they're making sales, more power to them! On the other hand, if a person wishes to build their own for a few pennies, and a bit of time, it's really not that complicated.

This forum is full of hobbyists, and ham operators. Lots of folks on here benefit a great deal from trying new things, such as DIY antennas.

BTW, I like your sig!

 

[Ubbe]

When looking at the Omni-X measurements it seems as they have just cut the lengths of the two VHF dipoles to the middle of the VHF airband and VHF-hi band and the fat dipole covers the UHF band. The VHF dipoles are tilted and have peak gain down in the ground and up in the air and from the side they are between horisontal and vertical polarisation.

Elements will interact and work at multiples of their tuned frequencies so it will be dips and peaks and not as consistant as a discone antenna and will sometimes be worse and sometimes better than a discone. It doesn't have much coverage of the 200-350Mhz range so they had to make another Omni-X antenna covering that mil air band but then also sacrificing other frequency bands. It's a lot of metal in the air and the more metal surfaces you have the more random RF signals it can capture. It's very similar in design to a Antennacraft ST-2.

/Ubbe

 

[JustinWHT]

Recommendations for mobile scanner antenna for VHF and UHF?