Suggest an outdoor antenna

blaster668 · #1 (**permalink**) 10-28-2010, 9:11 PM

Hi everyone, I would like to install an outdoor antenna for scanning on top of my roof. I'm currently just using a Diamond RH77. The only bands I need at all are 150-160 and 450-470. I already pick up the 450-470 frequencies pretty well, but the VHF are definitely in a fringe area. What would you suggest for these bands with more emphasis on VHF performance?

n5ims · #2 (**permalink**) 10-28-2010, 9:58 PM

Quote:

Originally Posted by blaster668

Hi everyone, I would like to install an outdoor antenna for scanning on top of my roof. I'm currently just using a Diamond RH77. The only bands I need at all are 150-160 and 450-470. I already pick up the 450-470 frequencies pretty well, but the VHF are definitely in a fringe area. What would you suggest for these bands with more emphasis on VHF performance?

Since you're only interested in the two specified bands, I'd recommend that you look into getting one of the various ham dual band antennas that cover VHF-Hi and UHF (aka 2 meter and 70 cm bands). Below are some to look at to help you decide what performance and price range you like. Please note that the coax is pretty important as well. LMR-400 would be a good choice if your running much over 50 foot or so.

Texas Towers, Comet Base Antenna Page
Texas Towers, Cushcraft AR-270B Page
Texas Towers, Cushcraft AR-270 Page
Texas Towers, Diamond X-500HNA Page
Texas Towers, Diamond X-510HD Page
Texas Towers, Diamond V-2000A Page (note, would also pick up some VHF-Lo rather well also)
Ham Radio Outlet | Ventenna VT-27 | 2M/440 DUAL BAND VENT ANTENNA (lower performance, but rather stealthy for those with restrictions on antennas)

wyomingmedic · #3 (**permalink**) 10-28-2010, 10:17 PM

Let me add my personal favorite to an already great list that was provided.

Diamond® Antenna ~ X50NA Dualband Base/Repeater Antenna

This is the X50NA antenna. I have one mounted up 60 feet on my tower and I use it for scanning and my 2/70 ham radio comms. It is EXTREMELY robust (135 MPH wind survival which is why I bought it), under 6 feet long, and has a decent amount of gain.

Give it a look at. It is a keeper IMO.

WM

madhatter66 · #4 (**permalink**) 10-28-2010, 10:28 PM

I have been using the RS 20-176 for those ranges, and it works really well... I have mine about 20' up and with a little loc-tite is a very robust antenna as well...

Outdoor VHF-Hi/UHF Scanner Antenna - RadioShack.com

blaster668 · #5 (**permalink**) 10-28-2010, 10:46 PM

Would I be better off with the commercial version, such as the Comet GP-6NC, of some of these antennas rather than the HAM version ? How much better would these antennas perform over say an inexpensive MFJ-1740 or RS 20-176? How well would a tuned VHF antenna pick up the UHF signals?

n5ims · #6 (**permalink**) 10-28-2010, 11:18 PM

Quote:

Originally Posted by blaster668

Would I be better off with the commercial version, such as the Comet GP-6NC, of some of these antennas rather than the HAM version ? How much better would these antennas perform over say an inexpensive MFJ-1740 or RS 20-176? How well would a tuned VHF antenna pick up the UHF signals?

The commercial versions would probably be more robust and perform a bit better, but at a much larger price tag than the ham versions. Commercial versions are made to be mounted and pretty much forgotten about for many years under constant and critical use (remember that they are designed to be mounted on commercial towers where you pay for tower space and pay dearly for someone to climb the tower to mount or work on them).

Ham antennas are designed to be self mounted and maintained as well as cost being more important than working forever without being looked at for decades. Many are made using thin fiberglass tubes (or thinner alluminum) while the commercial versions use fairly thick alluminum or fiberglass for their construction. The commercial versions may also be a single length tube while the ham version may come in sections (for reduced shipping costs). While the commercial versions may last longer, you probably can replace the ham version three or more times for what you pay for the similar commercial version.

The two antennas you mention (MFJ-1740 or RS 20-176) are simple ground plane antennas that provide you with no gain. Many of the ones I linked to have 6 or more dB of gain, which should provide better performance.

A tuned VHF antenna will pick up UHF signals fairly well, but not as well as one tuned for UHF (either as a single band UHF antenna or dual band VHF-Hi/UHF antenna).

brandon · #7 (**permalink**) 10-28-2010, 11:51 PM

I use a Comet GP9NC and it's a fantastic antenna for 155/460 reception. The ham version probably receives better in the VHF air band, so if you monitor aircraft then it might be worth considering.

blaster668 · #8 (**permalink**) 10-29-2010, 5:06 AM

Quote:

Originally Posted by brandon

I use a Comet GP9NC and it's a fantastic antenna for 155/460 reception. The ham version probably receives better in the VHF air band, so if you monitor aircraft then it might be worth considering.

The GP9NC and GP6NC are of the same basic construction and price range as the Ham versions correct? I don't believe they are constructed more ruggedly like the previous poster mentions. It appears to me that the only differences are they are tuned more for the public safety bands I want to monitor. I have no desire to listen to anything in the air bands, just public safety.

Since UHF signals already pick up so clear with my little whip antenna, I think I'm leaning more towards a tuned VHF like the tram 1487, 1490, or 1491 from antenna farm. These would cost significantly less and provide 4.5db, 6.7db, and 7.8db of gain respectively. Does anyone see an issue going this route?

brickcity1306 · #9 (**permalink**) 10-29-2010, 7:38 AM

I use the Ferret; I like the streamline look so it does not attract attention and keeps the Mrs happy. Just remember just because you do not monitor the full spectrum now it does not mean you will never wish to. The site is

Austin Antenna Ferret Omnidirectional Multiband Base Station Scanner Antenna

Good Luck

prcguy · #10 (**permalink**) 10-29-2010, 9:01 AM

Yes, the ham and commercial versions of the GP9 and GP6 are identical except for frequency range. This is a fine antenna for home use but not something you would put on a mountaintop repeater site, it would be in several pieces after a few seasons.

I would not recommend an amateur antenna for the ranges you specify because some are very narrow band and will loose quite a bit of performance at 160MHz.

The GP9 is a big bad antenna but its very narrow band on VHF. The commercial version is tuned to 155MHz and the VSWR gets very high when you go about +/- 1MHz from center frequency. UHF is fine and usable over the entire specified range.I have a well used commercial version for cheap, pick up only in So Cal.
prcguy

Quote:

Originally Posted by blaster668

The GP9NC and GP6NC are of the same basic construction and price range as the Ham versions correct? I don't believe they are constructed more ruggedly like the previous poster mentions. It appears to me that the only differences are they are tuned more for the public safety bands I want to monitor. I have no desire to listen to anything in the air bands, just public safety.

Since UHF signals already pick up so clear with my little whip antenna, I think I'm leaning more towards a tuned VHF like the tram 1487, 1490, or 1491 from antenna farm. These would cost significantly less and provide 4.5db, 6.7db, and 7.8db of gain respectively. Does anyone see an issue going this route?