Base Antenna Recommendation

[btlacer]

I'm looking to buy a good base scanner antenna. I monitor everything from air band to local 700 trunk systems. I'm going to have this antenna mounted at the peak of my house about 17 feet up. It's going to be about 50 feet worth of coax I have to run from the antenna to the scanner. I plan on using lmr400 to fees the scanner. Let me know what you guys think are a good base scanner antenna that isn't crazy in price.

 

[K6GBW]

If you’re going to cover everything from Low Band to 700-800 there’s not much that will do that except a discone antenna. There are disc ones by Comet, Diamond and others, but frankly if you’re just listening a Tram 1410 or 1411 will work just fine. They are not expensive and do the job.

 

[btlacer]

If you’re going to cover everything from Low Band to 700-800 there’s not much that will do that except a discone antenna. There are disc ones by Comet, Diamond and others, but frankly if you’re just listening a Tram 1410 or 1411 will work just fine. They are not expensive and do the job.

Mostly from air band up. I don't do much low band monitoring.

 

[APX8000]

Discones are garbage on 7/800. I recommend the DPD Omni-X. Use the Ultraflex LMR-400 as well.

 

[mmckenna]

I'm looking to buy a good base scanner antenna. I monitor everything from air band to local 700 trunk systems. I'm going to have this antenna mounted at the peak of my house about 17 feet up.

LMR-400 should be sufficient.
Don't forget proper grounding/lightning suppressor.

One option for an antenna would be:

Tri-Band 150-165, 450-470 & 806-940 MHz Mobile Two Way Radio Antenna Scanner

Tri-band antenna covers 150-165, 450-470 & 806-940, 100 Watts, Whip Length 16.5"

theantennafarm.com

and this base station adapter kit:

Mobile Antenna to BASE Convertor VHF UHF Antennas TE Connectivity MBCN

Mobile to Base Station Adapter Kit for NMO Mount Type Antennas. Includes bracket, clamps, radials and mounting bracket. Frequency Range up to 512MHz, N Female

theantennafarm.com

Make sure you properly waterproof the outdoor connections.

 

[Ubbe]

A discone type of antenna will do fine up to 500MHz. If you now can monitor what you want at 700MHz and up using an indoor antenna then a discone will do about the same when higher up on your roof, as its performance degrade above 500MHz. If you need to improve signal strength above 700MHz you could use a diplexer filter to instead take higher frequency signals from another antenna, a dedicated gain antenna for 700MHz and above.

All discones perform about the same if they are the same size, but the difference are how long they last when exposed to weather conditions. The cost will more or less say how long it will last. A Diamond costs 3 times more than a Tram but will also last more than 3 times longer.

If a discone will be easy to access I would probably go with a Tram and replace it earlier than what a Diamond would need, but I would also have the option to switch to another antenna type and I then haven't spent too much on the discone.

For coax the LMR400 will attenuate less than 1dB at VHF and 2dB at 900MHz. A RG6 coax will attenuate 1dB at VHF and 3dB at 900MHz.
The 900MHz degradation of a discone can be something between 6dB and 15dB.
RG6 are installed for cable tv in all buildings and a huge amount are needed that have kept coax and connectors at a low price level and it's thin and flexible that are easy to install.

/Ubbe

 

[btlacer]

Ok I ordered a DPD Omnix antenna. I'm going to mount it at the peak of my roof line so I'm going to need about 50 feet of coax. What coax should I get? Lmr400? Is there something similar at a cheaper price?

 

[btlacer]

A discone type of antenna will do fine up to 500MHz. If you now can monitor what you want at 700MHz and up using an indoor antenna then a discone will do about the same when higher up on your roof, as its performance degrade above 500MHz. If you need to improve signal strength above 700MHz you could use a diplexer filter to instead take higher frequency signals from another antenna, a dedicated gain antenna for 700MHz and above.

All discones perform about the same if they are the same size, but the difference are how long they last when exposed to weather conditions. The cost will more or less say how long it will last. A Diamond costs 3 times more than a Tram but will also last more than 3 times longer.

If a discone will be easy to access I would probably go with a Tram and replace it earlier than what a Diamond would need, but I would also have the option to switch to another antenna type and I then haven't spent too much on the discone.

For coax the LMR400 will attenuate less than 1dB at VHF and 2dB at 900MHz. A RG6 coax will attenuate 1dB at VHF and 3dB at 900MHz.
The 900MHz degradation of a discone can be something between 6dB and 15dB.
RG6 are installed for cable tv in all buildings and a huge amount are needed that have kept coax and connectors at a low price level and it's thin and flexible that are easy to install.

/Ubbe

The rg6 is that at 100 feet? I only need about 50 feet of coax to reach my room window where it will connect to my mfj window antenna connection. Plus with my omnix antenna having a N connection will adding adapters raise my losses? I'm trying to keep my losses low so I can pick up 700 mhz better.

 

[APX8000]

LMR-400 ultra flex.

 

[KMG54]

RG6 is fine, but use solid copper center wire, I use quad shield but that may be overkill. Also get good compression fittings like PPC or Beldon and the cheap stripping tool and a good compression tool.

 

[btlacer]

RG6 is fine, but use solid copper center wire, I use quad shield but that may be overkill. Also get good compression fittings like PPC or Beldon and the cheap stripping tool and a good compression tool.

Is rg6 good for 700 mhz at 50 feet? I want the least amount of signal loss.

 

[mmckenna]

Is rg6 good for 700 mhz at 50 feet? I want the least amount of signal loss.

So, there's a couple of things you need to consider here.

LMR400 has half the loss of basic RG-6 at 700MHz. So, LMR-400 is "better" in that sense.

LMR400 is large cable, has a larger bend radius, and unless you have the tools, putting connectors on is difficult. The tools to install connectors on it properly are expensive. Not worth it if you are installing one run. You can get custom lengths of cable with the connectors you want on the end.

LMR400 is stiff cable, and you do not want to connect it directly to your scanner. The stiffness of the cable will put a lot of strain on the antenna connector on the scanner and will risk breaking it. You'll want to use a short "whip" of thinner/more flexible cable to make that final connection.

RG-6 has more loss. But it's thinner cable, easier to route, and can be bent pretty tight without negative effects. It's also way easier to install or BNC connectors on, in fact you can get the stripper, installation tool and BNC connectors at your local Home Depot. That makes it easier to run the cable from outside to your scanner (don't forget the grounding block and proper grounding) and then terminate your own connector on the end. That can be better than having a lot of slack cable coiled up somewhere. And RG-6 is flexible enough that you can connect it directly to your scanner without issue.

Don't get hung up on loss quite yet….
Yes, less loss is "better", but it costs money. If you have a good antenna and are close to the site you want to hear, you may not need the more expensive lower loss cable.
Generally, if you can hear the radio site in your home with a scanner, then you don't need super high gain/low loss installation. But if you have a really hard time hearing the site when outside your home, then you need all the help you can get.

Low loss cable is helpful, but budgets are a real thing, and easier installation can be more beneficial. Not every installation needs the high end cable to work properly. But, it's your budget, your choice.

www.theantennafarm.com will make custom LMR400 cables for you. Make sure you order a short whip of RG-58 to make the final connection to your scanner if you go this route.

 

[Ubbe]

The rg6 is that at 100 feet?

The values where for 50ft.

Plus with my omnix antenna having a N connection will adding adapters raise my losses? I'm trying to keep my losses low so I can pick up 700 mhz better.

There's no measurable losses with connectors and adapters. But if the connector have issues and are faulty it will give problems. If I buy a pack of 10 adapters or connectors from China then usually two of them are bad. If I slowly bend the coax from side to side I suddenly can get a 10-20dB attenuation. Those connectors goes into the trash bin. Buying adapters that costs 5-10 times more of a well known brand will guarantee that they have no issues. But of course all connectors and adapters outdoors have to be weather protected properly using self fusing rubber tape with another tape on top of it, or shrink tubes with glue inside them.

/Ubbe