Base Station Anntenna (VHF/UHF) Recommendations

[depth10]

I'm fairly new to the space and want to get a good "home" antenna. I currently have a tri-band antenna for the BCD436HP that I just picked up (REM-842S) and a 700-900MHz antenna (REM-800S)--both for home/portable use. I get spotty reception on some further counties and was wondering if there was a home antenna I could install to get better reception?

If buying something I could sit on my counter and plug into my scanner is out of the question, then is my only option to buy an outdoor antenna and run coax? I'm hoping there are options for the former!

P.S. My intended frequencies are:
151-161MHz
451-465MHz (less priority as my County uses full encryption for most of the comms in this band)
759-859MHz

Thanks in advance

 

[mmckenna]

An antenna sitting on your counter probably isn't going to be much of an improvement because it's still inside the house and close to a lot of noise sources.

On the frequencies in question, they ~mostly~ work by line of sight, so if the antenna can 'see' the transmitter, you can receive it. Getting just about any antenna outdoors and connected to your scanner will be an improvement.

A good basic option is a Larsen NMO-150/450/800. It'll cover the frequencies you are interested in, and actually provide a bit of gain on UHF and 7-800MHz, where a discone will not. Mount that antenna on an NMO base station adapter and connect it with some quality coaxial cable to your scanner and it'll be a big improvement.

One of these antennas:

https://www.theantennafarm.com/catalog/index.php?main_page=product_info&cPath=191_192_466&products_id=1050

This mount:

https://www.theantennafarm.com/catalog/index.php?main_page=product_info&cPath=481_483_484&products_id=7531

Coaxial cable will depend on how long the run is. The longer the run, the higher the grade of cable you'll need to address feed line losses.
Grounding is necessary.
Add in a short adapter cable to connect to your radio if using heavier cable.

And don't forget proper weather sealing of all the outdoor connectors.


That'll give you a big improvement in performance.

 

[depth10]

Thank you! I'm going to go that route and pick up both the antenna and the mount. Can you dummy proof this and let me know what connector I will need for both the mount end and the Scanner end? I know I can handle the actual mounting part, it's the signal connections that I'll probably need guidance on.

I am going to go with LMR400 coax and I have an SMA scanner (BCD436HP). I have seen N-Male to N-Male for the coax, and also N-Male to RPSMA. I'm assuming the latter is the appropriate, given the termination on the scanner is RPSMA. If there are many options, then perhaps just provide a few recommendations? I think anything I choose will be better than what I have.

Thanks again.

 

[mmckenna]

Yeah, no problem...

The base station adapter has a female N connector on it.
You'll want one end of your LMR-400 to have a male N connector to mate up with it.

Ideally you need a lightning protector installed where the coaxial cable enters the house.

At the radio end, you do not want to connect LMR-400 directly to the scanner. It's a stiff/heavy cable and will put a lot of strain on the antenna connector. Instead, have a Male N connector installed on the radio end of the LMR400. Then order a short length of RG-58, LMR-195, or LMR-200 with a female N connector on one end, and a male SMA connector on the other. Use that to make the transition to the radio.

www.theantennafarm.com will do custom cables for you. They usually stock 'standard' lengths of LMR-400 with N connectors, so that may be available off the shelf. The short adapter cable will probably need to be custom.

For weather proofing, get a roll of this stuff:

https://www.theantennafarm.com/catalog/index.php?main_page=product_info&cPath=627_656_658&products_id=9023

Failing to weatherproof the outdoor connections can result in water intrusion. Water + copper will result in corrosion that will damage the cable and connector, and you'll end up having to redo everything.

 

[depth10]

Thanks so much for your help!

 

[AM909]

... I am going to go with LMR400 coax and I have an SMA scanner (BCD436HP). I have seen N-Male to N-Male for the coax, and also N-Male to RPSMA. I'm assuming the latter is the appropriate, given the termination on the scanner is RPSMA. ...

@depth10: Perhaps someone familiar with the scanner can confirm, but you mention the scanner has an SMA, but then talk about RPSMA. These are two different things. SMA has a center pin on the male (the part with the outside collar that you turn) and a center socket on the female (the part with the stationary threads). RPSMA is the opposite, with a center socket on the male and a center pin on the female, and is primarily used for things like WiFi. My guess is that the scanner has a female SMA and you need a male SMA on the "pigtail" jumper that connects the bigger cable to the scanner.

 

[depth10]

@depth10: Perhaps someone familiar with the scanner can confirm, but you mention the scanner has an SMA, but then talk about RPSMA. These are two different things. SMA has a center pin on the male (the part with the outside collar that you turn) and a center socket on the female (the part with the stationary threads). RPSMA is the opposite, with a center socket on the male and a center pin on the female, and is primarily used for things like WiFi. My guess is that the scanner has a female SMA and you need a male SMA on the "pigtail" jumper that connects the bigger cable to the scanner.

I believe you're right and that I mispoke. I most definitely meant to say SMA. I found a picture comparing the two, and my scanner and antenna definitely look like the two on the left.

https://www.spo-comm.de/media/image/86/53/33/SMA.png

 

[depth10]

One more question, does the new Antenna have to be literally on the top of my house? Would my attic work?

 

[mmckenna]

One more question, does the new Antenna have to be literally on the top of my house? Would my attic work?

Depends on the construction of your home.

Any roofing material that has a metallic component will block RF. That could be a metal roof or foil backed moisture barrier in the insulation.
If you have HVAC ducting up there, that can be an issue also. Copper water pipes or wiring can create issues.

If you have none of those, then mounting in the attic can work, but -all- building materials have some amount of RF attenuation. Might be minimal and not an issue.

Some other drawbacks of attic mounting is that it puts the antenna closer to noise sources that can impact reception. But many do mount antennas in the attic and don't have an issue. It would be worth taking the scanner with the stock antenna up in the attic and see if it reception is good. If it is, then installation up there might be sufficient.

But keep in mind the 'line of sight' thing I mentioned earlier. The higher up you can safely get your antenna, the more you'll hear. If all you need is local stuff and your attic is good, it's probably all you need.

I believe you're right and that I mispoke. I most definitely meant to say SMA. I found a picture comparing the two, and my scanner and antenna definitely look like the two on the left.

You don't have a RPSMA on your scanner. Reverse polarity connectors are usually used on consumer WiFi devices. The Uniden scanner doesn't use them. A standard SMA connector will work for what you need.

 

[jazzboypro]

I'm using a D130NJ discone antenna with around 75 feet of LMR400. The antenna is about 24 feet above the ground. I use the antenna with my SDS100 and sometimes with my R8600. It works well in the frequencies specified by the OP

 

[N5ZKK]

Any outside antenna is better than something sitting near your computer and radios. Same as you I had an HT and wanted to hear stuff farther away. I started with a donated/hand me down 144MHz ham radio antenna and some coax that was laying around.

 

[Rawkee1]

I'm starting to wonder if the solar panels on my roof will have an effect on the discone. The antenna will be on a mast about 15' above the closest panel.

 

[mmckenna]

I'm starting to wonder if the solar panels on my roof will have an effect on the discone. The antenna will be on a mast about 15' above the closest panel.

Unlikely.
The bigger risk is noise from the inverter, and those are usually mounted on a wall, often near the electric meter.

 

[Ubbe]

I have a neighbour 300ft away that has solarpanels and I have interferencies coming from that direction that are on low-vhf, high-vhf and uhf. It's a carrier modulated with noise. It would be ok if it was stationary on a frequency and could then be locked out from scan but it is sweeping over the whole band. Sometimes its a slow sweep but often fast where it goes from one channel to the next in 10 sec. Its weather dependent. After a while I have the whole band locked out. A HAM reported that his own solar panels blocked his whole shortwave band. Some experts from the solar panel company experimented with different inverters and shielding and grounding and finally managed to get it under control.

/Ubbe