Antenna Help

[dahicks1485]

i just bought a BCD436hp scanner. can anyone recommend the best trunk mounted antenna. the company i bought it from was no help at all. i live near a military base and the antenna t came with is not very strong and the signal is hit or miss.

 

[iMONITOR]

What exactly are you trying to receive? Different bands/frequencies require different antennas. Is it the military base you want to hear? Army, Aircraft, etc?

 

[dahicks1485]

I'm sorry i should have been more detailed.i am trying to get the police, fire ect. for Miami Dade county. i live at the end of the county and some departments are a little far away. the antenna on the scanner picks up the signal but very week. so i am looking for a trunk mounted antenna to put in my car so i can listen at work.

 

[Ubbe]

Todays cars are almost like a farradays cage, it screens out most radiosignal by special tinted windows to keep out ultraviolet light, but will also keep radio signals out. The rest of the car is metal. Also there's a lot of electronic noise in a car from all computers and digital signals that travels in unshielded cables.

Is the reception acceptable if you hold the scanner out the window?

If there's a range of frequencies you'll need to receive then the best bet are probably a 3-band antenna, which there are several manufactures of and there are also special trunk mounts that doesn't need you to drill a hole in the trunk.

/Ubbe

 

[danesgs]

Ubbe said it allshort of getting a 1971 Ford pinto and putting a scanner in it...

 

[MisterLongwire]

THIS IS JUST FREAKIN HILARIOUS! Drive around town with your hand out the window while holding your scanner....I heard it all. With all my scanners I never have to do that-they receive just fine INSIDE my vehicle. As for my bro-in-law who is a PO has his handheld at his side, talking on it more than his builtin- never any problems. Every vehicle produces noise with the amount of electricity that travels through. Most of it is shielded too, however the new radios...sorry...now so new radios since the 70's have improved so much with RFI it is almost unnoticeable. If you wish to buy a mobile antenna try Ham Radio Outlet and get an antenna for the bands you are listening to. They are cheap yet very effective. You won't lose your radio having your hand out the window. Don't worry- no one will throw you in a "cage" for just asking.

 

[MisterLongwire]

and yes...I know what a faraday cage is....chill

 

[blackbelter]

While I recommend a Larson Tri bander antenna for your use, 436 however may not be the best radio for receiving MPD.
To my experience the best radios for MPD are Unication and SDS series.

 

[bob550]

THIS IS JUST FREAKIN HILARIOUS! Drive around town with your hand out the window while holding your scanner....I heard it all.

I'm gonna give @Ubbe the benefit of the doubt and guess that he probably meant for the OP to do that as a test while the vehicle was stationary.

 

[bob550]

and yes...I know what a faraday cage is....chill

Then you should also know that Faraday should be capitalized as it's the last name of the man for which this is named.

 

[bob550]

Ubbe said it allshort of getting a 1971 Ford pinto and putting a scanner in it...

Just don't forget to wear your fire-proof suit.

 

[Ravenkeeper]

Todays cars are almost like a farradays cage, it screens out most radiosignal by special tinted windows to keep out ultraviolet light, but will also keep radio signals out. The rest of the car is metal. Also there's a lot of electronic noise in a car from all computers and digital signals that travels in unshielded cables.

Is the reception acceptable if you hold the scanner out the window?

If there's a range of frequencies you'll need to receive then the best bet are probably a 3-band antenna, which there are several manufactures of and there are also special trunk mounts that doesn't need you to drill a hole in the trunk.

/Ubbe

and yes...I know what a faraday cage is....chill

Having worked as a security manager for my last squadron, I'm versed in the effects of the Faraday cage.

My house acts like one. Outside my cellphone would have 4-5 bars of service; inside, we're lucky to get 1, often NONE.

To answer the OP's question, I've connected my scanner to the AM/FM antenna and received just fine.

 

[mmckenna]

i just bought a BCD436hp scanner. can anyone recommend the best trunk mounted antenna. the company i bought it from was no help at all. i live near a military base and the antenna t came with is not very strong and the signal is hit or miss.

OK, you have a two options for antenna mounting.
Trunk lip mounts will work, but having them lower than the vehicle roof line can impact performance.
A magnetic mount will allow you to put the antenna on the top of the roof, where it'll perform better.
Ideally, a permanent mount on the roof is going to work a bit better, as well as look better, but that will require drilling a hole in the roof, and that might be a little advanced just yet, but something to consider.

First, skip Tram, Browning, Diamond, and the hobby/amateur radio brand antennas and mounts. They are cheap Chinese knockoffs and while you might save a few bucks, in the long run you'll spend more. Use the name brand stuff...

For a trunk lip mount
https://www.theantennafarm.com/catalog/pctel-maxrad-tc-nc-1170
You can select the connector you need to match your scanner. It has an SMA female type connector, so you'll want an SMA Male on the end of the cable. SMA connectors are small enough that routing them while attached to the cable isn't a big deal.
With trunk mounts, you need to be careful about where the cable passes through the gap between the trunk and the body. If the cable gets pinched, it can damage it. If the jacket gets breached, water will get in and corrode the copper conductors resulting in failure. Route the cable carefully up to where you plan to have the radio. You want to keep the cable away from any heat sources or sharp edges.

For a magnetic mount
Silver: https://www.theantennafarm.com/catalog/laird-technologies-gm8smi-7512
Black: https://www.theantennafarm.com/catalog/pctel-maxrad-bgmsmai-4524
Which ever one floats your boat.
You'll need to be extra careful routing the coaxial cable for these. Passing through a door or window is going to result in damage, so figure on replacing this every year or so, or not using the door or window where it passes through. You might get more life out of it, maybe not. I'm not a fan of mag mounts. Mag mounts also will eventually damage the paint, if that's a concern.

For the antenna:
Use this one, accept no substitutes: https://www.theantennafarm.com/catalog/larsen-nmo150-450-758-8932
Larsen makes professional antennas. I have some that are 30 years old and still going strong. If you look after them, chances are it'll outlast your vehicle and your scanner. This antenna will work on VHF, UHF and the 700/800MHz band.

That should be what you need to get started.

 

[Ubbe]

I'm gonna give @Ubbe the benefit of the doubt and guess that he probably meant for the OP to do that as a test while the vehicle was stationary.

That goes without saying.

Driving around with one hand on the wheel and one out the window on public roads are not advised, and holding a $500 scanner out the window while driving could easily make you drop the scanner. Test with engine running to get a view on how much difference there is monitoring inside the car and outside. I have something like a 20dB difference, 100 times, in my old 2004 VW and the car radio sends out lots of empty carriers in hi-vhf and the low-vhf reception are swamped by electronic interferencies. It's in the air on the frequencies so it doesn't matter what scanner are used. I have a magmount I use whenever I need to listen while driving.

/Ubbe

 

[dahicks1485]

OK, you have a two options for antenna mounting.
Trunk lip mounts will work, but having them lower than the vehicle roof line can impact performance.
A magnetic mount will allow you to put the antenna on the top of the roof, where it'll perform better.
Ideally, a permanent mount on the roof is going to work a bit better, as well as look better, but that will require drilling a hole in the roof, and that might be a little advanced just yet, but something to consider.

First, skip Tram, Browning, Diamond, and the hobby/amateur radio brand antennas and mounts. They are cheap Chinese knockoffs and while you might save a few bucks, in the long run you'll spend more. Use the name brand stuff...

For a trunk lip mount
https://www.theantennafarm.com/catalog/pctel-maxrad-tc-nc-1170
You can select the connector you need to match your scanner. It has an SMA female type connector, so you'll want an SMA Male on the end of the cable. SMA connectors are small enough that routing them while attached to the cable isn't a big deal.
With trunk mounts, you need to be careful about where the cable passes through the gap between the trunk and the body. If the cable gets pinched, it can damage it. If the jacket gets breached, water will get in and corrode the copper conductors resulting in failure. Route the cable carefully up to where you plan to have the radio. You want to keep the cable away from any heat sources or sharp edges.

For a magnetic mount
Silver: https://www.theantennafarm.com/catalog/laird-technologies-gm8smi-7512
Black: https://www.theantennafarm.com/catalog/pctel-maxrad-bgmsmai-4524
Which ever one floats your boat.
You'll need to be extra careful routing the coaxial cable for these. Passing through a door or window is going to result in damage, so figure on replacing this every year or so, or not using the door or window where it passes through. You might get more life out of it, maybe not. I'm not a fan of mag mounts. Mag mounts also will eventually damage the paint, if that's a concern.

For the antenna:
Use this one, accept no substitutes: https://www.theantennafarm.com/catalog/larsen-nmo150-450-758-8932
Larsen makes professional antennas. I have some that are 30 years old and still going strong. If you look after them, chances are it'll outlast your vehicle and your scanner. This antenna will work on VHF, UHF and the 700/800MHz band.

That should be what you need to get started.

HOLLY BLEEP!!!! That help a lot. i love my scanner but i cant pick up what i need. i will try the one you said to use and let you know. thanks a bunch..

 

[kc2kth]

Just to comment on the Larsen recommendations, I can't recommend them enough. I've had three Larsen antennas for about 15 years now and they have never failed. Larsen support is second to none as well. I had a hard time finding some of the replacement seals (not the internal o-ring) and they were very responsive. Great personal service on the rare occasion I needed it with their products. Oh, and they also gave some good advice on cleaning the surface rust that formed when a mag mount and seal failed (hint - 50/50 white vinegar and water to soak and then steel wool and some WD-40 to polish it up).

 

[mmckenna]

HOLLY BLEEP!!!! That help a lot. i love my scanner but i cant pick up what i need. i will try the one you said to use and let you know. thanks a bunch..

Getting a decent antenna outside the vehicle will make a difference. Cheap antennas will work for a while, but you'll end up replacing them down the road. Spending the few extra bucks to get a professional grade antenna will pay off in the longer term.

Good luck, let us know how it goes.

 

[Firekite]

For the antenna:
Use this one, accept no substitutes: https://www.theantennafarm.com/catalog/larsen-nmo150-450-758-8932

That's an interesting one. I have the problem that I need to be able to monitor everything from primarily 155 in my home county to occasional 450 on the road but for sure a ton of everything from 770 on one end and 860 on the other end. I was originally looking at the Larsen NMO 150/450/800 and maybe adding a spring since my F250 roof is so high and I have to go under low things sometimes. What do you think? Add a spring and cut the antenna /800 down a little? Or will the /758 still provide great RX service up at 860MHz?

The beautiful thing about the NMO mount is you can readily swap out between the two if you want to give them a test drive, but I'd rather have a good idea of what to expect up front as to which one would do better for me.

EDIT: Wait, is the /758 just a /800 model with a spring? The vague pics look slightly different, but maybe that would explain why they market it as optimal for slightly lower frequencies...? No clue.

 

[mule1075]

That's an interesting one. I have the problem that I need to be able to monitor everything from primarily 155 in my home county to occasional 450 on the road but for sure a ton of everything from 770 on one end and 860 on the other end. I was originally looking at the Larsen NMO 150/450/800 and maybe adding a spring since my F250 roof is so high and I have to go under low things sometimes. What do you think? Add a spring and cut the antenna /800 down a little? Or will the /758 still provide great RX service up at 860MHz?

The beautiful thing about the NMO mount is you can readily swap out between the two if you want to give them a test drive, but I'd rather have a good idea of what to expect up front as to which one would do better for me.

Scroll down to the bottom of the page and download the pdf data sheet. It will give you most of the information you seek.

NMO150/450/758 Tri Band Whip 150-174 MHz / 430-520 MHz / 750-870 MHz Coil Base with Spring, NMO with Pogo Pin | Arcadian Antenna

 

[mmckenna]

EDIT: Wait, is the /758 just a /800 model with a spring? The vague pics look slightly different, but maybe that would explain why they market it as optimal for slightly lower frequencies...? No clue.

No, it's a new model that was released a year or so ago. The 150/450/800 was primarily a scanner antenna. When it was first released, it was tagged as "not for transmitting". Later on, they did away with the "no transmitting" disclaimer.

The new one was designed to support the Motorola APX multiband mobiles and will cover 800MHz just fine.

The spring is a good idea. I've got an F-350 and took it through a parking garage. It was the wide band VHF Larsen quarter wave, so a thick whip with the spring. After getting hit pretty hard, the spring took a permanent bend, but the whip, base and roof were just fine. I replaced the spring and the antenna was like new.