Antenna for BC350C

[fuzzymoto]

OK I'm new to this but I did some searching and I'm still a little lost...my apolgies for the potentiallly stupid questions to follow.

I just purchased a Uniden Bearcat BC350C with a telescoping antenna that came with it. My house sits up pretty high so I seem to get pretty good reception, but I'm wondering if I can do better.

I listen to anything and everything I can; which I am assuming makes an antenna choice more difficult. Mostly police/fire in the 148-160 range but I'm also wanting to tune in to anything else I can (aircraft-125.000, lifeflights-453.1250, medics-461 and up).

My scanner sits on our main floor near my computer (and wireless computer router) which I assume is also probably not optimal.

I've played with the telescoping antenna and honestly I'm not even sure how to test it. I hear what I hear. I can hear Taxi's (153.2450) in a town 20 miles away but don't get police or fire in that city or even state police (about 20 miles away also). I've looked at the following options for a replacement antenna:

-Buying a 900Mhz Radioshack rubber stubbie antenna (tried one for 10 minutes--not sure it helped much). I'm not sure this will help at all.

-Scantenna (recommended by a friend) on the roof of my house. This option would be a lot of work and I'm worried about high wind, lightning (My house sits up high and exposed), and signal loss getting cable to my scanner. My main worry is going thru the expense and effort to have minimally better reception.

-Indoor Antenna...I have a large attic space I can use but I'm worried this may make my antenna directional or again make it minimally beter for a lot of time and effort.

I know there is no magic bulllet but there has to be something that will definintely be better than my telescoping antenna. I also do not want to build a home-made antenna since I am not that handy/patient and I don't want the scanner area to look that messy.

Any advice out there? Thanks in advance.
FM

 

[Advanced-Specialties-Inc]

"Generally", an antenna mounted higher & outdoors (or attic), should be your best choice & make the most difference.
Swapping the indoor "back of set" antenna for a different one probably will only make a slight difference, at certian frequencies.
You say you listen to "anything & everything" between approx. 108-900Mhz .. A discone antenna is a good wideband choice to consider.....

 

[fuzzymoto]

Thanks. That is what I was hoping to hear. I've heard a lot of conflicting opinions on the discone which was what leaned me toward the Scantenna. I'll have to check the measurements and see if either will fit in my attic but I doubt it.

Any opinions on Scantenna vs Discone?
Any outdoor mounting advice (cable routing, lightning grounding...)?

Thanks again

 

[mgosdin]

Thanks. That is what I was hoping to hear. I've heard a lot of conflicting opinions on the discone which was what leaned me toward the Scantenna. I'll have to check the measurements and see if either will fit in my attic but I doubt it.

Any opinions on Scantenna vs Discone?
Any outdoor mounting advice (cable routing, lightning grounding...)?

Thanks again

My first install here in the country was a Radio Shack 20-176 1/4 Wave scanner antenna stuck up on a 5' piece of schedule 40 PVC Pipe that was bolted to the eve of the house. Ran a 15' length of RG58 to my desk. This worked well for over 2 years, until I got it into my head that I needed to hear some of the weaker signals that I knew were out there.

The bottom line was that the whole setup cost me only about $40.

If you live in a more metropolitain area vs the cowpasture that our house is located in, then you might find that you don't need to mount anything any higher.

You can do a quick search here on RR and find all kinds of Lighting & Mounting information.

Mark Gosdin

 

[fuzzymoto]

Thanks. I'm in a fairly rural area (about 20-miles from the nearest city). I think there is probably much more to hear if I can get more distance. I do want to keep it simple if I can. I also want to listen in all directions (non-directional antenna) if I can also. I'll check out the lightning and mounting suggestions on here.

Any suggestions on specific base antenna or cabling?

 

[fuzzymoto]

Gosh after reading all of the grounding hassles and checking out my best outdoor location I may be leaning back toward an attic installation. I have LOTS of trees and falling branches to deal with in an outdoor installation that I didn't realize.

Anyone have any comparisons of attic versus outdoor installations (assuming roughly the same overall height and normal roofing and shingles? Is it even worth going up 10 feet from my present location to my attic? Are there any antenna that will fit in an attic (without turning them sideways) that would also work outside?

Sorry...I seem to have more questions every time I think about this.

 

[mgosdin]

A scantenna sould work fine seeing as you are interested in a fairly common range of frequencies and the scantenna is reported to be good over that range.

Put it up as high as you can, 20 - 25' is easy to do using antenna masts from Radio Shack or Lowes.

Get as good a cable to use with it as you can afford. ( I used 1/2" heliax on my 25' installation, but that was only because I lucked on to a bargan with eBay. ) RG6QS is easily found in a variety of premade lengths. It may require you to use an adapter to attach it to the antenna and definitely will need one to attach to the scanner, typically $5 at Radio Shack.

Again, RG6QS being a common cable type used with CATV & Satellite you can get a grounding block kit easily at RS or Lowes. The grounding block should be attached just before the cable is run into your house. Run ground line from the grounding block to a grounding rod ( 8' copper clad steel ) driven into the ground with only about 4 - 6" exposed above ground. Use 8 guage copper grounding wire to run from the block to the rod and make the run as short as possible with no sharp bend in the grounding wire.

I know this sounds like a lot of work, but the results are quite likely to be worth it.

Mark Gosdin

 

[Al42]

On most frequencies we scan you can hear what you can see. Your antenna's horizon in miles is the square root of the height of the antenna in feet times 1.17. The horizon of the antenna you're trying to hear is the same for its height. Add the two to get the maximum distance your antenna can see the other antenna from. If that's less than the actual distance betweeen them you should be able to hear the signal.

That said, a discone only has a 3:1 frequency range over which it's only half as bad as a dipole (like the Scantenna). The "25-1300 MHz" claims are hype - there's no single element antenna that can receive any better over that range than a random length of wire can. (ANY wire is "an antenna that can receive from 25-1300 MHz". Or 0.01 to 13,000 MHz. The question is how well it receives.) And a discone has at least 1-2db loss over a Scantenna-type (or ground plane) antenna. "At least", because discones that aren't as well designed have even more loss at frequencies all over the place. In fact, one well-known supplier's discone is inconsistent - buy 3 of them and you'll see 3 different loss patterns.

A Scantenna-type of antenna is a dipole at 4 (I believe - it may be 5) distinct frequency ranges - one for each pair of elements. Radio Shack makes a ground plane that has the same idea - 3 elements to cover 3 bands. Your best bet, if you want to monitor many bands, may be to make your own ground plane in your attic (it's only wire) that covers all the bands you're interested in. There's no reason you can't make a 50 band antenna (using 50 wire ribbon cable). Only the vertical element has to have multiple elements. The radials are simulating a sheet, so they should be 1/4 wave long at the lowest frequency you're interested in. 3 or 4 radials are fine.

Aside from the cable, connector, etc., it should cost you less than $5 if you have to buy 10 feet of multi-conductor ribbon cable. And it'll work as well as a Scantenna, but on more frequencies. Don't save money on the cable - the best antenna does nothing if it's fed by junk cable. Use a cable calculator (http://www.ocarc.ca/coax.htm works) to see how much loss the cable you're thinking of will give you for the length you need at the highest frequency you're interested in. You should try for no more than 2db loss, but 3db is acceptable. Half the signal is lost for each 3db - IOW half for 3db, half of what's left for 6db [3/4 is lost], half again for 9db [7/8 is lost], etc. 2db loss leaves you with more than 2/3 of the original signal. (If the run is short and you can afford cable that gives you less than 1db loss, go for it.)

 

[fuzzymoto]

So where can I find plans for an easy Ground Plane antenna I can make for the attic? If it's easy I may try that.

I'd end up about 15 feet from my scanner to the attic. I have some recently removed DishTV coax I can use if that would work.

 

[fuzzymoto]

Here's an update. Turns out my scanner came with a "Mobile" antenna. It's a BNC connector on a black cable (smaller than coax). It has a length of what looks like narrow speaker-type wire (clear insulation with copper wire) at the end with a suction-cup at the end and where it turns from black cable to copper. I think it is supposed to stick on the windsheild. I connected it up and ran the cable up the wall as high as the cable length will allow. It SEEMS to work better but I'm not sure how to even tell. I heard a distant broadcast on the new antenna, switched back to the telescoping old antenna and it seemed to stop (or did they just stop talking?). I reconnecte dthe new antenna and heard them again. That's about the only test I can try. Other than that it seems the same.

Any idea why I can hear a Taxi company in a city 20-miles away but NOT their police or fire...and yes I believe I am searching the right frequencies for them?

 

[Al42]

So where can I find plans for an easy Ground Plane antenna I can make for the attic? If it's easy I may try that.

For 850 MHz? An SO-239 (female UHF) connector turned upside down (threaded part down). A wire running straight up from the center pin, so that the total length from the base of the pin to the top of the wire is 3.3". 4 wires connected to the mounting holes, coming off at about a 45 degree angle (downwards), so that the total length of each, from the center of the connector, is 3.3". Connect the cable to the bottom with a PL-259 connector. (No teflon insulation at these frequencies - it tends to be lossy. Ceramic is better. And no "solderless" connector - solder it. Solderless means connection-less.)

I'd end up about 15 feet from my scanner to the attic. I have some recently removed DishTV coax I can use if that would work.

That should be pretty low loss.

Here's an update. Turns out my scanner came with a "Mobile" antenna. It's a BNC connector on a black cable (smaller than coax). It has a length of what looks like narrow speaker-type wire (clear insulation with copper wire) at the end

Probably RG-174. Use cooked spaghetti - it's more flexible and probably lower loss. Seriously. In only 15 feet, at 850 MHz you lose almost 5db (65% loss). RG-174 is great mic cable - it's so flexible. It's terrible antenna cable. (But I use 4 feet of it from my hard-hat antenna to my portable. Less than 0.5db [10%] loss at 145 MHz.)

It SEEMS to work better but I'm not sure how to even tell. I heard a distant broadcast on the new antenna, switched back to the telescoping old antenna and it seemed to stop (or did they just stop talking?). I reconnecte dthe new antenna and heard them again. That's about the only test I can try. Other than that it seems the same.

You want a signal with a little noise on it with what you think is the better antenna. Then switch to what you think is the worse antenna. See how much the noise goes up.

Any idea why I can hear a Taxi company in a city 20-miles away but NOT their police or fire...and yes I believe I am searching the right frequencies for them?

The taxi company is running more power? They're on a (considerably) lower frequency (like 150 vs. 850)? Their antenna is much higher? (The local cab company is running one of its offices on a community repeater - at the 650' level on a tower.) There's an obstruction between you and the police and fire antenna(s)?

 

[fuzzymoto]

Thanks I'll look further and see if I can decipher the antenna building advice. The car suction cup type antenna is working ok. I'll try to find a weather channel to test it on. Otherwise no one transmist long enough to switch antennas. I am not finding much in the 800Mhz bands so most everything I can hear is in the 148-174 range.

I'm still a little confounded on the Taxi question. As far as I know both the taxi company and police/fire in that town are on the same area of frequencies. I'm actually hearing the Taxi's themselves louder than their base dispatching so I don't think it's a power or antenna height issue. I'll have to bring my scanner closer to see if I can find them. I do hear a county further away very clearly so I suspect there is something else going on here. They are not trunked but maybe they are not on the frequencies I think they are. I'll keep looking.

I have been investigating antenna that I can mount vertically IN my attic. We've had strong wind this week and it reminded me how badly an antenna would get blown and hit by branches...so I think the attic mount will be my best/safest option. ANY advice on an antenna that will mount vertically in a limited attic space? I hear mounting horizontally won't work well but I only have about 4 feet of room in the attic vertically. ANY SUGGESTIONS?

 

[Al42]

I have been investigating antenna that I can mount vertically IN my attic. We've had strong wind this week and it reminded me how badly an antenna would get blown and hit by branches...so I think the attic mount will be my best/safest option. ANY advice on an antenna that will mount vertically in a limited attic space? I hear mounting horizontally won't work well but I only have about 4 feet of room in the attic vertically. ANY SUGGESTIONS?

A 4 foot ground plane is about 56 MHz, so you can fit a ground plane for 56 MHz or any higher frequency in that attic.

 

[fuzzymoto]

So let me see if I have this straight. I run a coax cable from my scanner (bnc connector) to my attic (probably 15-20 feet by the time I snake it up there. At the end of that cable is 4-feet of what kind of wire and arranged how? Horizontally, vertically? I have some fairly new Dish TV cable (Rg-6 Maybe?) Can I use that somehow? Sorry but I'm really not that well versed in this stuff but I do appreciate the help.

 

[Al42]

So let me see if I have this straight. I run a coax cable from my scanner (bnc connector) to my attic (probably 15-20 feet by the time I snake it up there. At the end of that cable is 4-feet

Only if you're monitoring TV Channel 2. The wire should be 1/4 wavelength long at the frequency you want to monitor. Connected to the center conductor of the cable and running up. (You can connect more than one wire, of different lengths, to monitor different frequencies.) The shield of the cable should be connected to at least 3 (preferably 4) wires that are 1/4 wavelength long at the lowest frequency you want, arranged horizontally and equally (3 wires at 120 degree angles, 4 wires at 90 degree angles).

of what kind of wire

It really doesn't matter. Bell wire, hookup wire, baling wire, fence wire. Something that conducts electricity.

and arranged how? Horizontally, vertically?

As above.

I have some fairly new Dish TV cable (Rg-6 Maybe?) Can I use that somehow?

As the cable running to the scanner. Or you could use it as antenna wire. Or both.

Sorry but I'm really not that well versed in this stuff

I wasn't born knowing it either - but I've been working with it longer than most people posting on RR have been breathing, so I've learned a little something along the way. You probably will too.

 

[fuzzymoto]

Thank you again for replying. OK here's my plan. PLEASE stop me if I go wrong. I want to get an antenna up as high as I can, but probably just in the attic to start with. I have tremendous wind and tree limb issues if I go outside. My house sits at about 1400-feet altitude on the edge of a cliff about 200-feet up off a large lake. I get serious wind but I believe with a good antenna I should get serious reception.

I have this heavy duty coax cable with F-type connectors from my former DishTV install. I believe it is very low loss cable with very good F-type connectors. I think it is RG-6 but I'll have to look closely at it. To start at my scanner--I have a BNC to F-type adaptor to connect the scanner to the RG-6 then I'll run the RG-6 up to my attic. I'm not sure of the length of the RG-6 but I'm sure it is less than 50-feet as it stands.

Once in the attic I can try:

a) Just the plain RG-6 cable as an antenna in my attic and see how that works.
b) attaching my current antennas at the end of the RG-6
c) attaching the wire to the center conductor of the RG-6 as you described (see questions below) or
d) buying an antenna that will fit in my attic and attaching that to the end of the RG-6.

This I believe will allow me to test a number of options and the only hassle initially is getting the cable from my scanner to the attic. Once I have RG-6 to the attic I can try a number of different antenna and antenna positions within the attic. This HOPEFULLY will give me better signal and if nothing else a cheap basis for comparison....BUT

I'm still a little lost on building the antenna you describe. Do you or anyone know of a picture of such an antenna I can look at? By the way it seems that MOST of everything I try to hear is in the 150.000 to 170.000, but I am interested in some things I believe are in the 400.000 and 800.000 ranges---I just can't seem to hear. anything up there. I assume this will dictate what lengths of wire I use and how they are positioned?

Also will the length of the RG-6 act as an antenna of some wavelength? In otherwords should the length of the RG-6 to get to the attic be part of the wavelength calculation...and if so how? I'm hoping I can just run whatever length I have up there and then connect an antenna to that.

Thanks again. I will figure this stuff out. Honestly if I was in the middle of a city or low in a valley I wouldn't even worry about it. The fact that my house is so high has me very excited at what I may be able to hear. My goal is to pickup the police/fire in a city about 20-miles away. Hopefully that is possible.

 

[Al42]

My house sits at about 1400-feet altitude

Almost 44 mile line-of-sight in that direction.

a) Just the plain RG-6 cable as an antenna in my attic and see how that works.

Try using the center conductor - strip off about 18" of shield.

b) attaching my current antennas at the end of the RG-6

Should work pretty well.

c) attaching the wire to the center conductor of the RG-6 as you described (see questions below) or
d) buying an antenna that will fit in my attic and attaching that to the end of the RG-6.

There's not much you can buy for under $50-$75 that will outperform a plain old parallel (multiple elements in parallel) ground plane.

I'm still a little lost on building the antenna you describe. Do you or anyone know of a picture of such an antenna I can look at? By the way it seems that MOST of everything I try to hear is in the 150.000 to 170.000, but I am interested in some things I believe are in the 400.000 and 800.000 ranges---I just can't seem to hear. anything up there. I assume this will dictate what lengths of wire I use and how they are positioned?

One piece around 18", one around 6.1" and one around 3.3". Bottoms connected to the center conductor of the cable, tops tied together (insulated wire, so they're not connected together electrically at the tops - actually ribbon works well - just cut each wire at the point above the bottom connection it has to be and strip off the piece of wire above the cut) and suspended from a rafter with string and a thumb tack. 4-18" pieces arranged with one end of each connected together, the other ends going out in 4 directions, all connected to the shield of the cable.

Also will the length of the RG-6 act as an antenna of some wavelength?

The above lengths, 18", 6.1" and 3.3", include any length of cable center conductor not covered by shield, so that's included in the calculation of wire lengths.

In otherwords should the length of the RG-6 to get to the attic be part of the wavelength calculation...and if so how? I'm hoping I can just run whatever length I have up there and then connect an antenna to that.

No, just keep any antenna cable as short as is practical, to minimize loss.

My goal is to pickup the police/fire in a city about 20-miles away. Hopefully that is possible.

If they're in the direction you have 1400 foot elevation to, it's easy. You need about 300 feet total elevation (combined heights of your antenna and theirs) to get a 20 mile horizon.

 

[fuzzymoto]

Thanks...excellent advice and I'l be working on it this weekend. I sit at 1400-feet and the town I am trying to hear sits at about 600-feet. I have some hill North of me but the city I want to hear is due South. The lake is also due south of me. I'm sure there are mountins in between but I'm not sure if that matters. The city I want to hear is in a valley so we'll see. I'll watch for any other advice and reply back after I build something. I have the cable now but not the connectors I need yet...they're on the way. Thanks again!

 

[oregontreehugger]

How about pointing us to the database page here on RadioReference that shows the frequencies you want to monitor?

Depending on what you're trying to receive (that city in a valley, for example) it might help.

 

[fuzzymoto]

Sure...I believe the page is:
http://radioreference.com/modules.php?name=RR&ctid=2280

And the city I am trying to hear is/are Wilkes-Barre and Kingston. I'd like to hear the airport also but I'm not sure that will work. I have a feeling that I'm either too far away with the current antenna or the terrain is causing me problems. They are not trunked and I am searching the listed frequency ranges for any sort of activity. I do hear taxi's in Wilkes-Barre but they may be on a repeater?