Don't laugh....please.

[Santacarl]

Hi All,

I'm new to this radio world. Looking at the Uniden BCDx36HP line.

So...here's the question that will likely start the chuckle cascade.....Since this scanner covers such a wide frequency range.....Is it possible to go with a single antenna or do you need an antenna 'farm' for the different ranges?

I'd love to find one big honkin' antenna to cover all my bases....but I know so little about this topic that I hardly know how to ask an intelligent question without looking like an absolute doofus.....

Suggestions to point me in the right direction and get me in the ball park would be greatly appreciated. I'm already peddlin' as fast as I can and all this is a bit like drinking out of a firehose.....so please pardon the ignorance factor....

Thanks.

SC

 

[popnokick]

It is possible to use a single antenna. However, the general rules involve compromises:
- You can have a single antenna that covers the wide frequency range (27Mhz to about 900 MHz), but it will not do any one particular portion of that range with any gain or performance advantages
- If you select a specific range you can get some gain and directionality (if needed)
Do you need directional capability and gain? Depends on where you are and what you want to listen to.
Also:
- Can you put an antenna on the roof? (BEST)
- Can you put an antenna in an attic or crawl space? (MIGHT BE OK)
- Can you put an antenna in an upper story window? (MIGHT BE OK)
- Can you only use the telescoping or rubber attenuator that came with the radio mounted on the back of the radio? (WORST POSSIBLE OPTION IN MOST CASES)
So.... if we know what you want to listen to (frequencies) and where you can put the antenna.... we can supply some suggestions.

 

[n5ims]

Just because your radio covers a very wide area of spectrum doesn't really have much to do with where you will actually listen (think of it this way, your car can drive on nearly every road in the US, but you generally just drive on a very small group of them). Check the RR database for your area to see what's available in your area for you to monitor and using what you already have to see what you can hear. Chances are that you'll find that you only need an antenna that covers a very small part of what your scanner will monitor. Once you discover what frequencies you actually need the antenna to cover, you can most likely find a good antenna to cover them.

Rules on a selecting an antenna:
1) The smaller the frequency range, the better the antenna you can purchase.
2) The best performance is the range an antenna is designed to cover. Often, this will be the range they indicate that the antenna will transmit on. They'll often claim it will "work" on various ranges, but remember that "work" and "work well" are two very different things.
3) Height is generally your friend. A great antenna mounted low to the ground will generally work worse than a poor antenna mounted high off the ground. How high do you need, well generally just high enough to be above what will block the signal, like nearby trees.
4) Good low-loss coax is way more important than a good antenna. This is increasingly true as you go higher in frequency or longer in length.
5) Your reception will be good over a fairly large signal strength range. Once you exceed a certain level, you will do no more good and may even do harm. If your signal is noisy, perhaps a better antenna will help. If your signal is clear, a better antenna may make things worse (perhaps even much worse), especially if you monitor a simulcast system.

 

[Voyager]

Well said (both of you). Unfortunately one of the better broadband antennas is no longer made and no longer available (for now).

 

[SouthernRoller]

What would that be?

 

[Voyager]

Scantenna II (AKA ST-2). There are threads about it on the forums. The plant that made them has been sold to another (non-antenna) company.

But, there may be some light on the horizon. Can't say anything more for now.

 

[SouthernRoller]

Antenna Craft ST2 Scanner Monitor Antenna Kit 30 1300 MHz Made in USA | eBay

 

[Santacarl]

It is possible to use a single antenna. However, the general rules involve compromises:
- You can have a single antenna that covers the wide frequency range (27Mhz to about 900 MHz), but it will not do any one particular portion of that range with any gain or performance advantages
- If you select a specific range you can get some gain and directionality (if needed)
Do you need directional capability and gain? Depends on where you are and what you want to listen to.
Also:
- Can you put an antenna on the roof? (BEST)
- Can you put an antenna in an attic or crawl space? (MIGHT BE OK)
- Can you put an antenna in an upper story window? (MIGHT BE OK)
- Can you only use the telescoping or rubber attenuator that came with the radio mounted on the back of the radio? (WORST POSSIBLE OPTION IN MOST CASES)
So.... if we know what you want to listen to (frequencies) and where you can put the antenna.... we can supply some suggestions.

Well....I'll provide some answers...I'm still researching some...

Frequencies are spread out pretty well....from 45 to 468 MHz (lots in the mid 150 and 450-460 ranges)....there is 1 operating in the 800MHz band at this time in my area....

I can't get on the roof....too steep and there are no second story windows. But I could put one in the attic...as I still have an old TV antenna from analog days up there....I also have an HF antenna up there that runs the length of the house as well as a couple of FM antennas but none of these ever received well so I have doubts about a scanner antenna in that location.

Right now I'll be limited to the antenna that comes with the radio.....that's why I'm researching other options....

Thanks for the suggestions and questions...any helpful advice is greatly appreciated.

 

[Santacarl]

Just because your radio covers a very wide area of spectrum doesn't really have much to do with where you will actually listen (think of it this way, your car can drive on nearly every road in the US, but you generally just drive on a very small group of them). Check the RR database for your area to see what's available in your area for you to monitor and using what you already have to see what you can hear. Chances are that you'll find that you only need an antenna that covers a very small part of what your scanner will monitor. Once you discover what frequencies you actually need the antenna to cover, you can most likely find a good antenna to cover them.

I posted this in response in another part of this thread....."Frequencies are spread out pretty well....from 45 to 468 MHz (lots in the mid 150 and 450-460 ranges)....there is 1 operating in the 800MHz band at this time in my area...."

So....the frequencies in this area look like they were 'shotgunned' across the frequency bands.....Just my luck! And there are a couple I haven't been able to nail down yet.......Ha.....

Rules on a selecting an antenna:
1) The smaller the frequency range, the better the antenna you can purchase.
2) The best performance is the range an antenna is designed to cover. Often, this will be the range they indicate that the antenna will transmit on. They'll often claim it will "work" on various ranges, but remember that "work" and "work well" are two very different things.
3) Height is generally your friend. A great antenna mounted low to the ground will generally work worse than a poor antenna mounted high off the ground. How high do you need, well generally just high enough to be above what will block the signal, like nearby trees.
4) Good low-loss coax is way more important than a good antenna. This is increasingly true as you go higher in frequency or longer in length.
5) Your reception will be good over a fairly large signal strength range. Once you exceed a certain level, you will do no more good and may even do harm. If your signal is noisy, perhaps a better antenna will help. If your signal is clear, a better antenna may make things worse (perhaps even much worse), especially if you monitor a simulcast system.

Wow....this should be pinned to the top for newbies.....very helpful in understanding some of the basics and done so in a way that you don't need to have a degree in physics to understand....

 

[N5TWB]

Well....I'll provide some answers...I'm still researching some...

Frequencies are spread out pretty well....from 45 to 468 MHz (lots in the mid 150 and 450-460 ranges)....there is 1 operating in the 800MHz band at this time in my area....

I can't get on the roof....too steep and there are no second story windows. But I could put one in the attic...as I still have an old TV antenna from analog days up there....I also have an HF antenna up there that runs the length of the house as well as a couple of FM antennas but none of these ever received well so I have doubts about a scanner antenna in that location.

Right now I'll be limited to the antenna that comes with the radio.....that's why I'm researching other options....

Thanks for the suggestions and questions...any helpful advice is greatly appreciated.

As you have already acknowledged, there has been excellent advice given in the thread that was responsive to your inquiry without becoming overly technical. I'll add one bit of advice I haven't seen so far and that is to experiment. When you buy whatever you decide will fit your needs, interests, and budget, it will come with an antenna that can be attached to radio. Start your experiments there.

First experiment: use the stock antenna and note how it performs for the agencies of interest. Alternate where you put the radio in the house and note whether that affects reception. It is possible that you'll find that antenna can provide an acceptable level of performance. If so, great - if not, you have a baseline for comparison.

Second experiment: if your home is not well-sited relative to the agencies of interest (lower than nearby surrounding terrain, for example), take your radio with the stock antenna mobile to a nearby public space that is better sited than your home. Evaluate performance at that location and this will give some insight as to the value of an exterior elevated antenna.

Third experiment: your expressed frequencies of interest could be further investigated by getting a mobile ham radio antenna designed as a dual-band, VHF/UHF antenna. Go mobile with it to evaluate performance, especially in those bands it is not necessarily designed to receive. Any piece of metal in the air will receive most any frequency but it will be compromised by the design. I've had a 19" VHF quarter-wave receive 45 MHz low-band transmissions even though that design says it's not optimal.

Now you have more data that you can apply to your decision-making that is customized to your specific needs and circumstances. This is much better than anybody online can do from a distance. One final note: it is possible to have an antenna system that is "too good." Do a search on this website on "simulcast systems" and read the Wiki. It is possible to receive too much signal for a particular system and it will overwhelm the radio's ability to properly handle the signal.

 

[popnokick]

But I could put one in the attic...as I still have an old TV antenna from analog days up there....

You are in luck! TV antennas can be turned into very effective scanner antennas with very little effort an very low cost! There is much more info in this thread - be sure to read the 2nd page of posts, especially the one by user "zonian149" and the post I made referring to another user's success with a TV antenna (http://forums.radioreference.com/scanner-receiver-antennas/326746-antenna-outdoor-temperature.html)
http://forums.radioreference.com/scanner-receiver-antennas/62647-tv-antenna-scanner-reception.html

Why does this work, and why can you do it for little or no cost? Old TV antennas - whether on the roof or in the attic, whether "analog" or "digital".... receive in a very broad range of frequencies that overlap the public service scanner bands. This is all explained in the other posts I've referred to. They offer gain and are directional, but chances are they are already pointed in a direction that most of the signals you'll want to receive are coming from (two-way comms towers tend to be co-located with TV towers). There's nothing to install, and the lead-in cable is likely already coming down from the roof or attic. You just need to turn the antenna 90 degrees to make it vertically polarized, and make connection to the end of the antenna wire coming down into the house from the antenna.

TV antennas are normally mounted with the long elements parallel to the roof or attic floor. This gives them horizontal polarization for the TV signals. Two-way radio signals are vertically polarized, so you'll need to turn the antenna so that the long elements point up and down rather than parallel to the floor / roof. You may have to change the mounting a bit, but it could be as simple as loosening the bracket, rotating the antenna 90 degrees on its axis, and tightening it up again.

Next, you'll need to examine the feed line from the antenna. If it's really old it is probably flat brown wire known as "twinlead". Not a problem.... you can use a 300 to 75 ohm TV transformer to change from twinlead to 75 ohm coax cable. And yes, that 75 ohm coax will work just fine with your scanner. You will need an adapter to go from the male F-connector on the coax cable / adapter to whatever antenna connector is on the scanner (BNC, etc.). If the feed line(s) coming from the antenna are already 75 ohm coax, you can connect directly to it with and adapter and to your scanner. And you're ready to go!

My house had old cable TV outlets in every room. I have satellite and knew the old TV cables were not being used. I went into the attic and found the point of entrance for the cable TV. There was a splitter, which I replaced with a splitter / amp, and now I have a scanner antenna outlet in many rooms of the house.

If you're not sure about what you have or any other questions, post a pic here and we'll answer. Now get going with your FREE high-performance scanner antenna.... and possible whole-house distribution system!

 

[Santacarl]

You are in luck! TV antennas can be turned into very effective scanner antennas with very little effort an very low cost! There is much more info in this thread - be sure to read the 2nd page of posts, especially the one by user "zonian149" and the post I made referring to another user's success with a TV antenna (http://forums.radioreference.com/scanner-receiver-antennas/326746-antenna-outdoor-temperature.html)
http://forums.radioreference.com/scanner-receiver-antennas/62647-tv-antenna-scanner-reception.html

Why does this work, and why can you do it for little or no cost? Old TV antennas - whether on the roof or in the attic, whether "analog" or "digital".... receive in a very broad range of frequencies that overlap the public service scanner bands. This is all explained in the other posts I've referred to. They offer gain and are directional, but chances are they are already pointed in a direction that most of the signals you'll want to receive are coming from (two-way comms towers tend to be co-located with TV towers). There's nothing to install, and the lead-in cable is likely already coming down from the roof or attic. You just need to turn the antenna 90 degrees to make it vertically polarized, and make connection to the end of the antenna wire coming down into the house from the antenna.

TV antennas are normally mounted with the long elements parallel to the roof or attic floor. This gives them horizontal polarization for the TV signals. Two-way radio signals are vertically polarized, so you'll need to turn the antenna so that the long elements point up and down rather than parallel to the floor / roof. You may have to change the mounting a bit, but it could be as simple as loosening the bracket, rotating the antenna 90 degrees on its axis, and tightening it up again.

Next, you'll need to examine the feed line from the antenna. If it's really old it is probably flat brown wire known as "twinlead". Not a problem.... you can use a 300 to 75 ohm TV transformer to change from twinlead to 75 ohm coax cable. And yes, that 75 ohm coax will work just fine with your scanner. You will need an adapter to go from the male F-connector on the coax cable / adapter to whatever antenna connector is on the scanner (BNC, etc.). If the feed line(s) coming from the antenna are already 75 ohm coax, you can connect directly to it with and adapter and to your scanner. And you're ready to go!

My house had old cable TV outlets in every room. I have satellite and knew the old TV cables were not being used. I went into the attic and found the point of entrance for the cable TV. There was a splitter, which I replaced with a splitter / amp, and now I have a scanner antenna outlet in many rooms of the house.

If you're not sure about what you have or any other questions, post a pic here and we'll answer. Now get going with your FREE high-performance scanner antenna.... and possible whole-house distribution system!

Wow....how did I fall into that kind of "luck"? (Smiling).....

The downline from the antenna is RG-6.......I paid extra when the house was built and finally get to benefit from it....Yippee.....

Thanks for the links....and the information on orientation is something that I had no clue about....Excellent feedback....thank you so much....

 

[Santacarl]

As you have already acknowledged, there has been excellent advice given in the thread that was responsive to your inquiry without becoming overly technical. I'll add one bit of advice I haven't seen so far and that is to experiment. When you buy whatever you decide will fit your needs, interests, and budget, it will come with an antenna that can be attached to radio. Start your experiments there.

First experiment: use the stock antenna and note how it performs for the agencies of interest. Alternate where you put the radio in the house and note whether that affects reception. It is possible that you'll find that antenna can provide an acceptable level of performance. If so, great - if not, you have a baseline for comparison.

Second experiment: if your home is not well-sited relative to the agencies of interest (lower than nearby surrounding terrain, for example), take your radio with the stock antenna mobile to a nearby public space that is better sited than your home. Evaluate performance at that location and this will give some insight as to the value of an exterior elevated antenna.

Third experiment: your expressed frequencies of interest could be further investigated by getting a mobile ham radio antenna designed as a dual-band, VHF/UHF antenna. Go mobile with it to evaluate performance, especially in those bands it is not necessarily designed to receive. Any piece of metal in the air will receive most any frequency but it will be compromised by the design. I've had a 19" VHF quarter-wave receive 45 MHz low-band transmissions even though that design says it's not optimal.

Now you have more data that you can apply to your decision-making that is customized to your specific needs and circumstances. This is much better than anybody online can do from a distance. One final note: it is possible to have an antenna system that is "too good." Do a search on this website on "simulcast systems" and read the Wiki. It is possible to receive too much signal for a particular system and it will overwhelm the radio's ability to properly handle the signal.

Thanks for the experiments list....very helpful in getting started in the right direction....when you're learning this stuff from scratch it can be a bit overwhelming and sometimes you get confused and don't think as clearly as you might otherwise....having a starting list is very helpful.