A question regarding the extendable antennas

[Mprosser81996]

Whether if its the police, fire, marine, weather, or the railroad. Will a extendable antenna increase your reception range? or do you have to keep it set to the amount of mhz for that paticular channel type.

For some who know or don't know. I am a railfan, and range is the most important thing a railfan would need, knowing the locations of the trains before they get close.
Being in Round lake beach, I railfan trains on the Canadian National Waukesha sub, the freq. is 160.920mhz for those who have a BC125at, that's AAR Channel 79 for those who like to put the full name of it in.

Anyways, the Diamond 77 and Rubber duck antennas in terms of figuring out it's reception ranges, on a good day, At Round Lake Beach Station, at Milepost 48.5, I can hear the defect detector over in Grayslake at milepost 44.6 And rarely I have heard the defect detector at Milepost 54.3 in Lake villa. I've also heard a detector over at Milepost 55.5. But a CN conductor has told me that detector is not on the same line, but on the Leighton sub, a totally different section of track.

One detector is 6 miles away, the other is 4 miles away. Would the reception range be any different if I got an extendable antenna? or it won't make a difference because I would have to set the antenna to where it receives transmissions from 159-161mhz ranges.

 

[cmdrwill]

Will a extendable antenna increase your reception range? or do you have to keep it set to the amount of mhz for that paticular channel type.

A quarter wave length at the frequency is the most efficient for portable radios . So about 17 1/2 to 18 1/4 inches on railroad frequencies depending on the counter poise.

 

[WB9YBM]

Whether if its the police, fire, marine, weather, or the railroad. Will a extendable antenna increase your reception range? or do you have to keep it set to the amount of mhz for that paticular channel type.

For some who know or don't know. I am a railfan, and range is the most important thing a railfan would need, knowing the locations of the trains before they get close.
Being in Round lake beach, I railfan trains on the Canadian National Waukesha sub, the freq. is 160.920mhz for those who have a BC125at, that's AAR Channel 79 for those who like to put the full name of it in.

Anyways, the Diamond 77 and Rubber duck antennas in terms of figuring out it's reception ranges, on a good day, At Round Lake Beach Station, at Milepost 48.5, I can hear the defect detector over in Grayslake at milepost 44.6 And rarely I have heard the defect detector at Milepost 54.3 in Lake villa. I've also heard a detector over at Milepost 55.5. But a CN conductor has told me that detector is not on the same line, but on the Leighton sub, a totally different section of track.

One detector is 6 miles away, the other is 4 miles away. Would the reception range be any different if I got an extendable antenna? or it won't make a difference because I would have to set the antenna to where it receives transmissions from 159-161mhz ranges.

I've found that in most cases antenna length is not critical on receive, the only exception I've noticed is a Sony shortwave receiver I once owned; in general I've noticed signal improvements based on the longer-is-better approach. About the same level of importance (give or take a bit) is antenna height & feedline length: keeping the feedline length as short as possible (to avoid excessive line losses or the cost of higher quality feedline) and get the antenna as high as possible--at least above the worst of the ground clutter (i.e. metal vehicles, etc.) I've also experimented with the pre-amplifiers places like Radio Shack used to sell back when television was still analog and found those to be a help, too. (Don't know if those are still available though.)

 

[Mprosser81996]

A quarter wave length at the frequency is the most efficient for portable radios . So about 17 1/2 to 18 1/4 inches on railroad frequencies depending on the counter poise.

Is that the one where it would have to be coaxial? My scanner, the BC75xlt is a BNC connector. Male I'm guessing. Not sure whats the difference between male and female BNC's. Any suggestions on what I could get? Amazon preferably

I've found that in most cases antenna length is not critical on receive, the only exception I've noticed is a Sony shortwave receiver I once owned; in general I've noticed signal improvements based on the longer-is-better approach. About the same level of importance (give or take a bit) is antenna height & feedline length: keeping the feedline length as short as possible (to avoid excessive line losses or the cost of higher quality feedline) and get the antenna as high as possible--at least above the worst of the ground clutter (i.e. metal vehicles, etc.) I've also experimented with the pre-amplifiers places like Radio Shack used to sell back when television was still analog and found those to be a help, too. (Don't know if those are still available though.)

Any suggestions you can pitch me?

 

[doctordialtone]

Not sure whats the difference between male and female BNC's.

Male has the pin.

Female has the "socket"

BNC connector - Male/Female

 

[Mprosser81996]

Male has the pin.

Female has the "socket"

BNC connector - Male/Female

BC75xlt is a male bnc correct?

 

[doctordialtone]

BC75xlt is a male bnc correct?

If the antenna has the pin in the middle, IT is the MALE.

The scanner most likely has the FEMALE.

 

[krokus]

Where are you using your scanner? In your house? Your car? While walking around? An external antenna would be best for the first two, especially one cut for rail.

Sent using Tapatalk

 

[Mprosser81996]

Where are you using your scanner? In your house? Your car? While walking around? An external antenna would be best for the first two, especially one cut for rail.

Sent using Tapatalk

at the train station when I'm railfanning. If I was listening to police, I'd be anywhere. Home or in public.

If the antenna has the pin in the middle, IT is the MALE.

The scanner most likely has the FEMALE.

Well what kinda bnc does the diamond 77 and the standard rubber duck antennas have? or they have both

 

[doctordialtone]

Well what kinda bnc does the diamond 77 and the standard rubber duck antennas have

Male

The Male (Antenna) Plugs INto the Female (Radio), just like in real life!

 

[Mprosser81996]

Male

The Male (Antenna) Plugs INto the Female (Radio), just like in real life!

Thanks.

 

[wcsd45]

BC75XLT has female BNC. For rail frequencies, extend telescoping antenna to length 17 1/2 to 18 1/4 inches as noted earlier.

Antenna options on Amazon:

1) Search for

uxcell BNC Male Adapter RF Connector 7 Sections Telescoping Antenna Silver Tone


2) Search for
RH-789 by Diamond.
This one pricier, but prettier, likely better quality

Non-Amazon option, rubber ducky type:
5/8 Slim Duck 160 MHZ
Set connector option as BNC

 

[Mprosser81996]

BC75XLT has female BNC. For rail frequencies, extend telescoping antenna to length 17 1/2 to 18 1/4 inches as noted earlier.

Antenna options on Amazon:

1) Search for

uxcell BNC Male Adapter RF Connector 7 Sections Telescoping Antenna Silver Tone


2) Search for
RH-789 by Diamond.
This one pricier, but prettier, likely better quality

Non-Amazon option, rubber ducky type:
5/8 Slim Duck 160 MHZ
Set connector option as BNC

Okay

 

[W5lz]

For transmitting the antenna's length is important, makes it 'match' the transmitter better. For receiving the antenna isn't that critical at all. It's "easier" for a receiver to deal with a too-long antenna than a too-short one. Don't carry that to extremes though. Any antenna that's not at a resonant length, or close, is going to be less efficient than if it were resonant. That means a large 'fudge factor' for the 'best' antenna length. Very, very baically, if the thing is within 'ball-park' length of the frequency in use, get the thing as high as is practical for you. Didn't say -possible-, but practical which ain't the same thing at all. Do what you can and live with it. Wanna try something else just to see? Have at it, but expect to be disappointed a lot...

 

[Ubbe]

An antenna could work best as a 3/4 a 5/8 or 1 1/4 or anything else. What I used to do with telescopes are to extend them to max and try to find a transmitter that sends longer analog conversations and then quickly push the antennas top with the palm of my hand to make it 2 inch shorter and listen for 3 seconds if the signal got better or worse and continue with 2 inch shortening until it gets to shortest possible lenght. I try and remember what the lenght was when it had the best reception and restart from there and pull and push 1 inch at a time to find the best lenght.

Sometimes the best reception are when the antenna are working worse at an interfering signals frequency, if there is a strong one nearby. So there are no defined lenght of the antenna that you SHOULD use and not try other lenghts.

/Ubbe

 

[WB9YBM]

For transmitting the antenna's length is important, makes it 'match' the transmitter better. For receiving the antenna isn't that critical at all. It's "easier" for a receiver to deal with a too-long antenna than a too-short one. Don't carry that to extremes though. Any antenna that's not at a resonant length, or close, is going to be less efficient than if it were resonant. That means a large 'fudge factor' for the 'best' antenna length. Very, very baically, if the thing is within 'ball-park' length of the frequency in use, get the thing as high as is practical for you. Didn't say -possible-, but practical which ain't the same thing at all. Do what you can and live with it. Wanna try something else just to see? Have at it, but expect to be disappointed a lot...

While this might tune the antenna to the operating frequency, I'd like to point out that this doesn't necessarily mean that the impedance will be what the transmitter wants to see (that's why a 5/8, 3/8 & etc. have a matching coil on the bottom).

 

[W5lz]

WB9YBM - exactly. Resonance and input impedance are not the same things at all. Adjusting an antenna so that it's resonant is a common and good way of doing it (resonance = efficiency). Adjusting an antenna (length) for best SWR only means making that transmitter 'like' the thing better at the cost of resonance/efficiency. SWR, by it's self, is a terrible way of determining how well an antenna works. Classic example is a dummy load.

 

[WB9YBM]

WB9YBM - exactly. Resonance and input impedance are not the same things at all. Adjusting an antenna so that it's resonant is a common and good way of doing it (resonance = efficiency). Adjusting an antenna (length) for best SWR only means making that transmitter 'like' the thing better at the cost of resonance/efficiency. SWR, by it's self, is a terrible way of determining how well an antenna works. Classic example is a dummy load.

It can also be said that low SWR = efficiency since low reflected power means more signal going out of the antenna since it's not being reflected back to the transmitter.

 

[prcguy]

I have a couple of extendable whips for the 2m amateur band, one is a 1/2 wave and the other a 5/8 wave, both being a good 3 to 4ft long. These blow away any other full size 1/4 wave or magic shortened antenna I've ever tried on a hand held. I believe Smiley Antennas made the 1/2 wave and I'm not sure who made the other.

You can get the same thing for the RR band, a tuned resonant 1/2 wave or 5/8 wave extendable whip for a hand held scanner that will bring in stuff you can't get with an RH77 or anything similar.

 

[W5lz]

"You can get the same thing for the RR band, a tuned resonant 1/2 wave or 5/8 wave extendable whip for a hand held scanner that will bring in stuff you can't get with an RH77 or anything similar."

Yes. With a couple'a qualifications. An HT (or scanner) is only for convenience. It isn't ever going to be the 'best' way of doing any kind of communicating unless you are talking about -short- distances. The biggest problem is the antenna. Can't get it very 'efficient' unless you make it more inconvenient (longer). With VHF/UHF that inconvenience is 'do-able'. For lower bands it's not so 'do-able', ain't gonna use no 80 meter HT! I can yell louder than that. (Yeah, I know, but it illustrates the point.)