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does super narrow band reach farther?
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Author:  gregz [ Sun Jan 11, 2009 10:13 am ]
Post subject:  does super narrow band reach farther?
do (to borrow Wilrobnson's term) "super narrow" frequencies like 774.48125 reach farther? it seems that I'm able to receive father transmissions since this change.

does a 100 watt amplifier spread it's power over less bandwidth and perhaps have more distant punch?
Author:  chpalmer [ Sun Jan 11, 2009 11:21 am ]
Post subject:  Re: does super narrow band reach farther?
No. If you are trying to transmit more than one carrier through an amp then yes it would take up those resources. (IE spurs, broadband noise) A preamp on a recieve antenna would work the same way. The more it has to amplify, the less good it will do your intended frequency.

In fact the narrower you go the less coverage you should have due to SNR.

I have been a little impressed with the audio qualities of the Motorola CDM series with 12.5kc channels but the receiver is still pretty wide so adjacent channels still are a problem...
Author:  N7QOR [ Thu Jan 22, 2009 9:14 pm ]
Post subject:  Re: does super narrow band reach farther?
chpalmer wrote:
No. If you are trying to transmit more than one carrier through an amp then yes it would take up those resources. (IE spurs, broadband noise) A preamp on a recieve antenna would work the same way. The more it has to amplify, the less good it will do your intended frequency.

In fact the narrower you go the less coverage you should have due to SNR.

I have been a little impressed with the audio qualities of the Motorola CDM series with 12.5kc channels but the receiver is still pretty wide so adjacent channels still are a problem...


There is another take on this though.

"Extreme" narrow modes (> 6.25KHz channel width) are typically digital modes. Digital modes offer higher clarity at the further reaches of coverage areas when compared to similar range analog systems.

I have some customers who feel therefore that the digital range is "better". In reality the audio is clear all the way to the far end of the range, but then it drops off, just like a cell phone.
Author:  SpudGunMan [ Fri Jan 23, 2009 6:35 am ]
Post subject:  Re: does super narrow band reach farther?
and yet another take, the higher you do go the smaller the band and thusly you do go further (ie. Light) but that isnt really in scope here.


however the perception might be that higher bands go further, but most of the time as mentioned there is digital, also directional antennas are used such as microwave drums so its actually going further but other technology is enabling it to hit the mark on the other end, if you just stuck microwave out there on a omni your microwave would be wasted on the SNR
Author:  chpalmer [ Fri Jan 23, 2009 6:59 am ]
Post subject:  Re: does super narrow band reach farther?
Quote:
"Extreme" narrow modes (> 6.25KHz channel width) are typically digital modes. Digital modes offer higher clarity at the further reaches of coverage areas when compared to similar range analog systems.

I have some customers who feel therefore that the digital range is "better". In reality the audio is clear all the way to the far end of the range, but then it drops off, just like a cell phone.


When we played with digital years ago albeit using wideband we were able to hear and understand the analog comms further than the digital would go. But I see the potential. Interesting. Im going to have to play some more with this when it becomes available to me... :D

I havent found a receiver yet though that was selctive enough to keep the close in proximity adjacent's from interfering. Whether the digital technology covers it up or not its still potential so should be considered. I already see many areas that deal with interference from adjacent channels using wideband.
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