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Narrow channel works better in wide than it does in narrow?
Posted: Sun Mar 01, 2009 8:24 am
by nmfire10
Conventional UHF astro channel. It is narrowband (460.2875). I live in a pretty bad spot so the signal that reaches me is weak. If I accidentally program my portable for wideband, it receives GREAT. The audio doesn't get choppy or anything. If I program it correctly for narrowband, the audio gets choppy and cuts out due to the weak signal.
I would think it would be the other way around? Am tripping on something here? This is demonstrated with two different radios (XTS1500 and XTS3000).
Re: Narrow channel works better in wide than it does in narrow?
Posted: Sun Mar 01, 2009 3:13 pm
by Tom in D.C.
Sure sounds to me as if the signal is being sent wideband, regardless of the frequency being on a 12.5 kHz split.
Re: Narrow channel works better in wide than it does in narrow?
Posted: Sun Mar 01, 2009 4:51 pm
by nmfire10
Heh. Ya know, given the history of this system, which I believe you're probably familiar with due to all the problems I keep posting here about, I seriously would not be surprised if they screwed that up too. Unfortunately I don't have a cable for a Quantar to read it so I can only assume they did it right.... which would be a first for this thing.
Next time I get my hands on a service monitor, I'll park under the tower and see what is expelling fourth from its transmitter.
Re: Narrow channel works better in wide than it does in narrow?
Posted: Sun Mar 01, 2009 6:52 pm
by d119
Just because it's on a splinter channel does not mean that it is narrowband, Marc.
Re: Narrow channel works better in wide than it does in narrow?
Posted: Sun Mar 01, 2009 6:56 pm
by nmfire10
Oh I know the background of this system and it is supposed to be narrow. It is also licensed as narrow. In fact, the police chief claims "astro works better on narrowband" (direct quote). I don't know why it would make a difference and based on this experience, I think he might be mistaken
Re: Narrow channel works better in wide than it does in narrow?
Posted: Mon Mar 02, 2009 10:42 am
by Josh
I would say something is programmed wrong.
There is an Astro ham repeater here in narrow-band mode. I had my astro spectra programmed wide-band and couldn't RX worth a darn at a distance, it would get easily desensed by other nearby signals and repeaters. I made it narrow band as it should have been and RX cleared up and was way more selective. RX range significantly improved too.
Narrow band can work better than mis-programmed radios set up conversely!
Re: Narrow channel works better in wide than it does in narrow?
Posted: Mon Mar 02, 2009 11:02 am
by wavetar
In a given radio, selectivity, intermodulation & spurious rejection are all spec'd worse in narrowband than wideband, usually by at least 5 db, sometimes 10. Also, although I cannot find it listed separately in an Astro manual, sensitivity in a given radio was generally worse by 0.05 uV. So, it doesn't surprise me that a radio may work better with a weak signal in wide band mode as opposed to narrow.