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Narrowband or Wideband?

Sep 22nd 2011, 05:30

KC9TCZ

Joined: Sep 28th 2010, 09:57
Total Topics: 0
Total Posts: 0
Hi,
New Ham here, still learning the basics with my Wouxun HT, trying to hit the local repeaters and learn what my radio is capable of so far.
I'm curious whether I should select narrowband or wideband for my operational mode? I am not sure what the benefits of each are-I think I get the science of it somewhat, but I'm not sure what it all gets me.
Thanks for the help.
KC9TCZ
Sep 22nd 2011, 06:04

KE8DO

Joined: Apr 4th 1998, 00:00
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Total Posts: 0
I have not heard of a Wouxum HT. How wide is your wideband and how narrow is your narrowband width? Is this for the transmit, receive or both? Most FM repeaters use narrow bandwidth, about 10KHz wide. You want to transmit with a bandwidth equal to the bandwidth of the receiver, in your case, the receiver of the repeater.
If you transmit FM wider than the bandwidth of the receiver your signal will go outside of the receiver bandpass and clip. If you transmit narrorband to a wideband receiver you will loose signal to noise and sound weak.
73 Don KE8DO
Sep 22nd 2011, 13:00

WB1GCM

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
You can set your bandwidth to either, "wideband", or, "narrow" with the Wouxun HT. "Narrow" sets the transmitted deviation to 2.5 to about 3 kHz, where as, "wideband" sets the deviation to about 5 kHz or so. Since most repeater spacing is 15 kHz (20 kHz where you are), either mode will not cause interference to the adjacent channel.

Using "wideband" will make your audio sound a little louder and clearer to other hams.

Wouxun can be sold as a Part 90 radio, where business and town government channel spacings are closer together. "Narrow" deviation would be appropriate to use in the case of the business band user who is licensed within that radio service.

Bob Allison
WB1GCM
ARRL Lab Engineer
Sep 22nd 2011, 13:12

N0NB

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
For the most part, hams are still using 5 kHz deviation on our VHF/UHF frequencies including repeaters. There may be a repeater here or there that is using narrowband--ask your local repeater's trustee to be sure--but I suspect they are fairly rare. 5 kHz will likely remain the ham standard for some time to come in most areas.

In my experience with Part 90 systems, the two bandwidths are interoperable with weak signal performance of cross bandwidth systems being degraded a bit. Our experience finds that DTMF control is most affected by bandwidth mismatch (our company uses DTMF in various operations). Otherwise, a narrowband signal in a wideband receiver gets noisy quickly and a wideband signal into a narrowband receiver can result in the receiver squelching before the received signal drops to the SINAD level.

Narrowband is a big deal right now in the Part 90 services as it is mandated to be in use as of 1 Jan 2013.
Sep 22nd 2011, 15:11

KC9TCZ

Joined: Sep 28th 2010, 09:57
Total Topics: 0
Total Posts: 0
Lots of good info there. Thanks all!
73s
Jeff
May 27th 2013, 01:53

weastridge

Joined: Dec 14th 2011, 01:55
Total Topics: 0
Total Posts: 0
Another consideration is that the continuous tone signal might be too weak to trigger the repeater if using narrow band. My Wouxun HT couldn't hit one distant repeater on Narrow deviation but could on Wide deviation (which is only +/- 5 khz)
73, Wesley

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