Re: [Repeater-Builder] Narrowbanding
What's nastier is T-band sharing. WCVB in Boston on channel 20 routinely hammers a number of 500 MHZ public safety systems in New Jersey. From: Milt To: Repeater-Builder@yahoogroups.com Sent: Tue, August 3, 2010 6:56:05 AM Subject: Re: [Repeater-Builder] Narrowbanding That may be what the mask specifies. I have seen the curve plots of the mask. Now run the numbers and see what kind of signal levels that really equates to when the DTV station is running say 1 MW. It looks pretty on paper, it's not so pretty in the real world. - Original Message - From: "Glenn Little WB4UIV" To: Sent: Monday, August 02, 2010 11:23 PM Subject: Re: [Repeater-Builder] Narrowbanding >I do not know about Nextel, but, the US DTV signal fits into a 6 MHz >bandwidth. > We use a mask filter to ensure that the bandwidth is no more than 6 MHz. > 500 kHz from band edge <= -47 dB > 6 MHz from band edge <= -110 dB > > 73 > Glenn > WB4UIV > > At 10:58 AM 8/2/2010, you wrote: >>On 8/2/2010 10:45 AM, Scott Zimmerman wrote: >> > I was wondering about that myself. The bandwidths spec'd just didn't >> > seem to compute in my feeble mind. >> > >> > Scott >> > >> > Scott Zimmerman >> > Amateur Radio Call N3XCC >> > 474 Barnett Road >> > Boswell, PA 15531 >> > >> > >> > Jeff DePolo wrote: >> >> >> >>> Florida Repeater Coordinator proposes narrowbanding: >> >>> >> >>> http://www.florida-repeaters.org/FRC%202meter%20narrowband%20p >> >> olicy%20released%207-18-10.pdf >> >> >> >> Apparently Carson's Rule works different in Florida than it does >> everywhere >> >> else. >> >> >> >> --- Jeff WN3A >> >> >> >>Course, wiki says Carson's rule "is of little use in spectrum planning" >>anyway...(http://en.wikipedia.org/wiki/Carson_bandwidth_rule). These >>must be the same people that think Nextel's iDen 6:1 TDMA format fits in >>a 25 KHz channel, or that think the US DTV standard fits in a 6 MHz >>channel...NOT! >> >> >> >> >> >> >> >>Yahoo! Groups Links >> >> >> > > > > > > > Yahoo! Groups Links > > > Yahoo! Groups Links http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Narrowbanding
On 8/2/2010 11:23 PM, Glenn Little WB4UIV wrote: > I do not know about Nextel, but, the US DTV signal fits into a 6 MHz > bandwidth. > We use a mask filter to ensure that the bandwidth is no more than 6 MHz. > 500 kHz from band edge<= -47 dB > 6 MHz from band edge<= -110 dB > > 73 > Glenn > WB4UIV And that's why we see noise in the -60 to -90 dBm range 1 to 2 MHz beyond the band edges 10-20 miles from the transmitters... (thank god the ch2 here moved up to 17...6M is usable again!) 500 KHz from the band edge @ 47 dB down on a transmitter that is, say, 10,000W...10KW is +70 dBm minus 47db is +23 dBm, or 200 mW. Free-space loss at..let's be conservative and use 860 MHz (I happen to have the Bird mouse pad in front of me) @ 10 mi is 115 dB. +23 minus 115 is -92 dBm...nah, no one will hear that...free-space loss @ 150 for the same distance is 100 dB, my chart doesn't have 50 Mhz, but I suspect around 90-95. And while Nextel is better than that, because the Nextel channels are interspersed with other (25 KHz spacing), it causes total LOS sometimes as far as a mile or two from a tower. That's why they're moving them up to the top of the 800 band and getting normal 800 users as far away as possible.
Re: [Repeater-Builder] Narrowbanding
That may be what the mask specifies. I have seen the curve plots of the mask. Now run the numbers and see what kind of signal levels that really equates to when the DTV station is running say 1 MW. It looks pretty on paper, it's not so pretty in the real world. - Original Message - From: "Glenn Little WB4UIV" To: Sent: Monday, August 02, 2010 11:23 PM Subject: Re: [Repeater-Builder] Narrowbanding >I do not know about Nextel, but, the US DTV signal fits into a 6 MHz >bandwidth. > We use a mask filter to ensure that the bandwidth is no more than 6 MHz. > 500 kHz from band edge <= -47 dB > 6 MHz from band edge <= -110 dB > > 73 > Glenn > WB4UIV > > At 10:58 AM 8/2/2010, you wrote: >>On 8/2/2010 10:45 AM, Scott Zimmerman wrote: >> > I was wondering about that myself. The bandwidths spec'd just didn't >> > seem to compute in my feeble mind. >> > >> > Scott >> > >> > Scott Zimmerman >> > Amateur Radio Call N3XCC >> > 474 Barnett Road >> > Boswell, PA 15531 >> > >> > >> > Jeff DePolo wrote: >> >> >> >>> Florida Repeater Coordinator proposes narrowbanding: >> >>> >> >>> http://www.florida-repeaters.org/FRC%202meter%20narrowband%20p >> >> olicy%20released%207-18-10.pdf >> >> >> >> Apparently Carson's Rule works different in Florida than it does >> everywhere >> >> else. >> >> >> >> --- Jeff WN3A >> >> >> >>Course, wiki says Carson's rule "is of little use in spectrum planning" >>anyway...(http://en.wikipedia.org/wiki/Carson_bandwidth_rule). These >>must be the same people that think Nextel's iDen 6:1 TDMA format fits in >>a 25 KHz channel, or that think the US DTV standard fits in a 6 MHz >>channel...NOT! >> >> >> >> >> >> >> >>Yahoo! Groups Links >> >> >> > > > > > > > Yahoo! Groups Links > > >
Re: [Repeater-Builder] Narrowbanding
I do not know about Nextel, but, the US DTV signal fits into a 6 MHz bandwidth. We use a mask filter to ensure that the bandwidth is no more than 6 MHz. 500 kHz from band edge <= -47 dB 6 MHz from band edge <= -110 dB 73 Glenn WB4UIV At 10:58 AM 8/2/2010, you wrote: >On 8/2/2010 10:45 AM, Scott Zimmerman wrote: > > I was wondering about that myself. The bandwidths spec'd just didn't > > seem to compute in my feeble mind. > > > > Scott > > > > Scott Zimmerman > > Amateur Radio Call N3XCC > > 474 Barnett Road > > Boswell, PA 15531 > > > > > > Jeff DePolo wrote: > >> > >>> Florida Repeater Coordinator proposes narrowbanding: > >>> > >>> http://www.florida-repeaters.org/FRC%202meter%20narrowband%20p > >> olicy%20released%207-18-10.pdf > >> > >> Apparently Carson's Rule works different in Florida than it does > everywhere > >> else. > >> > >> --- Jeff WN3A > >> > >Course, wiki says Carson's rule "is of little use in spectrum planning" >anyway...(http://en.wikipedia.org/wiki/Carson_bandwidth_rule). These >must be the same people that think Nextel's iDen 6:1 TDMA format fits in >a 25 KHz channel, or that think the US DTV standard fits in a 6 MHz >channel...NOT! > > > > > > > >Yahoo! Groups Links > > >
Re: [Repeater-Builder] Narrowbanding
Here in Washington State our agency is running on 7.5 channels using 11K2F3D/11K2F3E. Frequency coordination has to be a little creative as the channels of course overlap. Need to keep the repeaters far enough apart such the signal level of the overlap is of no consequence to the adjacent channel. This is much the same concept used in CA years ago when two meters was switched 15 kHz channel centers. Rob K7TGU - Original Message - From: "MCH" To: Sent: Monday, August 02, 2010 13:16 Subject: Re: [Repeater-Builder] Narrowbanding >I was wondering about that myself. > > A couple of comments on the other aspects: > > 1. I see this as falling flat on its face. May as well mandate D-STAR. > > 2. How are the commercial people fitting SNFM in 7.5 kHz channels as > they have been doing on VHF? > > Joe M. > > Chuck Kelsey wrote: >> How wide is it? >> >> Chuck >> WB2EDV >> >> >> - Original Message ----- >> From: "wd8chl" >> To: >> Sent: Monday, August 02, 2010 10:58 AM >> Subject: Re: [Repeater-Builder] Narrowbanding >> >> >> > ...or that think the US DTV standard fits in a 6 MHz >>> channel...NOT! >> >> >> >> >> >> >> >> Yahoo! Groups Links >> >> >> >> > > > > > > > Yahoo! Groups Links > > >
Re: [Repeater-Builder] Narrowbanding
FWIW it would probably be made to workat a price, but for ordinary consumer type Amateur Radios, not really. We have been "conditioned" to the sub $400 price range radios that do everything, go everywhere and have less than ordinary receivers in them. :-) 73, Jack VK4JRC Sent from my Apple iPad Tablet PC On Aug 3, 2010, at 6:16 AM, MCH wrote: > I was wondering about that myself. > > A couple of comments on the other aspects: > > 1. I see this as falling flat on its face. May as well mandate D-STAR. > > 2. How are the commercial people fitting SNFM in 7.5 kHz channels as > they have been doing on VHF? > > Joe M. > > > > >
Re: [Repeater-Builder] Narrowbanding
I was wondering about that myself. A couple of comments on the other aspects: 1. I see this as falling flat on its face. May as well mandate D-STAR. 2. How are the commercial people fitting SNFM in 7.5 kHz channels as they have been doing on VHF? Joe M. Chuck Kelsey wrote: > How wide is it? > > Chuck > WB2EDV > > > - Original Message - > From: "wd8chl" > To: > Sent: Monday, August 02, 2010 10:58 AM > Subject: Re: [Repeater-Builder] Narrowbanding > > > > ...or that think the US DTV standard fits in a 6 MHz >> channel...NOT! > > > > > > > > Yahoo! Groups Links > > > >
RE: [Repeater-Builder] Narrowbanding
At 8/2/2010 06:37, you wrote: > > > Florida Repeater Coordinator proposes narrowbanding: > > > > http://www.florida-repeaters.org/FRC%202meter%20narrowband%20p >olicy%20released%207-18-10.pdf > >Apparently Carson's Rule works different in Florida than it does everywhere >else. Well put, Jeff. IMO 10 kHz is about the limit for any kind of voice emission, & it has to be digital in order to be anything less than 12.5 kHz. We have a small D-Star sub-band on 2 meters here in SoCal that's spaced @ 10 kHz & it seems to be working. I applaud the FRC's initiative in wanting to do something to increase spectrum efficiency, but 7.5 kHz is simply going too far. Heck, some parts of the country can't even make 15 kHz work, & have gone to 20 kHz spacing throughout the entire 2 meter band. Bob NO6B
Re: [Repeater-Builder] Narrowbanding
How wide is it? Chuck WB2EDV - Original Message - From: "wd8chl" To: Sent: Monday, August 02, 2010 10:58 AM Subject: Re: [Repeater-Builder] Narrowbanding > ...or that think the US DTV standard fits in a 6 MHz > channel...NOT!
Re: [Repeater-Builder] Narrowbanding
On 8/2/2010 10:45 AM, Scott Zimmerman wrote: > I was wondering about that myself. The bandwidths spec'd just didn't > seem to compute in my feeble mind. > > Scott > > Scott Zimmerman > Amateur Radio Call N3XCC > 474 Barnett Road > Boswell, PA 15531 > > > Jeff DePolo wrote: >> >>> Florida Repeater Coordinator proposes narrowbanding: >>> >>> http://www.florida-repeaters.org/FRC%202meter%20narrowband%20p >> olicy%20released%207-18-10.pdf >> >> Apparently Carson's Rule works different in Florida than it does everywhere >> else. >> >> --- Jeff WN3A >> Course, wiki says Carson's rule "is of little use in spectrum planning" anyway...(http://en.wikipedia.org/wiki/Carson_bandwidth_rule). These must be the same people that think Nextel's iDen 6:1 TDMA format fits in a 25 KHz channel, or that think the US DTV standard fits in a 6 MHz channel...NOT!
Re: [Repeater-Builder] Narrowbanding
On 8/2/2010 9:37 AM, Jeff DePolo wrote: > >> Florida Repeater Coordinator proposes narrowbanding: >> >> http://www.florida-repeaters.org/FRC%202meter%20narrowband%20p > olicy%20released%207-18-10.pdf > > Apparently Carson's Rule works different in Florida than it does everywhere > else. > > --- Jeff WN3A Wow-how...well...just wrong...As Jeff is alluding to, an analog FM signal that is deviated at +/-2.5 KHz occupies slightly less than a 12.5 KHz channel. (11.0 and 11.2 are common narrowband emission bandwidths in Part 90). Not 6.25. Then there's the comment that "Most if not all of the newer Amateur Radio equipment available on the market today in the 144-147 MHz and 430-450 MHz range is capable of using 6.25 KHz (2.5 KHz deviation) channels." Well, besides the gross bandwidth error, you pretty much have to buy Icom to get narrowband. Kenwood's have a toggle in the menu, but it's all or nothing. You can't program NB on a per-channel basis. And I doubt Yaesu is much different. That makes it unusable to me. And let's not forget that while Part 90 users can find ways to buy new radios, and indeed need to not use old radios that are unreliable, hams are footing the bill out of their own pocket, and can't afford to just go out and buy all new gear just to satisfy a few people who think we need more repeaters on 2M (which we don't, by the way. Not around here.) A group that WANTS to VOLUNTARILY narrowband their repeater is welcome to do so, and should notify the council when they do it. But what they propose here is just foolish and completely unnecessary. My advice to anyone in Ohio, and I have to believe FL will be the same, who wants to put up a new repeater is to look at UHF, then either 900 or 220. Unless you can knock a 'paper repeater' off the list, forget 2M. Besides, I'll give up my Heath dual-bander, and my Yaesu FT-270 mobile, and so on, when it dies and becomes unrepairable...not to mention the Micor repeater(s). Jim
Re: [Repeater-Builder] Narrowbanding
I was wondering about that myself. The bandwidths spec'd just didn't seem to compute in my feeble mind. Scott Scott Zimmerman Amateur Radio Call N3XCC 474 Barnett Road Boswell, PA 15531 Jeff DePolo wrote: > >> Florida Repeater Coordinator proposes narrowbanding: >> >> http://www.florida-repeaters.org/FRC%202meter%20narrowband%20p > olicy%20released%207-18-10.pdf > > Apparently Carson's Rule works different in Florida than it does everywhere > else. > > --- Jeff WN3A > > > > > > > > Yahoo! Groups Links > > > >
RE: [Repeater-Builder] Narrowbanding
> Florida Repeater Coordinator proposes narrowbanding: > > http://www.florida-repeaters.org/FRC%202meter%20narrowband%20p olicy%20released%207-18-10.pdf Apparently Carson's Rule works different in Florida than it does everywhere else. --- Jeff WN3A
Re: [Repeater-Builder] Narrowbanding
George, With the upsurge in FRS equipment this might be a worthwhile modification. Since the standard GMRS channels are 25K spaced and the FRS channels are dropped in between both the inputs and the outputs it is possible that a standard 25K rx will receive portions of the audio from adjacent FRS channels. Using narrower filters will cut down on reception of the adjacent channels. There is however a gotcha...other 25K users. The exact action the filters will have is hard to describe. The wider deviation users might sound more distorted, they will sound louder, and weaker wider bandwidth signals may not be heard. If you have "control" of the other transceivers that you will be communicating with, you can turn down the TX deviation to 3KHz which will easilly pass thru a narrowband filter. Good luck Milt N3LTQ - Original Message - From: "George Henry" <[EMAIL PROTECTED]> To: Sent: Tuesday, February 27, 2007 9:36 AM Subject: Re: [Repeater-Builder] Narrowbanding > -Original Message- >>From: George Henry <[EMAIL PROTECTED]> >>Sent: Feb 26, 2007 11:09 PM >>To: Repeater-Builder@yahoogroups.com >>Subject: Re: [Repeater-Builder] Narrowbanding >> > > [snip] > >>Just wondering if it was worth doing or not, particulary for a GMRS >>repeater >>& the potential for FRS interference. >> >> > > DOH!! > > No sooner did I shut the computer down and crawl into bed, than I realized > I was thinking "upside-down" - the FRS channels are between the repeater > OUTPUTS, not the inputs! (Must be that NorCal vs. SoCal repeater thread > that got me confused) So anyway, in a high RF environment like > Chicagoland, is it worth doing? I'm probably 30 miles from the next > nearest GMRS repeater, and the user base seems to be pretty localized. > > George, KA3HSW / WQGJ413 > > > > > > Yahoo! Groups Links > > >
Re: [Repeater-Builder] Narrowbanding
OMG, I need some more sleep. Guess I'd better not handle the soldering iron or any power tools today... George, KA3HSW / WQGJ413 -Original Message- >From: Johnny <[EMAIL PROTECTED]> >Sent: Feb 27, 2007 11:03 AM >To: Repeater-Builder@yahoogroups.com >Subject: Re: [Repeater-Builder] Narrowbanding > >George, >Hate to confuse you more, but there are also FRS channels between the >repeater inputs. >Johnny > > >George Henry wrote: > >> -Original Message- >> >>>From: George Henry <[EMAIL PROTECTED]> >>>Sent: Feb 26, 2007 11:09 PM >>>To: Repeater-Builder@yahoogroups.com >>>Subject: Re: [Repeater-Builder] Narrowbanding >>> >> >> >> [snip] >> >> >>>Just wondering if it was worth doing or not, particulary for a GMRS repeater >>>& the potential for FRS interference. >>> >>> >> >> >> DOH!! >> >> No sooner did I shut the computer down and crawl into bed, than I realized I >> was thinking "upside-down" - the FRS channels are between the repeater >> OUTPUTS, not the inputs! (Must be that NorCal vs. SoCal repeater thread >> that got me confused) So anyway, in a high RF environment like Chicagoland, >> is it worth doing? I'm probably 30 miles from the next nearest GMRS >> repeater, and the user base seems to be pretty localized. >> >> George, KA3HSW / WQGJ413 >> >> >> >> >> >> Yahoo! Groups Links >> >> >> >> > > > > > > >Yahoo! Groups Links > > >
Re: [Repeater-Builder] Narrowbanding
George, Hate to confuse you more, but there are also FRS channels between the repeater inputs. Johnny George Henry wrote: > -Original Message- > >>From: George Henry <[EMAIL PROTECTED]> >>Sent: Feb 26, 2007 11:09 PM >>To: Repeater-Builder@yahoogroups.com >>Subject: Re: [Repeater-Builder] Narrowbanding >> > > > [snip] > > >>Just wondering if it was worth doing or not, particulary for a GMRS repeater >>& the potential for FRS interference. >> >> > > > DOH!! > > No sooner did I shut the computer down and crawl into bed, than I realized I > was thinking "upside-down" - the FRS channels are between the repeater > OUTPUTS, not the inputs! (Must be that NorCal vs. SoCal repeater thread that > got me confused) So anyway, in a high RF environment like Chicagoland, is it > worth doing? I'm probably 30 miles from the next nearest GMRS repeater, and > the user base seems to be pretty localized. > > George, KA3HSW / WQGJ413 > > > > > > Yahoo! Groups Links > > > >
Re: [Repeater-Builder] Narrowbanding
-Original Message- >From: George Henry <[EMAIL PROTECTED]> >Sent: Feb 26, 2007 11:09 PM >To: Repeater-Builder@yahoogroups.com >Subject: Re: [Repeater-Builder] Narrowbanding > [snip] >Just wondering if it was worth doing or not, particulary for a GMRS repeater >& the potential for FRS interference. > > DOH!! No sooner did I shut the computer down and crawl into bed, than I realized I was thinking "upside-down" - the FRS channels are between the repeater OUTPUTS, not the inputs! (Must be that NorCal vs. SoCal repeater thread that got me confused) So anyway, in a high RF environment like Chicagoland, is it worth doing? I'm probably 30 miles from the next nearest GMRS repeater, and the user base seems to be pretty localized. George, KA3HSW / WQGJ413
Re: [Repeater-Builder] Narrowbanding
The particular radios I mentioned (UHF) were all designed for 25 kHz channel spacing, with correspondingly broader filters than current models... Com-Spec sells replacement filters, both singly and in kits for specific radios, to retrofit them for 12.5 kHz spacing. For example, the stock Johnson PPL 6060 has a 4-pole 10.7 MHz crystal filter with a 13 kHz bandwidth (3 dB?) and a 4-pole 455 kHz ceramic filter with a 20 kHz bandwidth. Com-Spec sells a replacement 10.7 crystal filter set with a 3 dB BW of +/- 3.75 kHz, and a 455 ceramic with a 6 dB BW of +/-4.5 kHz. Just wondering if it was worth doing or not, particulary for a GMRS repeater & the potential for FRS interference. - Original Message - From: "Dick" <[EMAIL PROTECTED]> To: Sent: Sunday, February 25, 2007 4:04 PM Subject: Re: [Repeater-Builder] Narrowbanding > George: > > What do you mean by narrowbanding? > What's the current FM deviation on the radios? > Way back when, it was called narrowbanding when the FCC changed > from +/- 15 KHz to +/- 5 KHz FM dev. > > 73, > > Dick W1NMZ > > - Original Message - > From: "George Henry" <[EMAIL PROTECTED]> > To: > Sent: 25 February, 2007 12:04 > Subject: [Repeater-Builder] Narrowbanding > > >> Has anyone narrowbanded a Mitrek, MastrII, or Johnson PPL6060 with >> Com-Spec's narrowband filter kits? Is it really worth doing? >> >> $25 per radio is $25 I could use elsewhere, if not. >> >> >> George, KA3HW / WQGJ413 > > > > > > > Yahoo! Groups Links > > >
Re: [Repeater-Builder] Narrowbanding
At 2/25/2007 12:04, you wrote: >Has anyone narrowbanded a Mitrek, MastrII, or Johnson PPL6060 with >Com-Spec's narrowband filter kits? Is it really worth doing? I retrofitted a VHF HB Mastr II with the ComSpec filters a while back. They definitely work. However, if your goal is to provide additional adjacent channel rejection at 15 kHz channel spacing for 2 meters, the entire retrofit may actually be too much, as 5 kHz deviated signals will be distorted (up to 4 kHz seems to be OK). In that case you can try installing only part of the kit & carefully tune the IF to get the response symmetrical. I tried this part way through the retrofit & it seemed to work but didn't leave the receiver in that state for more thorough testing. Bob NO6B
Re: [Repeater-Builder] Narrowbanding
George: What do you mean by narrowbanding? What's the current FM deviation on the radios? Way back when, it was called narrowbanding when the FCC changed from +/- 15 KHz to +/- 5 KHz FM dev. 73, Dick W1NMZ - Original Message - From: "George Henry" <[EMAIL PROTECTED]> To: Sent: 25 February, 2007 12:04 Subject: [Repeater-Builder] Narrowbanding > Has anyone narrowbanded a Mitrek, MastrII, or Johnson PPL6060 with > Com-Spec's narrowband filter kits? Is it really worth doing? > > $25 per radio is $25 I could use elsewhere, if not. > > > George, KA3HW / WQGJ413
Re: [Repeater-Builder] Narrowbanding
James wrote: > h, not that I dis-like code or anything but while we are thinking of > the end of an era, lets think about the new one! How about a narrow banding > requirement for VHF/UHF FM!!! > > just sticking my 2c in ;) > > James WJ1D Nah-if hams feel the need to narrowband, it will just happen. First there needs to be more equipment available that will do it, with switching on a per-memory channel basis as well. (Unlike my F6...) -- Jim Barbour WD8CHL
