[Repeater-Builder] Re: Does anyone else think of Power Factor like SWR?
--- In Repeater-Builder@yahoogroups.com, "kb9bpf" <[EMAIL PROTECTED]> wrote: > > Since I'm way more into RF than industrial power distribution, I've > always been able to think of "power factor" on the electrical power > grid in terms similar to antenna system reflections, which are > commonly measured in terms of SWR. After all, both are AC systems > where the voltage and current bear a phase relationship to each > other. > > When they are perfectly in phase the power factor is 1.0, and a 60-Hz > SWR meter would measure 1:1. When they are out of phase (power factor > <1) that SWR meter would read greater than 1:1. I suspect, though I > haven't done the math or looked up the specific matahematical > definition of power factor, that it would be direcly proportional to > the reciprocal of the power factor. And as we know, when that happens > the power generating end has more difficulty delivering power > efficiently to the load. > A while back I was doing some analysis of power factor to understand it better and I found that it has a lot in common with SWR. Both are focused on the issue of power transfer, so I guess we shouldn't be surprised. The thing they really have in common is for max power with AC signals, the voltage and current need to be in phase (phase angle of zero). For linear systems with nice sine waves, PF = cos (phase angle) where phase angle = the angle between voltage and current sinusoids Wikipedia has a good explanation of PF at http://en.wikipedia.org/wiki/Power_factor Play around with some typical circuits and you'll find that an SWR of 1 also has voltage and current in phase. Again, not a surprise since it represents the best power transfer. This is from memory, so the usual disclaimers apply :-) 73, Bob K0NR
[Repeater-Builder] Re: Part 97 question reference to Repeater control
--- In Repeater-Builder@yahoogroups.com, Nate Duehr <[EMAIL PROTECTED]> wrote: > On Nov 7, 2007, at 4:36 PM, MCH wrote: > > > But again, the question is: Are EITHER of these required? > > > > Can the repeater be run strictly with Automatic Control? Part 97 seemsto indicate it can. > > I think from a purely "legalese" point of view, you can get away with not having either one. I'd suggest sitting down and actually reading Part 97 once in a while. I have to admit that I "remember" things being in there that have been deleted years ago. Worse yet, I might remember things being in Part 97 that are really just folklore from wise, old repeater builders. In my view, the rules are surprisingly vague and flexible, which is generally a good thing. Good engineering judgment should always apply. But we don't actually debate Part 97 issues on this list anyway, right? :-) 73, Bob K0NR
[Repeater-Builder] Re: Repeating D-Star
--- In Repeater-Builder@yahoogroups.com, Bob Dengler <[EMAIL PROTECTED]> wrote: > > What would be far more interesting to me would be for one of the ham > manufacturers to offer a P25 user radio. How much would adding the vocoder > add to the cost of a current analog FM model? If it's comparable in price > to Icom's DStar radios (which are substantially more than their analog > counterparts - roughly double the cost), it just might be worth it. > > Something to add to my wish list of radio features to deliver to the reps. > at Dayton, along with better IMD performance & split CTCSS tone. > > Bob NO6B > I tend to agree...how about a Kenwood or Yaesu ham rig that runs analog and P25? Although used commercial gear is a great option to have, the feature set is, well, commercial. Easy front panel programming on the fly, VFO modes, etc. are usually left out or compromised. Bob K0NR
Re: [Repeater-Builder] Portable Repeaters
Re: Crossband/Portable repeaters - Here in Colorado, we have two 2 Meter pairs designated for statewide use for portable/emergency/special event repeaters. These pairs get used to fill in the dead spots when emergencies occur. A number of clubs and ARES groups have portable repeaters set up on these pairs. (Good band planning by whoever put these in place years ago.) - Some of the emcomm folks use dualband transceivers with crossband repeat as a inexpensive way to extend radio range (often used to extend HT range from inside a building or other bad spot). These radios don't meet the letter of the law (FCC regs) with regard to identification (my opinion, you mileage may vary.) - We do not have any designated frequencies for crossbanding to 440 MHz in the bandplan. Most people just find some lightly used uhf simplex frequency. - If conventional transceivers are used, the power needs to be reduced or additional cooling supplied due to 100% duty cycle operation. - I constructed a crossband repeater using two transceivers and an NHRC-6 controller that knows how to handle the ID of two transmitters appropriately (most repeater controllers do not). http://www.nhrc.net/nhrc-6/ - One issue with a vhf/uhf crossband repeat set up working into a repeaterthe repeater transmitter must drop before the crossband repeater can turn the link around. Shortening the hang time on the conventional repeater (or using CTCSS that drops with the received signal) helps this issue. 73, Bob K0NR [EMAIL PROTECTED] Repeater-Builder@yahoogroups.com wrote: > From: "Paul Yonge" [EMAIL PROTECTED] > Date: Sun May 7, 2006 10:12pm(PDT) > Subject: Portable Repeaters > > I've not been too successful in convincing the various Upstate New > York Amateur Radio Associations that simplex repeaters are the answer > for providing portable repeaters in critical incident response > situations. They are relying on the fixed repeaters to provide > adequate coverage but there are areas where it would be advantageous > to bring the repeater to the incident instead of trying to reach > fixed repeaters with hand-held units from some isolated locations. > There are, of course, coordination problems with portable duplex > repeaters and there is no apparent interest in agreeing on a wide- > split pair of odd frequencies to avoid the conventional-frequency pairs. > > What experience has there been with the use of portable cross-band > repeaters to enable hand-held units using a 440 MHz simplex channel > to reach the portable repeater that will relay the message through to > a two-meter fixed repeater? > > Paul Yonge, W2ARK > MIDLAKES REPEATER > > [EMAIL PROTECTED] > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: DR-235 for repeater
With regard to interfacing radios via "packet data" ports. Has anyone looked at the audio flatness of these ports? Also, some rigs have a 1200 baud in/out and a 9600 baud in/out, which (apparently) have very different audio levels. I suspect there are other characteristics that are different, too. 73, Bob K0NR --- In Repeater-Builder@yahoogroups.com, <[EMAIL PROTECTED]> wrote: > > Andy, > > I have not personally done this, but the data out connector should > suply pins for audio in , audio out, Squelch voltage or logic > and a reference ground. These signals should provide everything > you should need for direct linking of 2 radios. The DB9 is easy > to work with. > > Since these were designed for packet use, the audio is not > affected by front panel controls. It is conditioned and altered > after it enters the TNC; or > in this case, the other rig. > > I have set up crossband repeaters using data connectors from other > brands, and it works well with little external manipulation. > > Attached is the page from the manual describing pin function for > the DB9 connector. Email me if it doesn't go through. > > David > KD4NUE > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: trying to build my first repeater
--- In Repeater-Builder@yahoogroups.com, "nj902" <[EMAIL PROTECTED]> wrote: > > --- In Repeater-Builder@yahoogroups.com, "us_communications1" > <[EMAIL PROTECTED]> wrote: > "...WHAT I AM LOOKING FOR IS DIRECTION OF HOW OTHERS DID THIS. the > radios are 30+ years old so i can't believe that i am the first to > think of using the higer quality tube equipment. ..." > > ___ > > Higher quality? Just because they use tubes? TAS lifetime subscriber? > > But - to answer your question - you could build a tube type repeater - > it's your time to spend as you wish. > > A "high quality" troll, me thinks. - Bob K0NR Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
