Hi Steve Had a brief look at the site and congrats on a well informed tech type site.
Regarding the issue of max dev you may want to experiment with another approach which I use as my standard for my repeater setups. Use standard -10 dBm for 60 % dev .(make sure no clipping) Generate a high level such as +10 dbm . Then adjust the dev level for max that your system wants. Then reduce level to -10dbm again and double check it still corresponds to your 60% requirement. My reasonning for doing it this way is: In reality when a user talks he will never simultainiously change the deviation pot in the tx radio. In reality the only thing that will occur is that the user will over-deviate-producing a higher level. In some applications a low level compandor circuit will adjust most levels to the same level. In my 20yrs of mil/ commercial / ham repeater experience , because there are no strict guidelines accross all radio fields one has to adapt ones own standard or you will get confused. There are some tech documentation availible on the "Linked ham repeater sites that offer similar practices-well worth reading. Good luck . Regards Bradley Glen zs5WT node:8300 IRLP --- Steve Rodgers <[EMAIL PROTECTED]> wrote: > > > We are attempting to define an audio level setting > procedure for the > Asterisk/app_rpt internet linking project. (See > www.zapatatelephony.org). > > All analog audio is converted to signed linear PCM > in our controller; even the > local repeater receiver to transmitter audio path is > digital. Since the links > are digital and there should be little difference > between nodes, but > standardizing on a common reference level will allow > us to set audio levels > on all nodes consistently, and to have similar audio > levels between nodes. > > We just added some code to app_rpt to implement a > control operator command > to generate a -10dbm 1004Hz (in signed linear PCM > format) test tone digitally. > > Our proposed procedure is to do the following: > > 1. Disable any TX CTCSS source. > 2. Turn on the tone generator, and crank the tx > level pot on the repeater > interface all the way up. > 3. Adjust the transmitter deviation pot for a hard > limit on peak deviation at > 5KHz. > 4. Back off the tx level pot on the on the repeater > interface until it reads > 3KHz (60% of full deviation). > 5. Turn off the tone generator. > 6. Apply a 1KHz tone frequency modulated to 3KHz on > the repeater receiver. (No > CTCSS is preferable, but the codecs attenuate all > frequencies below 300 Hz > and with a low PL tone we don't see much > difference). > > 7. Adjust the rx level pot until we see 3KHz peak > deviation on the repeater > transmitter. > > > Does anybody see any problems with this approach? > > > Steve > WA6ZFT > > > > > > On Saturday 29 January 2005 00:39, bradley glen > wrote: > > Hi > > > > I do not think there is a standard accross all > radio > > systems. > > My experience comming from a telecommunications/ > > microwave background I still use 600 Ohm feeds to > my > > repeaters. > > My standard is -10 dbm for 60% system > > deviation(excluding PL)Remember PL tones are > generally > > attenuated due to the standard telco spec of > > 300-3400hz band pass-anyfrequency outside of this > is > > not guarenteed.This stems from the old analog > > multiplexed systems where guard bands were needed > to > > elliminate crosstalk. > > The reason is simplicity and generally before each > > inpur/output I have balanced pads so I can use my > audi > > test units accurately. > > Most commercial systems have a wide manual setting > > allowing the user to chose their own standard. > > > > Perhaps mention what make of system you are > putting > > together. > > > > Most of my uhf linked systems are all 600 / > balanced > > and uniform. > > > > If you are going this route remember to be careful > > between terminated /unterminated > reading-difference of > > 6dB . > > > > Regards > > > > Bradley Glen zs5WT node:8300 > > UHF linked repeaters linked on UHF.(Naturn) > > > > --- [EMAIL PROTECTED] wrote: > > > When connecting a transmitter and receiver to a > TDM > > > circuit with E&M termination, what is the TX > > > deviation setting for 0DBm of drive at 1004Hz? > > > > > > Most TDM circuits will go to +5dbm before > clipping, > > > so is this extra headroom into account, or is > 0DBm > > > supposed to generate 5KHz of deviation at 1004 > Hz? > > > > > > Thanks, > > > > > > Steve > > > WA6ZFT > > > > > > > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > [EMAIL PROTECTED] > > > > __________________________________ > > Do you Yahoo!? > > Yahoo! Mail - Find what you need with new enhanced > search. > > http://info.mail.yahoo.com/mail_250 > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > Yahoo! Groups Links > > > [EMAIL PROTECTED] > > > > > > __________________________________ Do you Yahoo!? All your favorites on one personal page – Try My Yahoo! http://my.yahoo.com 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/
