Hi Steve Just a note on the technology. The best point to point systems I have ever worked on were those with double E/M.(TX ,RX , E , M ,E1 ,M1) Effectively an advancement from the standard 6 Wire , now becomes an 8 wire circuit . The reason I got excited about these systems was that the Engineer who was going to look after these devices had a means to perfect the system for that enviroment. Let me rather give you some examples I have used over the years: With the extra signalling pair in both directions I was able to do a single swith at the remote side and get feedback in the opposite direction (M1 / E1 ) 1-Remotely reset a device 2-Remotely enable a dpdt relay with pad to do an end to end audio check (round trip of the audio link.) 3-Local alarm "Link Failed )By this have a closed loop that if it fails for any reason a local alarm is generated. 4-Remote equipment tamper switch 5-Remote door switch 6-Remote romm temperature exeded. These ideas saved thousands of miles of would be travel per year. The list is much more but I am sure I have explained the just of it.
Hope the idea makes you see the idea of simple idea can make the Engineering people deploying that system love your product. Kind regards Bradley Glen ZS5WT --- bradley glen <[EMAIL PROTECTED]> wrote: > > 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 > > > > > > > === message truncated === __________________________________ Do you Yahoo!? Take Yahoo! Mail with you! Get it on your mobile phone. http://mobile.yahoo.com/maildemo 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/
