I question that 9.2 dB antenna, is it actually 9.2 dBd or 9.2 dBi ?? Neil - WA6KLA
---- Original Message ---- From: [EMAIL PROTECTED] To: [email protected] Subject: RE: [Repeater-Builder] Re: Wount To Find Out About Buiding A New Repeter Date: Wed, 31 May 2006 14:36:47 -0000 >Jim, > >First add all the System Gains (SG)in dbW measurements, from that >figure you then subtract all your Sytem Losses (SL)in dbW, the result > >equals your ERP in dbW. Convert the ERP in dbW back to ERP in Watts. > > >Before you start adding the SG you must convert your Tx output pwr. >from Watts to dbW. (ie 50w=17.0dbW) I use a Conversion Table that is > >included in some old Rptr. coord, papers, however you should be able >to find a conversion table or the mathematical(sp?) formula on Google > >or on one of the Rptr. Bldr. site pages. > >Therefore the following example: > >1. 50w Tx out=17.0dbW + ant. gain 9.2 dbW = Tot. SG 26.2dbW > >2. Ant. FL lgth. /100 x loss per 100' at you freq band = Tot/FL loss >in db. (50 /100x1.04 = .52dbW (1/2"LDF @ 450mhza=1.04db/100'). > >3. Duplexer insertion loss = 1.5 dbW > >4. Other losses = 0.0dbW > >5. Tot. SL (.52+1.5) = 2.02dbW > >6. Tot. SG (26.2) - Tot. SL (2.02) = Tot. ERP in dbW (24.18dbW) > >7. Convert ERP in dbW back to ERP in Watts (24.18 = 250+ Watts ERP. > >Note: Some interpolation of the tables I use is required. > >Feedline looses per 100' @ given freq. are generally provided by the >mfg. If you would like a copy of my work sheet (Tables included) >email me direct. > >N3DAB/WPRX486 GMRS/WPJL709 LM > > >--- In [email protected], [EMAIL PROTECTED] wrote: >> >> "n3dab" <[EMAIL PROTECTED]> wrote: >> >You can go to the FCC site and pull Part 95 like I just did and >read >> >it for yourself. >> > >> >I'm running 50w from my Micor rptr. xmtr. with 1.5db loss from a >MOt. >> >1504 duplexer into 50' of 1/2' LDF4-50 heliax to a DB410 9.2db >gain >> >omni antenna. This all calculates out to approx. slightly more >than >> >250W ERP. This machine has been in service for at least 25 years >on >> >462/467. 675 in the Atlanta Ga. area >> > >> >N3DAB/WPRX486 GMRS/WPJL709 LM >> Doug, >> Can you show us your formula for converting power output to ERP? I >guess, power out(watts) - (1.5db)+(50' of LDF$-50)+9.2db=ERP output. >> >> More details please. >> Thanks. >> 73's, >> Jim Kh6jkg. >> >> >> __________________________________________________________________ >> Switch to Netscape Internet Service. >> As low as $9.95 a month -- Sign up today at >http://isp.netscape.com/register >> >> Netscape. Just the Net You Need. >> >> New! Netscape Toolbar for Internet Explorer >> Search from anywhere on the Web and block those annoying pop-ups. >> Download now at http://channels.netscape.com/ns/search/install.jsp >> > > > > > > > > > > >Yahoo! Groups Links > > > > > > 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/
