30 watts is correct for 1500 watts in a 50 ohm system and a coil Q of 226. The power loss is 0.1 dB and the coil temp rise is around 20 deg C.
WX7G On Jul 26, 2012 3:20 PM, "ZR" <z...@jeremy.mv.com> wrote: > ** > That is only 226 Ohms at 1.8MHz and at 1500W will be dissipating about 30W > in a 50 Ohm system but Phil didnt say how he is feeding his tower which is > resonant well below 160M. > > Yes it will work as well as survive a lot of energy at 35-50 Ohms compared > to a larger inductance 1A choke. > > Carl > KM1H > > ----- Original Message ----- > *From:* DAVID CUTHBERT <telegraph...@gmail.com> > *To:* ZR <z...@jeremy.mv.com> > *Cc:* philcleme...@centurylink.net ; topband@contesting.com > *Sent:* Thursday, July 26, 2012 4:35 PM > *Subject:* Re: Topband: Choke Construction Info Needed > > 20 uH should be sufficient at the base of a 1/4 wave length vertical. > > #4 copper wire is used to connect towers to ground for direct strikes. > > Such an inductor can be close-wound with insulated #4 wire, diameter 8", 8 > turns. > > It should survive intact except for the insulation. > > Dave WX7G > On Jul 26, 2012 2:02 PM, "ZR" <z...@jeremy.mv.com> wrote: > >> It all depends upon how much survivability you want, nothing will survive >> a >> direct hit. Any 1.5 to 2.5 mH choke will suffice, just look at the safety >> choke in a commercial amp for the smallest choice. >> >> The big ones are often found in scrapped BCB transmitters and tuning units >> as well as show up at hamfests and on Fleabay as old military gear had >> various candidates. >> >> Carl >> KM1H >> >> >> ----- Original Message ----- >> From: "Phil Clements" <philcleme...@centurylink.net> >> To: <topband@contesting.com> >> Sent: Thursday, July 26, 2012 3:03 PM >> Subject: Topband: Choke Construction Info Needed >> >> >> >I need to construct a heavy-duty choke to be installed from the feed >> point >> > of my 160 meter vertical to ground, for static drain and for lightning >> > protection. How large does the wire, form, and inductance need to be? >> > >> > >> > >> > Thanks in advance for your expertize! >> > >> > >> > >> > (((73))) >> > >> > Phil, K5PC >> > >> > >> > >> > _______________________________________________ >> > UR RST IS ... ... ..9 QSB QSB - hw? BK >> > >> > >> > ----- >> > No virus found in this message. >> > Checked by AVG - www.avg.com >> > Version: 10.0.1424 / Virus Database: 2437/5155 - Release Date: 07/25/12 >> > >> >> _______________________________________________ >> UR RST IS ... ... ..9 QSB QSB - hw? BK >> > ------------------------------ > > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1424 / Virus Database: 2437/5155 - Release Date: 07/25/12 > > _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK