well, I did jumper around it and as expected the rx now comes to life quickly, The fil voltage measured at 4.5 with the resaistor in and about 6.1 now. I did drop the line voltage to about 113 for the old stuff. no noticable differance in anything other than start up. ----- Original Message ----- From: <k4...@charter.net> To: <amradio@mailman.qth.net> Cc: <amradio-requ...@mailman.qth.net> Sent: Thursday, December 17, 2009 2:43 PM Subject: Re: [AMRadio] HRO question for the day
> >> National decided in the HRO50 design to use a 4.3 Ohm resister in series >> with the fil of both 6H6 dual diodes, ( noise blanker and detector) >> dropping the fil to about 5 v. In the Hro 50-1 the noise blanker 6h6 >> operates at normal Volts and the detector still at reduced voltage. I see >> no >> reason for this and the tube data sheets do not address lower volt >> operation. only effect I notice is that it takes several minutes for the >> detector to warm up and produce audio. It can not be for life as when >> this >> was designed and built 6h6s were cheap, still are. certainly not to save >> energy or battery operation. perhaps it fools the detector into >> something >> other that a square law detector due to low emission. tube life would be >> extended, but so what, this is not a transmitting valve and the only one >> I >> have seen where reduced voltage is recommended for standby is the 813, >> data >> recommends 8 volt when on standby and I have never done that or seen one >> used that way. So does anyone KNOW why national did this? I have >> never >> seen this in Collins so it must be wrong!!!! HI Bernie W8RPW > > I vaguely recall having the same question years ago when I was helping > Roger, N4IBF(SK) with his, and learning that the resistor was there for a > good reason, but I don't have a clue what it was now. Hopefully someone > will have the info. > > Don > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio@mailman.qth.net > To unsubscribe, send an email to amradio-requ...@mailman.qth.net with > the word unsubscribe in the message body. > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
