EF Johnson mad a similar screen modulator to the one WRL made. 73 Gary K4FMX
> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:amradio- > [EMAIL PROTECTED] On Behalf Of Rev. Don Sanders > Sent: Friday, April 14, 2006 11:56 AM > To: Discussion of AM Radio > Subject: Re: [AMRadio] Modulator for DX60 available > > Geoff, while you may not have seen it, > WRL made a screen modulator for a > couple of their CW only small transmitters > back in the 60's that was external to the > transmitter and plugged into an accessory > socket on the back of the transmitter. > Rather rare now. > BTW, I have copy of 2 articles for a > Bias-shift modulator from the 50's and > how to apply it to a DX60 for high > level plate modulation. It uses a > modulation choke for a form of > Heising modulation and used the > built in controlle modulator to drive > the modulator tube- usually the same > type as the final tube./ I recently > found a 6 henry 200 mil choke and > I am going to try it on my DX60B. > Healthfully yours, > DON W4BWS > ----- Original Message ----- > From: "W5OMR/Geoff" <[EMAIL PROTECTED]> > To: "Discussion of AM Radio" <amradio@mailman.qth.net> > Sent: Friday, April 14, 2006 9:27 AM > Subject: Re: [AMRadio] Modulator for DX60 available > > > > Alan Beck wrote: > > > > > I am sorry, did we work out how it could be interfaces with a DX 60? > > > Normally there is a transformer in parallel with the output plate I > > > think and modulation is applied to the other side to "squish" the RF > > > at Audio frequencies. > > > Is this what you mean by output iron? > > > > > > > > > John Lyles wrote: > > > > > >> I have a self contained, commercial looking modulator chassis that > > >> would work well with a DX60 sized rig. It uses a pair of 807s and has > > >> the input and output iron and driver tubes. It came from a SK's pile > > >> this summer. If there is interest, I would part with it to help out a > > >> DX60 conversion to high level plate modulation. Its a small thang. > > >> Technical details available upon request. > > > > > > > Alan, I'm pretty sure John's statement was meant to say that the > > external modulator he had, would work with a rig that was around the > > same size (ie: power output of around 50w) as a DX-60. > > > > Of course, we all know that typical high-level plate modulated AM > > requires a modulation transformer that is connected in series with the > > B+ supply from the power-supply of the final, to the final stage > > itself. The audio generated by a typical push-pull Class B modulator is > > coupled via the modulation transformer to the B+ line. > > > > I might be mistaken, but I don't think I've ever seen an 'external' > > modulator deck that was built with the intention of screen/grid > > modulating an RF final. > > > > Hope that helps clear up some confusion. > > > > -- > > 73 = Best Regards, > > -Geoff/W5OMR > > > > A: Yes. > > > > > Q: Are you sure? > > > > >> A: Because it reverses the logical flow of conversation. > > > > >>> Q: Why is top-posting annoying in email? > > > > > > > > ______________________________________________________________ > > AMRadio mailing list > > Home: http://mailman.qth.net/mailman/listinfo/amradio > > Help: http://mailman.qth.net/mmfaq.html > > Post: mailto:AMRadio@mailman.qth.net > > AMfone Website: http://www.amfone.net > > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb > > > > ______________________________________________________________ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
