Steve On 9/27/2018 10:48 AM, STEVE wrote:
I'm mostly familiar with the Drake R8 series, having worked on two R8Bs, converting them to true VLF-HF reception instead of the no-sensitivity below about 130 kHz. I don't know if the R7 uses PIN diodes. I'm not directly aware of other brands that used PIN diodes in the front end. Drake also used 200 ohm input switched band filters, with transformers to convert from 50 to 200 ohms, and the reverse on the output of the filters. Those diodes are associated with that and possibly are more sensitive to deterioration at the higher impedance than where PIN diodes are usually used in 50 ohm systems.Steve On 9/27/2018 10:40 AM, Nick Hall-Patch wrote:Thanks for pointing that out Steve. Are there other receivers of that vintage that might also suffer from deteriorating front end PIN diodes?best wishes, Nick ÂAt 17:38 2018-09-27, STEVE wrote:Drake uses PIN diodes in the front end switched band filters of the R8 series (and at least the SW8); those diodes deteriorate over time, significantly reducing sensitivity. Unless you had those diodes replaced at your service it's likely that's why your Drake is less sensitive than the Elad.Steve On 9/27/2018 9:34 AM, C B via IRCA wrote:An OK morning for TPs in CO. I did a preliminary comparison between my Elad FDM-S2 and the Drake R8A. As Bogey said "This could be the beginning of a beautiful friendship". I started with comparing the two JJ powerhouses, JOUB and JOIB. The Drake had weak, barely discernable audio with both the ALA 1530ln and the NW Corner-Fed loop. The Elad produced fair to good audio readily understandable to a JJ speaker. I did not expect the difference to be so evident. I had my R8A serviced a couple of years ago by a former Drake tech, so while a bit long in the tooth, it's working fine. More to come....This morning's results: 594 JOAK w/male in JJ weak (w/Elad, just a het w/Drake) 747 JOIB w/male in JJ good (w/Elad, weaker w/Drake) 774 JOUB w/male in JJ good (w/Elad, weaker w/Drake) 828 JOBB w/ weak audio (w/Elad, threshold audio w/Drake) A decent assortment of hets. 73 and Best of DX, Craig BarnesWheat Ridge, CO Elad FDM-S2, Drake R8A, ALA 1530ln, NW Corner-Fed loop, Quantum Phaser_______________________________________________ IRCA mailing list IRCA@xxxxxxxxxxxxxxxx http://montreal.kotalampi.com/mailman/listinfo/ircaOpinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officersFor more information: http://www.ircaonline.org To Post a message: irca@xxxxxxxxxxxxxxxxNick Hall-Patch Victoria, BC Canada _______________________________________________ IRCA mailing list IRCA@xxxxxxxxxxxxxxxx http://montreal.kotalampi.com/mailman/listinfo/ircaOpinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officersFor more information: http://www.ircaonline.org To Post a message: irca@xxxxxxxxxxxxxxxx
_______________________________________________ IRCA mailing list IRCA@xxxxxxxxxxxxxxxx http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@xxxxxxxxxxxxxxxx