Re: R4C Sherwood audio mod questions
¿ªÔÆÌåÓýHi Joseph, ? Point taken that a mail carrier may not take a walk on his days off.? That said, every product my cottage industry company produced was used extensively to be sure it worked as well as promised.? There were iterations of the R-4C upgrade boards over time, such as switching from a 40673 dual-gate mixer to an NE602? for the MIX-4.? There were three major versions of the SE-3 synchronous detector product. ?Some of the product updates were required as parts became obsolete.? This is particularly a problem when a product is in production for 30 years. ? I always wondered why the TR-7 DR-7 board was never updated to use a small fraction of the chips needed in the original design.? Why didn¡¯t Drake update the R-4C power supply to use a 3-terminal regulator once they were common and cheap? ?Why did Drake like high wattage resistors in power supplies such as the L4 amps? ? When Gerald Youngblood came to my rural QTH with his new Flex 6700, he had never heard it on the air at a quiet location.? There must have been a quiet QTH somewhere in Texas.? Isn¡¯t life strange.? Hi Hi ? Rob, NC0B ? ? From: [email protected] [mailto:[email protected]]
On Behalf Of Joseph K7CBR via groups.io
Sent: Sunday, January 05, 2025 11:16 AM To: [email protected] Subject: Re: [DRAKE-RADIO] R4C Sherwood audio mod questions ? Hello Mr. Rob, ? I have asked this same question several times about the designers actually using their own hardware! They DON'T... For if they did, they would have noticed the modulation of a CW note in the R-4C... Also they would have put squelch in the radio too... Unreal if you think about it. Yet no... If you are spending your day life designing and building? I too would not go home and turn it on and use it regularly. That would be over the top, and we need to have some kind of life also! (Don't tell everyone that...) ? I too have rotated the transformer as I was sick of hearing that. I would say 3 hours of time, yet I was cautious and do have all the punches and tools. It did cure the coupling issue which can also be heard when two AM carriers are interfering, and when listening to the calibration tone on WWV. ? Joseph ? On Sunday, January 5, 2025 at 12:03:35 PM EST, Rob Sherwood via groups.io <rob@...> wrote: ? ? Hi Floyd, ? Yes I rotated my transformer 90 degrees, and my technician? made the change to two other R-4Cs over time.? It takes less than two hours on the assumption you have a chassis punch, a hand drill and bits.? I am assuming Paul did the same thing.? It doesn¡¯t take all that much time to disconnect and re-connect the transformer wires. ? I did procure a sheet of mu-metal and inserted it between the transformer and the PTO. Grounded or not, it didn¡¯t do anything.? It is conceivable I didn¡¯t do it the correct way.? Maybe if one had a sheet metal brake, a mu-metal shield could surround the PTO can.? That wasn¡¯t an option.? ? ? Who was asleep at the switch at Drake deciding to make a change in the transformer mounting and not realizing it was a mistake? ? I often wonder if engineers? at various companies actually use the radios they manufacture and sell.? There are so many examples of design decisions, mechanical or electrical, that make no sense.? ? Rob, NC0B ? From: [email protected] [mailto:[email protected]]
On Behalf Of Floyd - K8AC via groups.io ? Sounds as if one of you has actually rotated the transformer 90 degrees.? I just took a look at that area of the receiver and decided that task ranks right up there with removing your own appendix.? I wonder if it wouldn't be possible to shield the PTO can with mumetal?? I have no idea what the material is like to work with, but it seems to be readily available.? And thanks for the comments on the capacitor value.? I'll finish getting my version of the AMP-4 board installed today and hopefully I'll have audio output. ? 73, Floyd - K8AC |
Rob Sherwood