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Re: LED pilot lamps again...
I was an early adopter of blue LEDs. The pure "ice blue" is hard on the eyes because it is monochromatic. Some ops get tired of it after a while and gravitate back to warm white LEDs behind Lee #172 or equivalent gels. I know I did, I and even documented it on a web page.
On Sun, 05 Jan 2025 17:17:16 -0500 "Jay W6CJ via groups.io" <lastradioman@...> wrote: Looks nice.-- 73 -Jim NU0C |
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Re: LED pilot lamps again...
Looks nice.?? Some other blue LED lamps looked like bug zappers or UV lights. Thanks & 73 On Sun, Jan 5, 2025 at 1:04?PM Floyd - K8AC via <floydsense=gmail.com_at_groups.io_lastradioman@...> wrote:
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Re: R4C Sherwood audio mod questions
Guess I'll look around for a chassis punch and add this to my project list.? I operate a lot of CW and really like to hear a very pure note.? I've been spoiled by the sound of CW from my RME 6900 the past few months.? RME used a balanced feed to the filaments, no chassis ground on the filament string.? And, they applied +80 VDC to the filament circuit.? I was puzzled by that until I went to my old RCA tube manual and read about filament recommendations.? It was described there and advised that it was a way of reducing hum.
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73, Floyd - K8AC |
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TR-7A issues part II
Hi folks, more challenges bringing this TR-7A back online. See if any of the following symptoms rings a bell:?
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I removed and did a de-oxit of all the molex pins on the PS and all center chassis boards. No difference.?
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Unit basically went tango uniform while listening. Let me know if you have any suggestions before I go deeper. Thanks
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Craig/W8CS
Greenville, SC |
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Re: VE3EFJ third mixer mod for the R4C
开云体育All my kit PDFs are now in the files archive under Sherwood.? Rob, NC0B ? From: [email protected] [mailto:[email protected]]
On Behalf Of Walt KA2NJF via groups.io
Sent: Sunday, January 05, 2025 12:11 PM To: [email protected] Subject: Re: [DRAKE-RADIO] VE3EFJ third mixer mod for the R4C ? I would also be interested in all the R4C boards. Also any instructions for populating the boards.? ? KA2NJF Walt? ? On Tuesday, December 31, 2024, 18:52, Tom WA6VZN via groups.io <tomwcunningham@...> wrote:
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Re: VE3EFJ third mixer mod for the R4C
I would also be interested in all the R4C boards. Also any instructions for populating the boards.?
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KA2NJF Walt? On Tuesday, December 31, 2024, 18:52, Tom WA6VZN via groups.io <tomwcunningham@...> wrote:
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Re: R4C Sherwood audio mod questions
开云体育Paul, ? The photos in the PowerPoint presentation were taken with an HP 3585A spectrum analyzer.? As you can see in the screen shots, the resolution bandwidth was 10 Hz.? The 3585A or B goes down to 3 Hz which could have been used for my project. ? A PDF of the PowerPoint presentation is attached for those who came late to the discussion. ? Besides the 3585A in both labs, I have other vintage analyzers like the 8568B and 3561A FFT analyzer.? There are fine modern analyzers from offshore that I don’t happen to own. ? Rob, NC0B ? From: [email protected] [mailto:[email protected]]
On Behalf Of Paul Christensen via groups.io
Sent: Sunday, January 05, 2025 11:53 AM To: [email protected] Subject: Re: [DRAKE-RADIO] R4C Sherwood audio mod questions ? Doing this kind of work is when a real spectrum analyzer with low RBW really pays off. ?IMHO, to get a good look at close-in 60 Hz sidebands requires an RBW of no more than 10 Hz, with 1 Hz offering excellent screen resolution. That rules out the toy analyzers like the TinySA.? ?I think Rob’s analyzers are all 1 Hz RBW.? I use an HP 8560E and Anritsu MS2721B. ? Paul, W9AC ? ? From: [email protected] <[email protected]>
On Behalf Of Floyd - K8AC via groups.io ? Well, I let my hole punches get away from me decades ago and I'd guess that they'd cost more than I'd like to spend these days.? Great work by you guys who figured out the source of the 60 Hz modulation.? I read some info at a mumetal manufacturer's site and had the idea of just building a can to fit over the existing PTO can.? They noted that the effectiveness could be greatly increased by adding a second layer with an insulating material in between (teflon sheet?).? Their description of the material said it was very malleable and ductile so maybe the work could be done by hand with a vise and steel ruler.?? ? 73, Floyd - K8AC |
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Re: R4C Sherwood audio mod questions
开云体育I used a 3/4-inch Greenlee punch because that’s the smallest in my tool case.? Photos attached showing the new holes and the abandoned holes that are offset by 90 degs.? The wiring is kinda’ in the way of a good view.? One of the new holes is directly below the fuse holder. ? That solves the question as to whether I drilled without transformer removal.? Clearly, removal was needed but overall, it wasn’t too difficult.? ? Paul, W9AC ? ? From: [email protected] <[email protected]> On Behalf Of Rob Sherwood via groups.io
Sent: Sunday, January 5, 2025 2:00 PM To: [email protected] Subject: Re: [DRAKE-RADIO] R4C Sherwood audio mod questions ? Stan, ? Either of those would work, but I suggest the larger one.? Mine are Greenlee and had no problem punching the two holes. ? I snipped off the transformer leads, removed the transformer, punched the holes, and then reinstalled the transformer and wiring. ? Rob, NC0B ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Stan Gammons via groups.io ? What size hole punch is required? ?I think I still have a 1/2” round and 9/16” round. ?I think 16 gauge steel is the thickest they can cut. ?Maybe find a single hole punch on the auction site? ? ? 73 ? Stan KM4HQE ? ? ? On Sun, Jan 5, 2025 at 12:30 PM, Floyd - K8AC via groups.io <floydsense@...> wrote: Well, I let my hole punches get away from me decades ago and I'd guess that they'd cost more than I'd like to spend these days.? Great work by you guys who figured out the source of the 60 Hz modulation.? I read some info at a mumetal manufacturer's site and had the idea of just building a can to fit over the existing PTO can.? They noted that the effectiveness could be greatly increased by adding a second layer with an insulating material in between (teflon sheet?).? Their description of the material said it was very malleable and ductile so maybe the work could be done by hand with a vise and steel ruler.?? ? 73, Floyd - K8AC |
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Re: LED pilot lamps again...
Interesting, and less amps on the power supply.? (I think incandescent 6.3V 47s were 100mA). Any before and after photos? On Sun, Jan 5, 2025 at 10:34?AM Floyd - K8AC via <floydsense=gmail.com_at_groups.io_lastradioman@...> wrote:
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Re: R4C Sherwood audio mod questions
开云体育Stan, ? Either of those would work, but I suggest the larger one.? Mine are Greenlee and had no problem punching the two holes. ? I snipped off the transformer leads, removed the transformer, punched the holes, and then reinstalled the transformer and wiring. ? Rob, NC0B ? ? From: [email protected] [mailto:[email protected]]
On Behalf Of Stan Gammons via groups.io
Sent: Sunday, January 05, 2025 11:52 AM To: [email protected] Subject: Re: [DRAKE-RADIO] R4C Sherwood audio mod questions ? What size hole punch is required? ?I think I still have a 1/2” round and 9/16” round. ?I think 16 gauge steel is the thickest they can cut. ?Maybe find a single hole punch on the auction site? ? ? 73 ? Stan KM4HQE ? ? ? On Sun, Jan 5, 2025 at 12:30 PM, Floyd - K8AC via groups.io <floydsense@...> wrote: Well, I let my hole punches get away from me decades ago and I'd guess that they'd cost more than I'd like to spend these days.? Great work by you guys who figured out the source of the 60 Hz modulation.? I read some info at a mumetal manufacturer's site and had the idea of just building a can to fit over the existing PTO can.? They noted that the effectiveness could be greatly increased by adding a second layer with an insulating material in between (teflon sheet?).? Their description of the material said it was very malleable and ductile so maybe the work could be done by hand with a vise and steel ruler.?? ? 73, Floyd - K8AC |
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Re: R4C Sherwood audio mod questions
开云体育Hi 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 |
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Re: R4C Sherwood audio mod questions
开云体育Doing this kind of work is when a real spectrum analyzer with low RBW really pays off. ?IMHO, to get a good look at close-in 60 Hz sidebands requires an RBW of no more than 10 Hz, with 1 Hz offering excellent screen resolution. That rules out the toy analyzers like the TinySA.? ?I think Rob’s analyzers are all 1 Hz RBW.? I use an HP 8560E and Anritsu MS2721B. ? Paul, W9AC ? ? From: [email protected] <[email protected]> On Behalf Of Floyd - K8AC via groups.io
Sent: Sunday, January 5, 2025 1:31 PM To: [email protected] Subject: Re: [DRAKE-RADIO] R4C Sherwood audio mod questions ? Well, I let my hole punches get away from me decades ago and I'd guess that they'd cost more than I'd like to spend these days.? Great work by you guys who figured out the source of the 60 Hz modulation.? I read some info at a mumetal manufacturer's site and had the idea of just building a can to fit over the existing PTO can.? They noted that the effectiveness could be greatly increased by adding a second layer with an insulating material in between (teflon sheet?).? Their description of the material said it was very malleable and ductile so maybe the work could be done by hand with a vise and steel ruler.?? ? 73, Floyd - K8AC |
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LED pilot lamps again...
I know this has been covered in depth in the past, but after reading all the old posts, I ended up ordering these () on eBay and installed them today.? They are very bright and the color is ice blue.? To my eyes, the result is about the same color as the original blue filters.? I left those in place as they were faded out where the light shines through.? These LED lamps are the size of the #47 bulbs and fit perfectly in the T4Xc and R4C.? Unlike my #47 bulbs, these illuminate the little XTALS window on the R4C very well.??
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73, K8AC |
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Re: R4C Sherwood audio mod questions
Well, I let my hole punches get away from me decades ago and I'd guess that they'd cost more than I'd like to spend these days.? Great work by you guys who figured out the source of the 60 Hz modulation.? I read some info at a mumetal manufacturer's site and had the idea of just building a can to fit over the existing PTO can.? They noted that the effectiveness could be greatly increased by adding a second layer with an insulating material in between (teflon sheet?).? Their description of the material said it was very malleable and ductile so maybe the work could be done by hand with a vise and steel ruler.??
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73, Floyd - K8AC |
Jim Shorney
Jay W6CJ
Floyd - K8AC
Craig W8CS
Rob Sherwood
Walt KA2NJF
Paul Christensen
