20090709.ba v04_n276.bam.20090709 >From ???@??? Thu Jul 9 14:37:39 2009 -0500 Date: Thu, 9 Jul 2009 13:36:56 CST From: Old Tube Radios To: Old Tube Radios Subject: BOATANCHORS digest 4276 Message-Id: <20090709193658.E232210B038@srvr1.theporch.com> BOATANCHORS Digest 4276 Topics covered in this issue include: 1) Re: [Milsurplus] [Boatanchors] Coils and the winding thereof by "Arden Allen" 2) Lambda Model 71 power supply repair note by "Tom Bridgers" 3) Re: Lambda Model 71 power supply repair note by Paul Beckwith 4) National PW Dial by "Jim Garland" <4cx250b@muohio.edu> 5) Night of Nights - Correction by Richard Dillman 6) Afterthought - my question about PW dial by "Jim Garland" <4cx250b@muohio.edu> 7) Audio Recording: Hear KSM on 500kc by Richard Dillman 8) CWA (Uruguay) to Participate in NofN X? by Richard Dillman 9) Night of Nights X Frequecy List by Richard Dillman 10) Night of Nights Low Reception by "B. Smith" 11) RE: Night of Nights X Frequecy List by "Brian Goldsmith" 12) Re: Night of Nights Low Reception by Richard Dillman 13) PW Dial Update by "Jim Garland" <4cx250b@muohio.edu> 14) PW Dial Update by "Jim Garland" <4cx250b@muohio.edu> 15) Re: PW Dial Update by "Paul Christensen" 16) Still more, re PW dial by "Jim Garland" <4cx250b@muohio.edu> 17) Re: PW Dial Update by Rich Post 18) Re: PW Dial Update by Rodger ---------------------------------------------------------------------- Message-ID: <001901c9ff04$8122e6b0$8e9e480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: [Milsurplus] [Boatanchors] Coils and the winding thereof Date: Tue, 7 Jul 2009 06:11:46 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit >Whatever happened to Q-Dope that GC used to sell? It's still available: http://www.hmcelectronics.com/cgi-bin/scripts/product/3480-0016/GC-Electronics-10-3702/ Arden Allen KB6NAX Adopt a shelter dog, save an innocent life, and make a friend forever =:-) ------------------------------ Message-ID: From: "Tom Bridgers" To: Old Tube Radios Subject: Lambda Model 71 power supply repair note Date: Tue, 7 Jul 2009 10:34:12 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit The Model 71 is a very nice regulated supply for up to 500 volts, and also provides bias voltage up to 200 volts. I use it a lot in repairing my old radios. Recently when in use it started giving out a most foul smell -- like a burned resistor. However after looking around, I couldn't find a resistor that looked even remotely charred or discolored. And I never was quite able to locate the source of the smell either. But when I checked to see if any of the transformers were hot, one on the left side of the chassis was very hot to the touch. After a few minutes it got extremely hot. Almost too hot to touch. Something was definitely wrong with it. I traced the leads from that transformer to the filaments of the 6X4 rectifier for the bias supply. From outward appearances the 6X4 looked fine. The voltage test on the 6X4 however showed it was faulty. I replaced the 6X4 and everything returned to normal. No more blisteringly hot filament transformer and no more burned resistor smell. So now it's back to work for the Model 71. 73's, -Tom ------------------------------ Date: Tue, 07 Jul 2009 07:43:30 -0700 To: Old Tube Radios From: Paul Beckwith Subject: Re: Lambda Model 71 power supply repair note Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Message-Id: <20090707144337.47B8F18E26E@relay04.roch.ny.frontiernet.net> Thanks for the post and info, Tom. I've been using a Model 71 for years. Do you happen to know where a manual copy might be available? I've been trying to locate one for quite awhile. 73's de Paul K2LMQ Kingman, AZ. At 07:34 AM 7/7/2009, Tom Bridgers wrote: >The Model 71 is a very nice regulated supply for up to 500 volts, >and also provides bias voltage up to 200 volts. I use it a lot in >repairing my old radios. > >Recently when in use it started giving out a most foul smell -- like >a burned resistor. However after looking around, I couldn't find >a resistor that looked even remotely charred or discolored. And I >never was quite able to locate the source of the smell either. But >when I checked to see if any of the transformers were hot, one on >the left side of the chassis was very hot to the touch. After a few >minutes it got extremely hot. Almost too hot to touch. Something >was definitely wrong with it. > >I traced the leads from that transformer to the filaments of the 6X4 >rectifier for the bias supply. From outward appearances the 6X4 >looked fine. The voltage test on the 6X4 however showed it was >faulty. I replaced the 6X4 and everything returned to normal. No >more blisteringly hot filament transformer and no more burned resistor smell. > >So now it's back to work for the Model 71. >73's, >-Tom ------------------------------ From: "Jim Garland" <4cx250b@muohio.edu> To: Old Tube Radios Subject: National PW Dial Date: Tue, 7 Jul 2009 10:22:38 -0600 Message-ID: <007201c9ff1f$27a23260$04000100@Garland> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0073_01C9FEEC.DD07C260" This is a multi-part message in MIME format. ------=_NextPart_000_0073_01C9FEEC.DD07C260 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Gang, Anybody know what the "PW" in the PW dial for the HRO series receivers stands for? I vaguely recall it may be the initials of the inventor, but I'm probably mistaken. Tnx, Jim W8ZR ------=_NextPart_000_0073_01C9FEEC.DD07C260 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------=_NextPart_000_0073_01C9FEEC.DD07C260-- ------------------------------ Message-ID: <18338390.1246985841970.JavaMail.root@elwamui-rubis.atl.sa.earthlink.net> Date: Tue, 7 Jul 2009 12:57:21 -0400 (EDT) From: Richard Dillman To: Old Tube Radios Subject: Night of Nights - Correction Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sorry, there's one small correction to be made in the listing for KFS for Night of Nights X: Instead of 12695.5 being available only after local sunset it's 17026.0: KFS will transmit on 12695.5 and 17026.0 - (17026.0 will be available only after local sunset Pacific time, 9:30pm, 0430 gmt) RD ================================= Richard Dillman, W6AWO Chief Operator, Coast Station KSM Maritime Radio Historical Society http://www.radiomarine.org ================================= ------------------------------ From: "Jim Garland" <4cx250b@muohio.edu> To: Old Tube Radios Subject: Afterthought - my question about PW dial Date: Tue, 7 Jul 2009 11:09:26 -0600 Message-ID: <008101c9ff25$b13f7a90$04000100@Garland> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0082_01C9FEF3.66A50A90" This is a multi-part message in MIME format. ------=_NextPart_000_0082_01C9FEF3.66A50A90 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit I should have mentioned in my original post that I had received an inquiry from Max de Henseler, HB9RS, about the PW dial. Max is a very distinguished and well-known Swiss ham and Hallicrafters collector, with an amazing career in amateur radio, including being the founder of ON4UN and the only ham to win the WAC/WAC award (worked all continents FROM all continents), etc. You can read about him at http://www.hb4fr.ch/max_de_henseler_(e).htm 73, Jim W8ZR ------=_NextPart_000_0082_01C9FEF3.66A50A90 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------=_NextPart_000_0082_01C9FEF3.66A50A90-- ------------------------------ Message-ID: <21504137.1247009270845.JavaMail.root@elwamui-rubis.atl.sa.earthlink.net> Date: Tue, 7 Jul 2009 19:27:50 -0400 (EDT) From: Richard Dillman To: Old Tube Radios Subject: Audio Recording: Hear KSM on 500kc Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit I've often lamented that the radio ops who preceded me didn't take the time to record the sounds of a typical day at work. Some did, and those recording are treasured. But mostly it was day to day work that didn't seem that important. Then I realized that *I* was failing to make audio recordings of a typical day at KSM. So last Saturday I recorded some KSM activity and have posted the recording for your enjoyment, especially for those who can't hear KSM directly on the air. It begins with the end of a QSO with SS JEREMIAH O'BRIEN/KXCH on 500kc. Many will immediately recognize the snappy bug of our very own Denice Stoops, RO on board during the 4th of July celebrations. Next is a small bit of the KSM wheel followed by the announcement of the traffic list on 500kc, then UP to 426kc/HF for the list itself. I left in the whole list knowing that some might want to fast forward through it but also that others will relish hearing every call sign. The beat note you can hear is the result of listening on both HF and 426kc during the list. After the list there's another bit of the KSM wheel followed by the sounds of Denice tuning up the KXCH Radiomarine console on 500kc, then a quick QSO with KSM. Following that there's the KSM wheel again but this time being sent via the Boehme keying head (notice the heavy keying). In the background you can hear the log being filled out on the Underwood mill. Next comes T T T on 500kc announcing a gale warning to follow, then UP to 426kc/HF. You can hear me tuning down (or up depending on your point of view) to 426kc to be sure the weather is going out properly on that frequency. This time I didn't include the whole transmission as it can be 1.5 hours long! Fair warning: the mp3 file at the URL below is 12mb in size but download times are pretty reasonable with most any type of high speed connection. http://tinyurl.com/kpgq37 Enjoy. And remember, Night of Nights X is coming up on 12 July Pacific time/13 July GMT with stations KSM, KPH and KFS (along with others) on the air for extended evening (Pacific time) hours to give you a better chance of copying. See details at our Web site http://www.radiomarine.org . GL ES VY 73, RD ================================= Richard Dillman, W6AWO Chief Operator, Coast Station KSM Maritime Radio Historical Society http://www.radiomarine.org ================================= ------------------------------ Message-ID: <21296142.1247011328529.JavaMail.root@elwamui-rubis.atl.sa.earthlink.net> Date: Tue, 7 Jul 2009 20:02:08 -0400 (EDT) From: Richard Dillman To: Old Tube Radios Subject: CWA (Uruguay) to Participate in NofN X? Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit OM Morgan/AL0I did us the honor of providing this interesting bit of information. I pass it along since I know there will a lot of folks listening for CW signals during Night of Night X. Try the frequencies below and maybe you can snag CWA. If you do I bet the OM there would appreciate a reception report. He may feel pretty lonely being one of the very few still standing and keeping the faith! VY 73, RD ----- Perhaps it is old news, but I wanted to make sure you knew that there will likely be at least one additional coastal station transmitting CW during Night of Nights X. Last February I came across CW transmissions from Cerrito Radio in Uruguay. I did some research on the Internet and found a reference to the station's frequencies in this document: http://www.nga.mil/MSISiteContent/StaticFiles/NAV_PUBS/RNA/117chapter3.pdf Frequencies for the station are listed as follows: 421.5 kHz, A1A, A2A 4346, 8602, 12750, 17230 kHz, A1A By monitoring for several days, I was able to determine that scheduled transmissions were taking place daily at 0000, 1400, and 1900 UTC on the frequencies given above. I checked over the last couple of days, and the transmissions are still taking place at the same times on the same frequencies. One thing to note is that transmissions don't always start exactly at the top of the hour. Some transmissions didn't begin on a given day until ten minutes after the times listed above, so it pays to be patient. Also, I had to tune off the frequencies listed above by as much as 300 Hz sometimes in order to hear the CW note using a narrow 250 Hz filter, so it is a good idea to use a wide filter until you know the station is there. The transmissions mentioned "SERVICIO DE OCEANOGRAFIA, HIDROGRAFIA Y METEOROLOGIA DE LA ARMADA," and I was able to find the following Internet sites: http://www.armada.gub.uy/sohma/web/index.html http://www.armada.mil.uy/sohma/web/tmareas.htm Here is my copy for the beginning of one of the transmissions in February: CQ CQ CQ DE CWA CWA CWA HR TFC LIST WX AND SVH QSW 4 8 12 AND 17 MHZ BT CQ CQ CQ DE CWA CWA CWA NW TFC LIST FOR BT NIL NIL STOP DE CWA NW WX BOLETIN METEOROLOGICO WARINO DE LA HORA 1500 UTR DEL 06/02/2009 VALIDEZ 24 HRS. AVISO DE WIENTO FUERTE SE FORMULA POR VIENTOA EQUIVALENT ES A LA FZA7/.... As you can see, there is a traffic list, weather, and notices for mariners (SVH), all in Spanish. Transmissions usually last 60-90 minutes. Since CWA will likely be transmitting at 0000 UTC on 13 July, it will be (inadvertently) participating in Night of Nights X! Todd AL0I ================================= Richard Dillman, W6AWO Chief Operator, Coast Station KSM Maritime Radio Historical Society http://www.radiomarine.org ================================= ------------------------------ Message-ID: <21030839.1247080003730.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> Date: Wed, 8 Jul 2009 15:06:43 -0400 (EDT) From: Richard Dillman To: Old Tube Radios Subject: Night of Nights X Frequecy List Mime-Version: 1.0 Content-Type: multipart/mixed; boundary=---------------------------5786122634313 -----------------------------5786122634313 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit OM Lewis/W9WGV has been good enough to compile a list of frequencies for the stations that will be on the air for Night of Nights X. It looked like a good listening guide so I edited it a bit and have attached it to this message for those who may be interested. As always, Night of Night details may also be found at http://www.radiomarine.org . VY 73, RD ================================= Richard Dillman, W6AWO Chief Operator, Coast Station KSM Maritime Radio Historical Society http://www.radiomarine.org ================================= -----------------------------5786122634313 Content-Disposition: attachment; filename="MRHS - Night of Nights X Frequency Listing.doc" Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * -----------------------------5786122634313-- ------------------------------ Message-ID: <3B8181ADECC1414EA42B95FFC35AB7FA@BCXHTR8HVC4P> From: "B. Smith" To: Old Tube Radios Subject: Night of Nights Low Reception Date: Wed, 8 Jul 2009 17:42:55 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Has anybody had any DX luck beyond a 1000 miles receiving KSM, KPH, WLO etc. on the lower frequencies, 400 to 500 Kcs during the annual Night of Nights transmissions? breck k4che ------------------------------ From: "Brian Goldsmith" To: Old Tube Radios Subject: RE: Night of Nights X Frequecy List Date: Thu, 9 Jul 2009 07:56:35 +1000 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit -----Original Message----- From: Richard Dillman OM Lewis/W9WGV has been good enough to compile a list of frequencies for the stations that will be on the air for Night of Nights X. It looked like a good listening guide so I edited it a bit and have attached it to this message for those who may be interested ****** Dick,guess what your attached message says:- * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * Brian G. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------------------------------ Message-ID: <32250193.1247091075477.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> Date: Wed, 8 Jul 2009 18:11:15 -0400 (EDT) From: Richard Dillman To: Old Tube Radios Subject: Re: Night of Nights Low Reception Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit >Has anybody had any DX luck beyond a 1000 miles receiving KSM, KPH, WLO >etc. on the lower >frequencies, 400 to 500 Kcs during the annual Night of Nights transmissions? > >breck k4che Some have. We've gotten reports on MF from Australia and New Zealand! We found that pretty amazing given our relatively low power (4 - 5kW) and an antenna with a ground system that could certainly use improvement. But the same listeners have reported our signals on successive years so I guess something's working right - that that part of the world at least. They didn't have solid, continuous copy, mind. But the signal peaked at a certain period if I remember correctly, then slid back into the noise. RD ================================= Richard Dillman, W6AWO Chief Operator, Coast Station KSM Maritime Radio Historical Society http://www.radiomarine.org ================================= ------------------------------ From: "Jim Garland" <4cx250b@muohio.edu> To: Old Tube Radios Subject: PW Dial Update Date: Thu, 9 Jul 2009 08:46:12 -0600 Message-ID: <00c701ca00a4$02ac4000$04000100@Garland> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00C8_01CA0071.B811D000" This is a multi-part message in MIME format. ------=_NextPart_000_00C8_01CA0071.B811D000 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit I received several emails in response to my inquiry about the National PW dial, not all of which were in agreement with each other. The most plausible, from Ralph VE7XF, is that PW stands for "Parallel Worm," in reference to the right angle worm drive that coupled the dial to the HRO main tuning capacitor. Another suggestion, from Russ WB3FAU, is "Position Worm." In both cases, the reference appears to refer to the worm drive which, curiously, is not actually part of the dial. In any case, I'd like to vote for the two-speed PW dial of the HRO-500 receiver as the best tuning dial of any radio ever made. It is silky smooth, esthetically elegant, and a marvel of creative engineering. Sadly, National abandoned the PW dial in the HRO-600 receiver, the company's final product. In all other respects, the HRO-600 greatly outperforms the earlier HROs, but its nixie tube display obviously lacks the cache of the PW dial. You can see a side-by-side photo of the HRO-600 and HRO-500 at http://www.w8zr.net/vintage/receivers/hro600.htm 73, Jim Garland W8ZR ------=_NextPart_000_00C8_01CA0071.B811D000 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------=_NextPart_000_00C8_01CA0071.B811D000-- ------------------------------ From: "Jim Garland" <4cx250b@muohio.edu> To: Old Tube Radios Subject: PW Dial Update Date: Thu, 9 Jul 2009 08:52:49 -0600 Message-ID: <00cc01ca00a4$eecd02d0$04000100@Garland> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I received several emails in response to my inquiry about the National = PW dial, not all of which were in agreement with each other. The most plausible, from Ralph VE7XF, =A0is that PW stands for =93Parallel = Worm,=94 in reference to the right angle worm drive that coupled the dial to the HRO main tuning capacitor. Another suggestion, from Russ WB3FAU, is = =93Position Worm.=94 In both cases, the reference appears to refer to the worm drive which, curiously, is not actually part of the dial. In any case, I=92d like to vote for the two-speed PW dial of the HRO-500 receiver as the best tuning dial of any radio ever made. It is silky = smooth, esthetically elegant, and a marvel of creative engineering.=20 Sadly, National abandoned the PW dial in the HRO-600 receiver, the = company=92s final product. =A0In all other respects, the HRO-600 greatly outperforms = the earlier HROs, but its nixie tube display obviously lacks the cache of = the PW dial. You can see a side-by-side photo of the HRO-600 and HRO-500 at http://www.w8zr.net/vintage/receivers/hro600.htm 73, Jim Garland W8ZR ------------------------------ Message-ID: <001001ca00a7$d5640200$1d3ca8c0@office> From: "Paul Christensen" To: Old Tube Radios Subject: Re: PW Dial Update Date: Thu, 9 Jul 2009 11:13:36 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit > In any case, I'd like to vote for the two-speed PW dial of the HRO-500 > receiver as the best tuning dial of any radio ever made. It is silky > smooth, > esthetically elegant, and a marvel of creative engineering. Jim, I just finished rebuilding a PW gearbox on a ca. 1935 HRO. While I have not seen the two-speed PW dial, the original PW gearbox design was a true "flash of genius." One needs to disassemble the gearbox to truly appreciate the logical complexity but mechanical simplicity of the design. I completely cleaned out the housing and applied Lithium grease to the gears. With a synthetic form of grease in its sealed housing, I suspect the gearbox could easily see another 70+ years of service. The only "wish list" item I would have for James Millen back in the mid '30s would have been to utilize a PTO instead of a meshed variable tuning cap. Still, tuning linearity is quite good. As I recall, Collins was the first major manufacturer to capitalize on the use of the PTO. If a PTO was used in a pre-WWII design, I am not aware of it. Anyone have some examples? Anyway, after the re-build and adding a NOS dial, the old HRO tunes as smooth as my Icom '7800. No exaggeration. The dial is properly weighted with just the right amount of spin and there's zero backlash and slop when tuning. Paul, W9AC ------------------------------ From: "Jim Garland" <4cx250b@muohio.edu> To: Old Tube Radios Subject: Still more, re PW dial Date: Thu, 9 Jul 2009 09:24:59 -0600 Message-ID: <00d001ca00a9$6cfe5240$04000100@Garland> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00D1_01CA0077.2263E240" This is a multi-part message in MIME format. ------=_NextPart_000_00D1_01CA0077.2263E240 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit I received a note from Max, HB9RS, about the PW dial: "I found in National publicity reference to PW condensers, in single...double, etc., sections. When these condensers are attached to the dial they become NPW models with micrometer dial." Interesting history, don't you think? 73, Jim W8ZR ------=_NextPart_000_00D1_01CA0077.2263E240 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------=_NextPart_000_00D1_01CA0077.2263E240-- ------------------------------ Message-Id: <6.2.1.2.2.20090709113139.05ab69b0@oak.cats.ohiou.edu> Date: Thu, 09 Jul 2009 11:43:16 -0400 To: Old Tube Radios From: Rich Post Subject: Re: PW Dial Update Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed I've been told it was "precision worm". "Parallel worm" was also mentioned. Lacking original sources, the academic in me hesitated to respond earlier. The "parallel worm" version is lent credence because the straight tuning dial - capacitor combo is named the NPW which could be interpreted as "not parallel worm". The dial is sheer genius, copied by Axis nations. Rich KB8TAD At 10:52 AM 7/9/2009, Jim Garland wrote: >I received several emails in response to my inquiry about the National PW >dial, not all of which were in agreement with each other. The most >plausible, from Ralph VE7XF, is that PW stands for "Parallel Worm," in >reference to the right angle worm drive that coupled the dial to the HRO >main tuning capacitor. Another suggestion, from Russ WB3FAU, is "Position >Worm." In both cases, the reference appears to refer to the worm drive >which, curiously, is not actually part of the dia ------------------------------ Message-ID: <4A5646BF.4060009@dtnspeed.net> Date: Thu, 09 Jul 2009 14:36:31 -0500 From: Rodger MIME-Version: 1.0 To: Old Tube Radios CC: Old Tube Radios Subject: Re: PW Dial Update Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Looking at the National Ad in the '47 Handbook, National refers to the PW "condenser" as having all rotor shafts Parallel to the front panel. They were available with from 1 to 4 "condenser" sections with models such as PW-3R which had w sections on the right and a single section on the left. Further down the page are listed the NPW models that are described as similar to the PW models except that the rotor shaft is perpendicular to the panel. National loved those "P" words! So I would guess that NPW does stand for "non-parallel" although they could just as easily have named the perpendicular model PW and named the other unit NPW (non-perpendicular). Probably the parallel unit was the first produced and received the more desirable short name. The only drawback I have found to the mechanically marvelous NPW is there is a bit of drag given the gearing setup. I have several HRO's, which do tune smoothly, but they don't compare to my NC-100, NC-101X, and NC-240D for ease of knob twirling. Rodger WQ9E Rich Post wrote: > I've been told it was "precision worm". "Parallel worm" was also > mentioned. Lacking original sources, the academic in me hesitated to > respond earlier. The "parallel worm" version is lent credence because > the straight tuning dial - capacitor combo is named the NPW which > could be interpreted as "not parallel worm". > > The dial is sheer genius, copied by Axis nations. > > Rich KB8TAD > > At 10:52 AM 7/9/2009, Jim Garland wrote: >> I received several emails in response to my inquiry about the >> National PW >> dial, not all of which were in agreement with each other. The most >> plausible, from Ralph VE7XF, is that PW stands for "Parallel Worm," in >> reference to the right angle worm drive that coupled the dial to the HRO >> main tuning capacitor. Another suggestion, from Russ WB3FAU, is >> "Position >> Worm." In both cases, the reference appears to refer to the worm drive >> which, curiously, is not actually part of the dia > > > > ------------------------------ End of BOATANCHORS Digest 4276 ******************************