20070223.ba v04_n017.bam.20070223 >From ???@??? Fri Feb 23 09:03:50 2007 -0600 Date: Fri, 23 Feb 2007 15:02:19 GMT From: Old Tube Radios To: Old Tube Radios Subject: BOATANCHORS digest 4017 Message-Id: <20070223150227.7F5A8187AF9@srvr1.theporch.com> BOATANCHORS Digest 4017 Topics covered in this issue include: 1) On the Subject of Ham Radio in the Movies and TV by David Hollander 2) cw demise by wb3fau@att.net 3) Re: BOATANCHORS digest 4016 by Roy Morgan ---------------------------------------------------------------------- Message-ID: <45DE810B.8020701@cox.net> Date: Thu, 22 Feb 2007 22:52:11 -0700 From: David Hollander MIME-Version: 1.0 To: Old Tube Radios Subject: On the Subject of Ham Radio in the Movies and TV Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Found this on wikipedia. Enjoy...Dave N7RK http://en.wikipedia.org/wiki/Amateur_radio_in_popular_culture -- *********************************************************** Dave N7RK Boatanchors Home Page: http://members.cox.net/n7rk Phoenix, Arizona *DXCC Honor Roll* *WAZ#22 - 75 Meter SSB* ex-XE2/N7RK, N7RK/ZB2, VK2ERK, ZM0AJN, WB6NRK, WN6IWX Boatanchor and Antique Radio Collector ------------------------------ From: wb3fau@att.net To: Old Tube Radios Subject: cw demise Date: Fri, 23 Feb 2007 14:26:52 +0000 Message-Id: <022320071426.14817.45DEF9AC000029B5000039E121602806519A0E00CC0D99@att.net> OK fellas, i will add my 2 cents. I am a general, and old enuf call to require 13wpm- back when? The point was brought up about "new blood". My opinion is- the code no longer matters. There just is not any interest in radio- period. Its for us old guys, yes, thats us. Remember the magazines you read when you were a kid? The new kids are not reading that stuff- they are reading about computer upgrades. I am 51, and i see it everyday. New guy at work, just out of college, he has an electronics degree, and all he knows about is computers. i think Ham Radio will wither as TOM said it would not. Russ. ------------------------------ Message-Id: <6.0.0.22.2.20070223094806.03f6da48@mailserver.nist.gov> Date: Fri, 23 Feb 2007 09:59:35 -0500 To: Old Tube Radios From: Roy Morgan Subject: Re: BOATANCHORS digest 4016 Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="=====================_262797906==_" --=====================_262797906==_ Content-Type: text/plain; charset="us-ascii"; format=flowed At 10:57 PM 2/22/2007, you wrote: >My recent work restoring an RAL to operation got me to pondering the >history of SW communications receivers in the Navy. Al, Thanks for the links to the info on old Navy radios. I have here some RAL's, RAK's, and an RBB and RBC. Do you know Richard Brunner, AA1P ? He is a nut about the RAL and old equipment, and did some extensive analysis and updates to the RAL. I have attached my notes file on these, including his updates and changes. It's quite interesting that he gets improved results from these radios. I have not done any of his mods yet, though I intend to. If you do any of them do let me know how you make out. I expect to restore my radios (at least some of them) and run them regularly. As you'll read in the notes, there are two Western Electric tubes with 10 volt filaments that are the same as the 6D6 and 41. I hope to find the second one (I have the 6D6 equivalent) and run the radio with these tubes. Trouble it the 41 equivalent tube I need is quite expensive and I don't want to pay that much. Roy --=====================_262797906==_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="ral-raknotes.txt" RAL-RAKnotes.txt from K1LKY (unknown date): Date: Thu, 27 Apr 2000 01:08:15 -0400=20 From: Jerry Proc =20 MIME-Version: 1.0=20 To: Old Tube Radios =20 CC: boatanchors@theporch.com=20 Subject: Re: Anyone Know Where I Could See A Pix of a RAK-7 =20 Hello David, To see an RAK receiver in the flesh, refer to my web page: http://www3.sympatico.ca/hrc/haida/radio/msgcentr.htm It's the very bottom most picture. Designed in the 1930's, this six tube regenerative receiver was capable of= =20 receiving signals between 15 and 600 kc. Tuning was accomplished through the= use of circular,=20 geared logging scales for both coarse and fine tuning. To determine an= actual=20 frequency, one had to look at the dial reading then consult a 'tuning= graph'. Since these=20 graphs were not that accurate, most operators calibrated the receiver by= noting the dial=20 positions after stations of known frequency were identified. +++++++++++++++++++++++++++++ DavidC wrote: > I have searched all of the usual military boatanchor sites for=20 > specs and a picture of the venerable RAK-7 Receiver. All I=20 > found was "Major component: CRV-46155 or CND-46155 and=20 > CRV-20131 or CND-20131, Coaxial connection for antenna." -- Regards,=20 Jerry Proc VE3FAB jproc@idirect.com=20 Web: www3.sympatico.ca/hrc/haida=20 HMCS HAIDA Historic Naval Ship, Toronto Ontario From: "Kenneth G. Gordon" =20 To: Roy Morgan =20 Date: Mon, 30 Apr 2001 10:57:30 -0700=20 Subject: Re: GB> RAK receivers...=20 CC: glowbugs@piobaire.mines.uidaho.edu =20 Sender: owner-glowbugs@piobaire.mines.uidaho.edu=20 > At 06:14 PM 4/28/01 -0500, Sandy wrote:=20 > > The RAK-8 DOES NOT have the switch that is between=20 > > > the regen control and the sensitivity control that switches the audio= =20 > > > bandpass filter out like the RAL does.=20 >=20 > There is a VERY good reason for this.. read on.=20 >=20 > > It is labled Audio Broad-Narrow.=20 > > > Shouldn't be hard to add to the RAK and if done right, should look= stock.=20 >=20 > Don't do it. It will get you nowhere.=20 >=20 > >The audio on the broadcast band is INDEED crappy with this switched in!= It is=20 > >meant for CW only.=20 >=20 >=20 > BOTH the RAK and the RAL are meant for CW only, ESPECIALLY the RAK.=20 >=20 > I cannot quote the RAK manual but it clearly states that it is not meant= =20 > for AM reception. Here is why:=20 >=20 > The thing is a tuned RF amplifier receiver.. it has two (or is it three)= =20 > tuned circuits at the received frequency.. These circuits are made with=20 > fairly high Q factors..they are NATURALLY NARROW BAND things. Their=20 > bandwidths are approximately some percentage of the received frequency..= In the=20 > RAL, at 4 megacycles that is enough to hear most of an AM signal.. At 300= KC it=20 > is not.=20 >=20 > You can have a high fidelity audio section flat from 20 cycles to 20,000= =20 > cycles and it will STILL be bad on AM.=20 >=20 > Before you modify an RAK or RAL, I suggest that you get a clip lead and= put it=20 > into the circuit where you plan to put your switch to short the audio= filter.=20 > Then try your radio for a while.=20 >=20 > An interesting exercise in getting to know your RAK is to tune in a=20 > aeronautical radio beacon in the 250 to 400 kc band.. find one that has an= audio=20 > ID in morse. If you tune carefully, use the low frequency audio filter,= set the=20 > detector at the ragged edge of oscillation, and think about what you are= =20 > hearing, you can split off the two sidebands of AM and isolate the steady= =20 > carrier. You have a manually swept spectrum analyzer. Its possible to= identify=20 > two beacons on the same frequency that have different ID modulating=20 > frequencies.. 400 cycles and 1000 cycles are common.=20 >=20 > NOTES:=20 > 1) Anyone looking for an RAK let me know.. I may know of one for sale in a= =20 > while. 2) Wanted: manual for CEI VLF-354 receiver. Roy and Roy and all: If you examine MOST VLF receivers, you will find that the RF bandwidth=20 MUST be significantly narrower than a particular proportion of the received= =20 FREQUENCY. I do not know what this value is, but it can be calculated. As an example, for the SP-600-VLF-31, two examples of which I just sold,=20 there is a plate on the front panel, which, in large letters, says,= "Warning! Do=20 not use 6 kHz or 3 kHz selectivity positions below 28 kHz. Set crystal=20 phasing at the diamond for 6 and 3 kHz." Also, in the Collins R-389 VLF=20 receiver, RF filters are automatically switched in or out depending on where= =20 you are tuning in the VLF spectrum. The RAK has very good RF selectivity. So good, in fact, that it is true= "single-=20 signal" over its entire range, there being only one side of zero beat, and I= =20 cannot remember EVER hearing the other side of zero beat, even on very=20 strong signals, such as Jim Creek, Washington which was less than 400=20 miles away, and on 18.6 kHz. I used an RAK-8 for a number of years for code practice before the Navy=20 changed its VLF stations from CW to narrow-shift phase-shifted TTY. After=20 that, a fellow I worked for used RAKs for VLF propagation research by tuning= =20 a number of them to various Navy VLF stations, rectifying the audio output,= =20 and feeding small chart recorders. The RAKs would stay on a particlar=20 station year in and year out, literally. Messing with the narrow bandwidth audio filter in the RAK is probably a good= =20 exercise, but I don't think it would work very well BELOW the broadcast=20 band, and as Roy Morgan says, probably wouldn't help much, if at all, to=20 increase the fidelity on that band. Ken Gordon W7EKB=20 Date: Mon, 30 Apr 2001 15:12:30 -0400=20 From: teda =20 X-Mailer: Mozilla 4.7 [en] (Win95; U)=20 X-Accept-Language: en=20 To: Roy Morgan , "Kenneth G. Gordon" ,= =20 "glowbugs@piobaire.mines.uidaho.edu"=20 =20 Subject: Re: GB> RAK receivers...=20 Actually, I disagree. I put that switch in and found that AM coming out of= the=20 detector from the output coupling cap - C-122 - is quite clear through my=20 Heathkit signal tracer ( with the filter disconnected in the RAK and using a= =20 straight-wire probe on the tracer ) I heard about 8 broadcast stations at or= =20 under 600 kc., and the quality was as good as you get on most HF receivers,= so=20 long as you remain below the regen. oscillating point. I might add that 6 of= =20 those stations I have never heard before - on any AM set I have around - and= this=20 was in broad daylight with an 8 foot hank of hookup wire on the floor as an= =20 antenna, and no earth ground. The RF SENSITIVITY and ANTENNA controls can= bring=20 the level up just fine without introducing the regen distortion. What's= amazing=20 is, they don't seem to affect the oscillation point - which is probably a= big=20 part of why the RAKs had such a reputation for excellent overload=20 characteristics. C-122 is an RPA (royal pain-in-the-ass) to get to. You have to take out= about 3=20 dozen screws and lift the bandswitch cover plate off. Then, with the= receiver=20 panel facing way from you, it's in the lower right hand side of the chassis,= a=20 square mica type with ring lugs ) bolted to the chassis wall just under the= =20 tensioning plate for the bandswitch. (I wouldn't take THAT off for= anything!) But=20 the fat white wire leading into the filter is closest the the chassis floor.= Not=20 hard to unsolder. Then remained the problem of insinuating a pair of= miniature=20 shielded audio cables out of the bandswitch enclosure and into the front= panel=20 area in such a way that they don't interfere with the bandswitch itself. You= =20 will need LONG nosed pliers for this! And another problem is that the wires= have=20 all become very stiff and brittle with age. I am doing this on my RAK-7 -= and=20 they used a lot of nautral rubber insulated wires - very like test lead= wires -=20 in many places. These guys are rock hard, now, and crumble like plaster, so= be=20 careful! You can't just shove them aside. So now I have a clean signal coming out of the detector and a return lead to= =20 reconnect the filter, so that end is good. I am still having a problem at= the=20 other end where the signal is sent into the first audio. I thought I had= found=20 the right blue rubber wire coming from the filter, but apparently not - the= =20 signal comes through with either position of the switch, but filter still= affects=20 it, either way - though there is a difference. There are several blue wires= up=20 in the first audio and filter-tune-switch area, and you can't move them .= So,=20 there is something yet to figure out with the first audio. Something's still= =20 attached. Trouble is - on my RAK-7 (RCA) - the components aren't numbered on= the=20 fiberboards they way the are one the RAK-8 - and the schematic I have gives= no=20 values. But I am convinced to can get decent AM audio on these things. I have heard= it. I'll update later. Ted A. KE3AL From: "Kenneth G. Gordon" To: glowbugs@piobaire.mines.uidaho.edu Date: Sat, 16 Jun 2001 22:40:21 -0700 =20 Subject: GB> RAL-6...=20 Fired it up today: had to remove a couple of mods someone did. It sure=20 works well though. Lots of fun to operate. The power-supply I mentioned here earlier works just fine with this RAL-6.= All=20 the VR tubes stay lit and the voltages measure 179.7 VDC, and 88.9 VDC at=20 the receiver. It looks like the RAK may have some really leaky capacitors. Current to the RAK is 35 mA at 185.6 VDC and both VR tubes go out, and=20 88.9 VDC at 0 mA (!) and the VR-90 stays lit. I hope I can find some ORIGINAL meters for the RAL-6. It looks like it is=20 going to be a pretty good rig. Ken W7EKB=20 From: "Barry Kirkwood" To: "Ted Althof" Cc: "Glowbugs" Subject: Re: GB> RBL receivers... Date: Wed, 18 Jul 2001 11:51:15 +1200=20 FWIW: WWII regens: The British Admiralty answer to the RAK was the Marconi=20type B29.= consisted of two 6K7 near equivalent tuned rf amps to a 6K8 equivalent. The hexode section of the latter functioned either as a detector in TRF mode for am or mcw ,or as a mixer for the triode oscillator section which was tuned to signal frequency. There was an audio filter with coupled two tuned circuits between two triode audio stages. covered ?30 to 600kc or thereabouts. Overall construction not quite as high spec as the RAK/RAL. But like the RAL /RAK the operators regarded them very highly and preferred them over their superhet successors. Like the RAL/RAK great care was taken to minimise radiation from these receivers. The RAL equivalent was the B-28 which was a conventional 2rf, 3 if 465 if superhet, tuned 60kHz to 30mHz with a gap around if freq. Was not thought as good on the low bands as the B-29. On the other hand the standard British Merchant ship of the time used a Marconi regen with no great shielding and not even an rf stage decoupling it from the antenna. These were infamous as U-boat bait. I have no knowledge of Kriegsmarine receivers, but the excellent German equivalent of the airborne ARC-5 sets were superb regens having 2 or 3 rf stages and turret coil change. 73 end Barry Kirkwood PhD ZL1DD Signal Hill Homestay 66 Cory Road Palm Beach Waiheke Island 1240 NEW ZEALAND www.waiheke.co.nz/signal.htm From: Boatanchor Bob NA4G Message-Id: <200107191902.f6JJ2dH29738@weedcon3.cropsci.ncsu.edu> Subject: Re: GB> techno-revenge=20 To: Glen Zook Date: Thu, 19 Jul 2001 12:02:38 -0700 (PDT)=20 > According to many "experts", back in the early 1920s > when regen receivers and crystal receivers were the > norm, many crystal sets were actually receiving > re-radiated signals from regenerative receivers in the > neighborhood. When the owner of the regen set turned > it off, the owner of the crystal set lost the signal, > often thinking that the "sensitive" spot on the > crystal had been lost. That owner would search for > hours to find another "sensitive" spot on the > germanium crystal. Then, when the regen set was > turned on again, the crystal set "magically" started > to work again. >=20 > Glen, K9STH Neat! .....(:+}}..... I would expect they were getting a little heterodyning action off the local signal. That would tend to boost the tin can output a bit, by adding some local signal injection, sort of like a way external heterodyne receiver......(:+}}.... On my R388, on weak AM signals, the few times I am AM'ing, I will sometimes turn on the BFO and zerobeat, to provide some added signal injection. It does work, but you have to get it right on zerobeat. I guess it strengthens the carrier a bit, sort of like synchronous AM detection(?) or whatever that means of carrier reinsertion AM detection is called. Also, it works similarly on a regen receiver such as my RAL. It requires you set the thing right on the edge of regeneration and let the thing pull just above oscillation as you zero the AM signal. There is a marked increase in signal strength at that time. I am assuming you get maximum regeneration then, plus the added benefit of the local injection. Operation in this mode tends to be slightly touchy, though. Bob/NA4G > > But, unshielded, non-trf regen sets (common on > > merchant vessels, up through the WWII) on 600M, could > > radiate, hundreds of yards. From: "Sandy W5TVW" To: , Subject: Re: GB> Re- Regen radiation Date: Wed, 8 Aug 2001 14:05:58 -0500=20 Been following this thread...... I have a Navy RAL-7 receiver. A friend of mine used to sail on the old diesel "fleet boats" from Pearl during WW2. He was a sparky and the sub used the RAL receiver. The radiation from my RAL is very negligible until I get up to 14 Mhz or 21 Mhz. I can't detect it at all on a nearby sensitive solid state receiver. On 14 Mhz and 21 Mhz. the signal is detectable, but still weak. Using a vertical antenna on the RAL-7 about 25' long, on 14 mhz. I can't hear the RAL's detector oscillating over about 100 yards distant with a solid state portable SONY ICR-5900 receiver on its self-contained whip. This is how much.....or how little.....my RAL-7 radiates. My "pig boat" buddy didn't mention anything about ever not using his receiver to listen to the traffic from Radio Pearl. 73, Sandy W5TVW From: Boatanchor Bob NA4G Subject: Re: GB> Anyone on the QRGs tonight? To: Mark_Dittmar@Maxtor.com (Dittmar, Mark) Date: Wed, 28 Nov 2001 16:53:26 -0500 (EST)=20 > I was just curious, what do you use to mute your RAL during > transmit? Do you just disable the plate supply? Good question. I use one of 3 methods, depending upon what I feel like at the time. The rig has an antenna changeover relay run from a small battery. The RAL is hooked up, via coax, to the relay. The rig likewise. 1. Switch at ops console under table lip. This switches the antenna relay, grounds the RAL input, and leaves everything else wide open. The detector overloads and flattops the audio, which essentially mutes the critter with a mushing sound. If that is too harsh on the ears, you can add a pair of back to back sillycondiodies across the floating tin can output, e.g., in the phone plug shell. A foot switch does the same for FD operations at QRQ. 2. Switch on RAL power supply, takes the non B+ set and uses those contacts to run the relay AND kill the B+ (this was an old novice hack I did about 25 years ago.... not pristine, but it works). You have to use a growler (monitor receiver) for side tone this mode, at QRQ. 3. Separate antennas and use the overloading method for QSK. This works well with the diodes in the audio, but the diodes can easily flattop the audio, so you may need to run a pair of diodes on each side, or a diode and resistor each side, back to back across the audio. Remember the RAL audio IS FLOATING. Keep it that way. On other simple regens I prefer to overload like 1, and let the time constant of the grid LC act as AVC. This is where the right choices of grid leak and grid cap pays off. ZUT OM DE NA4G/Bob UP From: Boatanchor Bob NA4G Subject: Re: GB> Anyone on the QRGs tonight? To: Mark_Dittmar@Maxtor.com (Dittmar, Mark) Date: Thu, 29 Nov 2001 10:31:10 -0500 (EST) Cc: na4g@weedcon1.cropsci.ncsu.edu ('Boatanchor Bob NA4G')=20 > Hi Bob, >=20 > Thanks for the ideas on the RAL muting. I have a switch on my > homebrew RAL PS which I have used to disable the plate supply during > transmit ( manually ). This works, and I have used it in the past, but= is > tedious. I just need to add some binding posts across that switch so I= can > connect contacts from antenna switching relay across it, so I can have a > single switch transfer from transmit to receive. Generally, I have not > grounded the RAL ant input, but did disconnect it. I have a generic > antenna switch box and relay which I use for various functions, as well= as > additional relays for keying those HV Hartley rigs! Do ground the antenna input, it makes a lot of difference. Grounded, you can use the RAL for spotting, since that way it is shielded well enough. With the antenna up, it totally swamps within 10khz of your target QRG. The relay I use is from an old Navy rig, GO-9, that I got for parts as a novice. I have been using that relay ever since, on OT sets. Good Karma to find one somewhere. It was also in the GP-7 sets. > I have also tried your version 1, but without the silicon diodes. > I couldn't stand the way it sounded! I think I will continue with the B+ > disconnect method, but I was curious whether or not there was a better= way. IFF you use 600 ohm or higher headsets, it won't kill your ears. But, it tends to operate better if you flattop the audio at whatever cutoff the sillycon diodes give you. A resistor off the bottom junction of the diodes to the opposite side of the audio line gives you some control of the flattop set point, which can be advantageous. You can also try using a variable resistor there. Also, you might try adding some capacity across the diodes, sort of like the Bishop filter. > Interesting you should bring up the RAL. I was just running mine > last nite after a long time without turning it on, checking to see how= 500 > khz sounded. I hope to pick up the KPH transmissions on 500 khz on= December > 12. It would be nice to use the RAL-7 for this. I then went up to 40 > meters for a listen, and remembered how nice the RAL works on CW! I'm > going to make it more convenient to use for QSOs by adding those contacts > across the B+ switch. As an unwashed heathen novice, I drilled a hole for a small RCA jack to use as the switch contact output to the relay line. I would probably route it out the back wire port, now.....(:+}}.... But, that same Ol' RAL, just keeps on a'tickkin' and takin' a lickin'......(:+}}... Thanks for the attempt at a QSO last night. You were just down into the static crashes enough that copy was mostly 50-75% on my gooseneck speaker atop the RAL. I stuck my head inside the cone, and that helped some, but copy was still rough. It will get better as the cold snaps in. You folks did not know that the RAL drives high impedance goosnecks quite well. Sandy was hearable upstairs even, when I topped off the mud cup. All you hands missed a fine QSO last night with the regulars. Sandy was 5999999, as usual, and Dennis and Darwin were 579 mostly, plus a little. That was 0300-0400Z. We gotta dust offs our sendin' irons an' tin cans, and areadys them up fer some fine winter rattle an' bangin' on the QRG. Bob/NA4G From: "Kenneth G. Gordon" To: milcom@softhome.net Date: Fri, 14 Jun 2002 15:32:26 -0700 =20 Subject: Re: GB>Rack mounting BAs, was HQ-129-X Story=20 > > > I agree with you about leaving units OEM for the most part, > > > but I'm finding it VERY difficult to find a vintage receiver > > > for rack mounting that is within my meager budget :-( There were versions of some BA receivers which were specifically built for= =20 rack mounting. I am thinking specifically of the HRO-50-R (rack)-1 and=20 the HRO-60-R. I have two of the HRO-50-R-1. They seem to sell for=20 MUCH less than the T (table top) models. I bought one of the above,=20 complete with 4 coil sets and the speaker/coil storage cabinet for under=20 $200. It was an ex-FAA receiver. A similar table model in comparable=20 shape went for over $500 that same week. YMMV. Then, as has been mentioned here previously, there are the R-390 series.=20 WAY above my meagre budget at the moment. And the GPR-90 which I=20 can only dream about.=20 Then again, I suppose we can use only one receiver at a time... Often you can find a good BC-779, which is a rack-mounted Hammarlund=20 SP-200 or 210 for reasonable prices, since they are SO DARNED heavy.=20 Excellent receivers IMHO. And the SX-28 comes to mind. I once rack mounted a case-less, very dirty, abused, RAK. I built a=20 completely new front panel on the appropriate sized rack panel. Braced at=20 the sides with triangular steel braces. Came out looking beautifully and=20 worked amazingly well for a number of years. I still have that one. Ken W7EKB Date: Wed, 16 Oct 2002 22:26:05 -0400 To: Roy Morgan From: Roy Morgan Subject: Re: RAL=20 Roy, OM: Can you identify the value of L-112, the rf choke in the detector plate circuit? Richard, It is 5 millihenry at 1l75 kc +/- 10 % 43.6 ohms dc wound on wood core.. (that is why you thought it was a toroid) It's "pi-wound".. my guess is sort of flat pancake shape. If you have two 2.5 mH chokes just put them in series. In the meantime we can look for a more proper replacement. I did not take a radio out of a cabinet to look for the thing, but did find= it in the manual I have here. (I noticed that the phones output filter= coils are L-117A and B and are mis-marked in one picture in this manual.) Roy From: "Richard Brunner" To: Roy Morgan Date: Sat, 16 Nov 2002 21:52:01 -0500=20 Subject: Re: GB> RAL Gear Lubrication=20 Roy, OM: Boy, you were right on - all the coupling capacitors were either leaky,= intermittent, or=20 open. And, they all look like micas. The RAL is working pretty good now,= but I think=20 I have more work to do; most of the resistors are a bit high, and the gain= control is=20 sitting between 4 and 8, 4 for a very strong signal, but most of the time= between 6=20 and 8. Also the input is high impedance, so I need an auxiliary antenna. = All the=20 signals sound pretty clean. Richard=20 From: "Richard Brunner" To: "Glowbugs" Subject: GB> RAL Stories Date: Tue, 24 Jun 2003 07:57:48 -0400=20 The saga continues... My RAL had been stored outdoors face down in the mud for some time, and required extensive work. First I repainted the cabinet and front panel with black crackle, and it looks quite handsome now. Restoring operation has been a much longer story. At first it had many frying and popping noises, and I replaced nearly all the mica capacitors, which were deteriorated in one way or another. Then I replaced the carbon resistors which I thought had increased in value unreasonably. I noted that it had a 1000 =B5=B5fd capacitor from the 1'st 6D6 audio plate to ground,= and .01 from the 41 audio plate to ground, thought they were superfluous, and left them out. Then I replaced the 6D6 and 41 cathode bias resistors, and it started oscillating. Adjusting the detector gain has no effect on the oscillation, thus feedback limited to the two audio stages, so decoupling should not be a problem, so maybe it's magnetic feedback! Right now I have 390 =B5=B5fd on the 6D6 and .002 on the 41, and it's stable in "narrow," but oscillates vigorously in "broad," otherwise it's working pretty good. Ambient noise increases when I connect the antenna on all bands, and CW sounds sweet. Worth noting: Nearly all the mica capacitors were bad, and none of the oil-paper capacitors were bad. Richard Brunner, AA1P From: "Kenneth G. Gordon" To: glowbugs@piobaire.mines.uidaho.edu Date: Sat, 16 Jun 2001 22:40:21 -0700=20 Fired it up today: had to remove a couple of mods someone did. It sure=20 works well though. Lots of fun to operate. The power-supply I mentioned here earlier works just fine with this RAL-6.= All=20 the VR tubes stay lit and the voltages measure 179.7 VDC, and 88.9 VDC at=20 the receiver. It looks like the RAK may have some really leaky capacitors. Current to the RAK is 35 mA at 185.6 VDC and both VR tubes go out, and=20 88.9 VDC at 0 mA (!) and the VR-90 stays lit. I hope I can find some ORIGINAL meters for the RAL-6. It looks like it is=20 going to be a pretty good rig. Ken W7EKB=20 From: "Richard Brunner" To: "Glowbugs" Subject: GB> RAL Stories Date: Wed, 25 Jun 2003 17:47:57 -0400=20 Someone asked which resistors I've changed: First of all, most are all up minimum 10%, and some 50% or more, so I could justly replace all of them, and may before I am finished. First I replaced all the rf grid leak resistors on general principles. The worst noise generators were the detector decoupling and plate load resistors, (and capacitors) and they were not greatly out of tolerance. Now I am working on the cathode bias resistors, and with each change the set sounds better. One thing I have noticed is that the audio output level to 600 Ohm headphones is too high. When the rf gain is adjusted for a comfortable level, I am always listening to what appear to be very weak signals, and with the 'phones on the table and the rf gain advanced they sound normal. Guess I need an attenuator on the audio output, or an added audio gain control. Richard Brunner, AA1P From: "Richard Brunner" To: "Glowbugs" Subject: GB> RAL - Postscript Date: Fri, 4 Jul 2003 18:53:02 -0400=20 I found the last intermittent noise source in the RAL - the sensitivity control. (dual 10K wirewound pot) Using a signal tracer I found some noise on the rf stage cathode bias resistors and the pot, but removing the rf stage tubes had no effect on the noise. Apparently the noise was propagated on the B+ line to the audio amplifier, several ways, in spite of bypassing. The pot came apart easily and I cleaned it with De-Ox-It. The RAL is singing nicely now. I now wonder why finding it took so long... Richard Brunner, AA1P From: "Richard Brunner" To: "Lord, Joe" , "Glowbugs" Subject: GB> RAL - Final Report Date: Fri, 11 Jul 2003 17:45:47 -0400=20 The audio amplifier oscillation problem is solved, and it was indeed capacitive feedback. I shielded all the long audio leads, most of which come out of the low-pass filter, and shielded between the 41 output plate and the nearby low level audio switching. To shield the leads I removed braid from old RG-58 coax, which is easy with a sharp knife and a steady hand. (see note below) Put one end in the vice and slowly back away, peeling off the jacket. Signals now sound about like they should. Listening to bc am, with the signal tracer connected to the detector output there is some distortion, but not too bad. Listening to the amplifier output there is a bit more, but also not too bad. I think degenerative feedback will improve things. I can now hear everything with the RAL that I can with the Drake 2B, but the 2B is not as noisy. In summary, it is now a pretty good receiver, but not the Gold Standard. All this seems pretty obvious, and surely shielded wire was available in 1939-40, but there is not much space between the 41 and the low level audio switching for shielding. Maybe the basic layout was cast in aluminum, and they couldn't change it to permit adding shielding, so they compromised and limited the audio amplifier frequency response to stop oscillation. Richard Brunner, AA1P Note from K1LKY about peeling coax outer jacket: Make up a little block of wood from two pieces of 1 by 2 about 6 inches= long, flat sides to each other. Fasten the two together with a couple of= wood screws. Drill a hole just slightly larger than the coax through the= combination along the middle joint, centered on the joint. Fasten a single= edge razor blade between the two pieces so it *just* pokes into the hole.= Then if you draw the coax through the hole, the blade will score the outer= jacket just enough so you can peel it off easily. From: "Richard Brunner" To: "Lord, Joe" , "Glowbugs" Subject: GB> RAL - Final Report Date: Sun, 13 Jul 2003 19:40:14 -0400=20 I noted that the grid capacitor in the 6D6 detector was 510 =B5=B5fd, which= is ungodly large, and changed it to 120 =B5=B5fd with very good results. The detector linearity is greatly improved, now swbc out of the detector sounds very good, and all cw signals have no rasp, unless it's really there. I added audio degeneration by adding a 2.2 Meg resistor from one side of the output transformer (the side that doesn't make it oscillate) to the 6D6 grid. This reduces audio output very little, and greatly improves linearity. I also added more capacitance across the audio cathode bias resistors. This amplifier was never high-fidelity, but is very servicable now. My RAL now works the way it was intended back in 1936 when it was designed, and may be the only one that ever has. Though swbc reception is very good, it is not good for standard (mw) broadcast. At mw I think there is sideband cutting from all the tuned circuits. Richard Brunner, AA1P From: "Richard Brunner" To: , "Rene" , "Morgan, Roy" , "Lord, Joe" , "Gordon, Kenneth G." Subject: RAL Modifications, for future reference. Date: Fri, 18 Jul 2003 10:33:57 -0400=20 These changes result in a smoothly operating receiver, the way it should have been in 1936. Richard Brunner, AA1P 18 Juli 2003 Detector: 1. Change C112, 510 =B5=B5fd grid capacitor to approx. 100 =B5=B5fd. 2. Change C120, C121, 51=B5=B5fd decoupling capacitors to 600-1000 =B5=B5f= d. These changes change signals from raspy to pure dc, and keep rf out of the audio amplifier. Audio Amplifier: 1. Disconnect C124, .001 =B5fd and C133, .01 =B5fd plate to ground bypass capacitors. 2. Add shielding to all low-level audio leads to the extent possible. Most come out of the low- pass filter. Strip braid from old RG-58 coax. Lift one end of the audio leads and slip braid over them. Ground one end only of the braid. 3. Add a tube shield to the 41 audio output tube. The 5 or 6 feet of unshielded wiring caused a supersonic oscillation (33 volts at the 'phones) and the developers added C124 and C133 to limit frequency response enough to kill the oscillation. This is why Broad and Sharp aren't much different. There is enough capacitance from the 41 plate to adjacent wiring for oscillation. (17 volts on the 'phones) 4. Add approx 4.4 Meg resistor from one side of the output transformer (the side that doesn't oscillate) to the 6D6 grid. Inverse feedback reduces ambient noise and improves linearity. 5. Add capacitance to the 6D6 and 41 cathode bypasses. 6. Pull back the dc power switch and tape/insulate it. Install an OC phone jack shunted with a 1 Meg resistor. Connect jack with a .01 =B5fd capacitor to the 41 plate. This gives hi-Z output. The resistor is to eliminate a big click and charging current when the 'phones are plugged in. Addendum: Change R121, 1 Megohm 41 grid resistor to 470 k Ohms. =20 RCA receiving tube manual recommendation. (portion above printed 7/18/03) From: "Robert Goff" To: baswaplist@foothill.net Subject: Wanted: RAL receiver Date: Mon, 28 Jul 2003 08:54:25 -0600=20 I'm looking for a Navy RAL regenerative receiver in fair or better condition= for restoration. The RAL is the HF companion to the RAK. Thanks, Robert Goff W7MKA From: "Richard Brunner" To: "Roy Morgan" References: <403A6A64.25731.F063A0@localhost>= <5.1.1.5.2.20040224110940.0273a5d8@mailserver.nist.gov> Subject: Re: GB> Dummy Load Q Date: Tue, 24 Feb 2004 14:35:23 -0500 Thanks for the backup... I just got my RBL-4 working again. This time it was merely dirty toggle switch contacts. (Gott sei Dank!) By the way, there is enough rf at the detector plate to drive a frequency counter - same for the RAK. There is more rf at the grid, but going there introduces mucho noise into the receiver. Richard From: "Dr. Rodger Singley" To: Old Tube Radios Subject: RAL receiver wanted Date: Thu, 17 Jun 2004 08:15:34 -0500 I picked up a nice RAK receiver at the Princeton, IL hamfest and now I have the "regen fever" and would like to find an RAL to go with it. Power supply would be nice but not necessary. Given the weight I would love to find one within a couple hundred miles of Central IL or one I could pick up on the way to the Tennessee mountains later this summer. In any case, if you have one you would like to sell please let me know. 73, Rodger WQ9E From: "Rodger Singley" To: Old Tube Radios Subject: And lets drop the Dr.!!! Date: Thu, 17 Jun 2004 08:31:41 -0500 It seems our tech support people decided to go formal when they updated Microsoft Outlook so professional titles were added to our names. Since my doctorate is in business I can be of no assistance with medical problems-well actually my specialty is international marketing so I guess I could do consulting in international organ sales :) In any case, I prefer just plain Rodger (who is still looking for an RAL receiver) 73, Rodger WQ9E Message-ID: <40D1B24A.2060609@ix.netcom.com> Date: Thu, 17 Jun 2004 10:01:30 -0500 From: David Stinson =20 Subject: Re: RAL receiver wanted=20 Dr. Rodger Singley wrote: I picked up a nice RAK receiver at the Princeton, IL hamfest and now I have the "regen fever" and would like to find an RAL to go with it... You and me both... Date: Mon, 21 Jun 2004 12:24:11 -0400 To: Old Tube Radios From: Roy Morgan Subject: Re: BOATANCHORS digest 3666 At 10:27 PM 6/18/2004 -0500, you wrote: I picked up a nice RAK receiver at the Princeton, IL hamfest and now I have the "regen fever" and would like to find an RAL to go with it. Rodger, Good for you! I have a couple of RAK's and about three RAL's here. (None= for sale/trade though.) Very nice receivers. Bob Keys has used an RAL for= his main CW receiver for some decades now. NA4G@aol.com Another very capable ham, "Richard Brunner" has done a= lot of poking around in his RAL and come up with some improvements. They= are detailed in the notes file I have attached. I have not done any of= these changes to any of my radios yet, but I do expect to once I get my= cellar overhauled and find time. I have a set of notes that tell about the overhaul and checking of the RAK.= (sent to me by Ken Gordon, I am pretty sure). I can dig those out and send= you a copy if you like. Also, do read Richard's notes to me in my notes= file on all the things he found to fix in an RAL.. Your RAK may have= similar things to work on. Don't give up on the radio until you have= tested for changed resistors and leaky caps.. fixing those kinds of things= will make a big improvement in the performance. The troubles with these old radios are normally leaky caps or changed= resistor values. His notes help you find at least the changed resistor= values. As you may have discovered, there are very few components in an= RAK.. it's just that the whole thing is so well built that it runs superbly= once fixed up. The power supply is simple: I run mine with a little supply I built from a= very small receiver transformer - a 6X4 rectifier to make the 150 volts,= and a VR tube to make 90 volts steady for the detector. The whole radio= will run just FINE on 90 volts by the way. Bob Keys runs his on batteries= only, and tells of very low noise, no hum, and a kind of transparency in= the signals almost never heard from modern receivers. This is another= thing I'll do with mine once I get organized. Your power supply could be as simple as a 6.3 volt transformer for filament= and a 12 volt transformer running back to back on that, with a= diode/capacitor/choke/capacitor filter from it's 115 volt winding. You'll= get maybe 100 volts or so from all that with low hum and only a few parts. Remember the RAL/RAK audio IS FLOATING. Keep it that way. Don't ground one= side of the output.. it's center tap grounded in the set. (I heard from= one fellow who's applied line voltage to the audio output screw terminals= on the terminal strip.. he unhooked it only after it smoked.. damned fool!) You may discover that there is not too much to listen to with the RAK. = But.. if you get intersed in beacon DX-ing, (aviation and marine beacons)= there is a whole subculture of SWL-ers (or LWL-ers actually) who go nuts to= log ever weaker and more distant beacons. I have gathered a bunch of info= including a beacons heard list and web site lists, but have done very= little listening. if you have one you would like to sell please let me know. I keep my eyes open for them.. Most folks have no idea how wonderful a REAL= trf receiver can be. Note: the normal radio room of that era would have an LM frequency meter,= possibly mounted atop the receiver (picture attached.) The RAL and RAK,= with no frequency readout, needed that. You really should start looking for= an LM, or even a BC-221 frequency meter. Running one of them is as much= fun as running the receiver. I have manuals, and other lore if/when you do= locate one. Hamfest values are $5 for one with no calibration book, or up= to $35 or so for a really good, late one with book. Having no book is a= bad thing, but, Bob Keys had a computer program that would recreate a book= for you. Roy =20 =20 Date: Tue, 23 Nov 2004 15:12:02 -0500 To: "Kenneth G. Gordon" From: Roy Morgan Subject: RAL/RAK tube substitutions Cc: roy.morgan@nist.gov Mime-Version: 1.0 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 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * --=====================_262797906==_-- ------------------------------ End of BOATANCHORS Digest 4017 ******************************