[Drakelist] R4C deaf and TR7 questions AGC, tx all band mod
Greetings from over the Pond, oddly I have had a R4C stored in a damp area, and years later when I fired up it still works..though I have only run it short periods. The 2nd R4C is rather deaf both with normal rx and with the xtal calibrater..if its not the valve and I have both 6ej7 and the uk version EF 184 to replace it with. There doesn't seem any exccessive drift, so I wouldn't think voltages are down. 2nd subjest is about the TR7 are there any mods to change the agc speed to something like fast attack with either fast or slow delay for the CW position etc .. I saw a Mod for the TR 7 which involves cutting some pcb tracks for all band tx option..it certainly would be great to operate on the 30 metre WARC band. Any thoughts over this mod is it too risky ?? I got my first R4C about 1978 it took all my college holidays working night shifts, ten tec came along and I forgot just how good Drfake euipment is, hence the recent purchase of the TR7 and A/C psu. I haven't the uers handbook fot the TR7 but a service manual..now figured out what the up/down buttons are for. 73 de ian G3YRQ..best bent wires to 1 and all.. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake R4B
Gary - KE9PQ has feet! Yes, the serial numbers are sequential and there are three versions of the 'B' that set data points. WB4HFN has a 'Serial Number Database' on his site for most Drake gear. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com GARY ELLIOT wrote: Good Evening to the group. I just picked up a nice R4B receiver and I am missing one of the rear feet. Any suggestions where to obtain one ? Is there a way to tell by the serial number where in the production run the receiver was made ? Thanks. 73 Gary ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake R-4b upgrade
Guillermo - I tried to send you a direct message last night, but was refused by your ISP. Do you have another address that will work? 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com GGLL wrote: Hello Garey, my name is Guillermo, LU8EYW/W in Puerto Madryn, Chubut province, Argentina. I'm troubleshooting my R-4B receiver and searching the schematic, the model which has the OB2 regulator voltage included (V11) and a PCB board not included in the first models (or at least, different as I'm seeing in various different schematics already downloaded). In my receiver, this regulator tube is located between front panel and V2. So far, I've had no luck yet, but found and downloaded three different copies, no one of these has the OB2 regulator tube. Furthermore, I've supposed my R-4b to be a later serial number model, but looking photographs at Drake virtual museum, I see one which has a larger serial number than mine, but no OB2! (looking in detail, you can see just printed OB2 onto the chassis, only). Can you enlighten me about which version of this receiver had this upgrade?. Many thanks in advance Regards Guillermo - LU8EYW/W. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake R-4b upgrade
Guillermo - Actually the 0B2 was a 'downgrade' that was only used in the first 1000 (s/n 7000 - 7999). It was holdover from the R-4A which still had a tube based CALIBRATOR that needed the 'regulated' +150 VDC. Starting with the R-4B, the CAL circuit was changed to an FET with RTL dividers to provide 25 kHz markers, meaning the 0B2 was no longer needed. The lower voltage stages had their own Zener regulator, (BAND, PTO and CAL,) and this was supplied direct from the 'un-regulated' +150V bus. I guess it took the first 1000 units for Drake to realize that the 0B2 no longer contributed any improvement and could be removed!! So your R-4B is one of the first 1000, with a s/n in the 7000 range. There are other changes in later versions, such as changing the oscillator in the PTO from bipolar to FET for improved stability. If you can get me a good email address, I can send you the correct schematic. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com GGLL wrote: Hello Garey, my name is Guillermo, LU8EYW/W in Puerto Madryn, Chubut province, Argentina. I'm troubleshooting my R-4B receiver and searching the schematic, the model which has the OB2 regulator voltage included (V11) and a PCB board not included in the first models (or at least, different as I'm seeing in various different schematics already downloaded). In my receiver, this regulator tube is located between front panel and V2. So far, I've had no luck yet, but found and downloaded three different copies, no one of these has the OB2 regulator tube. Furthermore, I've supposed my R-4b to be a later serial number model, but looking photographs at Drake virtual museum, I see one which has a larger serial number than mine, but no OB2! (looking in detail, you can see just printed OB2 onto the chassis, only). Can you enlighten me about which version of this receiver had this upgrade?. Many thanks in advance Regards Guillermo - LU8EYW/W. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] TR7 questions AGC
Hi Ian, There is no risk performing the all band TX mod on the TR7 and it is an easy way to get the WARC bands using the UP-DOWN buttons. I used that method before I installed the AUX7 module. Regarding the AGC. Do you want something faster than the current FAST setting via the front panel AGC switch (F/S)? Or do you want it to change with the mode selection? I haven't seen any such modification as it's kind of nice to be able to select the AGC speed independently of the mode. I would assume if you feel the current FAST isn't fast enough that we couldn't dig into the schematic and play with a resistor value that could speed it up more. I just haven't read of anyone who felt it was to slow in the FAST setting. 73 Don N9OO www.radiolabworks.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R4C deaf and TR7 questions AGC, tx all band mod
On Tue, 27 Sep 2011 07:41:03 -0400, ian parkinson wrote: I saw a Mod for the TR 7 which involves cutting some pcb tracks for all band tx option..it certainly would be great to operate on the 30 metre WARC band. Any thoughts over this mod is it too risky ?? The only real risk, per se, is that you may accidentally transmit somewhere that you shouldn't and the communications authorities will notice. However There is a right way and a wrong way to do this mod. Surprisingly, the published method from Drake is the wrong way to do it. It does give you all band allband transmit as described, but the method for doing so has the side effect of disabling the out-of-lock (OOL) transmit inhibit signal from the PLL. This could allow you to accidentally transmit out of band if the PLL happens to unlock for some reason, and also prevents G4ALG's mod to eliminate the TX spike when power is turned on from working. I have published a method that preserves the OOL signal and involves two trace cuts on the old version Digital Control board. I haven't worked it out for the newer version board yet, not having one at my disposal, and there seeming to be no interest. Most people seem to go with the bad method, despite explanations as to why it is not a good idea 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime. HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] A liitle off, but...
Is an antenna matcher a balun or unun since it matches the antenna to the input impedance? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] A liitle off, but...
- Original Message - From: Neil M Califano cchange...@yahoo.com To: Drakelist@zerobeat.net Sent: Tuesday, September 27, 2011 3:30 PM Subject: [Drakelist] A liitle off, but... Is an antenna matcher a balun or unun since it matches the antenna to the input impedance? I'm not sure if this is a generic question. If it is there are many varieties of matching circuits. Some are narrow band some wide band, also some change balanced to unbalanced lines with out without a change in characteristic impedance. I'm not sure where to start with this other than suggesting that you read the tutorial material available on the web. Its possible to get a good, practical, understanding of impedance and its transformation without getting too deeply into theory but the real theory is pretty deep stuff. BTW, matching may not be too important in some instances; its often not for receiving antennas. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] A *little off, but...
Is an antenna matcher a balun or unun since it matches the antenna to the input impedance? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] PRN1000
Is subject rcvr. equivalent electronically to the SW2? I need a manual and schematic. tnx.Gordy___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] De-crudding the PBT
Yes, it really is as easy as it says on Garey's B-Line CD. The old grease was pretty dried out - I cleaned all the metal parts with brake cleaner, used Rem Oil for the thin shaft and moly grease for the cam, larger shaft and bearing surfaces. The moly grease is very low-viscosity compared to axle grease and is used for CV joints. Rem oil is a spray lubricant that contains Teflon - marketed as a lube for guns but I've also used it on baitcasting reels with success. Also works great on the PTO worm drive! The whole thing comes apart fairly easily - don't be afraid to tug to get the slug carriage out, as there's bound to be a ridge of dried-out grease on the inside. Just be careful not to stress the springy slug carriers (the things that look like a wound guitar string). Now, on to restoring the headphone connector and undoing the AGC mods! 73, 73, Steve Wedge, W1ES/4 To be is to do - Socrates To do is to be - Plato Do be do be do. - Sinatra All my computers have my signature with various pearls of wisdom appended thereto. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Grounding the mic input
It looks in the schematic as though there's plenty of resistance in series with the mic input. I'm willing to use PTT only and the easiest way (and least degrading to the low-level audio signal from the mic) is to jumper one of the NC contacts in the PTT switch that goes to GND over to the non-grounded side of the mic (I.e., grounds the ring when not in use). My aim is to not have the VOX trigger without having to fiddle with the VOX settings that I optimized for CW. Just for a sanity check - there should be no problems with this, right? It looks like there's at least a couple hundred k in series with the grounded terminal if I'm following the wafer switch diagram correctly. 73, Steve Wedge, W1ES/4 To be is to do - Socrates To do is to be - Plato Do be do be do. - Sinatra All my computers have my signature with various pearls of wisdom appended thereto. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
