Re: [Drakelist] TR-7 - More Info Cont'd
?I was plagued with the 40M oscillation problem with the same symptoms - a 40M antenna with a bit of reactance resulted in the oscillation. I decided to build the PIN diode attenuator per the PA1HFO design and solved the problem that way. That allows you to set the signal level fed to the pre-driver stage to a different level on each band. You can then adjust each band so that the drive control can be left in the same position as you switch bands and you don't have to adjust it for every band change. With the input signal thus attenuated on 40M, the oscillation was never heard from again. There are other advantages to the attenuator and the whole thing is described in an article on WB4HFN's site. The mods to the original TR7 are minimal - the attenuator sits in the coax feed to the PA brick and you have to pick up the supply voltage and band switch information from points on the motherboard. The entire mod can be removed in very short order if desired. 73, K8AC - Original Message - From: Jim Shorney jshor...@inebraska.com To: drakelist@zerobeat.net Sent: Saturday, October 16, 2010 6:09 PM Subject: Re: [Drakelist] TR-7 - More Info Cont'd On Sat, 16 Oct 2010 16:50:50 -0400, K8JDC wrote: I had trouble keeping it from oscillating when I followed the instructions. I tried to follow the service manual carefully but it wanted to oscillate. I had to fiddle with it a fair amount going between the two adjustment pots to make it happy. Maybe it's still too hot. My meter says I'm getting about 125W out on 40m. I would bet that if you had a frequency counter coupled to it, you would find that it is oscillating somewhere in the 9 MHz area. That is the symptom of the 40 Meter oscillation problem that I found. 125 Watts is below the spec that Drake says to align it to, so you should be able to get more out. I would have to go back and look at my notes, but I think 330 Ohms paralleled across R2203 on the REV. 2 predriver board was what I used to increase the amount negative feedback at lower frequencies. It may be possible or necessary to go even lower in value, but this is what worked for me on two samples that I had. I was just able to make rated output through adjustment of the predriver pot and ALC pot without oscillation. It's hard to get it to oscillate into a dummy load, it seems to need an antenna to take off. 73 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] 6JB6 vs.6JB6A
?A comment regarding the height of various tube brands: A few years back, I bought a new set of 6550 finals for a CE 100V transmitter I was restoring. Unfortunately, they were too tall for the final cage. When I called the company I bought them from (Antique Electronic Supply in Arizona), they were extremely helpful and called me back after measuring the height of each of the various brands of 6550s they had in stock. Only one of the current manufacturers (Svetlana at that time) had the same height as the original tubes and AES happily exchanged my tubes for a pair of those. So, if you have problems with the physical size of any tube substitutes, it may be worth a call to AES to see if they have a brand that will fit. 73, Floyd - K8AC - Original Message - From: Garey Barrell k4...@mindspring.com To: drakelist Drakelist@zerobeat.net Sent: Thursday, September 30, 2010 9:10 AM Subject: Re: [Drakelist] 6JB6 vs.6JB6A Gary - I have run into the size problem also. The RCA manual specifies outline 18A and 32 for the 6GJ5 and 6GJ5A respectively. As discussed yesterday, I have also seen 6JB6(A) that were too tall, but not of the 'four' brands. Do you have a transmitter open where you can measure the ACTUAL internal height of the cage. I've done it before, but can't find the info. I have NOT run into the failure to neutralize though, but I stick to the 'four'. Some 6JB6(A) of off brands will not neutralize, and I assume the GJ's that fail are made by the same manufacturer! It's perhaps possible to neutralize these by adding or subtracting the neutralizing capacitance, but I figure if they need that, then there may well be something else that could cause trouble later. Bottom line is these are 15 kHz tubes, NOT 30 MHz tubes.! 73, Garey - K4OAH Glen Allen, VA ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] RF Signal Generator
I went through that a few years back. I'd recommend something with a digital frequency readout, a meter for reading the signal output level, and a calibrated attenuator on the output so you can accurately adjust the output level. When I was looking, that narrowed the field down to a Boonton or HP. I was lucky in finding a Boonton 103F that had just been calibrated and worked perfectly. A few years later, someone gave me a working HP-8640B and I sold the Boonton. Now I wish I had the Boonton back. Note that these are both rather old technology, but the Boontons seem to hold up a bit better than the HPs. The HPs have nylon gears that often fail and are very difficult to find replacements for. The only problem I ever had with the Boonton was a failed power supply filter cap. Both of those generators have an upper frequency limit that's adequate for working on any Drake gear you're likely to have. 73, Floyd - K8AC - Original Message - From: James Bridgers n4...@coastalnet.com To: Drakelist@zerobeat.net Sent: Tuesday, February 09, 2010 12:55 PM Subject: [Drakelist] RF Signal Generator I would like to have a rf signal generator for my use. Any suggestions as what to look for? Thanks in advance for your help ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Need 02 Digital Control Board for R7[A]
Dave - I have no knowledge of the R7 board and don't have the schematic for that, but did recently do some work on my TR7 digital control board and will tell you what I found. Excuse me if I go over some stuff you already know. U201 is simply a BCD to Decimal decoder. On the TR7, two sections of the bandswitch produce a 4 bit BCD code by grounding various of those 4 bits. All four are tied up with 10K resistors on the digital control board. These 4 bits can be accessed on the TR7 at pins 1-4 of the second board position on the motherboard (that's where the digital control board is). There's absolutely nothing unique to Drake in this case - the BCD to Decimal converter (MC14028B in my case) converts the 4 bit input to a one-of-8 decimal value and pulls one of the output pins low for each unique value. The first two bits, identified as Q0 and Q1 on U201 are NOT used in this case as the possible BCD values don't translate to those decimal values. I had a need to be able to sense the bandswitch position, and produce a single bit output, so I needed a device to duplicate the U201 function on a new board using Pins 1-4 described above as input. While MC14028B is long obsolete, I found no shortage of BCD to decimal converters when I went looking at Mouser and Jameco. The problem was the truth table (published for the TR7 on page 2-7 of the service manual I have - mine does not show a version using a Prom). Some of the converters outputted the decimal value by holding a pin high, others by holding it low (ground). I found a TI IC that pulled the pin low, but then found conflicting info on another datasheet for the same device. I finally ended up calling Jameco and talking to one of their tech people (try that at Mouser!) and he steered me to the correct datasheet and the device did indeed pull the output pin low. The truth table in the datasheet matched the one in the TR7 manual perfectly, with the exception I already mentioned - the TR7 doesn't produce the decimal values 0 and 1. The cost of the IC was something like 27 cents. My new board, which uses the converter to select the proper PIN diode attenuator for the PA input, works perfectly using the scheme. I'm guessing that the outputs from both versions of the TR7 board (with and without PROM) are identical, but can't venture a guess on the R7 board. I don't know if the pinout for the MC14028B, Prom, and my converter IC are identical. I used a 7445 BCD to decimal converter IC and Jameco shows only the expensive TI version on their site, but the very inexpensive version from other vendors is available and the pinout is the same. If you think I may be able to help you further, don't hesitate to contact me. The digital converter board outputs are very easy to check with just a VOM, so if someone has an R7 they could open up, they could check those for you. 73, Floyd - K8AC ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO
Why there are any VF-1s left on the planet is a mystery to me. I owned a couple of them, beginning in 1959, and they were absolutely dreadful. Guaranteed to drift and chirp. You could always tell who was using a VF-1 when you heard the CW signal. The Eico 722 was a good stable VFO and I still run into one of them from time to time. A pair of VF-1s make a nice set of nostalgia bookends, but that's about the extent of their usefulness. 73, K8AC - Original Message - From: Gary Winkelman thewink...@gmail.com To: drakelist@zerobeat.net Sent: Tuesday, January 05, 2010 9:25 AM Subject: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO I'm looking for a VFO for my new to me 2-NT. I've read where several older VFOs will work with some modifications, mainly converting to grid block keying. Has anyone had experience with the old Heathkit VF-1? I believe it has to be modified for grid block keying but I'm not exactly sure how to accomplish that. I also understand that they are known to drift a lot. Could that be somewhat remedied by replacing some of the components with newer ones? TNX in advance for any advise! Gary N2UM ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 Help please
Make sure to check the 10V adjustment FIRST! This affects everything and is the reason you need to use the PBT to tune in SSB. The Service Manual covers that well and shows it as the first step. The adjustment pot is on the power supply board and easy to bump, throwing everything that depends on the 10V line off. As I mentioned in a previous email, the real solution to that repeating problem is to replace the adjustment pots on the power supply board with multi-turn Bourns pots which won't change value when bumped or vibrated. 73, Floyd - K8AC - Original Message - From: Adrian Rees (MW1LCR) ree...@btconnect.com To: 'drakel...@.zerobeat.net' drakelist@zerobeat.net Sent: Saturday, December 12, 2009 2:25 PM Subject: Re: [Drakelist] TR7 Help please Hello everyone I have now stripped cleaned the Molex connectors,and all the connectors on the Digital display board. This leaves So far my TR7 is now receiving on all bands apart from 28MHz. I injected a signal on the amateur bands at 1uV and this was certainly discernable. However, still no 28MHz and now 7MHz appears to be starting at 8MHz and I press the down button twice to get to 7MHz. Changing the band switch up or down and then returning to 7MHz does the same...ie 8MHz.So I guess further board cleaning is called for tomorrow.I'll finish off the connectors and switches tomorrow. I tried the RX sie of things and noticed that the PBT is needed to resolve an SSB signal, so I guess I need to look at that as well. I'll get the receive side going on all bands first, then look at alignment voltages. Thanks all for the help so far. Regards Adrian MW1LCR -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Adrian Rees (MW1LCR) Sent: 12 December 2009 09:27 To: 'drakel...@.zerobeat.net' Subject: Re: [Drakelist] TR7 Help please Hello everyone Thank you all for your replies, both on and off list. I'll start by stripping cleaning the PC Board connectors, as per the many suggestions I received. Over here in the UK, we have a product called Servisol, which I guess is the same as your Dexoit. Both switch contact cleaners. The guy I bought the TR7 from had started restoring the radio and had changed two transistors, before stopping work on it. These were two transistors are in the power supply section, specifically Q2104 and Q2105 (TIP31). He had also acquired two spare boards for the radio, an IF Switching board and what appears to be a interstage RF amplifier, identified by the serial C3988W on the board. I'll clean the connectors and see what we have got then. Since it's a week or two before Christmas, and we live up in the hills, the XYL wants to go shopping, so its doubtful I'll achieve much on it today, although I may have time this evening, between contacts in the UBA Low Band contest which is on tonight tomorrow morning.(I'm running my rebuilt FT102 Dentron Linear for a bit of nostalgia !) Best wishes many thanks ! Adrian MW1LCR North Wales. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 Help please
Here's the link to the original article: http://members.ziggo.nl/cmulder/drake.htm#bookmark5 It's been a while now, so I don't recall if the exact numbers listed there are still available, but you should be able to find out on mouser.com - that's where I bought mine. Note that a resistor (one per pot) located near each pot position must be relocated to the back of the board to make room for the pots. 73, K8AC - Original Message - From: Jack wa9...@nconnect.net To: K8AC k...@k8ac.net Cc: Adrian Rees (MW1LCR) ree...@btconnect.com; 'drakel...@.zerobeat.net' drakelist@zerobeat.net Sent: Saturday, December 12, 2009 3:26 PM Subject: Re: [Drakelist] TR7 Help please Hi All, Does anyone know the Bourns (also Dale maybe?) 10 turn pot part number that will drop into the TR-7? I have been wanting to do that for a while. Those one turn guys are just too touchy. Thanks. 73, Jack WA9NQW On Dec 12, 2009, at 1:50 PM, K8AC wrote: Make sure to check the 10V adjustment FIRST! This affects everything and is the reason you need to use the PBT to tune in SSB. The Service Manual covers that well and shows it as the first step. The adjustment pot is on the power supply board and easy to bump, throwing everything that depends on the 10V line off. As I mentioned in a previous email, the real solution to that repeating problem is to replace the adjustment pots on the power supply board with multi-turn Bourns pots which won't change value when bumped or vibrated. 73, Floyd - K8AC - Original Message - From: Adrian Rees (MW1LCR) ree...@btconnect.com To: 'drakel...@.zerobeat.net' drakelist@zerobeat.net Sent: Saturday, December 12, 2009 2:25 PM Subject: Re: [Drakelist] TR7 Help please Hello everyone I have now stripped cleaned the Molex connectors,and all the connectors on the Digital display board. This leaves So far my TR7 is now receiving on all bands apart from 28MHz. I injected a signal on the amateur bands at 1uV and this was certainly discernable. However, still no 28MHz and now 7MHz appears to be starting at 8MHz and I press the down button twice to get to 7MHz. Changing the band switch up or down and then returning to 7MHz does the same...ie 8MHz.So I guess further board cleaning is called for tomorrow.I'll finish off the connectors and switches tomorrow. I tried the RX sie of things and noticed that the PBT is needed to resolve an SSB signal, so I guess I need to look at that as well. I'll get the receive side going on all bands first, then look at alignment voltages. Thanks all for the help so far. Regards Adrian MW1LCR -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Adrian Rees (MW1LCR) Sent: 12 December 2009 09:27 To: 'drakel...@.zerobeat.net' Subject: Re: [Drakelist] TR7 Help please Hello everyone Thank you all for your replies, both on and off list. I'll start by stripping cleaning the PC Board connectors, as per the many suggestions I received. Over here in the UK, we have a product called Servisol, which I guess is the same as your Dexoit. Both switch contact cleaners. The guy I bought the TR7 from had started restoring the radio and had changed two transistors, before stopping work on it. These were two transistors are in the power supply section, specifically Q2104 and Q2105 (TIP31). He had also acquired two spare boards for the radio, an IF Switching board and what appears to be a interstage RF amplifier, identified by the serial C3988W on the board. I'll clean the connectors and see what we have got then. Since it's a week or two before Christmas, and we live up in the hills, the XYL wants to go shopping, so its doubtful I'll achieve much on it today, although I may have time this evening, between contacts in the UBA Low Band contest which is on tonight tomorrow morning.(I'm running my rebuilt FT102 Dentron Linear for a bit of nostalgia !) Best wishes many thanks ! Adrian MW1LCR North Wales. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Replacement caps for the PS7
I changed out the caps in my PS-7 a couple of years back and used caps from Mouser. Not sure why you're concerned about current rating - that's not a factor. I think you'll find the caps rated only by voltage and capacitance - oh yes, and by temperature max. In the PS-7, you ought to worry more about the physical characteristics. It's nice if you can find caps of the same diameter so you don't have to change the mounting hardware. Also, the post height for the terminals is a factor. I can't remember now whether the original caps had the longer posts or whether or not I ordered the right height. Before ordering, take everything off of one of the terminals and measure the height. My caps have been running several hours per day for a couple of years with no problems. I may be able to dig out a receipt if you have problems locating a replacement. 73, Floyd - K8AC - Original Message - From: Don Cunningham wb5...@martineer.net To: Ron wd8...@yahoo.com; drakelist@zerobeat.net Sent: Wednesday, October 28, 2009 9:42 PM Subject: Re: [Drakelist] Replacement caps for the PS7 Well, I hope since you asked this, it will bring on one of the guru's that will explain ripple current. I have been seeing that lately, and this old guy will admit to not knowing what the heck it is I wouldn't think you would need the same rating as the power supply current though What say experts??? I'm wanting to change out my PS7 caps too. 73, Don, WB5HAK - Original Message - From: Ron wd8...@yahoo.com To: drakelist@zerobeat.net Sent: Wednesday, October 28, 2009 8:34 PM Subject: [Drakelist] Replacement caps for the PS7 Okay before everyone says Heathkit shop like they did last time, note that the PS7 is the 13.8 volt power supply for the TR7 not the L7 power supply. I need new filter caps, any thoughts on where and which ones? I spotted some on mouser, but I can not find their ripple current ratings. Apparently Mallory has changed numbers slightly and all I can do is guess given the size above and below that they are about the correct current rating. On that subject, I presume the ones in the supply are at least 12 amps each. That would get them close for the 25 Amp constant current that the supply is suppose to be able to run. With the fan cooling them, I would think 12 amp caps would be about right. TNX es 73, Ron WD8SBB ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.698 / Virus Database: 270.14.37/2466 - Release Date: 10/28/09 14:39:00 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 and key click
The person who told you about the clicks was probably 100% correct. The fact is, most of the people you'll work today on CW wouldn't know a click if they heard it, or how to check for clicks. I detected the problem on my TR7 a while back and was very fortunate to find someone who had the solution. It's a rather simple fix that really works. Check here: http://www.k8ac.net/KeyClicks.html Check out your TR7 clicks before and after the fixes to see the results. I ran the TR7 into a dummy load at about 100W output and listened to the signal on my Icom 781. I tuned across the signal from zero beat until the clicks were no longer heard, and noted the signal strength at points along the way. The fixes made a tremendous reduction in the clicks, with the remaining click bandwidth no greater than that of my 781. Best of luck! 73, Floyd - K8AC - Original Message - From: J. Crit Harley, MD, C.Ht. To: drakelist@zerobeat.net Sent: Monday, August 17, 2009 9:51 AM Subject: [Drakelist] TR7 and key click I was told last night on 40 mtr CW that my beloved TR7 has key clicks. This is the first time I have been told that. Have always gotten sounds great comments on CW. When I listen on my Omni VII to the TR7, I do hear key clicks. When I listen to my Omni VII on the TR7, I do not hear any key clicks. This do sit on the same desk. Suggestions? Comments? Tnx. 73/Crit/K4BXN -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] experience with TR-7 CW filter
I have the 500 and 300 Hz filters in my TR7. I found the tuning to be a bit sharp with the narrow filter using the TR7 VFO, but with my DDS VFO the tuning is very slow and the filter is much easier to use. It doesn't ring any more or less than any other narrow filter I've ever heard and I haven't found the insertion loss to be a problem. 73, Floyd - K8AC - Original Message - From: Dennis Monticelli To: drakelist@zerobeat.net Sent: Monday, August 10, 2009 2:06 PM Subject: [Drakelist] experience with TR-7 CW filter I am considering buying a 300Hz filter for the TR7 and wonder if any of you guys out there have experience with that narrow filter. Does it ring excessively or have excessive insertion loss? Also, would you recommend an new InRad filter rather than a used Drake original filter? Dennis AE6C -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Article in April 2009 QST
- Original Message - From: Jim Shorney jshor...@inebraska.com On Mon, 16 Mar 2009 18:50:18 -0400, K8AC wrote: The sensitivity of the TR7 is certainly lacking on the higher bands and a good preamp is a great addition and doesn't require any metal work. I bought one of the DF4NW preamps and you can turn it on/off by using one of the TR7 front panel pushbuttons that's very rarely used for its original purpose. My sensitivity measurements don't bear this out. Sensitivity is relatively flat across the HF spectrum, and I did all of my critical measurements on 10 meters. snip Your one of the lucky ones then. Before the sunspots went away, I was using my TR7 for daily DXing on the higher bands where the DX was often down at the noise level. I inserted an external preamp (that used a low-noise cable TV transistor) in the receive antenna chain and found that the S/N ratio was improved enough to make a signal solid copy where it wasn't before. When I acquired an R7, I found that indeed Drake had thought it necessary to include a preamp in that unit and it also heard the weak ones better than my TR7s. After installing the DF4NW preamp in the TR7, I was able to switch it in and out using the STORE button and could easily hear the improvement in S/N ratio on the weak ones. Does the preamp increase the IMD susceptibility? I'm sure it does, but that isn't a factor when digging out weak ones on 10 or 12 when there aren't strong signals nearby. Whether or not the preamp makes a difference on 15 meters could be argued, but at least in my case, the improvement on 12 and 10 meters was very noticeable and worth the minor effort and cost. And, the external appearance of the TR7 is unchanged by the mod. 73, K8AC ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Article in April 2009 QST
I think you need an additional opinion on this! First, the QST article is a very poor condensed version of the DK4DDS (PA1HFO) mods that have been floating around for a few years now. For some inexplicable reason, many of his solutions were left completely out of the article (e.g. solution for power output not flat, and solution for low sensitivity on the higher bands. ) I don't think it's worth all the work to install all of the mods shown in the article, but the ones NOT shown are interesting. The sensitivity of the TR7 is certainly lacking on the higher bands and a good preamp is a great addition and doesn't require any metal work. I bought one of the DF4NW preamps and you can turn it on/off by using one of the TR7 front panel pushbuttons that's very rarely used for its original purpose. The other DK4DDS mod I found interesting (not in the QST article) was the PIN diode attenuator board that allows you to set the drive control to the same position and get the same output on all bands. If you operate CW with your TR7, you might also want to look into the key click mod (see the WB4HFN site for that). I just checked the magazine, and see that they left out the PTO stabilizer mod as well. That one can be added without extending the cabinet in any way and is documented on the Web. Personally, I prefered to address that problem with an outboard DDS VFO which has served me quite well for a while now. 73, Floyd - K8AC - Original Message - From: DW Holtman tubest...@comcast.net To: Drakelist drakelist@zerobeat.net Sent: Monday, March 16, 2009 4:51 PM Subject: [Drakelist] Article in April 2009 QST Hello, Did anyone read the article on modernizing a TR-7 by DK4DDS. It has information on adding a ton of features, such as DSP Noise reduction, curing the PTO Drift, Notch Filter, Improving the sensevity on the higher bands, Speech Processor and a bunch of others. It is some great food for thought, for bringing a great radio into the 21st Century. Great Stuff. I'm thinking very hard about trying most of them out. Most of them do not require modifing the original Circuit boards, just adding boards. If anybody had some comments/information on these mods, I sure would be interested. Best, DW Holtman WB7SSN ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Microphone Jack Trivia
Actually, a good question and one that I've never seen a good explanation for. A few years ago, I bought a new aviation headset to use with my station and guess what? It had a 1/4 inch plug for either the mic or headphone (don't recall which) and a .207 Drake-like plug on the other pair. Apparently that's been standardized over the years so any headset can plug into any aircraft radio (at least for private planes). Whether or not that started before Drake began using the smaller plug, I don't know. 73, K8AC - Original Message - From: Richard Bell To: drakelist@zerobeat.net Sent: Sunday, August 17, 2008 4:08 PM Subject: [Drakelist] Microphone Jack Trivia I don't recall seeing this question asked but why did the Drake Co. choose to use a smaller mic jack on the T-4 line? Surely someone out there knows the answer. Please feel free to direct any comments, including flames, for asking a such trivial question, off the reflector. I've already have used up too much bandwidth. W5BXE -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [drakelist] Touch Paddle Electronic Keyers....
I believe the manual for the keyers can be downloaded from their website - that should address the voltage/current limits and then you'll able to tell whether or not it's safe to use with the Drakes. The issue with these keyers is not their quality or endurance, but rather your ability to adapt to the keyer. I got to the point with one where I could send fairly well, but it was then very difficult to move back and forth between the touch paddle and a normal paddle. If you decided to never again use a regular paddle, perhaps you could adapt to the touch keyer and do well with it. I ended up selling mine. 73, K8AC - Original Message - From: Philip Grocki To: drakelist@zerobeat.net Sent: Monday, July 28, 2008 3:54 PM Subject: [drakelist] Touch Paddle Electronic Keyers Does anyone know if the TouchPaddle.com keyers will work with Drake tube transceivers? Are these keyers worth their cost in quality and endurance? Thank you. PHILIP AB8ZP
Re: [drakelist] A better TR7 allband transmit mod
K8AC - k8ac [EMAIL PROTECTED] made an utterance to the drakelist gang -- I'm sure there must be a good reason for wanting to transmit on the 2.5 MHz band, but I'm just behind the times and don't know what it might be. At any rate, I still think the best approach is to use an Aux board and they can easily be homebrewed. One advantage to the Aux board approach is that the synthesizer is set to the correct 500 KHz segment and you don't have to hit the up or down buttons to get to the right band segments. That of course is true with the WARC bands when using an Aux board, but I seldom see it mentioned. 73, K8AC - Original Message - From: Ron Wagner [EMAIL PROTECTED] To: drakelist@zerobeat.net Sent: Monday, July 28, 2008 4:31 PM Subject: Re: [drakelist] A better TR7 allband transmit mod Ron Wagner [EMAIL PROTECTED] made an utterance to the drakelist gang -- FWIW, in John Loughmiller's (KB9AT) book A Family Affair, the R L Drake Story on page 145, Steve Rawling, G4ALG is credited as saying that To enable the TR-7 to transmit on all frequencies 1.5-30 MHZ (excluding 2.5 and 5.0 Mhz bands) simply unsolder collector Q9001 on the DR7 board. I beleive Jim's thread was to be able to add those bands back in with his mods w/o defeating the out-of-lock inhibit. I know that my TR-7 (actually John's backup rig) is TX on all bands and the out-of-lock inhibit is not cut. I just tried CW on the 2.5 and 5 Mhz bands and it works fine. A caveat is that I do have an aux board installed with 10Mhz prgrammed. My aux switch it in the normal position. 73, Ron WD8SBB -- On Mon, 28 Jul 2008 03:26:20 -0400, Joe Pyles wrote: Simply remove Q9001 from the DR7 board accomplishes the same thing without cutting any traces and is easily reversed. This simply stops the TX inhibit signal from U9003 Ham Band PROM. 73, Joe KC9LAD. -- Submissions:drakelist@zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net -- -- Submissions:drakelist@zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] TR7 oscillation
K8AC - k8ac [EMAIL PROTECTED] made an utterance to the drakelist gang -- Jim - Just received this message via email and it appears to have come from the drakelist at zerobeat.net site, but when I go there, your message is not in the forum there. Maybe you can tell me the exact URL of the site where you posted it? My TR7 with the rebuilt PA ran just fine for quite a while, until I erected a new 40 meter vertical. The first time I used that antenna with the TR7 on 40, the final oscillated. Switching back to a dipole antenna - no oscillation. Really odd, since there is virtually no reactance seen on either feedline and the antennas are a ways from the rig. Anyway, dialing back the gain pot in the pre-driver eliminated the oscillation but of course reduced my output on 10 meters again. I'll have to try your change and see if that changes things. 73, Floyd - K8AC - Original Message - From: Jim Shorney [EMAIL PROTECTED] To: drakelist@zerobeat.net Sent: Sunday, July 20, 2008 12:40 PM Subject: Re: [drakelist] TR7 oscillation Jim Shorney [EMAIL PROTECTED] made an utterance to the drakelist gang -- On Fri, 11 Jul 2008 23:13:07 -0500, Jim Shorney wrote: You may recall from our previous episode, I was experiencing instability in the 7-10 MHz band of my TR7 when operating at or near full power levels (140-150 watts) with the upgraded transistors. The instability seemed to be related to the setting of the predriver gain pot, so I was guessing that the predriver board was breaking into oscillation. I have been unable to confirm this. I'm wondering if anyone has been down this road before or has any suggestions? The silence is deafening. So, diving in to the problem with wild abandon and a hot soldering iron Googleing the problem turned up two or three references to notes from other hams in various forums that were experiencing the 40 meter oscillation problem. The only fix that was offered was to turn down the power level, along with speculation regarding the PIN diodes as the source of all evil. This was not satisfactory. I also found references to the power output of a properly working TR7 being 140-150 watts on 80/40 meters, gradually decreasing to a little over 100 watts on 10 meters. From my experiments, it seems that the PA deck is easily capable of this, especially with the upgraded transistors. Looking at the schematic of the (version 2) predriver board, it looks like the R2203-RFC2202-C2204 network from collector to base of buffer Q2201 is designed to flatten the gain of the predriver board across the HF range by providing increasing negative feedback as frequency is decreased. I added a 1K resistor across R2203, which should reduce the net resistance to 338 Ohms. This did decrease the gain somewhat, and I am now able to adjust the ALC for 150 watts CW output on 40 meters at the point where the ALC LED *just* comes on. There is no longer any apparent instability or oscillation on 40 meters at this point. Power on 10 meters is now 105 wattts at 28.3, decreasing to 95 watts at 29.8, with ALC action across the entire band. The predriver gain pot was adjusted at 29.8 MHz, as I previously described. This provides plenty of ALC at 28.3, and just enough at the high end of 10 meters. So far, the PA has been rock stable on all bands after this modification. As the manual states, for proper operation under normal operating conditions the carrier level should not be set beyond the point where the ALC LED just comes on. Observing the output on a scope, power does not increase but the carrier does start to garbage up beyond this point. Better yet, back it off so the ALC light just goes out. On SSB, I like to stay out of ALC as much as possible for the reasons cited here: http://www.nitehawk.com/sm5bsz/dynrange/alc.htm So in a nutshell, to cure a TR7 that oscillates at full power on 40 Meters, try this: 1. Decrease the value of R2203, either by adding a 1K in parallel or replacing it with a 330 Ohm resistor, and readjust ALC and predriver pots per service manual spec. 2. If output on 10/15 meters is still low, try the PA board grounding improvements described by DL7MAJ at http://www.dl7maj.de/TR- 7.html. This MAY NOT work for all cases - this is what worked for me, it may not work for you. YMMV. Standard disclaimers apply. It's your responsibility if you let the smoke out. In stereo, where available. Contains no trans-fat. Note: I do not believe this problem to be a reflection on the upgraded transistors suggested by K8AC, VE3EFJ, and others. Rather, the notes I found seemed to indicate that it can happen in a completely stock TR7, and it seems likely that it is related to component and build variations in individual radios. The work these gentlemen have done is excellent, and I humbly thank them
