Re: Topband: DX-100 adventure - progress
For the 0A2 replacement...might want to check this out.. http://www.solidstatetubes.com/0a2-and-0b2.html Thanks..Rich N7TR Rich N7TR ex KI3V, N3AMK, WB3JOV www.n7tr.comhttp://www.n7tr.com http://www.qrz.com/db/N7TR Telnet: dxc.n7tr.com N7TR DXCluster -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Charlie Cunningham Sent: Friday, December 20, 2013 9:21 PM To: 'Bill Cromwell' Cc: 'top Band' Subject: Re: Topband: DX-100 adventure - progress Hi, Bill! That's great! You're good to go with the elecrolytics, then! BTW - as for the chirp on the signal - the DX-100 VFO and voltage regulator was pretty much what they sold separately as the VF-1 vfo. The DX-40 had a socket to power it, but I never could get rid of the chirp, until I built a separate PS for the VFO. The OA2 gas tube just wasn't stiff enough to eliminate the chirp. You might be able to eliminate most of the chirp by replacing the gas tube with a Zener Diode. By the time you get up ro a 100 volts with the Zener, it's really avalanche breakdown and has a pretty stiff knee. Might improve your chirp! Have Fun! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Bill Cromwell Sent: Friday, December 20, 2013 11:12 PM To: Charlie Cunningham Cc: 'top Band' Subject: Re: Topband: DX-100 adventure - progress On 12/20/2013 11:00 PM, Charlie Cunningham wrote: BTW, Biii - tip/suggestion - for those series-connected electrolytics you probably should put a pair of equal value resistors - one across each series capacitor, as the leakage currents will not be equal in each capacitor in each series string and the DC voltage won't divide equally across each capacitor unless you put individual bleeder or swamping resistors across each cap in the series pair to equalize the DC across each capacitor in the series! I'll be interested to see how it turns out! I never had a DX-100 Benton Harbor Kilowatt! I did have a DX-40 for a while, but no 160 on that one, though! I do have an EF Johnson Navigator in pretty good condition that needs to have all of its electrolytics replaced because of their age. I does have 160 (and 11 meters also!). Good luck and Merry Christmas! 73, Charlie, K4OTV Hi Charlie, In the DX-100 there is already a big honking pair of bleeder resistors so that the bleeder is divided with one half across each half of the series pair. I think that's what you meant. The DX-100 originally had two caps rated at 450 volts in series and the bleeder set up that way. 73, Bill KU8H _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: DX-100 adventure - progress
Ive been using a 6AH6 in the VFO and regulating the screen and plate with a 120V 5W zener and suitable dropping resistor and a 47uF 'lytic with a .01disc. Grid drive is still sufficient for 100W+ on 10M with full audio after those mods are also done. A 6AH6 is also the better tube in the VF-1, Johnson 122, Globe Champs and others using a 6AU6. The change to choke input on the LV goes back decades since the original way was too much LV for some circuits for long reliability. I use a scope to get ripple down in all circuits to where I like it since most of my customers use them on AM but it shouls also help on CW. I did make a few contacts in the Stew using a 1939 Meissner Signal Shifter at 7W and a 1934 National FB-XA receiver. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Bill Cromwell' wrcromw...@gmail.com Cc: 'top Band' topband@contesting.com Sent: Saturday, December 21, 2013 12:21 AM Subject: Re: Topband: DX-100 adventure - progress Hi, Bill! That's great! You're good to go with the elecrolytics, then! BTW - as for the chirp on the signal - the DX-100 VFO and voltage regulator was pretty much what they sold separately as the VF-1 vfo. The DX-40 had a socket to power it, but I never could get rid of the chirp, until I built a separate PS for the VFO. The OA2 gas tube just wasn't stiff enough to eliminate the chirp. You might be able to eliminate most of the chirp by replacing the gas tube with a Zener Diode. By the time you get up ro a 100 volts with the Zener, it's really avalanche breakdown and has a pretty stiff knee. Might improve your chirp! Have Fun! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Bill Cromwell Sent: Friday, December 20, 2013 11:12 PM To: Charlie Cunningham Cc: 'top Band' Subject: Re: Topband: DX-100 adventure - progress On 12/20/2013 11:00 PM, Charlie Cunningham wrote: BTW, Biii - tip/suggestion - for those series-connected electrolytics you probably should put a pair of equal value resistors - one across each series capacitor, as the leakage currents will not be equal in each capacitor in each series string and the DC voltage won't divide equally across each capacitor unless you put individual bleeder or swamping resistors across each cap in the series pair to equalize the DC across each capacitor in the series! I'll be interested to see how it turns out! I never had a DX-100 Benton Harbor Kilowatt! I did have a DX-40 for a while, but no 160 on that one, though! I do have an EF Johnson Navigator in pretty good condition that needs to have all of its electrolytics replaced because of their age. I does have 160 (and 11 meters also!). Good luck and Merry Christmas! 73, Charlie, K4OTV Hi Charlie, In the DX-100 there is already a big honking pair of bleeder resistors so that the bleeder is divided with one half across each half of the series pair. I think that's what you meant. The DX-100 originally had two caps rated at 450 volts in series and the bleeder set up that way. 73, Bill KU8H _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3658/6938 - Release Date: 12/20/13 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: DX-100 adventure - progress
BTW, Biii - tip/suggestion - for those series-connected electrolytics you probably should put a pair of equal value resistors - one across each series capacitor, as the leakage currents will not be equal in each capacitor in each series string and the DC voltage won't divide equally across each capacitor unless you put individual bleeder or swamping resistors across each cap in the series pair to equalize the DC across each capacitor in the series! It is worse than that. With a single bleeder for two series capacitors, the capacitor with the least capacitance will always be reversed charged upon every power down. So even you have equal voltages by equal leakages, you have to add a parallel diode or the discharge will reverse charge the cap with the lowest capacitance value. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: DX-100 adventure - progress
I REALLY don't care for connecting electrolytics in series. However, Bill does say that the DX-100 already is configured with individual bleeders across each capacitor in those series pairs - so he may be OK. -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Saturday, December 21, 2013 1:02 PM To: Charlie Cunningham; 'Bill Cromwell'; 'top Band' Subject: Re: Topband: DX-100 adventure - progress BTW, Biii - tip/suggestion - for those series-connected electrolytics you probably should put a pair of equal value resistors - one across each series capacitor, as the leakage currents will not be equal in each capacitor in each series string and the DC voltage won't divide equally across each capacitor unless you put individual bleeder or swamping resistors across each cap in the series pair to equalize the DC across each capacitor in the series! It is worse than that. With a single bleeder for two series capacitors, the capacitor with the least capacitance will always be reversed charged upon every power down. So even you have equal voltages by equal leakages, you have to add a parallel diode or the discharge will reverse charge the cap with the lowest capacitance value. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: DX-100 adventure - progress
Diodes across the electrolytics ro prevent reverse chargin would probably be a good idea. 1N4007 1000 PIV, 1 A rectifiers should do nicely. -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Saturday, December 21, 2013 1:02 PM To: Charlie Cunningham; 'Bill Cromwell'; 'top Band' Subject: Re: Topband: DX-100 adventure - progress BTW, Biii - tip/suggestion - for those series-connected electrolytics you probably should put a pair of equal value resistors - one across each series capacitor, as the leakage currents will not be equal in each capacitor in each series string and the DC voltage won't divide equally across each capacitor unless you put individual bleeder or swamping resistors across each cap in the series pair to equalize the DC across each capacitor in the series! It is worse than that. With a single bleeder for two series capacitors, the capacitor with the least capacitance will always be reversed charged upon every power down. So even you have equal voltages by equal leakages, you have to add a parallel diode or the discharge will reverse charge the cap with the lowest capacitance value. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: DX-100 adventure - progress
After reflecting on your point, that is obviously true, Tom, I would go ahead and spend a few cents on some rectifiers to put across those electrolytics! Operating electrolytics in series is just something I don't do -except in a voltage-doubler or a Cockroft-Walton multiplier. Have a Merry Christmas! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Charlie Cunningham Sent: Saturday, December 21, 2013 1:32 PM To: 'Tom W8JI'; 'Bill Cromwell'; 'top Band' Subject: Re: Topband: DX-100 adventure - progress Diodes across the electrolytics ro prevent reverse chargin would probably be a good idea. 1N4007 1000 PIV, 1 A rectifiers should do nicely. -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Saturday, December 21, 2013 1:02 PM To: Charlie Cunningham; 'Bill Cromwell'; 'top Band' Subject: Re: Topband: DX-100 adventure - progress BTW, Biii - tip/suggestion - for those series-connected electrolytics you probably should put a pair of equal value resistors - one across each series capacitor, as the leakage currents will not be equal in each capacitor in each series string and the DC voltage won't divide equally across each capacitor unless you put individual bleeder or swamping resistors across each cap in the series pair to equalize the DC across each capacitor in the series! It is worse than that. With a single bleeder for two series capacitors, the capacitor with the least capacitance will always be reversed charged upon every power down. So even you have equal voltages by equal leakages, you have to add a parallel diode or the discharge will reverse charge the cap with the lowest capacitance value. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: DX-100 adventure - progress
Hi, Recently I posted about my DX-100 and an effort to get it usable in time for the Stew Perry. I have made progress and it looks like I'll have it ready to use in time and never mind about the holidays, the holiday mail overload, etc. I successfully recapped and tested the low voltage supply and changed the circuit to choke input. I like doing that and some other hams suggested doing it, too. So I did. The VFO and RF stages - excluding the finals - sound very good on 160 through 40 meters. No chirp shows up at all until I get to 20 meters and there is barely enough chirp to notice if I pay attention. 15 meters and, finally, 10 meters there is noticeable chirp and some drift. I didn't really let it warm up well before I tried those higher bands. I was more interested in the 160 meter operation since that is the immediate goal. I had to order new caps for the high voltage final amp plate supply. I thought I had suitable caps but mine would have given me only 50 uF with a pair in series. That is NOT enough. I am afraid the new caps will not arrive with enough bench time left to make it for the Stew. So I doubled down on the caps I already have. I built two banks of caps with two caps each. Each set is a series pair of course and the two sets of caps are in parallel to give the needed 100 uF at 900 volt rating. The center connections of the two banks are also connected in parallel so that the bleeder sees them as *ONE* pair of caps in series. The thing is built on a pair of terminal strips with reinforced connection points to accommodate the bleeder and switch wiring that was already in the transmitter. I have it completely fabricated AND mounted in the DX-100. This weekend I'll get to wire it and test it. Hopefully it will be ready to operate. I'll be cleaning up some other messy wiring that previous owners left in there and then put all the screws back in place. A little DeOxit on a few more controls and then the smoke test. And then... CQ de KU8H. If the caps don't work out for some reason I can hope the new ones arrive in time. I started taking pictures so maybe I'll finally do some on-line show n tell when I'm done. 73, Bill KU8H aka Santa Claus _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: DX-100 adventure - progress
BTW, Biii - tip/suggestion - for those series-connected electrolytics you probably should put a pair of equal value resistors - one across each series capacitor, as the leakage currents will not be equal in each capacitor in each series string and the DC voltage won't divide equally across each capacitor unless you put individual bleeder or swamping resistors across each cap in the series pair to equalize the DC across each capacitor in the series! I'll be interested to see how it turns out! I never had a DX-100 Benton Harbor Kilowatt! I did have a DX-40 for a while, but no 160 on that one, though! I do have an EF Johnson Navigator in pretty good condition that needs to have all of its electrolytics replaced because of their age. I does have 160 (and 11 meters also!). Good luck and Merry Christmas! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Bill Cromwell Sent: Friday, December 20, 2013 10:27 PM To: 'top Band' Subject: Topband: DX-100 adventure - progress Hi, Recently I posted about my DX-100 and an effort to get it usable in time for the Stew Perry. I have made progress and it looks like I'll have it ready to use in time and never mind about the holidays, the holiday mail overload, etc. I successfully recapped and tested the low voltage supply and changed the circuit to choke input. I like doing that and some other hams suggested doing it, too. So I did. The VFO and RF stages - excluding the finals - sound very good on 160 through 40 meters. No chirp shows up at all until I get to 20 meters and there is barely enough chirp to notice if I pay attention. 15 meters and, finally, 10 meters there is noticeable chirp and some drift. I didn't really let it warm up well before I tried those higher bands. I was more interested in the 160 meter operation since that is the immediate goal. I had to order new caps for the high voltage final amp plate supply. I thought I had suitable caps but mine would have given me only 50 uF with a pair in series. That is NOT enough. I am afraid the new caps will not arrive with enough bench time left to make it for the Stew. So I doubled down on the caps I already have. I built two banks of caps with two caps each. Each set is a series pair of course and the two sets of caps are in parallel to give the needed 100 uF at 900 volt rating. The center connections of the two banks are also connected in parallel so that the bleeder sees them as *ONE* pair of caps in series. The thing is built on a pair of terminal strips with reinforced connection points to accommodate the bleeder and switch wiring that was already in the transmitter. I have it completely fabricated AND mounted in the DX-100. This weekend I'll get to wire it and test it. Hopefully it will be ready to operate. I'll be cleaning up some other messy wiring that previous owners left in there and then put all the screws back in place. A little DeOxit on a few more controls and then the smoke test. And then... CQ de KU8H. If the caps don't work out for some reason I can hope the new ones arrive in time. I started taking pictures so maybe I'll finally do some on-line show n tell when I'm done. 73, Bill KU8H aka Santa Claus _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: DX-100 adventure - progress
On 12/20/2013 11:00 PM, Charlie Cunningham wrote: BTW, Biii - tip/suggestion - for those series-connected electrolytics you probably should put a pair of equal value resistors - one across each series capacitor, as the leakage currents will not be equal in each capacitor in each series string and the DC voltage won't divide equally across each capacitor unless you put individual bleeder or swamping resistors across each cap in the series pair to equalize the DC across each capacitor in the series! I'll be interested to see how it turns out! I never had a DX-100 Benton Harbor Kilowatt! I did have a DX-40 for a while, but no 160 on that one, though! I do have an EF Johnson Navigator in pretty good condition that needs to have all of its electrolytics replaced because of their age. I does have 160 (and 11 meters also!). Good luck and Merry Christmas! 73, Charlie, K4OTV Hi Charlie, In the DX-100 there is already a big honking pair of bleeder resistors so that the bleeder is divided with one half across each half of the series pair. I think that's what you meant. The DX-100 originally had two caps rated at 450 volts in series and the bleeder set up that way. 73, Bill KU8H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: DX-100 adventure - progress
Hi, Bill! That's great! You're good to go with the elecrolytics, then! BTW - as for the chirp on the signal - the DX-100 VFO and voltage regulator was pretty much what they sold separately as the VF-1 vfo. The DX-40 had a socket to power it, but I never could get rid of the chirp, until I built a separate PS for the VFO. The OA2 gas tube just wasn't stiff enough to eliminate the chirp. You might be able to eliminate most of the chirp by replacing the gas tube with a Zener Diode. By the time you get up ro a 100 volts with the Zener, it's really avalanche breakdown and has a pretty stiff knee. Might improve your chirp! Have Fun! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Bill Cromwell Sent: Friday, December 20, 2013 11:12 PM To: Charlie Cunningham Cc: 'top Band' Subject: Re: Topband: DX-100 adventure - progress On 12/20/2013 11:00 PM, Charlie Cunningham wrote: BTW, Biii - tip/suggestion - for those series-connected electrolytics you probably should put a pair of equal value resistors - one across each series capacitor, as the leakage currents will not be equal in each capacitor in each series string and the DC voltage won't divide equally across each capacitor unless you put individual bleeder or swamping resistors across each cap in the series pair to equalize the DC across each capacitor in the series! I'll be interested to see how it turns out! I never had a DX-100 Benton Harbor Kilowatt! I did have a DX-40 for a while, but no 160 on that one, though! I do have an EF Johnson Navigator in pretty good condition that needs to have all of its electrolytics replaced because of their age. I does have 160 (and 11 meters also!). Good luck and Merry Christmas! 73, Charlie, K4OTV Hi Charlie, In the DX-100 there is already a big honking pair of bleeder resistors so that the bleeder is divided with one half across each half of the series pair. I think that's what you meant. The DX-100 originally had two caps rated at 450 volts in series and the bleeder set up that way. 73, Bill KU8H _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
