Re: [AMRadio] Negative Loading circuits - good, bad, or ?
In a message dated 1/10/06 6:37:54 AM, [EMAIL PROTECTED] writes: > I have used the 3 diode, power supply (variac) and load > resistor setup on various rigs, the first one was the > pair of 813's modulated by a pair of 4x150 (4cx250b) tubes > in AB1. > The circuit worked very well on the mod monitor and scope, and > I could get ungodly amounts of positive modulation. > Like 2500 to 3000 watts pep out of a 600 watt carrier, without > any audible distortion > > I've had good results with the "three diode" circuit too. Earliest reference to the scheme I can find is in QST, October 1956 using 866 rectifiers. Covered again in ER #3, July 1989, this time with solid state diodes. More simple schemes can also give some useful benefit, ex., using a weak tube on the side of a P-P modulator circuit that conducts on the negative half of the audio cycle. Other cheap and dirty tricks include lowering the screen voltage on the same side or inserting a resistor in series with the plate. Can end up sounding bloody awful, though, if not done carefully and with restraint. > I suspect the high voltage brick diodes I use have some sort of problem, > switching speed? that caused very bad splatter when I would exceed > 100% neg modulation. I saw no signs of it on the scope or mod monitor, > but it showed up on the spectrum analyzer. > Don't believe the type of diodes used would have any significant effect on this. Splatter is generated in the PA tank circuit when plate voltage is suddenly cut off on the audio negative half cycle. Same splatter would be produced if the PA was being fed straight off the secondary of the mod transformer. Dennis D. W7QHO Glendale, CA
Re: [AMRadio] 3TF7 Ballast Tube
Bob, in AM Press/Exchange #57, there is an article on replacing the 3TF7 with SS components, plus the circuit changes in the R-390 and R-390-A. If you can't find it, let me know and I will mail a copy.The AM P/E issues can be found at www.amfone.net. 73 de Joe W4AAB - Original Message - From: "W5OMR/Geoff" <[EMAIL PROTECTED]> To: "Discussion of AM Radio" Sent: Sunday, January 01, 2006 12:40 PM Subject: Re: [AMRadio] 3TF7 Ballast Tube > Bob Peters wrote: > > >Anyone out there have one Would appreciate.. > > > > > > If you're not already there, Bob, you might consider joining the > T-368/BC-610 mailing list... they're a Yahoo group, just like NewOldStock > > t-368/bc-610 info: > http://groups.yahoo.com/group/T-368_BC-610/ > > NewOldStock > http://groups.yahoo.com/group/newoldstock/ > > First AM QSO for me, for this year, was with a surprise! A returning AM > Veteran, and the keeper of the AM Window, Steve/WB3HUZ was back on the > air, from his new location in Williamsburg, VA. Sure was great to hear > Steve on the air, again. His FT-102, driving into a pair of 3-500Z's > and an outboard modulator,, with that 350W carrier here, sure was > sounding -great-. > > See y'all on the air! > > -- > 73 = Best Regards, > Happy New Year > -Geoff/W5OMR > > __ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb >
K1JCL 6m AM Repeater - was [AMRadio] Modulator iron & ideas needed
Todd, Thanks for the information. No wonder I can't hear the repeater :-) I copied ER Magazine where it is listed under Vintage Nets. bob...w2ami - Original Message - From: "Todd, KA1KAQ" <[EMAIL PROTECTED]> To: "Discussion of AM Radio" On 1/8/06, RJ Mattson <[EMAIL PROTECTED]> wrote: Hi Mark, Are you in range of the K1JCL 6m 50.4 AM repeater in CT? I tried 50.4 here from the Catskills but never heard anything with my 6m Clegg. Bob - Last I knew, Al had taken the repeater off the air due to problems with some nitwit anti-AM types and frequency coordination issues. I think he just got sick of the BS. I've heard no AM up this way, and only the occasional SSB signals. We have a couple of big guns (K1LPS & W1AIM) up north on SSB, maybe you've heard them? Would be nice to have some AM activity though... de Todd/'Boomer' KA1KAQ
Re: [AMRadio] Millen High Voltage Connectors
In a message dated 1/10/06 11:37:54 AM, [EMAIL PROTECTED] writes: > If you over tighten the millen connectors they will crack the shell of the > chassis part pretty easily. You may not realize they have cracked. This can > be a leakage point. > > Yep, they sure will. For HV I like to use a ceramic feed through insulator covered by a removable housing to prevent accidental contact with the exposed screw stud. The Navy SRT-14/15/16 transmitters used ceramic plate caps (807 size) on the cable ends and ceramic feed throughs with appropriately sized brass mating lugs on the chassis side for HV connections. Clever solution. Dennis D. W7QHO Glendale, CA
[AMRadio] Ebay item #5852017489
Attention, DON CHESTER/K4KYV In regards to Ebay item #5852017489, is this the same transformer you said was on-board most liberty ships, used as an MCW modulation transformer? RCA 1:1 Pri: 5500 ohms Sec: 5500 ohm Secondary max current: 0.198Amps DC with a screen winding. ? --- 73 = Best Regards, -Geoff/W5OMR
RE: [AMRadio] Millen High Voltage Connectors
I agree. The Millen connectors have served on thousands of rigs over five decades or so. I think they are a proven commodity. The question is what has gone wrong with this particular set of connectors. 73, Don Merz, N3RHT -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Gary Schafer Sent: Tuesday, January 10, 2006 2:32 PM To: 'Discussion of AM Radio'; [EMAIL PROTECTED] Subject: RE: [AMRadio] Millen High Voltage Connectors If you over tighten the millen connectors they will crack the shell of the chassis part pretty easily. You may not realize they have cracked. This can be a leakage point. 73 Gary K4FMX -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of david knepper Sent: Tuesday, January 10, 2006 8:05 AM To: [EMAIL PROTECTED]; amradio@mailman.qth.net Subject: [AMRadio] Millen High Voltage Connectors Thanks to all of you for your insightful suggestionis. In using coax connectors and coax cabling, I would recommend that one uses the red high voltage cable so as to clearly know the difference between an R.F. connection and a high voltage connection. I am going to try another set of Millen connectors since the input seems to be that the ones that I used were just defective. Most of the ARRL, etc. homebrew construction projects used those Millen H.V. connectors. Perhaps, expanding the mounting hole on the chassis slightly might place less strain on the insulation properties. Thank you again for taking the time to assist me. Dave, W3ST Publisher of the Collins Journal Secretary to the Collins Radio Association www.collinsra.com - the CRA Website Now with PayPal CRA Nets: 3805 Khz every Monday at 8 PM EST and 14255 every Saturday at 12 Noon EST __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb The information contained in this e-mail may be confidential and is intended solely for the use of the named addressee. Access, copying or re-use of the e-mail or any information contained therein by any other person is not authorized. If you are not the intended recipient please notify us immediately by returning the e-mail to the originator.(16b)
RE: [AMRadio] Millen High Voltage Connectors
If you over tighten the millen connectors they will crack the shell of the chassis part pretty easily. You may not realize they have cracked. This can be a leakage point. 73 Gary K4FMX -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of david knepper Sent: Tuesday, January 10, 2006 8:05 AM To: [EMAIL PROTECTED]; amradio@mailman.qth.net Subject: [AMRadio] Millen High Voltage Connectors Thanks to all of you for your insightful suggestionis. In using coax connectors and coax cabling, I would recommend that one uses the red high voltage cable so as to clearly know the difference between an R.F. connection and a high voltage connection. I am going to try another set of Millen connectors since the input seems to be that the ones that I used were just defective. Most of the ARRL, etc. homebrew construction projects used those Millen H.V. connectors. Perhaps, expanding the mounting hole on the chassis slightly might place less strain on the insulation properties. Thank you again for taking the time to assist me. Dave, W3ST Publisher of the Collins Journal Secretary to the Collins Radio Association www.collinsra.com - the CRA Website Now with PayPal CRA Nets: 3805 Khz every Monday at 8 PM EST and 14255 every Saturday at 12 Noon EST __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
[AMRadio] Fw: Modulator iron & ideas needed
I think it's still off the air. Last I heard there were a bunch of guys in the New England area who meet early in the mornings on 50.4. Almost every evening I hear SSB QSO's on 50.150 from the New England area. K1JJ in CT has a small array set up for 6 meters. You should be able to work him. See: http://home.comcast.net/~k1jj/wsb/html/view.cgi-photo.html--SiteID-186247 3.html Or, if the link gets cut apart, go here: http://tinyurl.com/dcuvt January 21-23 is VHF Sweepstakes. You should here lots of 6 meter activity. Remember, you can work SSB stations with an AM rig. They'll just think you're running a Swan rig. Pete, wa2cwa On Mon, 9 Jan 2006 11:51:21 -0500 "Todd, KA1KAQ" <[EMAIL PROTECTED]> writes: > On 1/8/06, RJ Mattson <[EMAIL PROTECTED]> wrote: > > Hi Mark, > > Are you in range of the K1JCL 6m 50.4 AM repeater in CT? > > I tried 50.4 here from the Catskills but never heard anything with > my 6m > > Clegg. > > Bob - > > Last I knew, Al had taken the repeater off the air due to problems > with some nitwit anti-AM types and frequency coordination issues. I > think he just got sick of the BS. > > I've heard no AM up this way, and only the occasional SSB signals. > We > have a couple of big guns (K1LPS & W1AIM) up north on SSB, maybe > you've heard them? Would be nice to have some AM activity though... > > de Todd/'Boomer' KA1KAQ
[AMRadio] Re: capacitor
Hi Brian; Subject arrived in good condition. Thank you. 73, Ed Richards K6UUZ Simi Valley, Ca 93065 Home of the Air Force 1 pavilion
Re: [AMRadio] Negative Loading circuits - good, bad, or ?
Todd, There are various reasons for using "Negative Loading circuits". If you are ineterested in maintining a high average modulation percentage without splattering from negative cycle over modulation, then may I suggest a few first steps: 1.) get your speech polarity correct since your voice on a scope is probablly asymetrical. 2.) Use some form of peak limiting (not hard clipping) in the audio chain. 3.) Use a scope while modulating to keep track of where you are. I like X;Y or Trapezoid mode for this. As far as modifying your transmitter to achieve the same end, lots do it, some sound like hell, and others work out pretty well. I prefer the approach that is transparent until a certain - modulation percentage is achieved, say 85% negative. At that point a combination of a bias supply, diodes, and resistors kick in to either load, or attenuate the negative cycle from that point on. The circuits that load the negative cycle all the time are the ones that in my opion sound like hell, and need to be avoided. I have used on a couple of rigs a circuit that I call PNCL, "progressive negative cycle loading", but that is another story. As for protecting your iron, a spark gap on the primary plate to plate might be better than one across the modulation transformer secondary...opinions? Regards, Jim WD5JKO --- "Todd, KA1KAQ" <[EMAIL PROTECTED]> wrote: > Just curious to get some opinions on these circuits, > the best design > to use, or if I should use one at all. > > Brett, I heard talking about the negative loading > cycle circuit > causing problems for you, I wonder if you could > explain more? It's > something I had thought about adding and have talked > with folks who > swear by them. Is there are good way and bad way to > do so, or is it > just a bad idea from the start? The initial reason > that interested me > was protection of the mod iron. > > ~ Todd/'Boomer' KA1KAQ > __ > AMRadio mailing list > Home: > http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul > Courson/wa3vjb >
RE: [AMRadio] Negative Loading circuits - good, bad, or ?
I have used the 3 diode, power supply (variac) and load resistor setup on various rigs, the first one was the pair of 813's modulated by a pair of 4x150 (4cx250b) tubes in AB1. The circuit worked very well on the mod monitor and scope, and I could get ungodly amounts of positive modulation. Like 2500 to 3000 watts pep out of a 600 watt carrier, without any audible distortion I suspect the high voltage brick diodes I use have some sort of problem, switching speed? that caused very bad splatter when I would exceed 100% neg modulation. I saw no signs of it on the scope or mod monitor, but it showed up on the spectrum analyzer. I also put the circuit in the push pull 812a rig, and the pair of 4d32 rf deck, with the same results. Unless you are running a mod transformer within an inch of its life, I don't see the need to protect it that way. I insulate the mod iron from ground, and never had problems. I once had a qso with someone (cant remember who) who told me the circuit was no good, but would work with the addition of another diode...I think that is what he said... I suppose the solid state 14kv 1 amp bricks just can not react fast enough and let a real short pulse through? In the old days, they used tube type rectifiers, and they may have worked better, just a guess... I thought about trying to add a (very high voltage) capacitor someplace in the circuit to damp out any spikes, but never looked into it. I now tend to think limiting the audio in the low level stages and not exceeding 90% negative modulation is the cleanest way to go. Brett N2DTS
Re: [AMRadio] coils
Well, with thicker tubing, the outer layer will be thicker! How much thicker would it be? As I understand it, the frequency determines how deep the current flows. 73 Jim W5JO
RE: [AMRadio] coils
Well, with thicker tubing, the outer layer will be thicker! It would also be stronger and not sag if you have a longer larger coil. No, I don't plan on coating the coil with anything. Brett N2DTS -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Edward B Richards Sent: Sunday, January 08, 2006 11:27 PM To: amradio@mailman.qth.net Subject: Re: [AMRadio] coils Thanks, Brett. I understand that RF only travels through the very outer layer of a conductor, called "skin effect", so thickness does not matter, just surface area. BTW, are you going to silver plate or spray some kind of clear-coat on your coil? 73, Ed Richards K6UUZ Simi Valley, Ca 93065 Home of the Air Force 1 pavilion
[AMRadio] Negative Loading circuits - good, bad, or ?
Just curious to get some opinions on these circuits, the best design to use, or if I should use one at all. Brett, I heard talking about the negative loading cycle circuit causing problems for you, I wonder if you could explain more? It's something I had thought about adding and have talked with folks who swear by them. Is there are good way and bad way to do so, or is it just a bad idea from the start? The initial reason that interested me was protection of the mod iron. ~ Todd/'Boomer' KA1KAQ
[AMRadio] Millen High Voltage Connectors
Thanks to all of you for your insightful suggestionis. In using coax connectors and coax cabling, I would recommend that one uses the red high voltage cable so as to clearly know the difference between an R.F. connection and a high voltage connection. I am going to try another set of Millen connectors since the input seems to be that the ones that I used were just defective. Most of the ARRL, etc. homebrew construction projects used those Millen H.V. connectors. Perhaps, expanding the mounting hole on the chassis slightly might place less strain on the insulation properties. Thank you again for taking the time to assist me. Dave, W3ST Publisher of the Collins Journal Secretary to the Collins Radio Association www.collinsra.com - the CRA Website Now with PayPal CRA Nets: 3805 Khz every Monday at 8 PM EST and 14255 every Saturday at 12 Noon EST
Re: [AMRadio] Modulator iron & ideas needed
On 1/8/06, RJ Mattson <[EMAIL PROTECTED]> wrote: > Hi Mark, > Are you in range of the K1JCL 6m 50.4 AM repeater in CT? > I tried 50.4 here from the Catskills but never heard anything with my 6m > Clegg. Bob - Last I knew, Al had taken the repeater off the air due to problems with some nitwit anti-AM types and frequency coordination issues. I think he just got sick of the BS. I've heard no AM up this way, and only the occasional SSB signals. We have a couple of big guns (K1LPS & W1AIM) up north on SSB, maybe you've heard them? Would be nice to have some AM activity though... de Todd/'Boomer' KA1KAQ
[AMRadio] FS: 160m and 40m crystals $4.00 and 5.00 closeouts.
JANUARY SPECIALS: FT243 Crystals on 1977.5 kHz QTY 8 available for $5.00 each plus shipping. Or buy 5 for $20.00 plus shipping FT243 crystals on 7000 kHz QTY 8 available for $5.00 each plus shipping. Or buy 5 for $20.00 plus shipping FT243 crystals on 7000, 7100, 7200 kHz QTY 4 each available for $5.00 each plus shipping. Many other FT243 crystals on popular ham frequencies available at: http://www.af4k.com/crystals.htm
[AMRadio] FT-101 on AM
For Dan -- WAØJRD, You may want to initially use a 2nd receiver combined with the transmitter in the FT-101. The rig has a provision on the back with an RCA jack to take your service antenna over to an external source unless transmitting. The internal receiver remains active, but you can just pot it down. This lets you spend time on efforts to refine the transmit audio while not givng you the FT-101 receiver's distortion, vulnerability to overload on strong signals, limited audio response and the expense of a 6Kc filter. I ended up using my FT-101EE as an RF exciter for a 1953 homebrew transmitter that I completed in 1976. Most recently it was up on 10 meters, where the 101's stability proved very nice. For the modifications you may wish to consider, check this link. http://www.amwindow.org/tech/htm/ft101.htm Rgds, Paul/VJB __ Yahoo! DSL Something to write home about. Just $16.99/mo. or less. dsl.yahoo.com
Re: [AMRadio] AM modulation
Jim Wilhite wrote: Look here: http://www.qsl.net/wa5bxo/amtech.html I imagine he was just catching up, and reading the list-mail, and saw the one message where I forgot to inclue the URL (which was immediatly done in the -next- message). A Lot of times, someone will ask the whole of the group a question. Instead of jumping in on -that- particular message, I'll read through the list, -first- to make sure it hasn't already been answered, -or-, someone elses point of view has been given (if that's what the situation requires) and one that is similar to mine has been brought to light, then there'd be no need for me to chime and and say (basically) -me, too-, unless my whole intent and purpose was to take up bandwidth. We could all use a little refresher guide in email nettiquette from time to time. Like: DO Quote the previous mesage, but only quote the relavant text needed for the conversation. intersperse replies throughout the message, to simulate a normal flow of conversation Remove all other unnecessary 'junk' from the message. In this group, every message has the group-id and url on where to get information on the list, and who's taking care of the list, etc... When someone is reading a message -thread- , who in the world wants to see that at the bottom of a message, 17 times, because no one took the time to clean off that message and make it look -proper-? It's pretty much the same as being excessivly wide. Those are just -my- thoughts and opinions. --- 73 = Best Regards -Geoff/W5OMR
