Re: [AMRadio] High-power tuners
The Johnson Matchbox has its own area of usefulness. There was a set of calculations and measurements made on several "feedline impedance transformation devices" a while ago. The article pointed out that is was possible to dissipate much of the energy in the transformation device which would result in interesting pyrotechnic displays. The Matchbox had a foot in each camp, certain impedances were handled with great efficiency while others made for another winter shack heater Now to find the article. Larry K2LT Rick Brashear wrote: I was asking because I have one and plan on using it with the RCA when it's up and running. Rick Geoff/W5OMR wrote: Rick Brashear wrote: Would a KW Johnson Matchbox stand up to the load? yes. That old Johnson stuff was DESIGNED for AM operation. this crappy stuff that's out now, was designed for 2kW of ssb. -huge- difference. __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
[Fwd: Re: [AMRadio] Hazernut was MFJ]
Original Message Subject:Re: [AMRadio] Hazernut was MFJ Date: Thu, 07 Dec 2006 19:06:14 -0600 From: Larry Taft <[EMAIL PROTECTED]> To: Discussion of AM Radio in the Amateur Service References: <[EMAIL PROTECTED]> *THIS IS THE FIRST GOOD IDEA ON THE THREAD! The Hazernut!* Buttzer? Larry K2LT [EMAIL PROTECTED] wrote: Sorry if I missed this earlier in the thread but you might just run your Butternut up on the Hazer and give it a shot. I mention this only because back in the day when the Hazer was up here, a friend dared me to run an old 5 band HyGain up on the Hazer (had 40 feet of Rohn 25) and it played phenomenally on 40 and pretty darned good on 80, with one radial for each band, and the Butternut is easily twice as efficient I would think. It was also really neat to flip between the beam and the vertical on 20, 15 and 10, and the vertical was very impressive there as well. Did not win the neighbor's aesthetic appreciation award that winter, however. 73 Scott __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] MFJ
How about hanging an inverted V dipole from the Hazer for now. Mine is 35 feet in the air and has 3 sets of wire, 80, 40, and 20 which I adjusted for a reasonable SWR on each band by adjusting 80 first, 40 and then 20. The RG-8 coax feed has a 8 turn coil on a gallon plastic jug at the center of the dipoles. The SWR will never be 1:1 so a tuner is still needed. I have run run FULL power to the Drake MN2000 tuner and antenna with out any problems. The MFJ rotapole sounds like it would be a bit stressed on 40 and 80 with max AM power. Also it would have to be 120 feet in the air to see any real benefit of rotation on 80. 73, Larry K2LT Rick Brashear wrote: Before you explode over the "Subject", please, read on... I am in an antenna dilemma at this time. I have to wait a few months before I can install the HyTower and folded dipole I have. In the mean time I am stuck with an expensive Butternut 160/80/40 "Dummy Load" as my buddy calls it. So, I am looking into the new MFJ 80 meter rotatable dipole to put on the Hazer and run up the tower. Has anyone had any experience with it or know of anyone who has? I know Bob, PE, had or has a rotatable dipole up he really likes. I would welcome any constructive comments you might have. It is supposedly rated at 1500 watts PEP on SSB/CW, however, there are no specs stated for AM operation, of course. Do you think the 375 watt carrier would fry it or do you think it would hold up? Thanks, Rick/K5IZ __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Audio... the Pics
To repeat an earlier comment, try a load resistor on the output leads, say 5K or something in that range at least 20 watts and 50 watts would be ideal for full power tests. Pull the 6146 and the osc tubes to get rid of the RF. You have to have a load on the mod iron to keep things under control. The waveform that is puzzling is the 6L6 in standby. What is the amplitude? Looks like we have a parasitic oscillation in the amp circuit and it could still be there mixed in with the audio on xmit. There is hum too as it is showing up as a variation in the peak amplitude of the 500 Hz wave. You'll have to put back the bypass caps to gain some control over the RF getting into the audio. Maybe a few RF chokes in the audio lines to eliminate the RF. As you have seen. sticking the scope probe into a medium or low impedance is OK usually. But a high impedance like the 6L6 grid introduces more errors. Another antenna. Larry Jack Schmidling wrote: I did some more sig tracing and came up with some pics of where the trouble seems to be. Putting a 500 hz sine wave into the mic input, I see a nice sine wave until I get to the modulator tubes. The grid in standby looks close enough but when I go to phone mode it gets flaky. The plates look really flaky in standby but look more normal in phone mode but there seems to be a bunch of waves competing for the space. I posted some pics to http://schmidling.com/mod.jpg Comments eagerly awaited js __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Audio... the numbers
Try again, only this time wait to push "send". Unfortunately an ohmmeter test on the leads of a xfmr will not show a turn to turn short in the same winding. The real way to test is send AC, ie audio, into the iron at a modest power level and look at the waveform coming out. Distorted waveform is the result of the shorted turn. In power xfmrs the short causes gross overheating and depending on the size of the xfmr some spectacular fireworks. 6L6 or 1614: For all practical purposes they are the same at the voltages and power levels in the Ranger. The 6L6 long term might be a bit stressed and not give as long a life. 73, Larry K2LT Jack Schmidling wrote: Gary Schafer wrote: It's beginning to sound like a partially shorted mod transformer. I checked the resistances of the transformer earlier in the game and they are nominal. >With 20 volts signal on the grids of the mod tubes I would think that >you should see at least 200 volts on the plates?? I have no idea but if mine is off by a factor of 4, would it work at all? Could be bad 6L6's. Or back to a reason for using 1614's perhaps? Can you easily get high modulator plate current with audio applied? Will the mod plate meter peg or nearly so if you hit it hard? Yes. If it will that is an indication that the tubes are good and the transformer may be shorted. Except that the transformer appears to be ok. To refresh.. we are talking about a max of about 75% modulation on peaks but no problem over modulating at the base line. js __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Audio... the numbers
Jack Schmidling wrote: Gary Schafer wrote: It's beginning to sound like a partially shorted mod transformer. I checked the resistances of the transformer earlier in the game and they are nominal. >With 20 volts signal on the grids of the mod tubes I would think that >you should see at least 200 volts on the plates?? I have no idea but if mine is off by a factor of 4, would it work at all? Could be bad 6L6's. Or back to a reason for using 1614's perhaps? Can you easily get high modulator plate current with audio applied? Will the mod plate meter peg or nearly so if you hit it hard? Yes. If it will that is an indication that the tubes are good and the transformer may be shorted. Except that the transformer appears to be ok. To refresh.. we are talking about a max of about 75% modulation on peaks but no problem over modulating at the base line. js __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Audio... the numbers
Gary has, I think, hit the tube on the plate cap. I went looking for a set of curves for the 6L6 in my pile of old books and data but no find yet. Just from "rule of thumb" for audio tube amps you should get a couple hundred volts audio swing (not related to BIRD WATTS) at each plate to ground. 50 v is only a couple of watts audio. Soft tubes or/and shorted xfmr. Try disconnecting the RF section from the power supply and put a 5K power resistor across the output winding of the mod xfmr. Now you can test the audio chain and figure out where it is failing. This removes the possibility of RF back into the audio chain and power supply variations from the load of the 6146. Actually, just pull the 6146 AND hook the 5k resistor across the mod iron output leads. Now, Redemption! I earlier said to reverse the OUTPUT leads on the mod iron. Reversing the plate leads on the 6L6s would definitely make the ampalator into an oscillafier. It isn't often that I'm really wrong. Just ask any of my ex-wives. 73, Larry K2LT Gary Schafer wrote: It's beginning to sound like a partially shorted mod transformer. With 20 volts signal on the grids of the mod tubes I would think that you should see at least 200 volts on the plates?? Could be bad 6L6's. The reason that you see a slightly distorted audio pattern on the audio amplifiers when in tx and not in standby could be the result of the negative feedback loop trying to correct distortion from the mod transformer. Can you easily get high modulator plate current with audio applied? Will the mod plate meter peg or nearly so if you hit it hard? If it will that is an indication that the tubes are good and the transformer may be shorted. 73 Gary K4FMX -Original Message- From: [EMAIL PROTECTED] [mailto:amradio- [EMAIL PROTECTED] On Behalf Of Jack Schmidling Sent: Friday, November 17, 2006 9:45 AM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] Ranger Audio... the numbers Gary Schafer wrote: Check at the center tap of the mod driver transformer with your scope and see if you see anything there. Could be a bad or missing bypass cap there. It's brand new but I didn't have a 15mf so I used a 47mf.. ditto for C59A. Check the jumpers on the plug in the back to be sure that the proper taps on the mod transformer are selected. All ok. Check the clamp tube circuit. Could be holding the screen slightly low on the 6146 and clipping the modulation peaks to the screen. Screen voltage is 150 and the nom is 190. However, R35, the Modulator Screen Voltage Adjustment resistor seems to go to the clamp circuit and it is not at all clear what is going on here. It seems to me that diddling with it changes the screen voltage on the 6146. So does diddling with the modulator current effect the 6146 screen voltage or do I have a screen voltage problem? Check modulator screen voltage. It is the nominal 250V... but again, why is it nominal if that resistor is there to diddle with the current? js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Modulation
Thanks for the encouragement, Gary. I've done a bit of work on broadcast transmitters and you're right, every part and tube has to be up to snuff to get complete modulation. Still on the table...how about the sig gen into the mic input test. After putting the leads back! Larry K2LT Gary Schafer wrote: -Original Message- From: [EMAIL PROTECTED] [mailto:amradio- [EMAIL PROTECTED] On Behalf Of Larry Taft Sent: Thursday, November 16, 2006 11:06 AM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] Ranger Modulation Well, I tried...I wasn't right so now I'll be left Sorry about the bad info. 73, Larry K2LT Better to be wrong sometimes than to never try. Wish I had a nickel for every time I was wrong. That's the value of posting to the list, everyone learns. 73 Gary K4FMX __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Modulation
Well, I tried...I wasn't right so now I'll be left Sorry about the bad info. 73, Larry K2LT Gary Schafer wrote: You can't reverse the plate leads on the modulator tubes because it uses negative feedback from a winding on the transformer. Reversing the plate leads puts the feed back in phase rather than out of phase. It will oscillate! First check to see that you have proper grid current on the 6146. Low grid current will not allow full positive peak modulation because the tube runs out of steam with low drive. It is much more important to have proper grid current with AM than it is with cw. The tube has to have enough emission to handle the peak power 4x the carrier. Be sure the screen voltage is high enough on the 6146. Be sure that you are not overloaded - more power than the transmitter is rated for. If you have it loaded too heavy again the tube runs out of emission and will not allow the modulation peaks to go high enough. Try another 6146. 73 Gary K4FMX -Original Message- From: [EMAIL PROTECTED] [mailto:amradio- [EMAIL PROTECTED] On Behalf Of Jack Schmidling Sent: Thursday, November 16, 2006 10:28 AM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] Ranger Modulation Larry Taft wrote: Try reversing the phase of the audio by swapping the output leads of the modulation xfmr. First I swapped the tubes to no avail. I then swapped the wires and now have a strange buzzing that I can not locate but it shows up on the audio with the gain at zero. Don't know if I barfed something up or not but I vaguely remember reading somewhere that this an an indication to reverse the leads. Weak tube in the audio chain causing lack of gain needed for the positive peak. Just ordered new audio tubes. Now I notice another discrepancy. the manual that came with it says to adjust the mod current to 75-90 ma. The manual that Rick sent me for the new version which I seem to have says 55-70 and no clue why the difference. Which is correct and should I make an allowance for using 6L6's instead of 1614's? js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Modulation
What happens when you hook the sig gen to the mic input, skipping the D104? While you're at it do a frequency response curve of the setup. Oft times this is an interesting test. Larry K2LT A.R.S. - W5AMI wrote: You might also try reversing the leads soldered to the cartridge. On 11/15/06, Larry Taft <[EMAIL PROTECTED]> wrote: Try reversing the phase of the audio by swapping the output leads of the modulation xfmr. Asymmetrical modulation? And too much in the negative direction is the flat line. Weak tube in the audio chain causing lack of gain needed for the positive peak. I understand what I'm trying to say. I reserve my right to say it wrong! Larry K2LT Jack Schmidling wrote: > I suspect my mic problem is with the cartridge and I will be getting a > new one. > > The now problem seems to be that I just can not seem to get 100% > modulation no matter what mic I use. > > When I adjust the scope so the carrier is +/- 1 div, I can never get > it quite to +/- 2 and 1.5 is pretty typical. > > On the other hand, I have no trouble getting a flat line between > cycles with too much audio which I understand is the indication for > over modulation. > > I am using a audio generator at 1 kHz talking to an earphone, against > the mic. The modulation meter can easily be pinned if I use an > amplified mic but it has no effect on the top of the envelop. > > What does all this mean? > > js > __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Modulation
Try reversing the phase of the audio by swapping the output leads of the modulation xfmr. Asymmetrical modulation? And too much in the negative direction is the flat line. Weak tube in the audio chain causing lack of gain needed for the positive peak. I understand what I'm trying to say. I reserve my right to say it wrong! Larry K2LT Jack Schmidling wrote: I suspect my mic problem is with the cartridge and I will be getting a new one. The now problem seems to be that I just can not seem to get 100% modulation no matter what mic I use. When I adjust the scope so the carrier is +/- 1 div, I can never get it quite to +/- 2 and 1.5 is pretty typical. On the other hand, I have no trouble getting a flat line between cycles with too much audio which I understand is the indication for over modulation. I am using a audio generator at 1 kHz talking to an earphone, against the mic. The modulation meter can easily be pinned if I use an amplified mic but it has no effect on the top of the envelop. What does all this mean? js __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Audio Testing
That sounds terribly eastern! Hooie-yah followed by QTF and dropped carrier while tracing the arc sound is good 5 land AM. Larry K2LT (in 5 land) [EMAIL PROTECTED] wrote: Remember, always be extra careful using..Oh. La for testing Great discussion fellows. 73, Bob,W4WSZ [EMAIL PROTECTED] EarthLink Revolves Around You. __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Ranger Audio
I have three D104 mics wired up for different rigs. On the SDR-1000 into a Delta 44 sound card I use the built in preamp in the mic base to get enough audio to drive the line-in input. This minimizes the RF pickup through the audio wiring. For the Drake 4 series I run straight into the mic input. Same for the TR-7. My guess is the TR-7 doesn't sound as good as the 4 stuff because of the lower input Z. But then again I don't listen to myself either. And I usually run a 7077 mic on the TR-7 which is a dynamic. On the O'scope a good "Hooie-yah" gives 200 mv P-P from each of the elements. Thats 0.2 volts using a 10X probe on the scope input. You can do the same test with a digital voltmeter too. Then you should see 70 mv RMS if my math is good today. Needs to be a 10 meg input meter, an old Simpson will give a lower reading. Google the D104 or Astatic and you can find a bunch of good info on the care and feeding of the crystal elements. One site had a comment attributed to an Astatic engineer who said that the preamp was necessary to get the mic sounding good because of impedance matching. Just turn the preamp gain down a bit 73, Larry K2LT drakerepair.com I know this is a dumb question, but are you sure the D-104 is of the High Z variety? Not dumb at all. How can I tell? It puts out about 10mv ptp into a scope. Did not measure the DC resistance because I am not sure I can apply voltage to it safely. js __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] 813/811 Rig
Gates BC250GY that will run better than 500 W out with full modulation. 810s in parallel driven by 813 with 807 osc stage. Mod is PP810s driven by PP6L6s. RF section is edgewound fixed coils with large variable air caps. Modulator is a long one piece chassis vertical mount. Big iron goes in the bottom. Take the compete rig with its phonebooth sized cabinet or just all the parts as a "Heathkit sans chassis" Can easily be put in a 48 inch rack. With some thought it can be made a lot smaller or a two cabinet combo. 220 vac primary only. Apx 600 lb $750/offers If you're really brave I have a Gates BC1G with 833s all around. This WILL stress the RG-8. Rotary inductors and fixed caps in RF output stage. Same size phonebooth cabinet or all parts. Again, 220 primary only. Apx 700 lbs. $ 950/offers. All are located in south Texas in (scenic, snow free) Rockport, 40 mi north of Corpus Christi. Larry K2LT. 800-687-9161 drakerepair.com Jack Schmidling wrote: I am looking for an 813/811 rig or parts to build one. Open to ideas. js __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] BC610 110v using one leg of 220
Brian, Both wires are hot with the ground as a safety connection. Check with your voltmeter. By your description do you have a 3 prong 220vac outlet as used for an older dryer outlet? Or an air conditioner? Any idea as to the wire size? Is the ground wire the same size as the hot wires? Many older 220 outlets were wired with say 10 gage for the hot lines and a smaller ground wire, say 12 or 14 gage. The 220 lines in a house are really 110 each side to neutral/ground which is the center tap on the pole pig outside your house. It is poor form to use the ground wire as the neutral. You would have to redo the wiring in the circuit breaker panel to get the black hot 110, white neutral and green ground. Modern 220 installations have 4 wires. 2 hots L1 Black,and L2 Red, Neutral White and Ground Green. If you have this setup then either Red or Black and White will give you the 110. Ground is only for safety. I try to give good advice...some day I'll follow it too. Larry K2LT A.R.S. - W5AMI wrote: Trying to get a BC610 going and need to hook to one leg of existing 220 outlet, and now I'm just confused to say the least. The 610E does not have any polarity indicators on the 110vac AC chassis plug. I'm using a 3 wire 220 outlet with ground, hot and neutral. In order to get 110, I have to use ground for one side. Which of the other sides do I use in order to also hook up a heavy Earth ground to the 610 without causing a short?! I'm assuming the hot (black) wire... tnx - Brian __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Octal Sockets.... more Ranger stuff
Run any tests on the iron to check for shorts or opens? Maybe hook some B+ through a resistor to be sure no arcing Larry K2LT drakerepair.com. Jack Schmidling wrote: [EMAIL PROTECTED] wrote: Hey Jack et al: I think the original owner was a CW operator and intentionally removed the modulator capability so no one would run AM and ruin the rig. Or... had a thing about restorers and tried to make sure it couldn't be. js __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Phone band expansion
For good AM (I mean REALLY GOOD AM) try a SDR-1000 by Flex-Radio. This is a computer driven little black box that can create any form of modulation and make it sound beautiful. The receiver uses a quadrature mixer into a sound card with some free software to make the AM sound really great. Has synchronous detector too and filtering that is truly brick wall stuff. The filtering is fully adjustable on each side of the carrier so if an aflack is causing trouble on one side just use the cursor to shave it off. No knobs, glowing tubes or 1000 lb cabinets. Stick a linear on the tail end and go up against anyone on the band. Want to try the new Digital Radio Mondail DRM stuff? Load up the free software and have at it. This from one who does spectrum measurements on 300 +/- AM broadcast stations each year. Also owns 4 Gates, 1 Westinghouse MW-1 and 1 Western Electric AM type transmitters. They will soon be for sale. Maybe I'll keep the Western Electric, its art deco neat. 73, Larry K2LT Bob Maser wrote: Yeah, right. - Original Message - From: <[EMAIL PROTECTED]> To: "Discussion of AM Radio in the Amateur Service" Sent: Thursday, October 12, 2006 8:40 PM Subject: Re: [AMRadio] Phone band expansion Icom, Kenwud, Yeasu least). If AM is getting so popular, why aren't there any manufacturers producing any equipment? Bob W6TR __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Packaging Radio Gear
Don, You that old that you wear diapers again? Seniors? 73, Larry K2LT Don Merz wrote: Well, I once shipped a Heathkit Mohawk to a guy. When it arrived, he found a used plastic diaper among the packing! That's as close as I've gotten to accidentally shipping a kid in with a radio... 73, Don Merz, N3RHT --- Bob Peters <[EMAIL PROTECTED]> wrote: Well I can tell ya all one big thing here ...Don Merz knows how to pack gear...My god it took me a whole day to unpack a box that I got from Don... More packing material then gear...Must have been the kitchen sink in the box Hi ... I expected to find his first born in the bottom of the box...
Re: [AMRadio] CHU
John, Suggest you check the bilge, maybe your yacht sank. Larry K2LT [EMAIL PROTECTED] wrote: Hi Dave, I have beeh having a lot of trouble hearing CHU here also. Used to get them on my TR-7 with NO antenna connected! Now I cannot hear them on my Sony Yacht Boy! 73, John, W4AWM __ 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] Smoothing Choke
Let me clear my perfectly description make! Collins: 10 hy 10 hy Rectifier --choke---choke|HV out |---cap---| | 0.08uf cap 8 uf | /// Larry Taft wrote: Typical values for a Gates BC-1G 1 KW broadcast transmitter 2500 VDC supply are 5-15 hy at 1 amp swinging choke with 8 uf filter cap. The load is 500 ma continuous for the class C final ( 2 833s in parallel) plus another 500 ma variable for the class B modulator ( 2 833s in push-pull). The audio frequency response is speced at 30 to 12,000 cycles per second. The broadcast people used a single supply with the final acting as a fixed minimum load to get around the filter resonance problem at low frequencies. Collins also used a cap across a choke for parallel resonance. For the 20V3 there is a 10 hy choke with a 0.08 uf cap across it in parallel to a second 10 hy choke (no cap) to an 8 uf cap to ground. Again, the final is a fixed load for the single supply. Tubes are 4-400s. Audio speced at 50 to 10,000 cycles per second. Old technology. Still good as long as the limits are understood. Larry K2LT Jim candela wrote: Rick, I understand your feel for the nostalgia, and passion for pursuing it. All of us more or less on this group have some common ground here. __ 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] Smoothing Choke
Typical values for a Gates BC-1G 1 KW broadcast transmitter 2500 VDC supply are 5-15 hy at 1 amp swinging choke with 8 uf filter cap. The load is 500 ma continuous for the class C final ( 2 833s in parallel) plus another 500 ma variable for the class B modulator ( 2 833s in push-pull). The audio frequency response is speced at 30 to 12,000 cycles per second. The broadcast people used a single supply with the final acting as a fixed minimum load to get around the filter resonance problem at low frequencies. Collins also used a cap across a choke for parallel resonance. For the 20V3 there is a 10 hy choke with a 0.08 uf cap across it in parallel to a second 10 hy choke (no cap) to an 8 uf cap to ground. Again, the final is a fixed load for the single supply. Tubes are 4-400s. Audio speced at 50 to 10,000 cycles per second. Old technology. Still good as long as the limits are understood. Larry K2LT Jim candela wrote: Rick, I understand your feel for the nostalgia, and passion for pursuing it. All of us more or less on this group have some common ground here.
Re: [AMRadio] D104 mic element testing
The D104 mic element is a high impedance crystal so resistance doesn't mean anything. Unplug the D104 head from the stand since there is no assurance the stand is wired correctly. There are 3 pins in the head connector. The 2 close together are the mic element. Use a high impedance digital meter, VTVM or oscilloscope connected to the 2 pins. Give a nice long WHIE into the mic and you should get over 200 millivolts RMS on the meter, or 500 mv peak to peak on the scope. Google "Astatic D104" and you will get an evenings worth of entertainment and education. 73, Larry K2LT drakerepair.com [EMAIL PROTECTED] wrote: OK, how do you test a D104 mic element to see if is bad? Resistance? Check with an oscillosope? I dunno. Alan __ 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] DX-40
You have checked out the D104 also? The elements can go bad. Make sure you aren't using the amplifier in the base which would way overdrive the audio input of the DX-40 73, Larry K2LT. Rick Brashear wrote: Thanks Brian. I've noticed that the loading of the DX-40 can be a little cantankerous at times. I'm going to revisit the D-104 dilemma again today if I can . I am obviously doing something wrong since so many people have replied telling me they use a D-104 with great success.
Re: [AMRadio] possible interference coming up
I would give him a bunch of literature on the use of ferrites and maybe a sample and a list of suppliers and let him solve the problem. 73, Larry K2LT I feel it is interference waiting to happen. Does anyone have any experience with this? Am I to expect to QRM him? Alan, Maybe, maybe not, but it's not your problem. If his audio equipment is responding to your transmissions then HIS equipment is malfunctioning, not yours. Dennis D. W7QHO Glendale, CA
Re: [AMRadio] FS: 211s, ZM-11, URM-25D, TS-375A, Millen 90651
Don, I'll take the 211 VT-4C pair. I have a Western Electric 451A that I will get on the air this year. Uses 6 of the 211 tubes. 73, Larry K2LT Merz Donald S wrote: For Sale. All prices plus shipping. 211 VT-4C tubes, one pair, used but tested by me and found to have excellent emission. $100/pair
Re: [AMRadio] 1977 Antenna ?
Any plastic parts will be suspect. Put it up if the effort isn't too great and see how it works. Larry K2LT At 10:43 AM 12/6/2004 -0500, you wrote: I have this new, old-stock antenna here. It's a two-trap dipole made by Western Radio Electronics dating from 1977. It's brand new in the box, and 27 years old. It appears to be made of copper-clad wire, two plastic-encased traps and a section of RG-58U feedline. This looks like a decent antenna, rated at a KW on AM and CW, supposed to be no-tuner-required on 80 and 40, it's 103 feet long. I have a hankering to put up a new antenna and I am wondering whether or not to trust this old guy. I am worried about the effects of aging on the traps, center insulator and maybe the RG-58/U. Any thoughts on this? 73, Don Merz, N3RHT 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.(A) __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.805 / Virus Database: 547 - Release Date: 12/3/2004 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.805 / Virus Database: 547 - Release Date: 12/3/2004
RE: [AMRadio] Re: Gates BC250L efficiency
The measurements were done several years ago with an old HP 851/8551 analyzer and I didn't write down the data. I'll do the tests again with my Tek 2712 and plot the results. The only question is "When?" What I see in my rounds of making the NRSC spectrum plots on AM broadcast stations is an occasional increase in harmonics over the previous year. Many times the engineer will say that they had a recent nearby lightning strike. Checking the harmonic trap series cap usually finds the problem as that gets blown by the lightning surge. The increased harmonics don't show on the station metering as the only RF meter is current in the feedline to the antenna. The change in power is minuscule and not noticed on the meters. But the station is out of spec for harmonics. Larry K2LT T and T Measurements 800-687-9161 At 06:30 PM 9/29/2004 -0400, you wrote: Well, if not going into a dummy load, the swr would go up. Just because you run an antenna tuner does not mean the amp is running clean and not wasting power in harmonics. Measure the TR-7 by itself and its likely clean, and overdriving the amp is likely the problem. Modern solid state rigs likely wont allow much harmonics out unless you tweak things inside for more power out than they are supposed to run. Most will put out quite a bit of extra power if you tweak the alc circuit, but it wont be clean. Brett N2DTS --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.771 / Virus Database: 518 - Release Date: 9/28/2004
RE: [AMRadio] Re: Gates BC250L efficiency
I made a set of interesting measurements with my spectrum analyzer on a Drake TR-7 driving a L-4 amp. Set the output at 1kw through a W-4 wattmeter into a dummy load. Harmonics looked good, down quite a ways. Crank the TR-7 up a bit to the L-4 and the power went up to 1100 watts. The fundamental stayed the same, it was the harmonics that went up! The power meter didn't care what frequency the energy was. Now I always run a MN2700 pi network antenna tuner with any of the Drakes. Larry K2LT drakerepair.com 800-687-9161 Efficiency is often a function of the tank circuit Q. Lower Q often gives more efficiency. It can be quite dramatic if you are far off. Grid bias needs to be way beyond cutoff, and with a lower Q, efficiency should go up. I did some experiments on the push pull 812 rig when it was done. I was getting 200 watts out of it, until I shorted 2 or 3 turns on the final coils. Power went up 50 watts! I removed the turns to prevent weird stuff going on, but still only got the 250 watts out, so the shorted turns were not causing problems in my application. Maybe try shorting some tank coil turns as a test and see what happens. If you left a lot of turns in the coil, your Q could be above 20 or more. >From memory, a Q of 15 is 'normal'. A Q of 12 should be ok, who has harmonics these days? Brett N2DTS --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.771 / Virus Database: 518 - Release Date: 9/28/2004
