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Not all alternators are capable of charging 16-18 Volts. The factors that determine an alternators output are stator windings, stator/rotor spacing, rotor current and number of poles, and RPM.
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There are cheap, loosely coupled, small winding alternators that can barely achieve 1.2V above battery volts (under load), even with full battery volts applied to the rotor.
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-John, N9RF
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On Thu, 11 Jan 2007 08:18:54 -0800, PA3DUV <pa3duv@...> wrote:
> That's an interstuing approch, thanks. I was not aware of the fact that? > a 12 > V (or 14.4 Volt) alternator would supply 16 or even 18 VDC when connect? > to a > 16 or 18 V battery stack. . Most comprehensive set of free safety and security tools, free access to millions of high-quality videos from across the web, free AOL Mail and more. |
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Re: Gu84b anode voltage
Harold Mandel
开云体育Dear Jan, ? I am currently building a GU-84b Grid-Driven Tetrode amplifier and my Anode Transformer is 3.0KV at 2 amps, and the output from the rectifiers and filters are 4,242.0 Volts, D.C. ? When designing the amplifier and anticipating a certain Anode Voltage, the Grid and Screen are affected, as is the anticipated output impedance of the tube, which in turn affects the tank-Q and the components making up the tank circuit. ? So feel free to crank 4KV, Jan. It’s been done before, and the GU-84b, as long as it’s cooled appropriately and is presented the right impedances, will serve well. ? Please also remember to carefully monitor the filament voltage, as a few hundredths high will severely age the tube! ? Hal Mandel W4HBM ? From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of on6zg
Sent: Thursday, January 11, 2007 5:17 AM To: ham_amplifiers@... Subject: [ham_amplifiers] Gu84b anode voltage ? Hi, |
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Re: Mobile power supplies revisited
On Thu, 11 Jan 2007 08:18:54 -0800, PA3DUV <pa3duv@...> wrote:
That's an interstuing approch, thanks. I was not aware of the fact that It only works because for the "sense" lead to see the "14.4" volts it needs to, the alternator has to put out 18 volts... It has to make up that 4 volt pad... It's the location of the sense lead and automotive electronics that make this method work.
I'd go with the method your looking at, or another one we did in the keydown circuit was a 12 volt and an 6 volt battery. Works just like before, just more Vcc.
If you do the 18 volt stack, using 12 and 6 volt batteries, you could pull from the 12 volt side, use a steering diode (large current, stud mount) to charge another 12 volt battery just for the car electric system. That would give you isolation, and a psuedo dedicated circuit for your amp as well. --Toll_Free |
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Re: Mobile power supplies revisited
PA3DUV
That's an interstuing approch, thanks. I was not aware of the fact that a 12 V (or 14.4 Volt) alternator would supply 16 or even 18 VDC when connect to a 16 or 18 V battery stack.
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In mmy case battery capacity is no issue, there is plenty of space to even fit 8 two volt cells. The point is the absolute lack of space for a second or larger frame alternator. On second thought is might be an option to use an 18 V battery stack (with the stock alternator connected to the +18 VDC of the stack) and use a 18 => 12 V DC DC 30 amp converter to supply the needed charging current to the starter battery and the car electrical system. Cheers, Dick PA3DUV ----- Original Message -----
From: "1800 Toll Free" <TollFree1800@...> To: <ham_amplifiers@...> Sent: Thursday, January 11, 2007 1:05 AM Subject: [ham_amplifiers] Mobile power supplies revisited Here's another thought, more geared towards the gentleman in .eu who was |
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Re: hi power mobile
PA3DUV
开云体育Peter,
?
3 dB is what we've measured using S-meters from an
Icom 756ProIII, so for what it's worth. Coupling from the vertical also occurs
with the 5 inch loading coil, I can see if cars are passing on the other lane by
looking at the VSWR. Even lightpoles, traffic signs etc result in detuning. This
sometimes results in a fast flutter, as reported by fixed stations during mobile
QSO's on 80 meter.
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On next occasion I will do a temperature
measurement on?a centerloaded vertical with a 3" and 5" loading coil, in
order to get a better?impression of the dissipated RF in the coil. But,
without doubt there is a significant difference in antenna performance when
the?loading coil goes from 1.7 inch to 5". The difference between a High
Sierra HS1500, featuring a 1.7 inch diameter loading coil and a HiQ 5-80 with a
5 inch loading coil was 10 dB on 3600 kHz.?I rember?the loading coil
on the 1.7 inch antenna ran hot to the touch and the contactor almost burned
out.
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Cheers, Dick
PA3DUV
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Re: hi power mobile
Peter Voelpel
Hi Dick,
That is very unlikely at same wire size. 3db difference would mean half of the transmitting power being lost across the coil. The ARRL program "mobile" calculates 1,3db difference. But you are right, the larger coils give no remarkable improvement, but make it much easier with tabs for band change. The disadvantage is the detuning while passing trucks. 73 Peter ________________________________ From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of PA3DUV I found approx. 3 dB difference between a 3 and 5 inch loading coil in on air test on 80 meter. Anything larger than 5 inch the difference was neglectible. |
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Re: hi power mobile
PA3DUV
开云体育Peter,
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I found approx. 3 dB difference between a 3 and 5
inch loading coil in on air test on 80 meter. Anything larger than 5 inch the
difference was neglectible.
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Cheers, Dick
PA3DUV
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Re: hi power mobile
PA3DUV
开云体育I could not agree more Greg.
If multibanding is required there is always a
compromise. Also remote control is an issue here, this morning when I was
tooling down the highway in drizzling rain?alI had to do was run the
contactor down by pressing a switch in order to check out 3780-3800 kHz. The 10
kHz bandwidth of a short centerloaded vertical makes remote control a no
brainer.
My experience on 160, 80 and 40 from the mobile is
that hearing is much easier than being heard. @ -8.5dB antenna gain the 1 kW
input makes a mobile signal equal to the barefoot crew.?
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Cheers, Dick
PA3DUV
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Re: hi power mobile
Robert B. Bonner
The highest performance antenna I have ever had was the Texas BUGCATCHER.
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Sort of like Peter's. That antenna could get as tall as I wanted and I carried a bundle of parts to do whatever I felt like at the time. 10-12-15-17 used NO COILS, they were combos of masts and Steel CB whips, (fullsized) I used about 1-3 turns on 20 meters of the 40 meter bug coil and about half of it on 40. That setup was UNBELIEVABLE FOR DXING ON 40. HOWEVER, convenience finally took over and I mounted up the Predator Screwdriver. I then used many of my BUG masts, whip parts and top hat to super dooper the PRED and closed the gap some between them. All my BUG friends have since changed over now for the ability to be rolling and changing bands. With these high performance antennas like the Predator, you don't give up much in performance after you do some of that good BUGCATCHER radio stuff to it. Then crank up the amp. For anybody who thinks Hamsticks or Hustlers are mobile antennas shame on them. BOB DD -----Original Message-----
From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of badgerscreek Sent: Thursday, January 11, 2007 6:04 AM To: ham_amplifiers@... Subject: [ham_amplifiers] Re: hi power mobile For a 5 base and a 6ft whip. The base being 1 inch and the top being a 1/4 inch in diameter, i calculated that the optimum coil diameter is 7.5 inches. This is for 10 Gauge Wire. I used the Mobile.exe program from the ARRL antenna handbook. This is for a frequency of 3.5 mhz. I always wondered how the screwdriver makers can make the claim that bigger coils are always better especially when you want to cover from 3.5 to 30 mhz. For best efficiency when i did an exhaustive analysis using many antenna lengths, i found that you need two different coil diameters for the high and low fequency ranges for maximum efficiency. You still cant beat a monoband coil with a tophat. However the differences are fractions of a S unit so it might be a moot point. Its far easier getting gain from the amplifier in the mobile once you close to optimum efficiency in the antenna department. Greg --- In ham_amplifiers@..., PA3DUV <pa3duv@...> wrote: for a multiband centerloaded vertical with 3500 kilocycles as the lowest frequency. coils, 500W are all one needs to work any station heard on 80m and breakmost dx pileups easily.[mailto:ham_amplifiers@...] On Behalf Of 1800 Toll Freeyou just need to do a little bit of lookin around before you spend the hardearned dollars :) Yahoo! Groups Links |
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Re: hi power mobile
Peter Voelpel
Hi Dick,
We found not much more benefit from increasing coil size beyond 40cm diameter on 80m. Coils sized from 25-40cm diameter were close in competition, just the wide of the S-meter needle in difference. Band change was done by using banana plugs right at the coils windings. Coils were air coils wound either with 3-4mm copper wire or tubing. Still got mine (25cm) From our 80m mobil gang (~20 qro) in the seventies, LX1GM was the strongest station. He was using 5 additional alternators in his car, beside 6x100AH batteries and the inverter. The inverter 900V/600Hz fed 12xPL36 to 2500W out (keydown) on 80-20m. While driving through the Luxembourg city shopping mile at night he switched on lots of burgler alarms ;-)) 73 Peter ________________________________ From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of PA3DUV :-) Alles klar Peter. What diameter loading coil would you suggest for a multiband centerloaded vertical with 3500 kilocycles as the lowest frequency. |
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Gu84b anode voltage
on6zg
Hi,
Has anyone built an amplifier with a gu-84b tetrode? In the datasheet the maximum anode voltage is 2.2kilovolt, but I've found a few websites where they apply 3.5 to 4 kilovolt. I wonder if this is a good idea, and if the life time of the tube is changed with this higher voltage. Who has experience ? best regards, Jan , ON6ZG |
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Re: GG Push-pull Amplifier
OK Hsu --
Rather than sending it and something happening I just uploaded it to my website and you can download it at your convenience. Go to: < amp.zip> or just go to my website at: choose Downloadable files from the menu and then the file is "400w amp.zip" There were two pages so I just zipped them both together and they're just over a meg. Good luck with your project --- I hope this helps. I hope I can catch you on the air sometime. 73, Jim - K5LAD On 11 Jan 2007 at 13:18, Hsu wrote: "It's so simple to be wise. Just think of something stupid to say and then don't say it." -- Sam Levenson ======================================= My Web Page - |
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Re: GG Push-pull Amplifier
Hsu
开云体育Jim!
?Great!I have not get the
information.
please send it to my another mail box bd2rh@....
?this e-mail located in China can
not?recieve large file
from oversea?,because of fiber problem. in Taiwan
Gulf.
?? Thanks in advance!
????? 73!
Hsu?
?
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Re: GG Push-pull Amplifier
Hi Hsu --
Have you been able to find the information you needed from the Holiday issue 1976 73 Magazine? If not I have that issue in hand. 73, Jim - K5LAD On 6 Jan 2007 at 22:10, Hsu wrote: Hi,"It's so simple to be wise. Just think of something stupid to say and then don't say it." -- Sam Levenson ======================================= My Web Page - |
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Re: hi power mobile
craxd
--- In ham_amplifiers@..., "badgerscreek" <qrp73@...>
wrote: antenna running 1 or more kilowatts at the higher frequencies would have meabout your health, or maybe theres no danger?I've heard of this causing some health problems for a few in those key-downs they do. Long term exposure though could be pretty bad I'd think. Yup, that's the name of those batteries, I couldn't remember it when I wrote the post. |
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Mobile power supplies revisited
Here's another thought, more geared towards the gentleman in .eu who was looking at running a bunch of 2 volt batteries in series, and home charging it.
I have done this in the past, and although it isn't the best method, since your going to use 2 volt batteries, you can still accomplish this and stay within the realm of 16 volts. Take 2 of those 2 volt batteries and run them in series, creating 1X 4 volt cell. Connect that in series, neg from the new bank to + on the car battery, and run your amp from the + side of the new battery bank. From vehicle ground to amplifier B+, you will see app 16 volts. Now, the trick is here... Take ONLY the B+ out from the ALTERNATOR (I always disconnect the vehicle CHARGE lead at the alternator, then run a dedicated lead from the alt to the battery stack), and connect it as well to the top of the battery stack (to the 16 volt side). Since the cars electronics will all still see 12 volts, and the alternator will have to produce 18 volts to charge the 16 volt system, everything charges nicely. I also think it is best to take and run a relay / solenoid setup to disconnect the extra 4 volt stack when not being used, to prevent overcharging. Usually 10 to 45 minutes of charging while driving around is sufficient. Just use a solenoid to disconnect the B+ from the alt to the top of the 16 volt stack to the + / - junction of the 12 and 4 volt batteries. This works well in systems where you can't install a second alternator. Your car works fine, the amp works fine, everything charges nicely, BUT, you don't get something for nothing. Your alternator is usually running > manuf ratings, and you won't see rated Aout at 18 volts.... Expect about 20 percent less... Or even less efficiency. Still, makes it easy to run increased collector voltage cheaply. --Toll_Free |
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Re: The real benefits of running qro.
Harold Mandel
开云体育Now this is what hamming is all about! ? Oh, yes! ? The knife switches with 5/16” thick copper bars, the contactors that go CHUNG!. ? The smallest RF connector in your shack is a 7/16DIN and the stuff going out to your antenna is 1-5/8”? diameter. ? My friend Dale runs two 4-1000A’s modulated by two 4-1000A’s on A-M, with reactors, no less. Push-pull! ? He says he barely uses more than $100.00 of electricity a month with that puppy. ? Can you imagine Guglielmo Marconi’s reaction the first time he keyed that 50KW spark station on Cape Cod? The station’s biography says that neighbors a half-mile away could hear the spark. ? Thanks for the great posting. Hal ? From: ham_amplifiers@...
[mailto:ham_amplifiers@...] On
Behalf Of Philip Leonard WV?T
Sent: Wednesday, January 10, 2007 5:23 PM To: ham_amplifiers@... Subject: Re: [ham_amplifiers] Re: The real benefits of running qro. ? pentalab
wrote: |
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Re: The real benefits of running qro.
pentalab wrote:
### qro heats ur home... makes u feel better, reduces stress.. u feel like u just beat collins/henry/harris, at their own game... lots of satisfaction, ur friends are all impressed..esp wide eyed computer geeks, and it's fun to watch plate meter's bouncing up/down...ditto with wattmeter. You have the only 0-5 A plate meter in town. You have the only 0-1 A grid meter in town. You have the only 10/25 kw slug in town. Ur plate xfmr will power 8 x homes in winter. Ur girlfriend will be dully impressed. You have more power than the local college FM station. Ur friends with 25 watt push pull tube audio amps are really impressed, [esp with a 2 x4-1000 amp.. and a window, and tubes cherry red] U have more power than 99.99% of the hams on the planet. Ur mother would be proud. Pundits think you are actually a 'broadcast engineer'. 11m ops are really impressed. You can dim all the lights on your street. Who else can say they actually smoked the pole-pig in front of their home.... and plunged the entire street into darkness. No need for counselling or self medication. You are more focused, and have better concentration..esp around 8-10 kv. You can light up several 8' fluorescent tubes in your back yard... with no wires attached. People stay clear of you in aisle 6 of your local grocery store. You can casually mention stuff at the local hamfest... like how you set the tree's on fire.. and blew the end insulator's off ur dipole. You can give a real Corona demo late at night. You once melted RG-17 on 10m. QST will never publish your schematic.This is one of the funniest things I've read in a long long time! Thank you. I'm going to print this out and hang it on the wall!! Philip |
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Re: hi power mobile
PA3DUV
开云体育:-) Alles klar?Peter. What diameter loading coil would you suggest for a multiband
centerloaded vertical with 3500 kilocycles as the lowest frequency.
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Cheers, Dick
PA3DUV
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