Re: SB-1000
I believe the problem isn't the voltage itself, which would be found (measured) between gate and ground. The problem is knowing where, in the circuit, the input power is dissipated. The gate-to-ground
By
Fran?ois
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#41169
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Re: SB-1000
Just to add some elements to the discussion. Here's what I noticed on my Drake L-7, so with 2 x 3-500Z. The -9V bias on the grid is generated directly on the grid; the 9V zener is not in the cathode
By
Fran?ois
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#41167
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Re: SB-1000
Pg=Vgc X Ig
By
KG2RG
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#41166
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Re: SB-1000
VK4TUX.? ?Nope.? that -75 vdc is for BIAS? voltage and only when operating Class C.... (either grid or cathode driven).
Look under? cathode driven....and 0 vdc? bias voltage. U will see 215 V
By
Jim VE7RF
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#41165
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Re: SB-1000
Yes, that¡¯s what Eimac says typical grid should be. I Eimac also states max limits:
Ig 108mA
Ip 400mA
max output 740W
but Heatgkit SB-1000 and AL 80B must have special permission from god. Their
By
KG2RG
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#41162
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Re: SB-1000
I can't find this magic formula in the Eimac documents I have. Could you post this document or a URL that allows us to find it?
--
F1AMM
Fran?ois
De la part de Adrian Fewster via
By
Fran?ois
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#41161
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Re: SB-1000
1st,
voltage squared divided by resistance equals power.
2nd,
The Eimac formula for grid dissipation is:
Pg=Vgc X Ig
where Vgc is the peak positive grid to cathode voltage
and Ig is the DC grid
By
KG2RG
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#41159
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Edited
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Re: SB-1000
Eimac states driving impedance is 115 ¦¸
grid dissipation = peak voltage X grid current.
so at 100W drive, peak grid voltage is 150V
150V X 0.2Ig = 30W grid dissipation. 30W
I don't think you
By
Fran?ois
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#41158
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SB-1000
I own a Heathkit SB-1000. Have not had it to long, just a few months. Had a few issues and just wanted to share them and what I did to fix them.
one day on 80M I think I hit a bad something. Bad tune
By
KG2RG
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#41156
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Re: Commander HF-2500 meter lamps and HV PS
Jim, VE7RF,
that is a boatload of FB info!!! I had not had a chance to respond but have read it twice and may need to read it a few more times and drill it in. Thank you!!! Great contribution to me
By
KG2RG
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#41155
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AL-80A tx led removal
Is there a way to remove the red tx led without taking off the front panel?? I cannot see in the back because of the large filter caps.? TU ..Bill
By
Bill K3HZP
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#41154
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Re: CTR Engineering/W8JI Response?
Tom is great. Just email him again
By
KG2RG
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#41153
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Re: Commander HF-2500 meter lamps and HV PS
Yeah. Weird.
It printed out fine here.
"Email me at gudguyham@.... Lou"
Alek VK6APK
By
Alek Petkovic
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#41152
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Re: Commander HF-2500 meter lamps and HV PS
Ok, thanks. I just emailed you Lou
By
KG2RG
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#41151
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Re: Commander HF-2500 meter lamps and HV PS
Whoops @aol.com. Sorry
Sent from the all new AOL app for iOS
By
Louis Parascondola
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#41150
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Re: Commander HF-2500 meter lamps and HV PS
Come to think of it... if your ISP won't display A O L dot com, then it
may not even allow you to e-mail to A O L dot com.
--
See my QRZ.com page at *https://www.qrz.com/db/K0XP*
By
Steve
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#41149
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Re: Commander HF-2500 meter lamps and HV PS
"That" was supposed to be "at A O L dot com" without the spaces. Your
ISP probly doesn't like the A O L part and removed it.
Steve K0XP
--
See my QRZ.com page at *https://www.qrz.com/db/K0XP*
By
Steve
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#41148
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Re: Commander HF-2500 meter lamps and HV PS
gudguyham@.... Lou.
what is that??? ? Not an email?
By
KG2RG
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#41147
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Re: Commander HF-2500 meter lamps and HV PS
Email me at gudguyham@.... Lou
Sent from the all new AOL app for iOS
By
Louis Parascondola
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#41146
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Re: Commander HF-2500 meter lamps and HV PS
Plate load Z? =? loaded B+ / (1.8 x? DC plate current).
On all those old amps, the higher voltage was always 41.4 % higher than the lower B+ setting.? ?The DC plate current was 41.4%? higher,
By
Jim VE7RF
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#41145
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