Re: 572B
Another piece of ham lore is -- if you run the heater for a day, the getter will get hot and absorb the gas. That's worth a try, and won't set your backyard or basement on fire. 73 Jim N6OTQ
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Jim Strohm
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#39478
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Re: 572B
That's prolly the answer. I put my friends amp back together so I cannot test it now plus it obviously puts stress on everything so I'll mark it bad and test it at a later date. Your theory makes
By
Bob
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#39477
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Re: 572B
The tube is likely gassy and will only conduct when HV is applied. It usually takes a few hundred volts for a gassy tube to conduct so the low voltage from a test meter will not reveal a gassy tube.
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Chuck Neal
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#39476
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Re: 572B
Rich Measures (SK) wrote about this, and suggested (for different tubes) a possible way to fix it by swinging a live tube around your head. I guess if you do it outdoors and the tube is already
By
Jim Strohm
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#39475
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Re: Operating RTTY FSK and Alpha 86
Jim, Can you point us to a good filter material to use? Maybe a link? Jim ¨C KR9U Sent: Friday, September 8, 2023 1:13 AM To: [email protected] Subject: Re: [ham-amplifiers] Operating RTTY FSK
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James Wolf
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#39474
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572B
Hi all, I'll condense this, you'lll get the idea. A friend has an 811H with 3 year old 572B's. One shorted and causes the fuse to blow immediately. Tube replaced and all is well. Measuring with a DVOM
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Bob
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#39473
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Re: Operating RTTY FSK and Alpha 86
This is exactly why you install or retrofit a filter on the air intake. https://www.arraysolutions.com/amplifiers-rf?product_id=14890 On a side note, a shop vac on the bottom of the tube will get most
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Jim VE7RF
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#39472
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Re: Operating RTTY FSK and Alpha 86
Gents, {S N I P} ... make sure you check the tubes occasionally for a buildup of dust in the cooling fins. Don't simply look at the bottom of the tubes, but pull them out and look through them at a
By
HaL Mandel
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#39471
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Re: Operating RTTY FSK and Alpha 86
Of those two specs, the GRID current is the most critical. Protect against high grid current at all costs. 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com
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Jeff AC0C
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#39470
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Re: Operating RTTY FSK and Alpha 86
One other thing Ron, make sure you check the tubes occasionally for a buildup of dust in the cooling fins. Don't simply look at the bottom of the tubes, but pull them out and look through them at a
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James Wolf
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#39469
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Re: 12 KW CCS ON 160-15M...USING THE 3CX-6000A7... PART 2
On your tetrode, you are matching 50 ohms to? 1000 ohms (now 500 ohms), so the PI net values are all different........ vs? the 50 ohms to 50 ohms on the 3x6 (and 3x3). When matching to 500 ohms, the
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Jim VE7RF
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#39468
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Re: Operating RTTY FSK and Alpha 86
Morning Jim Got it. Thank you Ron KK7GO Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ Sent: Monday, September 4, 2023 8:32:01 PM To: [email protected]
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Ron KK7GO <ron@...>
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#39467
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Re: Operating RTTY FSK and Alpha 86
The muffin fan on the back is the optional fan. The optional fan adds to the air flow through the tubes and a lot of air movement around the transformer. Jim - KR9U From: [email protected]
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James Wolf
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#39466
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Re: Operating RTTY FSK and Alpha 86
Dear Jim, (et al), Nice to see a good suggestion about running RTTY through an amplifier, e.g., TubeMax. I run an Alpha 76A with a coupla 3CPX800A7's with an outboard supply, and the W7RY triode board
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HaL Mandel
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#39465
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Re: Operating RTTY FSK and Alpha 86
Thanks for your reply. My 86 has the blower and a fan on the rear panel. Is there another fan that can be installed? The blower does have ducting to the tubes. Ron - KK7GO Get Outlook for
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Ron KK7GO <ron@...>
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#39464
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Re: Operating RTTY FSK and Alpha 86
There¡¯s no problem running RTTY on this amp. If you keep the grid current under 40 ma and the plate current under 875ma, you will still make rated power and the tubes will last forever. If it
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James Wolf
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#39463
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Re: Kenwood TL-922-Need a plate current meter.
I had to do that as well. A little Dremel and a few seconds. Lou does a good job with those replacement meters. Bob W4JFA
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Bob
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#39462
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Re: Kenwood TL-922-Need a plate current meter.
Hi Bob, You asked that I let the group know how things went. Lou sent the meter, and a soft key module, and both are installed and working perfectly. And the new meter looks just like the original.
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Jim McPhee
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#39461
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Operating RTTY FSK and Alpha 86
Hi, New to RTTY. Looking to see what I need to know regarding the use of the Alpha 86 and FSK on RTTY at recommended power settings if any. 73 Ron KK7GO
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Ron KK7GO <ron@...>
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#39460
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Re: 12 KW CCS ON 160-15M...USING THE 3CX-6000A7... PART 2
Not bad on the switch. Its worth the money For a tube like this. Input sound standard. Similar to mine but less spacing on caps. Also not band switched but just 14 taps of inductance from an air dux
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W7WRX
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#39459
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