The 811 was built to be the cheapest HF amp as the number one priority.
And that's from the man that designed it.
As for AM mode with the 811
May this image be forever burned into your memory.
73
Jeff
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Looking for amplifier options for SSB (10-12)m
- Thread starter Chris120
- Start date
The 811 was built to be the cheapest HF amp as the number one priority.
And that's from the man that designed it.
As for AM mode with the 811
May this image be forever burned into your memory.
73
Jeff
FYI - For what its worth, Amprepairguy (KB1SEL), won't even work on a 811 amp unless the owner is willing to convert it to a 572b. The Chinese 811's have such a poor vacuum, it's not worth the money or effort to repair them.
He is pretty well respected by a lot of folks when it comes to tube amps.
He is pretty well respected by a lot of folks when it comes to tube amps.
M
Mr Fix it
Guest
Has to do with the way the Chinese construct them . They are so poorly made that plate to filament arcs are not uncommon .
I have repaired hundreds of al-811 and al-811h amplifiers produced by Ameritron.
9.9 times out of 10 the cause for need of repair is due to a 811 tube flashing.
Once the customer switches over to 572b tubes, no more issues. Even though they are also of China origin
The emission life of a China 811 or China 572b is far less than a old rca 811 or cetron 572b. But it is what it is.
I re hi pot all new tubes when I purchase them, I used to see countless plate to grid short failures right out of the box on new 811 tubes.
Even with a pre tested, good set in hand installed and working in a amplifier, issues would occur during shipping to a customers qth. After they re installed and tried to fire amp up.
This is with amp packed in one box , tubes in another box both shipped separate via FedEx.
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I ended up going with an Icom 7300 and an Ameritron AL-80B. I'm happy!
If you run AM, run away from today's 811A's. It's not just that they melt when trying to produce the highly inefficient carrier, the melting causes them to short out. This almost always causes amplifier damage and in some cases can back up into the receiver, severely damaging it.
They haven't made a real 811A tube in 40 years. Just pull up a Google image of an old RCA 811A tube and right away you'll notice all manufacturers have deleted 12 horizontal radiator fins, in favor of two vertical ones.
The original 12 fins not only provided much better mechanical stability, they also removed heat from the critical center area of the anodes. For reliable AM or FM operation, 811A tubes must be switched out with 572B's.
The only reason the six pieces of metal were removed, that were bent to make the 12 fins, is because that required two extra steps. The fins had to be made on another machine and then spot welded to the anode. They eliminated those two steps in order to sell you a supremely junkie tube.
On the other hand, the anode inside the 572B tube is approximately five times thicker and made of graphite material which will not melt. Having the same pin out and inter electrode capacitance, makes it a direct drop-in replacement for the 811A.
They haven't made a real 811A tube in 40 years. Just pull up a Google image of an old RCA 811A tube and right away you'll notice all manufacturers have deleted 12 horizontal radiator fins, in favor of two vertical ones.
The original 12 fins not only provided much better mechanical stability, they also removed heat from the critical center area of the anodes. For reliable AM or FM operation, 811A tubes must be switched out with 572B's.
The only reason the six pieces of metal were removed, that were bent to make the 12 fins, is because that required two extra steps. The fins had to be made on another machine and then spot welded to the anode. They eliminated those two steps in order to sell you a supremely junkie tube.
On the other hand, the anode inside the 572B tube is approximately five times thicker and made of graphite material which will not melt. Having the same pin out and inter electrode capacitance, makes it a direct drop-in replacement for the 811A.
Sweet, i was getting ready to post this and walk away lol. Hopefully ill be buying a 7300 early next year. Glad you like yours.
https://www.dxengineering.com/parts...7_I4mMixujS5segD6wmLUOle2KbEFaAoaAgfpEALw_wcB
Anyone that can Read the Specs can figure it out & my last statement said TWO Ameritron amplifiers work on 6 meters.They are BOTH Solid State amplifiers so No Tube amplifiers manufactured by Ameritron work on 6 Meters.Is that clear enough that you can understand it? {:>)
SIX-SHOOTER
Hmmm. Glad you went with a 80B and Icom 7300. As for all the whining about the 811A tubes, yeah they are fragile for carrier modes, and Toll Free is right they will happily produce the power you demand of them whilst burning a hole in the anode (thin, yes).
Only thing I'd like to add is, 811A tubes are not a deal breaker, especially if you use SSB. AM mode maybe tough on them, but even if you burn a hole in the Anode they still usually work fine. I know that isn't the way you're supposed to do it, LOL, but it does happen, has happened to myself and countless others. Mystified when you take the cover off your amp to clean the fan or something and the tubes and notice that at least one of them has a hole burned in the Anode.
For the AL-811H version (the only good version for 10/11M) no matter if Chinese or other 811A tubes, A safe bet (IMO) would be:
SSB no more than 500 Watts PEP output
AM no more than 150 Watts Carrier Power, no more than 500 PEP modulated.
I did a lot of FT8 (straight up carrier mode) with my AL-811H for about 3 years, maybe 4 years, up to 450W carrier power and yeah I might have dulled the shine or put a tiny hole in a Anode at some point, not instantly, but the output power remains the same, then and now. If a tube goes bad and flashes or shorts I'll just repair the damn amp. I run it hard and I know it, but I also know how to repair it. If you don't then don't run it hard!
Only thing I'd like to add is, 811A tubes are not a deal breaker, especially if you use SSB. AM mode maybe tough on them, but even if you burn a hole in the Anode they still usually work fine. I know that isn't the way you're supposed to do it, LOL, but it does happen, has happened to myself and countless others. Mystified when you take the cover off your amp to clean the fan or something and the tubes and notice that at least one of them has a hole burned in the Anode.
For the AL-811H version (the only good version for 10/11M) no matter if Chinese or other 811A tubes, A safe bet (IMO) would be:
SSB no more than 500 Watts PEP output
AM no more than 150 Watts Carrier Power, no more than 500 PEP modulated.
I did a lot of FT8 (straight up carrier mode) with my AL-811H for about 3 years, maybe 4 years, up to 450W carrier power and yeah I might have dulled the shine or put a tiny hole in a Anode at some point, not instantly, but the output power remains the same, then and now. If a tube goes bad and flashes or shorts I'll just repair the damn amp. I run it hard and I know it, but I also know how to repair it. If you don't then don't run it hard!
IDK he never really said, but he ended up with a IC-7300 and a AL-80B. Maybe he has license or is aspiring to get one because 10/11M DX is just dead. Sounds like they have a local group. We use to have one too, 39LSB really enjoyed it when solar minimum talking local. However now most of those operators are passed on, we still have a few.
I CB'd (only CB) for 20 years before I got Amateur License, but now been General Class Ham for 10+ years. I still enjoy CB with the very few locals, most of them I've known for 30+ years now, and occasional DX too.
Antenna polarisation is not really an issue on HF frequencies. Your mountain is always going to be in the way no matter how much power you use.
As you are getting ready to study for your Amatuer radio liscense now would be a good time to invest is a few books about how antennas work.
http://www.arrl.org/arrl-antenna-book
ON4UN's book "Low Band DXing" is a great source to learn about antennas. Not just the low bands but antennas in general. It is out of print so you will have to find a used version. It is an easy read.
You have invested a lot of money in your radio and amplifier. Find a local ham that can give you advice. They will save you a lot of frustration an money.
As someone said earlier, prepare to take both the Technician and General exam. You will be frustrated that you can only use a small segment of 10m for SSB if you only have a technicians license. 10m is dead right now. With a General license you can use your radio on all bands all modes.
The only reason I asked, when someone is new to ham radio and they come.from 11 meters there is the prevailing thought that they need an amp. 11 meters is amp happy and with all the Crap and noise that is out there I can understand why you might think you need one. The ham bands are different, you generally don't need an amp on the ham bands. I personally have works almost every country in the world on only 100 watts, I have never found the need for one. The antenna is everything on the ham bands and there are so many options you can buy or build. The OP is admittedly will be new to ham radio, even if he has been on 11 meters for 20+ years like I was ham radio is a whole new ball game and the rules of 11meters dont replay apply here.
I'm sorry, I really mean no disrespect, the antenna you use is everything on any band. Most CB'ers that become hams I think initially bring a lot of the CB Snakeoil with them, but they'll lose that quick, usually.
As far as needing an amplifier on Amateur bands, depends on what you are doing. You can make DX contacts all day long, on 100 watts, with a halfway decent wire antenna, but when you get into a group, a local group, where conditions come and go, and QRM'ers are abundant, your buddy's are going to insist you get an amp, if you are only running a puny 100 watt amateur station. I been a ham for more than 10 years, and I thought I didn't need an amp either, until I got into 75 Meters. 40 Meters and up not so much.
I have been a ham for more than 30 years and I will concede that the importance of the antenna happens in every radio band. I will also concede that on 75 meters yes you do need an am for the most part. Generally what I have, and again I mean no disrespect, found that most coming from 11 meters want to run big power and really don't have a full understanding. I have taught intro ham radio classes for years and most that attend are coming from 11 meters. When asking what they have now most have a fancy export, some type of amp, and the cheapest antenna. Most think that hams are always running 1.5k with huge towers full of antennas. When I have pointed out that you don't need that to talk all over the world they don't believe it.
I mean no disrespect to any 11-meter operator here, OP, or anyone reading this, I am merely pointing out what I have seen in the 30+ years I have been a ham.
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