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Author Topic: What Changes Would You Do To Your Ameritron 811/811H?  (Read 28286 times)
KH6DC
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Posts: 771




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« Reply #15 on: April 06, 2015, 10:17:54 AM »

I would change the TX/RX relay.  Not sure if the current models have it enclosed but my AL-811 had an open relay where the contacts tarnished and I had to burnish it occasionally.  Maybe enclosing it may or may not help.  Anyway, I sold it for a Tokyo Hy-Power HL1.2KFx which I sold for a Elecraft KPA-500.  The AL-811 was a great linear and still worked great after 16 years.
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73 and Aloha,
de Delwyn, KH6DC
MM0IMC
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Posts: 220




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« Reply #16 on: April 07, 2015, 06:20:57 AM »

I personally have found no problems with my AL-811H.

It works well on 10-12 meters and all the other band segments it covers. Is it fancy, sexy, most modern; no it just works.

Tuning, no problem; I came up with sweep tube rigs that required the same care when tuning the transceiver. Remember, dummy loads are marginal during long tuning sessions. It won't take your amp to long to toast a cantenna if care isn't used and the dry ones die faster.

I will admit one problem with my AL-811H, the set screws on the loading capacitor had vibrated loose in shipment. I fixed those at the same time I activated the Aux (10-12 meter) bandswitch position.

Would have to run 240 VAC to the shack if I were to go anything higher, so I will stay with what I have. it works.

KF7CG

Don't get me wrong, it's the only long term complaint I have against the amplifier, once I got to know it's wee quirks. Wink  The only time a valve (tube) has died on me was when I was having a good old ragchew with an American station on 10m using 400W PEP. Everything was loaded and plated correctly and there were no issues, the antenna has an SWR on about 1.4:1, etc.  After the QSO, I put the amp back on 40m and tuned it up accordingly as per usual with no problems.  The next day I switched the amp on and the mains power fuses blew.  A quick look revealed a valve had died on me and D16 diode also blew, both were quickly replaced with no further problems...

It's a very capable amplifier on all bands except 10m and 12m, with bags of reserve power it loafs along at the 400W UK legal limit all day long, perfect for a ragchewer like me! Grin
« Last Edit: April 07, 2015, 06:25:15 AM by MM0IMC » Logged
MM0IMC
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Posts: 220




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« Reply #17 on: April 07, 2015, 06:22:31 AM »

I would change the TX/RX relay.  Not sure if the current models have it enclosed but my AL-811 had an open relay where the contacts tarnished and I had to burnish it occasionally.  Maybe enclosing it may or may not help.  Anyway, I sold it for a Tokyo Hy-Power HL1.2KFx which I sold for a Elecraft KPA-500.  The AL-811 was a great linear and still worked great after 16 years.

There's a pair of sealed relays in the modern one, I'm sure that what's in mine.  I bought it brand new in September 2012 and the date code stickers inside state it was made in June 2012.
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W8JX
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Posts: 13268




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« Reply #18 on: April 07, 2015, 06:58:38 AM »

[quote author=MM0IMC link=topic=102532.msg836740#msg836740 date=1428412857
It's a very capable amplifier on all bands except 10m and 12m, with bags of reserve power it loafs along at the 400W UK legal limit all day long, perfect for a ragchewer like me! Grin
[/quote]

You are being most generous with bags of reserve. It is a decent 400 watt amp but not at rated output. Its a shame they did not base that amp on a modern version of old SB200 with two 572's and higher plate voltage. It would of made a much better amp than one with four 811's. A lot of those old SB200's are still going strong and some with original tubes too.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
K4PDM
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Posts: 144




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« Reply #19 on: April 07, 2015, 07:23:24 AM »

And where would we be getting our new 572Bs when we need them?

At least 811 tubes are still being made, even though the quality seems to be hit-or-miss.

I put a set of real Svetlana 572Bs in my Clipperton L when I got it a few years ago but now, Svetlana is no more and no one else seems to be supplying those tubes either.

73, Paul K4PDM
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W8JX
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Posts: 13268




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« Reply #20 on: April 07, 2015, 08:05:01 AM »

And where would we be getting our new 572Bs when we need them?

At least 811 tubes are still being made, even though the quality seems to be hit-or-miss.

I put a set of real Svetlana 572Bs in my Clipperton L when I got it a few years ago but now, Svetlana is no more and no one else seems to be supplying those tubes either.

73, Paul K4PDM

25 years ago there was not a 572 problem and had it been built back then the higher demand for tubes all along might have prevented dry spell as there was a bigger market to feed/profit from.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
MM0IMC
Member

Posts: 220




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« Reply #21 on: April 07, 2015, 08:45:31 AM »

The main reason that I would like to run 400W PEP on 12m/10m is that I can't have any type of beam antenna up due to moaning neighbours.  Last year I had a HB9CV 2 element yagi up for 6m, it was about 18 feet above the ground and the neighbours moaned to my landlord, so it had to come down.  Wire antennas and the odd temporary vertical for 12m/10m are okay.
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W8JX
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Posts: 13268




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« Reply #22 on: April 07, 2015, 08:51:41 AM »

The main reason that I would like to run 400W PEP on 12m/10m is that I can't have any type of beam antenna up due to moaning neighbours.  Last year I had a HB9CV 2 element yagi up for 6m, it was about 18 feet above the ground and the neighbours moaned to my landlord, so it had to come down.  Wire antennas and the odd temporary vertical for 12m/10m are okay.

In all fairness, 400 watts is just one S-unit so it is rarely a deal killer.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
N9XTF
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Posts: 282




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« Reply #23 on: April 07, 2015, 09:23:57 AM »

Someone commented about the plate voltage and not being able to run 572B's to their rated limit.  Ameritron makes the AL-572, so if someone wants full plate voltage for 572's then that's the amplifier to get.  Apparently someone is still making 572b's or Ameritron would not be able to make an amplifier around them.

I have had three AL-811 3 tube versions and have not had trouble out of any of them, except the normal QC Ameritron problems.  Loose screws, poor solder joints etc.  When they work, they are a nice tabletop operating amplifier and I did run mine at 500 watts PEP on SSB.  I did get very tired of the cooling down noise of the cheap 811A tubes between transmissions and installed some old RCA 811A tubes that I had in the closet.

Tom Raunch, the designer of the amplifiers, published new Ip and Ig ratings and tuning instructions.  It is well worth the read at www.w8ji.com, as others have stated. 

I am not a proponent of Ameritron stuff, everything and I mean everything I have of theirs I have had to work on shortly after purchase.  I have even found their techinal staff to be very unfriendly and useless; just my personal experience.  With that said, where are you going to find an AL-811 or AL-80B style amplifier for the money.  They are designed well, until the bean counters change Tom's designs to save money, and are priced well.  I ran and AL-80B for years before converting it to a 6M mono-band amplifier.  It was used in 6M service for 4 years before I sold it to another ham that wanted it worse than I did.

All of this comes down to how much money you have to spend on an amplifier and how much output power you expect to run.  Keep the AL-811, visit Tom's website, make his updates and follow his tuning procedures and you should be good to go.  I would find a trio of NOS 811A RCA tubes and stick them in there if you can find them.  I sold several sets for a very reasonable price last year on EPAY.  Maybe you'll find some reasonably priced as well.

Hope things work out in your favor,

Doug - N9XTF
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W8JX
Member

Posts: 13268




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« Reply #24 on: April 07, 2015, 09:43:40 AM »

To me a using AL811 amp at its rated output is like using a 1/2 ton pickup to haul 2 tons. I might work for a while if your careful but odds are against you. If you put a smaller load in pickup, it will last much longer. Same with AL811 if you run it well below factory ratings.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
N9XTF
Member

Posts: 282




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« Reply #25 on: April 07, 2015, 12:06:45 PM »

To me a using AL811 amp at its rated output is like using a 1/2 ton pickup to haul 2 tons. I might work for a while if your careful but odds are against you. If you put a smaller load in pickup, it will last much longer. Same with AL811 if you run it well below factory ratings.

John,

Everything we do in ham radio exceeds the original specifications.  We go by ICAS instead of CCS; this is how all amplifiers are able to obtain the quoted power ratings.  If one were to use digital modes instead of SSB then the story changes.

I have upward to 18 Drake transmitters and transmitters.  They all use 6JB6 tubes in the final amplifier stage.  This tube was never rated for RF until Sylvania started rating them as such.  I have used the same finals for 15 years and have never had a failure (knock on wood) but they are pushed well past their ratings.  As with the 811A, long tune up periods and excessive heat will end their life.

Dummy loads are rated at 1000 watts but this is for a 3 or 4 second period and then some long cool down period.  Some transformers are rated ICAS and some CCS.  So we, in the ham community, push the design limits of everything we use or build.  The only way to get past this would be to buy an Alpha (or whatever they are called these days) with unlimited carrier at legal limit.  I personally cannot afford a new Alpha and most cannot so we buy Ameritron and push the envelope.

Just my $.02 worth of rambling.

73,  Doug - N9XTF
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KM1H
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Posts: 4722




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« Reply #26 on: April 07, 2015, 02:22:22 PM »

Quote
The 811H is already the most refined 811A-based amp ever. But to deal with arc-over faults of Chinese tubes the past couple years, make sure it has W8JI's suggested mods (these may be present in recently manufactured units already): http://www.w8ji.com/al811_important_modifications_changes.htm

You really are a shill for that POS arent you?
Last I heard JI is no longer involved at MFJretron so its better to call the factory for the latest voodoo fix which may work untli the next batch of tubes arrives.

Quote
Keep a bag of spare fuses and diodes. Almost certainly in an arc-over, D16 on the metering board will fail shorted to save the meters.

Very good advice and make it a full big bag.

The 30L1 was the best of the 811A amps of its era and even better with a few simple upgrades. The Heath Warrior and Gonset GSB-201 was far superior to the maximally cheapened, shoddy construction, overhyped by marketing, AL-811 series. Even the Dentron 160-10L was better!

Carl
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KF7CG
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Posts: 1212




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« Reply #27 on: April 07, 2015, 02:43:37 PM »

Carl,

Say what you will, mine works well for me. I treat it with respect. No long tuning sessions, no use in digital modes, and it just works. It is hard to get an amplifier that doesn't cost more than $1.50 a watt.

David
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KM1H
Member

Posts: 4722




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« Reply #28 on: April 07, 2015, 03:15:24 PM »

Some people liked the Yugo also, and actually got a good one.
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N9XTF
Member

Posts: 282




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« Reply #29 on: April 07, 2015, 05:14:58 PM »

I have two questions for the haters of the Ameritron AL-811 amplifiers; bear in mind that I am totally pissed over the HyGain antenna that I bought in November and have fixed 4 times and that I have had QC issues with every Ameritron product that I have owned.

1.  Do you have the liquid money to justify purchasing an amplifier in the $5 to $6K range
2.  Have you actually owned or used the AL-811 or AL-811H for any length of time
3.  What are you basing your distain on if you have not owned one of these?

Doug - N9XTF
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