Help, I Need a Cheap HF Amplifier!
from
James Benedict, N8FVJ
on
January 4, 2007
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"Editor's Note: Due to the popularity of some of eHam's older articles, many of which you may not have read, the eHam.net team has decided to rerun some of the best articles that we have received since eHam's inception. These articles will be reprinted to add to the quality of eHam's content and in a show of appreciation to the authors of these articles."
Ever try 75 meter SSB early to mid evening with 100 watts? Chances are your 'ham buds' won't even hear you (or do not want to hear you). Hey, 75 meter SSB is suppost to be the easy 'armchair copy' band. Same story on rare 15/10 meter DX. Although a beam antenna helps, the only problem is the 75 meter guys are using beam antennas with the same HF amp used on 75 meters last night and are lined up a mile deep! Perhaps it is time to get a HF amplifier even if you are not loaded with cash. Lets say you can afford $250 to $375, lets look at what is available.
HEATHKIT SB-200 or SB-201:
This amp has to be the 'work horse' king of the bands and my first choice- value & cost. 80 to 10 meters (SB-201 is limited to 15M), this amplifier uses a pair of 572B/TL160 tubes. 100 watts input will produce 600 to 700 watts SSB PEP output on 75 meters. The tube replacement costs are still reasonable at less than $100 for two tubes. The 572B tube is fairly rugged with a large carbon type plate. The Heathkit built-in tuned input will present a good SWR match for your solid-state HF transceiver and has ALC control. The multi-function meter measures high voltage, SWR, relative output, plate & grid current. The amplifier is completely TVI shielded as well. The keying relay switches 120 VDC bias thus an interface relay must be used with most of the newer HF transceivers. Operation off of 120 VAC is ok, no expensive 240 VAC distribution is required. These amplifiers cost anywhere from $250 to $350 in good to excellent condition and are a bargain. Breakdowns are rare, perhaps a newer set of late model used B+ capacitors are in order- usually less than $20 for six (6) capacitors (this applies to all older amplifiers, just not Heathkit). Size is 14.75"w x 7.75"h x 14.75"d. The measurements includes extended front 'feet' and control knobs. Yep, got one on the desk in front of me!
AMERITRON AL-811:
The AL-811 is a great amplifier and of current manufacture. The bands are 160 to 15 meters with an easy modification to extend coverage to the 10 meter band if not so equipped on the used market. The amplifier uses three inexpensive 811A triode tubes. The 811A tubes cost about $20 each. If the 811A becomes unavailable, three 572B tubes will directly replace the 811A. I mention this as Svetlana removed their 811A from manufacture due to not wanting to market a low profit tube. The 811A plate is much more fragile than the 572B, just pay attention during tune up. I have seen holes burned thru 811A plates, however the tubes still produced good power output! Approximately 70 watts input will produce 500 to 550 Watts SSB PEP. Tuned input provides a good SWR match for your solid-state HF transceiver. 120 VAC distribution will operate the amplifier. The keying circuit is low voltage for all except the IC-706 series of radios that are current and voltage restricted. Two meters measure HV, plate & grid current. The amplifier also has ALC control. Size is approximately 14.5"w x 8.5"h x 15"d (no advertised spec listed). I have found these amplifiers as low as $350 used in good condition. A real bargain with fresh electronics and parts.
Gonset GSB-201:
This older 1960s amplifier operates on 80 to meters. Using four (4) 811A tubes, 100 watts input will produce approximately 700-800 Watts SSB PEP output. The meter measures plate current and relative power output. A front panel switch provides reduced output tuning and the power supply is of solid-state rectifier design. The keying circuit voltage is not known, an interface relay may be necessary. The amplifier did not specify tuned input, however four 811A tubes present a 75 ohm cathode input without any circuitry. Perhaps like the older Heathkit Warrier, a broadband design input is used to meet the Gonset advertised 50 ohm input. Size is 8.5"h x 12.63"w x 17"d. This amplifier is very heavy- watch shipping costs. Prices vary from about $250 to $350. Unlike the SB-200, this amplifier is rarely advertised for sale.
DENTRON CLIPPERTON L:
This is a reliable 160 to 15 meter (modifable to 10 meters) amplifier. The amplifier uses four (4) rugged 572B tubes for 1100 Watts SSB PEP output with 100 watts input. Early models were without a tuned input. Four 572B tubes have a cathode input of 75 ohms without any circuitry. A real neat feature of this amplifier is a lower plate voltage 'CW' selection switch on the front panel. I have used four cheap 811A tubes with the 1800 VDC on the plates. DO NOT use the 2600 VDC SSB selection on 811A tubes. The output is 800 Watts SSB PEP with 100 Watts drive. As for higher than 811A specified voltage at 1500 VDC plate rating, the Collins 30L-1 applies 2000 VDC no signal dropping to approximately 1700 VDC at 700 Watts output. The amplifier has a single meter for plate & grid current. Low voltage antenna relay switching is used. Operation at 120 VAC is usable, however a 120 VAC 20 amp circuit is best. A cover on the rear panel provides an easy conversion to 240 VAC operation using simple jumpers. I do not have an exact size specification, the amplifier is rather compact at approximately 6"h x 15"w x 15"d. The lowest price is about $375, but this is the only easily obtainable amplifier in the 1KW+ output range.
HUNTER BANDIT 2000B:
The Hunter Bandit 2000B is simular to the Dentron Clipperton L. Using four 572B tubes, this amplifier will also produce 1KW output with 100 Watts drive. The amplifier has two meters, one for relative output and the other for plate & grid current. The RF output meter is interesting in that adjustments for different feedline impedances and sensitivity adjustment on all bands has been engineered in the metering circuit. The amplifier does not have a selectable tuned input, however with four cathode tubes the specifications state 50 to 75 ohm input. Like the Clipperton L, 120 VAC operation is available. I would prefer the Clipperton L, but a Hunter Bandit at $300 would be interesting. Size appears simular to a SB-200.
Collins 30L-1:
This collectors item is over budget for this article.
YAESU FL-2100B:
I do not highly recommend this HF amplifier as arcing is somewhat common on the band switch and the amplifier operates somewhat hot. Perhaps it is a matter of improper tuning or a part upgrade eliminated the issue. With plenty of SB-200s available and usually at better prices, the FL-2100B is not my first choice.
AMP SUPPLY LA-1000, DENTRON GLA-1000:
I do not recommend these amplifiers as replacement 6LQ6 or 6MJ6 'TV type' tubes cost about $40 to $50 each. The amplifiers use four tubes and power output is about 400 Watts SSB PEP.
GALAXY 2000, SBE SB2-LA:
The Galaxy uses ten (10) 6HF5 TV type tubes and the SBE uses six (6) 6JE6 or 6LQ6 TV type tubes. As with the LA-1000 and GLA-1000, the tubes are very expensive unless your uncle has an old TV shop with NOS tubes. Sell the NOS tubes and buy a high-end amp!
HEATHKIT HA-14 'KW KOMPACT':
This amplifier is simular to the SB-200 in that most of the circuitry including a tuned input is available. The tubes used are a pair of 572B. The title 'Kompact' is that the amplifier makes use of a remote power supply that looks and measures size wise like a HP-23 AC series power supply. A DC power supply is available, however I bet the switching transistors squeal like heavy equipment back-up alarms! The amplifier is reliable, however be very CAREFUL with the high voltage cable that travels from the remote power supply to the amplifier. The cable may have poor insulation due to age. The amplifier is only 3.375"h x 12.5"w x 10"d. Plate operating voltage is approximately 200 volts lower resulting in about 500 to 600 Watts SSB PEP output. Prices vary widely, however $300 to $350 with a 120 vac power supply is available on the used market. Much more rare than a SB-200, collectors may cause the price to rise.
This list of amplifiers is about all that is available on a budget. 3-500Z equipped Ameritron, Drake, Kenwood, Heathkit, Henry, AMP Supply and other amplifiers using ceramic tubes are way above the budget limit of this article. So, who cares if the 1500 watt amplifier produces approximately 1/2 to 3/4 an 'S' unit less on the receive side. The above bargains will provide a respectable signal. Good luck.
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Help, I Need a Cheap HF Amplifier!
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by K7PEH on January 4, 2007
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When these "classic" articles are reposted, it would be nice to also see the original posting date and also the original article number. If the article is still available on-line, sometimes it is interesting to refer back to the earlier discussion.
OK, at least I think it would be interesting.
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Help, I Need a Cheap HF Amplifier!
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by KC9HGJ on January 4, 2007
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This was a very informative and helpful article. Thanks for the elmer.
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RE: Help, I Need a Cheap HF Amplifier!
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by W4LGH on January 4, 2007
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I would have to agree that the Heathkit SB-200 is probably the most BANG for the buck going. Plenty of them out there, easy to work on, and tons of mods to bring it up to date. Will easily do 700watts, altho it is a lot more comfortable doing around 600. Usually can find them for $250-$350 price range. Hard to beat for the money.
If you wanna go NEW, the only real choice yo have is teh Ameritron AL-811. Good amp, but trying to get the rated 600watts out, you will distroy the 811A's pretty quick. Replace the 811's with 572B's, keep it around 600watts and it will last a lifetime! You can pick them up used for $400-$500, new around $650, but the 572B's will cost you another $140.
Solid state amps are great, but much more expensive, and lot less forgiving. Not that I believe in antenna tuners, but ts best to have one big enough behind the SS amp, as a 2:1 swr will cut it back big time. The Pi-L networks in the tube amps is more than broad enough to handle that.
Yes sir, the pole SB-200 is the way to go! Would have to give it an A+! Heath had a real winner there.
73 de W4LGH - Alan
http://www.w4lgh.com
PS...you can pick up a SB-220 used for about the price of the AL-811 new, then you'll get a pair of 3-500z's that are super tough, and run around 1200watts!
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RE: Help, I Need a Cheap HF Amplifier!
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by W7ETA on January 4, 2007
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The current QST has a great article about what should be replaced in those old "work horses".
73
Bob
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RE: Help, I Need a Cheap HF Amplifier!
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by AA8LL on January 4, 2007
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K7PEH, a quick "articles title search" gives:
http://www.eham.net/articles/3722
73,
Wade
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RE: Help, I Need a Cheap HF Amplifier!
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by N9AOP on January 4, 2007
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Good article - I have an 811A with 572's and its pretty bulletproof.
If you get the clipperton, besides working dx, you will get to know all your neighbors quite well.
Art
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RE: Help, I Need a Cheap HF Amplifier!
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by W4LGH on January 4, 2007
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~"Good article - I have an 811A with 572's and its pretty bulletproof. If you get the clipperton, besides working dx, you will get to know all your neighbors quite well."~ Art
Actually I think its the other way around...your neighboors will get to know YOU! Being in a CC&R neighboorhood myself, I try to stay as low key as possible. For the time being, I have about 50 acres of wetlands behind my house that host my HF antennas.
Makes for long cable runs, but using LMR-400 on HF freqs is like a pipeline out there. This also puts the antennas away from the "other" houses as well.
So I figure its a good trade off for all.
Alan
http://www.w4lgh.com
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RE: Help, I Need a Cheap HF Amplifier!
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by VA3SAX on January 4, 2007
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I say a better antenna is always a solution...because on 75 metre especially most opertors will have a compromise antenna. I don't really believe in running anything more than 100 watts; I don't believe that it's constructive. you guys can flame me if you like but I'm of the opinion that an antenna is a much better and cheaper investment because the better the antenna the more you can hear. it's like buying a megaphone to talk to people because you're wearing earplugs...you'd be better and communicating with people if you used a hearing aid and whispered rather than blowing everyone else away. that's my 2 cents worth on the topic
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RE: Help, I Need a Cheap HF Amplifier!
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by N3OX on January 4, 2007
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"I say a better antenna is always a solution...because on 75 metre especially most opertors will have a compromise antenna. I don't really believe in running anything more than 100 watts; I don't believe that it's constructive."
75m and 160m are where this becomes less true.
The problem is that *gain* doesn't help you at all on the lower bands as far as recieving goes. The noise level is so high that what you need is *directivity* so you only hear the noise that comes from the direction you're listening in, not the aggregate noise from all points on the compass. On 80m and 160m, you can sacrifice a LOT of signal LEVEL as long as it gets you directionality... hence a beverage antenna... -10dBi gain, but it'll outhear other antennas because you only listen to the noise you have to.
It's very hard and very expensive to build gain antennas on the lower bands. If you could put up a 3 element 80m yagi at one wavelength (240 feet!) above ground, you'd have both gain and directivity on 80m and your antenna would hear and transmit well.
===BUT===
There's no way an HF amplifier and a few thousand feet of wire 10 feet off the ground for a beverage farm is a bigger investment than a 3 element 80m yagi at 240 feet. As W8JI put it in another amp thread, the first 10dB of improvement of your transmitted signal on 10m is easiest achieved by improving the antenna. The first 10dB of improvement in your transmitted signal on 160m is easiest achieved by buying an amp.
You can use very inefficient but very directional receiving antennas and lots of transmitter power into a modest gain transmitting antenna on the low bands and do very well... it's the most economical way to go.
Dan
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RE: Help, I Need a Cheap HF Amplifier!
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by AE1X on January 4, 2007
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I agree. Most of the people that seem to be running amplifiers are not aware of the real effects of using them. They have not considered the real improvement that can be expected or the consequences of running high power.
One amateur has already been cited for running high power too close to a neighbor's home. There are regulations that limit the exposure to high RF fields.
An amplifier should only be considered after one has installed the best antenna possible for the station configuration and then care must be taken to insure no one is endangered by the high fields producted.
Look, the real question is: can you contact the stations you are trying to work. Not whether your signal is 30dB over S9 or 10dB over. This is the effect of increasing your output from 100w to 1000w. It seems that most of those using the amplifiers are not familiar with the physics involved and should bone up on these subjects before adding an amplifier.
Ken
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RE: Help, I Need a Cheap HF Amplifier!
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by N6AJR on January 4, 2007
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I find there are really about 4 levels of power that are important.
first is qrp level, usually around 5 watts plus or minus. When the cycle is good and the bands are open a qrp signal can work any where, especially if the have a great antenna, but will not usually be busting any DX pileups.
second level is 100 watts barefoot, which most hams use and into good to great antennas you can make lots of contacts most of the time, especially if you work with the propagation in mind. You can get DX but will call for a while if working a pileup, usually. This just makes it easier than qrp and you are competing on an even base with about 80 % of the hams in the world.
if working a NEW dxpedition, you may have trouble getting in the first couple of days if they are rare.
third level is the ones talked about in this article. This is the 300 to 1000 watt level and you are in the top 20 % or so of hams in the world and you will quite often bust a pileup with a lot less calling than when barefoot, as this set's you above the "noise level" on most parts of the bands and your signal sticks out from the crowd. this is also a good setup in the shack because you can use the modest coax cable and mid range tuners and have less problem with TVI, RFI and such.If working a New dxpedition you actually have a decent chance to get in on the first day or two of the expedition.
the last level is legal limit. Into a modest antenna this will be the help you need to really work some serious DX and with a great antenna, you can often get DX on 1 or 2 calls. you put out an excellent strength signal and are louder than probably 90% of the rest of the hams. ( assuming that all other criteria are the same). BUT at this level you need to use coax that is rated for the power, and also antennas that are rated for this power level, and if you use tuners etc. they need to be stronger too. ( in a word , more $$$) and more problems on RFI and such. With a little luck you can usually work the NEW dxpedition in the first couple of days, unless the bands are just rotten or the dx is at your antipose.
If you really want an eye opener, have a friend on hf who has an amplifer meet you on a frequency and have him start at legal limit the drop to 600 watts , the 300 watts then 100 watts and the 5 watts. you can hear the difference your self. And you will see that the difference between 5 watts and a hundred watts is about the same as from 100 watts to legal limit. So burning up your finals to try and get that last watt of power from your rig is pretty much a non issue.
I have had many , many amps over the years, from the old sweep tube amps, to an LA 1000NT, to 3 or 4 clipperton L's ( with 4 572 b's) and several ameritron 811 and 811H amps, and alpha 76 a ( uses 8874's) several solid state amps, als 500) and more.
I current have 3 HF amps on line, I use an alpha 87A with the orion, and an ameritron ALS600 through an LDG AT1000 tuner for the TS2000, and I use an IC 2-KL with an AT500 for the IC 746 pro. All the rest of the rigs run bare foot. I have these set up specifically because I do not have to tune any of these when operating. I do some contesting and some DXing and this makes it easy to operate, espically when using telnet spots and electronic logging.
The Alpha and the Icom 2-KL both autotune and auto bands switch, and on the TS 2000 I have only to switch the band switch and not tune this one either.This is great for Search and Pounce.
but remember it is cheaper to gain 6 dB in an antenna than in an amplifier, and the antenna helps make the incoming signal louder too.
Life is too short for QRP :)
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RE: Help, I Need a Cheap HF Amplifier!
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by N3OX on January 4, 2007
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"but remember it is cheaper to gain 6 dB in an antenna than in an amplifier"
To a point. I just gained 6dB on 160 by going from a very, very poor antenna to an acceptably poor antenna (say -10dBi to -4dBi)
I could probably do another 6dB antenna improvement for four or five hundred dollars in radial wire and top loading (assuming I would move to someplace with more land anyway). (-4dBi to 2dBi)
The next 6dB antenna improvement would probably cost, I dunno, $5000, if I was clever about it? (2dBi to 8dBi)
The gain vs. dollars distribution would be different on 20m. The place in the sequence where "buy an amp" becomes the most economical would be different on 20m.
73,
Dan
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RE: Help, I Need a Cheap HF Amplifier!
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by K5YF on January 4, 2007
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Great article and the timing of it is superb!
The sunspot cycle is predicted to bottom out in July and this time next year propagation conditions are likely to be about as they are now.
The lower bands will continue to be usable, but consider the ambient noise of the lower bands. A 500w amp sure would come in handy.
A more efficient antenna is usually better at receiving undesirable RF (noise) along with desired RF. (Horizontal loops are some of the quietest IMHO.)
If you live in hurricane alley, consider adding an amplifier to your station at least for the next couple of years.
Also, consider that the people you might need to communicate with could be dealing with as much noise as I do at my QTH. Seldom less than S5-S7 static and crashes to S20. Snow storm hiss is nothing compared to the thunder storms we have rolling in the Gulf most of the time. Lightening crashes propagate very well over salt water.
best 73 everyone!
-Brandon
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RE: Help, I Need a Cheap HF Amplifier!
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by NS6Y_ on January 4, 2007
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This is why there are antennas like the Moxon, EWE, and Beveridge (that last for recieve only).
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RE: Help, I Need a Cheap HF Amplifier!
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by W6TH on January 5, 2007
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.
I thought this post was for:
Help, I Need a Cheap HF Amplifier!
Why the constant change of pace; antennas?
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RE: Help, I Need a Cheap HF Amplifier!
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by G3RZP on January 5, 2007
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How much do you value your time at? For $300 at various hamfest flea markets, you can garner more than enough parts to build a full legal power amplifier. It's also quite possible that there's some older ham (or hams) in your vicinity with old parts such as variable capacitors, switches, transformers, tubes, etc., that you can beg, buy cheaply or even trade for helping him with antenna maintenance or similar.
I managed to get a 1kW output capability amplifier for about $100 complete: most of that was on paint for the scrounged 19 inch rack cabinet 5 feet high, and the panels for the various units! But the downside is the time that building the amplifier takes. A rebuild is under way, and has been for over three months, although admittedly, a lot of overseas travel resulting from work QRM is responsible for that delay.
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Help, I Need a Cheap HF Amplifier!
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by G8KHS on January 5, 2007
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I agree that the SB200 is a good budget choice, I own one.
Rugged, simple and easy to work on.
The FL2100B does run hot, but most people use a fan on top of the case for additional cooling. I have found the bandswitch problems seem to come from abuse, but the switch is not the highest quality. The FC102 tuner suffers in the same way if you change bands while transmitting as was done to my friends FC102 by another G4 station who should have known better.
Don't discount the FL2500, a good one should go for $100 - $200, and you can still obtain 6KD6 Tubes if you look around.
73 John G8KHS
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RE: Help, I Need a Cheap HF Amplifier!
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by WX1F on January 5, 2007
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I don't know what planet this guy was on but I have never seen a decent used amp for less than $450. The only way anyone can find a $250 amp is to be johnny-on-the-spot when a ham's estate is parted out and rip off the widow. There's a guy on one of the auction sites that seems to have a sixth sense. He has ripped off 100's of widows for cheap gear to resell on his auctions. Just do a search for Drake and Collins gear sittin on a red draped background.
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RE: Help, I Need a Cheap HF Amplifier!
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by KE3HO on January 5, 2007
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<< I don't know what planet this guy was on but I have never seen a decent used amp for less than $450. >>
I believe he was on Earth at the time. Keep in mind that this is a re-post article. It was originally posted in 2002. A quick search for SB200 in the classifieds here on eHam (including sold items) shows a number of SB200 amps sold in the $200 to $300 range, well under the $375 "premise" price stated in the article.
73 - Jim
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RE: Help, I Need a Cheap HF Amplifier!
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by WA2JJH on January 5, 2007
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A used SB-220 with harbach mods (replacement capacitor bank and improved regulator board) is not a bad way to go either.
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RE: Help, I Need a Cheap HF Amplifier!
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by N4SL on January 5, 2007
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I think the SB220 is the best deal. Lots of power, really much better design than the SB200.
I have an SB220 for my K2/100 and an Alpha 99 for my FT1000MP MkV. What a combo!
The only RFI issues I have is a neighbor with really crappy guitar amps that tweak out with 50W on some bands. We have worked out a schedule arrangement (because his 120' tall tree supports one end of my 500' zepp for 160m, that's why!!).
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RE: Help, I Need a Cheap HF Amplifier!
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by W7ETA on January 5, 2007
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For some strange reason, I thought the article was about good values in used amps.
Bob
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RE: Help, I Need a Cheap HF Amplifier!
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by W6TRI on January 5, 2007
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I regularly see the SB200/201 sell for under $400 on E-Bay and those are usually inflated prices.
I recently picked up a pristine SB200 at a local hamfest/auction for $250. I consider that quite a bargain!
73,
W6TRI
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RE: Help, I Need a Cheap HF Amplifier!
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by KB7XU on January 5, 2007
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I recently snagged an almost-perfect Collins 30L-1 amp from eBay for less than $475.00! Good buys are out there. Just list the features you want in an amp and start looking everywhere for it.
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Help, I Need a Cheap HF Amplifier!
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by G8KHS on January 5, 2007
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I paid $275 for a near mint SB200 from a G3 station a few years ago. He was the original owner and the tubes are the ones supplied with the kit and still capable of supplying the rated output. I bought a pair of new cetrons for $110 from a G4 in Exeter UK, just in case! Harbach will get my next expenditure on it though.
My friend bought an FL2500 from a cber who had fried the tubes. He paid $85 for it, got hold of a set of 6KD6, replaced a few resistors and hey presto, 1KW out for less than $180 total.
A cosmetically damaged amp will always fetch a low price as will a faulty one. Also a non warc banded amplifier will be not as pricey, so consider this when on a budget.
73, John.
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RE: Help, I Need a Cheap HF Amplifier!
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by KG8JF on January 6, 2007
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Just a quick note about the ALS-600 from Ameritron. They have pretty well dummy-proofed it, ALC notwithstanding. They put a "load fault" circuit that will shut you down if it encounters either of the two biggest bugaboos, hi SWR and hi drive (>100 watts).
I have a friend who built a hombrew version of it and went thru several sets of MRF 150, which someone, fortunately, had given him.
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RE: Help, I Need a Cheap HF Amplifier!
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by AD5TD on January 6, 2007
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"RE: Help, I Need a Cheap HF Amplifier! Reply
by WX1F on January 5, 2007 Mail this to a friend!
I don't know what planet this guy was on but I have never seen a decent used amp for less than $450. The only way anyone can find a $250 amp is to be johnny-on-the-spot when a ham's estate is parted out and rip off the widow. "
I have seen the same here in South Texas. One Crooked ham "helped out" a SK widow by "getting rid of that junk Alpha 87 (mint cond)" for the very fair price of less than $1000. I hope he rots in hell.
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RE: Help, I Need a Cheap HF Amplifier!
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by KA5IWO on January 6, 2007
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It was mentioned in some of the amps listed in this article that with (4) 572b tubes, the amp would present a 50 to 75 ohm input impedance without a tuned input circuit. Can anyone tell me on the Amp Supply LA1000 and the Dentron GLA1000 amps using the (4) 6LQ6 tubes without a tuned input in the amp, what impedance could one expect from these amps. I have both amps and both work good with 400 to 550 watts output depending on band with all new matched tubes in them.
Do these amps with the 6LQ6 tubes also present 50 to 75 ohms without a tuned input?? I figured they must be close because the rig used (FT-890 no tuner) did not seem to frown upon what is was "seeing" and turn back its power.
Thanks
Kevin
KA5IWO
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RE: Help, I Need a Cheap HF Amplifier!
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by KA5ROW on January 7, 2007
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The Heathkit 230 is a nice looking amplifier 10 - 80 meters with 500 to 600 watts output.
This amp can be found for about $400 + or so. BUT be ware the replacement of the 8873 tube is a $600.00 + investment. So the amplifier + replacement tube = a new Ameritron 811H with money left over.
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RE: Help, I Need a Cheap HF Amplifier!
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by WA7PRC on January 7, 2007
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N4SL:
"I think the SB220 is the best deal. Lots of power, really much better design than the SB200."
Ya sure, you betcha! Waaay back in the mid 70s, I bought a used '220 for $275 (if I recall correctly, the new price was $365). I replaced the single 4-65A that was in it (with a pair of used Eimac 3-500Zs) and returned the bias circuit to the way Heath designed it. Afterwards, the unit has worked GREAT for many years. The 3-500Zs makes it the Timex watch of amplifiers: "it takes a lickin' and keeps on tickin'!"
Bryan WA7PRC
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RE: Help, I Need a Cheap HF Amplifier! Heath HA-14
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by K0VH on January 7, 2007
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In reference to the author's mention of the HEATHKIT HA-14 KW KOMPACT...simular to the SB-200, uses a pair of 572B, only 3.375"h x 12.5"w x 10"d for the RF deck.
I picked up a used "estate auction" unit from a friend 2 years ago and repopped it with new 572Bs a year ago taking it from 400+ to 600W out. I have a review on eham.com and am generally happy with it's operation; for a small SSB-only basic amp to get one in the half KW range with minimal desk space it's hard to beat. CW operators stay clear as there is no CW rating. I mainly use it for 20m SSB QSOs when the band is full although I anticipate when 15 & 10 get more solid I will use it occasionally there as well.
The only quirk appears to be some artificial extra impedance generating a SWR even in pass through mode, which I have yet to debug so I sometimes bypass the unit entirely when conditions are good and I don't need to turn it on (oh yes, it's "instant on" as well). I did add an external fan to help tube life/cooling too.
Sure I'd prefer a SB220 but this little guy does the trick for the little I need a half KW on 20m. Perhaps a collector will look me up in a few years when the bands improve and I decide to give it up. 73s K0VH
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RE: Help, I Need a Cheap HF Amplifier!
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by KO6UJ on January 7, 2007
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I owned an AL-82, which was okay, but destroyed in a Ham Radio Outlet fire. I replaced it with a VL-1000 set and forget sand amplifier. Both of these are too expensive.
I came close to purchasing an 811, but was derailed by a well-meaning ham. In retrospect based on the total number of reviews on this site and if they are an accurate indicator, statistically the 811 HF amp is the best bang for the buck in the ham community. If you analyze the responses on all HF amp you will find that the shear gravity and quantity of repsonses weigh the heaviest in flavor of the 811. And that includes ALL amps, i.e. the Bulgarians Acom and Alpha; the Americans QRO, HF, Collins, Heath, etc.
It's hard to beat a "throw away" amp like the 811 that you can buy brand new with a warranty and no hassles of wonder about build quality or parts availability.
HTH,
73
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RE: Help, I Need a Cheap HF Amplifier!
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by WA2JJH on January 8, 2007
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having owned both SB-220 and gla-1000, I can only recommend the SB-220.
It is true that the GLA-1000 is the only amp you can buy used for $250 today, they simply are not a good deal.
for $250, you will find most gla-1000 amps need a few tubes replaced. Replace all 4, you may get 500w
out.
Result is an amp that arcs, and you must have a decent SWR.
Say you got an SB-220 for $500. Even if there are 10 year old eimac 3-500's, you will output 600W minimum.
Put in a new set of 3-500z's and spend $75 for a new capacitor bank from harbock, you have a 1KW minimum amp
that will take much SWR abuse.
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RE: Help, I Need a Cheap HF Amplifier!
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by KASSY on January 8, 2007
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I saw six SB-200s at the last hamfest I attended. Asking prices were $225 to $325 and nobody was interested. There was dickering room. Probably could have carried one home for less than $200. The only mod the SB-200 needs is the "soft key" mod, and check the grid resistors. It's blessedly free of the problems that plague the SB-220, so it really doesn't need "mods".
I'm always put off by those who claim "improving the antenna is cheaper than an amplifier". They must live in a fictitious world. An SB-200 gives you 8dB of gain on five bands, and costs under $300. How can you improve your antennas by 8dB on FIVE bands for under $300?
Let's say a ham has wire dipoles in trees at 40-50 feet. A three-element Yagi at the same height will only improve the antenna by 5.5 dB - and a FIVE BAND three-element Yagi will cost a lot more than $300. In fact, you won't even find a decent three-band Yagi for $300 used. Then you have to add a tower to hold it up, and now that you've narrowed your beamwidth, a rotator to turn it.
Plus, as others have said, on 160, 80, 40 and 30, atmospheric noise is so high that improving your antenna rarely improves your ability to receive.
I ended up buying an SB-220. I haven't grown all that fond of it...components are undersized for the voltages they're using, and the cooling system is poor enough that solder can melt from the tube base pins. Frequent arcing problems caused by poorly-chosen components are fixed seemingly only with mods that reduce the gain and power out. Plus, when you buy one, it usually has badly-done modes that you have to remove. Mine's not for sale, but I wish I'd kept one of granddad's SB-200s.
-k
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RE: Help, I Need a Cheap HF Amplifier!
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by WA2JJH on January 9, 2007
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I liked the SB-230 also. I built one. I was stupid enough to lend it to WB2J-I 25 years ago. He never gave me the $500 I wanted for it!
WANT A CHEAP AMP.....Steal one from a High School buddy! Rather pretend your going to buy it. Use it.
Then claim you just gave it too them.
Believe it or not I found out the dude is still active. Hmmmmmmmmmm! Tony, if you are reading this.......do the right thing!
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Help, I Need a Cheap HF Amplifier!
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by K9MI on January 9, 2007
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A gain antenna on 75/80 meters is not exactly common. And neither is the structure that is going to hold it up. There is a 4 square, but that is pretty labor intensive and takes up a lot of space. Not sure, but in town it could be noisey.
If you are going to buy an amplifier for use with your dipole, loop whatever, the antenna needs to be as far away from the house as you can manage.
On 75/80 cw you can use 100 watts and not do too bad. On 75 phone, unless you have that 3 elements at 240 feet, which is going to cost a lot more then an amplifier, buy an amp if people are having trouble hearing you, and you want to work 80 and 160.
Higher frequencies, the propogation gods will go a long way to help you. On 80 and 160 you need to make some of your own propogation. If your antennas are close to the house, and not high, 500 watts, may be your limit. I've tried a pair of 3-500z's here, and that was too much on too many devices in the house. 500 watts out is just about right for me, and yes it does make a difference.
Put the best antenna system up you can, but when that still isn't enough on the low bands, then it's time to increase the transmitter power.
Mike, K9MI
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RE: Help, I Need a Cheap HF Amplifier!
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by KASSY on January 9, 2007
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If using QRO interferes with gadgets in your house, then get rid of the gadgets. There are too many of 'em anyway.
In my case, having the antenna directly over my house gets the antenna as far from the neighbors as I can. My own family members, I can negotiate with. The neighbors? I'd rather not.
When my family members notice that I'm on my radio, they know which of the household entertainment devices works and which does not. We don't own a TV, so that's a moot point.
-k
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RE: Help, I Need a Cheap HF Amplifier!
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by K5MO on January 10, 2007
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"but remember it is cheaper to gain 6 dB in an antenna than in an amplifier"
And what really makes a difference is doing both!
John K5MO
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RE: Help, I Need a Cheap HF Amplifier!
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by KASSY on January 11, 2007
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>"but remember it is cheaper to gain 6 dB in an antenna than in an amplifier"<
>And what really makes a difference is doing both!<
>John K5MO<
John,
For the ham who has a wire G5RV held aloft at 50 feet between trees, please describe the "cheaper" antenna that will provide 6dB of gain from 80 through 10 meters.
Thanks.
-k
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Help, I Need a Cheap HF Amplifier!
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by KA3DPW on January 12, 2007
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I generally agree with your opinions in this article.
I have an Yaesu FL-2100B and I have it exited by a Kenwood TS-830S. The first hing to be encounterd is the ALC and relay cables.
Once you get that issue settled the next issue I encounterd was the Amplifier was overdriven by the transiever. I found that if I reduced the ALC voltage I could reduce the overdrive problem. (Those of you with newer radios will want to check the ALC for its compatibility, you may need to interface the two for the reconciliation of the differences.)
Next, The finals need better ventilation. blowing a fan in the top is about all you can really do for this. If you try to open a larger hole thru the bottom I'm told you stand tehrisk of RFI issues you'd prefer to avoid. Running the Amp at lower power levels would most likely be the way to go. Use ral good ground and the better antena will usually be the choice for QSO rather than up the power. I use a good vertical and keep an end fed horizontal for recieve in case the noise is a problem.
Many of the FL-2100's out there do not have 160 either. So you may want to consider that factor.
The insides of these Amps are tight for space too. Heat is something you want to watch with them. But I find mine works very well since I learned to adapt to it's pluses and minuses.
Take care of them and they are not a bad unit. But a word to the wise: know what you're doing when you use it. I use 220VAC and good ventilation and it works better. If you damage something inside sometimes a replacemant may take a little hunting.
772B's are a good tube pair. Watch the bandswitch contacts and be gentle with the parasitic chokes, they take the heat at the top of the tube.
my 220 clone has problems of it's own also. You can't leave the standby switch in the operate position for to long since there is transformer leads that get cooked with to much heat for to long. If the unit has not been used for a long time it should be brought up slowly to power. The caps might suprise you when they go. The new capacitor bank is a way around this I hear and worth the money. Upgrading to 3-500z's would be a good step in the right direction and will provide a better performance.
It does come at some investment. You'd better consider how long you want to use vintage tube gear into the long run. As for me that's all I use at HF.
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Help, I Need a Cheap HF Amplifier!
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by KA9DTZ on January 14, 2007
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Interesting post. It answered some questions for me. I was given a LA1000 some time ago but hadn't used it since I was in an apartment and not active on HF during that time. Now that I am back into a house, I pulled it out of storage, powered it up and found exactly what I read in the post... about 400W output. I quickly assumed the tubes were flat. Over the years I have never had an amplifier to use with any of my HF rigs so the 400W is welcome.
I wonder, did these amps ever really come near the 1KW they claim? Since this is a four tube amp. has anyone ever changed tube sockets and tried to convert one over to 811A tubes? It just seems a waste to scrap the amp and seems equally a waste to put the money into another set of 6MJ6 tubes. I've never seen a 811 tube so I don't know how the physical size compares to the 6MJ6 tubes.
73, Greg
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RE: Help, I Need a Cheap HF Amplifier!
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by W4LGH on January 17, 2007
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~"I was given a LA1000 some time ago, about 400W output. I quickly assumed the tubes were flat. Over the years I have never had an amplifier to use with any of my HF rigs so the 400W is welcome I wonder, did these amps ever really come near the 1KW they claim?"~
The tubes are flat...The 1KW it was rated @ was INPUT power...and the sweep tubes it uses run about 40-50% effecient, minus some other losses..so 400Watts out is about right. All of the older amps were rated in INPUT power, since the max input in the old days was 2000watts input, max out was accepted at 1KW. As designs changed, tube got as high as 70% and things were changed to 1500watts OUTPUT as the MAX.
Hope this clears things up for you.
73 de W4LGH - Alan
http://www.w4lgh.com
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RE: Help, I Need a Cheap HF Amplifier!
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by WA2JJH on January 18, 2007
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Thats a Sweep tube amp for ya. Low efficacy comes with the beast. I had a GLA-1000. 400-450W was a maximum out. Output would sag to 300W on 10M.
I also got used to tuning 3-500z amps. They are very forgiving.
My GLA-1000 would chew up tubes during every tune up.
Back when the cheapy sweepy amps came out, sweep tubes were dirt cheap and easy to find. One could afford to swap out 4 tubes every couple of months. Now many upgrade those amps to beefier russian tubes.
Today I see 6MD6's,6DQ6,6DK6,6JS6's on ebay selling for $40 bux a tube!!!!! One can buy slightly used 3-500Z's for $85. Make an amp around a single 3-500zd.
You will get 600W. Seems silly to spend $150 for 4 tubes that may get you 450-500W with alot of effort.
6L6's are still reaonable in price because Real guitarist's want tube amps. Many have used 6 6L6's
in parallel to get 500W or more on 20M.
Heathkit amps sure were the best investment hams made. Do not look for bargains on ebay. The word is out! What really sucks is that "estate dealers" USE EHAM REVIEWS to get top dollar on EBARF!
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RE: Help, I Need a Cheap HF Amplifier!
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by WA4DOU on January 20, 2007
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Help, I Need a Cheap HF Amplifier! Reply
by KA9DTZ on January 14, 2007 Mail this to a friend!
Interesting post. It answered some questions for me. I was given a LA1000 some time ago but hadn't used it since I was in an apartment and not active on HF during that time. Now that I am back into a house, I pulled it out of storage, powered it up and found exactly what I read in the post... about 400W output. I quickly assumed the tubes were flat. Over the years I have never had an amplifier to use with any of my HF rigs so the 400W is welcome.
I wonder, did these amps ever really come near the 1KW they claim? Since this is a four tube amp. has anyone ever changed tube sockets and tried to convert one over to 811A tubes? It just seems a waste to scrap the amp and seems equally a waste to put the money into another set of 6MJ6 tubes. I've never seen a 811 tube so I don't know how the physical size compares to the 6MJ6 tubes.
73, Greg
------------------------------------------------------Greg,
Your sweep tubes are not flat! There was nothing wrong with the amplifiers that were based on four (4) TV sweep tubes. Yes, they were light duty amplifiers but they were inexpensive and they held up and worked well if the owner could master the tuneup within proper time constraints and allow reasonable cool down time after key down and also not over drive them. They were NOT 1000 PEP input amplifiers, regardless of what may have been advertised or popularly believed. Plate dissipation of the sweep tubes was typically 30-40 watts and the amplifiers were capable of about 550-650 watts input. They had typical efficiencies of 65% on 80 meters down to roughly 50% on 10 meters. Typical output was 400 watts. Thats all you can expect out of them and if you get more, you are severely overdriving them or the accuracy of your measuring device is suspect. They filled a niche in the market and 400 watts was 2 db down from the typical output of KW amps. of the period and 6 db higher than 100 watt exciters.
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RE: Help, I Need a Cheap HF Amplifier!
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by WA4DOU on January 20, 2007
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I failed to make clear that typical output of the sweep tube amps. was 400 watts on 80-40-20 and declining to 300 or a bit more on 10 meters.
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RE: Help, I Need a Cheap HF Amplifier!
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by WA4DOU on January 20, 2007
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"I wonder, did these amps ever really come near the 1KW they claim? Since this is a four tube amp. has anyone ever changed tube sockets and tried to convert one over to 811A tubes? It just seems a waste to scrap the amp and seems equally a waste to put the money into another set of 6MJ6 tubes. I've never seen a 811 tube so I don't know how the physical size compares to the 6MJ6 tubes."
No they did not ever really come near the 1 kW they claim. It was a bogus claim.
The transformers chosen for duty in the sweep tube amplifiers were not chosen for duty someday at 150% of their rating. They were chosen solely for the particular duty they were assigned. They are not suitable for four 811A's. Leave the tubes alone that are in your amp. and take care of them. Keep your eyes open for bargain NOS replacements.
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RE: Help, I Need a Cheap HF Amplifier!
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by WA2JJH on January 21, 2007
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The 1000W could have refered to total input power consumed by the tubes. That was with the times of how power was designated.
Novices used to have a power limit of 75W input. On closer inpection, input included ALL power delivered to the final amp.
That included filament wattage as well as plate voltage, and current. I think input power to the tube was also in that 75W input calculation. That was one of the questions asked on the old novice test for many years.
I have to admit it did get very confusing. I am sure those sweep tube amps do comply with the old way we USED to spec power. I am sure that these amps are 1 kilowatt INPUT.
If you were a Novice back before 1975, the 1 kilowatt
ads we saw in QST seemed like a lot of power no matter how we sliced it.
Our 75W input rigs got 30-40 watts to the antenna. We could only dream about a bunch of tubes consuming a Kilowatt.
The problem as I see it is that ALL Hams got a Raw deal.
Solid State finals are the norm today. Solid state technology has come a very long way. Tubes are not used much more at all.
Some TV transmitters are 50KW and solid state. However it seems that the price breaks on solid state devices over a few hundred watts have not "trickled down" to hams.
So most of us are still using tube amps for over 400W
or so. A set of MRF-150MP's(175W out)cost the same as 3-500zd-M(1500W out or more.)
Somrthing can be said about finals you can just swap out as well. The Warm glow is nice too. I am amazed by the abuse 3-500z's can handle. Sweep tubes are just too expensive and fragile.
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RE: Help, I Need a Cheap HF Amplifier!
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by WA4DOU on January 21, 2007
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WA2JJH-
Sir, you are in error. The power input of an amplifier is also known as the "plate power input" and it is the product of the plate voltage and the plate current. Amplifier input did not take filament current, screen grid current or driving power into consideration.
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RE: Help, I Need a Cheap HF Amplifier!
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by WA4DOU on January 21, 2007
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Come to think of it, the FCC probably required us to also take into consideration the driving power in the case of the grounded grid, cathode driven amplifier as part of the driving power did appear in the output. OK, we'll allow the sweep tube amps. to be called 650-700 watts input amps. since they were gg/cathode driven.
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RE: Help, I Need a Cheap HF Amplifier!
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by WA2JJH on January 21, 2007
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I am only going by what was on my Novice test in the 1970's.
I guess the FCC wanted to make sure us newbies did not create too much havock.
Your are correct in what input power is today.
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RE: Help, I Need a Cheap HF Amplifier!
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by WA2JJH on January 21, 2007
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The budget amps also used plate and load caps that would arc.
With some of the cheapy sweepys one could order a PC board from "Far Circuits inc." They had the space for the larger tubes.
Eventually one for all extensive purposes, will end up building their own amp. An ATU that can handle 400W comes in handy. Add all that up, one finds that cheap HF amp becomes an investment. Perhaps not a bad project to work on.
The sweep amps in general use lower high voltages.
After one 3000V zap from a 3-500z amp, you remember the one hand rule again.
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Help, I Need a Cheap HF Amplifier!
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by KA2RIT on January 21, 2007
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I have a SB200 which I've had for years. also have a AL80 My sb200 is in very bad shape. For one it fell off a shelf and the cabinet is badly damage. Meter and knobs are damage. After just buying a home last Dec. I found out the basement leaks and yes the amp was on the floor at the time. After drying it out i tryed turning it on. yes it come on but at the same time it trips the breaker. I'm going to be looking for parts to rebuild this amp. Anyone know of a good source for parts, and mods for this amp
Don't think I'll be able to fine a cabinet for it. I was thinkg of rebuilding it into a rackmount cabinet. Any ideas from anyone out there.
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RE: Help, I Need a Cheap HF Amplifier!
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by WA2JJH on January 21, 2007
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KA2RIT. HARBOCH AND RF PARTS are two that come to mind.
Harbock sells upgrade kits too. Hope your filiment Xformer is OK. The filiment xformers for the 200 and 220 are scarce.
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