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Author Topic: Why can't you buy an hf amp in the USA running more than the legal limit?  (Read 25003 times)
K2ACB
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Posts: 99




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« on: November 15, 2015, 10:54:50 AM »

The legal limit to run an hf amp in the USA is 1.5 kw. There have been in the past some companies in the USA that have made hf amps that run more than the legal limit. However the companies that made these amps have always noted that these amps are for export only and they cannot be shipped to anyone with a USA address.

Yet it is possible for an American to buy an amp for hf from companies based in Australia and Europe (Slovakia)that make radio amateur hf amps that run a lot more than the legal limit here. Is that because these amps are not FCC approved?

From time to time you see ads on E.Ham,QRZ or QTH.Com for hf amps, some made by american companies, that run more than the legal limit. Some of these ads have said they are export models. Are these amps reimported into the USA or can american radio amateurs actually buy more than legal limit hf amps here if they have the right connections and are willing to pay for them?

Many years ago in the mid 1980's i lived in the UK for three years and had a reciprocal call. At that time and I think it is still the case today, the legal limit to run an amp in the UK was only 400 watts DC. There was one company,I forget the name, that made hf amps in the UK and one of the amps they made was similar to a Heath SB220 that could run a KW.It used two 3-500 tubes.  It was not illegal for that company to sell that amp there. However it was illegal for UK amateurs to run more power than the legal limit  

When i was there i did a favor for two UK hams i knew at the time. They paid me and i did bring in for them on different  trips back to the USA amplifiers that ran a lot more than the 400 watts DC input. One of those amps was a Heath HL2000 which was the newer version of the Heath SB220 and another was for the Amp Supply Company Amp that ran the three 3CX800 ceramic tubes. That amp could easily run 2.5 KW. The UK radio amateur that bought that amp  is now an SK.

I never new anyone in the UK who was a licensed radio amateur,who was reprimanded or lost their license, for running more than 400 watts DC. I think at one time some other European countries had similar power requirements as the UK , like Germany ,but they have since become more realistic and have raised their power restrictions. European radio amateur amp companies like SPE of Italy, AECOM of Bulgaria and OM Power of Slovakia all make hf amps that run more than 400 watts DC. These companies all sell their amps in the UK today through UK dealers.

Why the UK doe not raise their power limits to be more realistic with the rest of the world I do not know. Why the USA will not allow hf amp manufacturers here to sell amps they make running more than the legal limit but will allow US radio amateurs to import more than legal limit amps from abroad is a bit hypocritical. If they are illegal to sell here why should they not be illegal to import?

Any comments?

73
Alan-K2ACB
« Last Edit: November 15, 2015, 11:04:56 AM by K2ACB » Logged
KB4QAA
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Posts: 3327




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« Reply #1 on: November 15, 2015, 11:05:51 AM »

No hypocrisy involved.

1. The UK is not the US.  No arguments are valid.

2. The FCC does not put significant (if any) effort in policing eBay, Web, magazines, and the myriad ways that commerce is conducted.  Keep in mind that foreign manufacturers are not responsible for independent vendors who purchase, sell and ship their products.

3. US Customs doesn't concentrate on policing the minuscule sales of amplifiers to hams, when they are overwhelmed with important things like drug shipments, illegal pharmaceutical prescription orders, Trademark and Logo counterfeiting, etc.

Suggestions:
If you want a higher power amplifier for technical reasons i.e. head room, cooler operation, [features],longer life, etc., purchase one intended for commercial purposes, or build one.  Nothing illegal or unethical there.

[edited]
« Last Edit: November 15, 2015, 11:24:17 AM by KB4QAA » Logged

KA0HCP, ex-KB4QAA Relocated to Ks. April 2019.
SA4MDN
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Posts: 99




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« Reply #2 on: November 15, 2015, 11:11:02 AM »

is this one not over the usa limit but you can buy it in the usa, Ameritron HF Power Amplifiers AL-1500

Amplifier, Linear, EimacĀ® 3CX1500A/8877 Tube, 2,500+ W Output PEP, 160-15 meters, 240 Vac, 15 A Max., Each

Availability: In Stock
Estimated USA/International Ship Date: Tomorrow
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KM4AH
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Posts: 939




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« Reply #3 on: November 15, 2015, 11:13:03 AM »

Quote
The UK radio amateur that bought that amp  is now an SK.


Yeah, I never trusted those LK800's.
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KB4QAA
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Posts: 3327




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« Reply #4 on: November 15, 2015, 11:17:55 AM »

The final reason why reputable US amplifier manufacturers don't sell monster ham amplifiers?

-They want to uphold both the letter and spirit of FCC regulations and do so by not tempting honest hams to break the regs!
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KA0HCP, ex-KB4QAA Relocated to Ks. April 2019.
N9AOP
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Posts: 1119




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« Reply #5 on: November 15, 2015, 11:27:38 AM »

Always remember what Ten Tec used to say--'loud is good'.
Art
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REASTON
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Posts: 61




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« Reply #6 on: November 15, 2015, 01:04:59 PM »

When did the FCC say amplifiers over 1.5 KW were illegal to sell or use in the US?  What the FCC won't allow is an amp much above 1.5 KW to be certified for sale as a ham amp.  That is the difference.  If any ham can get a bigger amp than 1.5 KW, they can use it as long as its use complies with FCC rules. If you want to run a 10 KW at 1.5 KW, go ahead.  Really stupid to use an amp that way but it would be legal.
« Last Edit: November 15, 2015, 01:12:53 PM by REASTON » Logged
KK5DR
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Posts: 631


WWW

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« Reply #7 on: November 15, 2015, 01:16:55 PM »

No hypocrisy involved.

1. The UK is not the US.  No arguments are valid.

2. The FCC does not put significant (if any) effort in policing eBay, Web, magazines, and the myriad ways that commerce is conducted.  Keep in mind that foreign manufacturers are not responsible for independent vendors who purchase, sell and ship their products.

3. US Customs doesn't concentrate on policing the minuscule sales of amplifiers to hams, when they are overwhelmed with important things like drug shipments, illegal pharmaceutical prescription orders, Trademark and Logo counterfeiting, etc.

Suggestions:
If you want a higher power amplifier for technical reasons i.e. head room, cooler operation, [features],longer life, etc., purchase one intended for commercial purposes, or build one.  Nothing illegal or unethical there.

[edited]
Nail struck directly on the head.
Canada has a "legal limit" of 2.25 kW output, but I don't see many amps built to that spec. The market just isn't large enough.
As a side note, the legal limit has not stopped US hams from buying of building Amps that are capable of far above the limit. Many contesters have amp capable of double or triple the limit. Henry radio once posted info that 90% of all the 8K Ultra model were purchased by US hams.
The legal limit is only adhered to by those hams who are honest about operations.
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G3RZP
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Posts: 1090




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« Reply #8 on: November 15, 2015, 02:06:18 PM »

Actually, the UK limit is (on many but not all) bands, 400 watts P.E.P. OUTPUT, measured at the antenna......This was because of representations made by VHF/UHF contesters where significant cable losses occurred.

So if you have a 160m antenna with a feed impedance of 1200 + j350, the possible measurement uncertainty of power in the antenna starts getting to the +/- 25% or worse level....which wasn't a consideration when agreeing to 'power at the antenna' at V/UHF.

Add to that the UK Administration in practice isn't that worried unless there's a problem (mainly because they haven't enough money in the budget to worry about too much about amateurs!)... so you can see why there is a relaxed attitude. Having said which, they are generally pretty good in coming out to deal with QRM from things like solar power invertors and so on......The necessary performance standard for AR equipment is the ETSI one and that has no power level specified....I am told because above 170 watts, no IEC standard exists.
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AD4U
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Posts: 2536




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« Reply #9 on: November 15, 2015, 02:13:33 PM »

Back in the 1970's there was a ham near Chicago running over 50KW. I know that for a fact. I still remember him in the pile ups. PORTUGAL PORTUGAL JAPAN. If he came on everybody else might as well go QRT.

I guess you could ask Wizzard to build one for you. His 25KW amps are all over youtube.

Dick AD4U

PS: MANY on this site (myself included) have the knowledge to build a 25++KW amp. Some do but most do not. Even though I have an Alpha 77SX (2X8877) with external Peter Dahl transformer that will run the legal limit X 3, it has not been used in several years. I am having too much run running a 50+ year old Drake 2B receiver and a Drake 2NT 50 watt transmitter. So far 293 countries on 40M CW. After over 50 years hamming, this has put the fun back into radio for me.
« Last Edit: November 15, 2015, 05:20:47 PM by AD4U » Logged
N4ATS
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Posts: 1274




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« Reply #10 on: November 15, 2015, 04:03:08 PM »

You CAN buy any amplifier you want IN the USA. they are all over the place. My friend just bought a brand new O.M. 5K amplifier from eBay and the seller was out of New York. He only bought it to play around and see what it was built like, NOT to flood the waives with illegal power.

They are everywhere... Google is amazing...
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N7WR
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« Reply #11 on: November 15, 2015, 06:08:02 PM »

There are numerous HF amplifiers, made and sold in the USA, that are very capable of more than 1.5 KW.  Why one would want one is beyond me.  With a good antenna system much less than max legal can usually work through most pileups
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KM1H
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Posts: 4722




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« Reply #12 on: November 15, 2015, 06:26:56 PM »

Quote
Yeah, I never trusted those LK800's.

A stock LK-800A with the external transformer option will easily run about 3500W with 150W drive. Using 3CPX version tubes and about 3300V with the same drive it will easily do 5000W with some improvements in the tank circuit or as a monoband amp for 6m EME.

Those tubes are rugged when kept cool, run minimal grid current for the power, and have good plate and grid current trips.

Carl
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G3RZP
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Posts: 1090




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« Reply #13 on: November 16, 2015, 01:17:45 AM »

At 5kW out, you must need a fairly substantial 240 volt line - around 45 to 50 amps or so, depending on efficiency and power factor. I suspect few amps of that size will be single phase as stock, either.

How hard is it to get a 3 phase supply to a non-industrial property in the US?
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SWL2002
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Posts: 895




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« Reply #14 on: November 16, 2015, 04:14:26 AM »

To really make any noticeable difference, you'd have to step from 1.5 kW up to 6 kW.  Is the extra strain and heat worth it to run your 1500 W amp at 2500 W.  Not really...
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