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Author Topic: Why can't HF amps above the legal limit made in USA be sold legally in USA  (Read 31375 times)
K2ACB
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« on: November 19, 2016, 07:01:41 PM »

Why is it that one can import or even purchase from domestic companies like Array Solutions amplifiers like the OM4000A that can legally put out more than the legal limit? However, domestic manufacturers of hf amps cannot make hf amps above the legal power limit and sell them in this country.? These hf amps can only be made for export.  Perhaps the answer is that they would not get FCC approval to make these amps here. If that be the case, why can you still import hf amps that can run far above the US legal limit like the OM4000A or the largest Emtron hf Amp? These amps do not have FCC approval. However they still can be imported here.

Does US Customs care about this?

I know that the UK has different rules and regulations than the USA. UK radio amateurs are only limited to 400 Watts DC. Many years ago i lived in the UK for several years and had a reciprocal license. I also operated HF when I was in the UK. i knew at that time quite a few British radio amateurs who legally had hf amps that could run more than the allowed power. When I was in the UK I personally brought into the UK from the USA a Heath SB220 amp for a British Radio amateur friend with no problems. I also arranged for another friend from the USA to bring into the UK from the USA for another British radio amateur friend an Amp Supply hf amp running three CX-800 tubes. This amp could easily run a lot more than 400 watts and the fellow who bought the amp who is now an SK did run a lot more than the legal power there. There was no problem bringing this amp into the UK  It was even declared at British customs . British customs charged some duty but let the hf amp go through British customs without any problem.

The point is if an HF amp whether it is here in the USA,the UK or some other country , and is commercially made ,can run far above the legal limit, why should it be allowed to be brought in and sold in the country? This question is specific to the USA but other radio amateurs from other countries like the UK can also comment.  A lot of people who buy these amps will probably drive them above the legal limit.

Any comments?
73
Alan-K2ACB

« Last Edit: November 19, 2016, 07:22:41 PM by K2ACB » Logged
KM3F
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Posts: 909




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« Reply #1 on: November 19, 2016, 07:20:35 PM »

First, US made amps at that level can go above legal limit if they are driven hard enough. There is no built in limit on their power.
Second, it's keeping the costs down.
Third, some other countries have limits higher than 1500 watts.
Notice some amps are in the $7000 range and some are in the $3500 range for the same power.
No mater what amplifier you get that can run over legal limit, your Ticket is an agreement with the FCC to abide by the rules and limits set in part 97.
Good luck.
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K2ACB
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« Reply #2 on: November 19, 2016, 07:28:49 PM »

To KM3F:

I do agree with you. However I have seen advertised hf amps made in the USA that say they will be sold only for export. Why should these amps only be sold for export and foreign made hf amps like the Emtron DX4 or OM4000A can legally be imported here? It does not make sense.If these amps can be imported here US manufacturers of Amps above the legal limit should be allowed to sell their hf amps here as well.
73
Alan-K2ACB
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VK3BL
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« Reply #3 on: November 19, 2016, 08:16:46 PM »

Ameritron have a few offerings that will easily exceed the legal limit.

Its more of a matter that no one is producing new designs in the USA using the current popular tetrode - the FU-728F.
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J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
VK3BL
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« Reply #4 on: November 19, 2016, 08:19:41 PM »

To KM3F:

I do agree with you. However I have seen advertised hf amps made in the USA that say they will be sold only for export.

It is probably party to do with marketing, like the 'export' radios sold to the 11M crowd, who seem to be the primary market for massively exceeding licence conditions.

I bet if you ask nicely they'll sell them to you.
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J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
WB8VLC
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« Reply #5 on: November 19, 2016, 08:47:43 PM »

vk3bl nailed it, it's because our FCC is still stuck in the 1970's mentality of attempting to control CB'RS while us law abiding hams get the short end.

We US hams are stuck with a max RF IN TO RF OUT GAIN LIMIT of 15 db on amps sold in the US market while every LDMOS solid state amp typically has a stabilized gain figure of  20 db.

This means the amps sold in the US market are required to have at minimum a 5 db or greater gain reduction, that's a lot of potential wasted in needless feedback etc just to knock the gain down to archaic FCC regulations.

Why this is stupid is because I recently heard a couple of US east coast CB'RS on 27.025MHZ bragging about running 5KW or greater AMPS.

Judging by their spec-analyzer signal levels of around -63 dbm I have no reason to not believe they were using such high power.
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G3RZP
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« Reply #6 on: November 20, 2016, 02:37:25 AM »

I think the points are:

1. Customs have no clue about FCC (or anybody else's ) licence limits
2. The FCC have insufficient staff to do enforcement - but according to the few FCC technical staff that I know, plenty of money for lawyers!
3. Customs remit is to get money in. A nice expensive imported amplifier attracts more duty and so does that!

In the UK, there is a requirement that the goods be CE marked. I haven't seen yet an HF + 6m amplifier that according to the manufacturers specifications, should be CE marked. This is because for CE marking, the harmonic production when on 6m should be 43 + 10log P dB down without needing to be more than 70 dB down. The amplifiers around are all aimed at meeting the FCC  43 + 10log P dB down without needing to be more than 60 dB down, and so are specified at about -65dB. There's also an EMC Directive requirement about harmonics impressed upon the AC supply, which a capacitor input transformer and bridge (or voltage doubler) supply won't meet. But there is no money for enforcement, and in the UK, the department responsible for enforcing EMC measures are people with no technical knowledge. While amateurs are not causing problems, the authorities are apparently happy to let sleeping dogs lie. I suspect that the FCC (and many other Administrations) have the same attitude.
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W1QJ
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« Reply #7 on: November 20, 2016, 03:50:15 AM »

There is a whole underground of CB " box builders"  throughout the US.  They build amps that dwarf anything available to hams.  I'm talking major triodes and tetrodes with handles.  Many which require a separate 200 amp service just for the amplifier.  The serious boxes start at 5kw and go up.  Cascading solid state devices in numbers of small travel size pain relief bottles, if you know what I mean.  A simple YouTube search
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VK3BL
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« Reply #8 on: November 20, 2016, 03:58:59 AM »

In the UK, there is a requirement that the goods be CE marked. I haven't seen yet an HF + 6m amplifier that according to the manufacturers specifications, should be CE marked. This is because for CE marking, the harmonic production when on 6m should be 43 + 10log P dB down without needing to be more than 70 dB down. The amplifiers around are all aimed at meeting the FCC  43 + 10log P dB down without needing to be more than 60 dB down, and so are specified at about -65dB. There's also an EMC Directive requirement about harmonics impressed upon the AC supply, which a capacitor input transformer and bridge (or voltage doubler) supply won't meet. But there is no money for enforcement, and in the UK, the department responsible for enforcing EMC measures are people with no technical knowledge. While amateurs are not causing problems, the authorities are apparently happy to let sleeping dogs lie. I suspect that the FCC (and many other Administrations) have the same attitude.

We're very lucky here in VK in so much as the individual / station is type approved rather than the equipment.  A licensed Amateur can possess and use equipment without it meeting specific compliance standards, so long as it can be used within our licensed conditions.

There are a few grey areas surrounding radios modified for unrestricted TX, with some reportedly having been confiscated, but my understanding is that if someone were to have a legitimate reason for owning such equipment (e.g. it is an older model radio or home brew) and does not have a history of having operated outside of their license conditions, things should be fine.

There are of course other legitimate reasons for modifying a radio for unrestricted TX, but I shouldn't have to explain any of those to a knowledgeable amateur, and am not in the business of providing excuses to those intent on doing the wrong thing.

Interestingly enough, my Cambodian licence simply specifies the 'HF Band'.  When I'm over there I could theoretically use any frequency from 3 - 30 MHz, but who would I talk too?!

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J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
VK3BL
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« Reply #9 on: November 20, 2016, 04:10:24 AM »

There is a whole underground of CB " box builders"  throughout the US.  They build amps that dwarf anything available to hams.  I'm talking major triodes and tetrodes with handles.  Many which require a separate 200 amp service just for the amplifier.  The serious boxes start at 5kw and go up.  Cascading solid state devices in numbers of small travel size pain relief bottles, if you know what I mean.  A simple YouTube search

Its just crazy isn't it.  There are some real monsters going around on youtube, and the guys that build them seem to be lacking basic technical knowledge.

Somehow or another, they've learnt what to solder together to make things work, and then push poor tubes and transistors to within an inch of their life. 

Aside from the terrible in band distortion products (the out of band products can be cleaned up with a mere TVI filter, but I bet they don't bother with that), I'd hate to think about how much money they must burn through with replacement finals.

I often wonder if the amps even really make the claimed outputs - after all, it wouldn't be too hard to change the label on a bird slug... Which would explain the popularity of bird meters among the builders of those boxes...

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J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
VR2AX
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« Reply #10 on: November 20, 2016, 04:34:41 AM »

Compliance issues also. US companies and their foreign subsidiaries must comply with 'all applicable laws and regulations '. That is an anathema concept to EU and other suppliers. Some parts like Chinese valves may also be non-exportable to certain markets.
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W1QJ
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« Reply #11 on: November 20, 2016, 05:52:08 AM »

IMHO FCC "type acceptance" is just a money issue.  It cost money to get approval and knocking down any candidates for approval is shooting themselves in the foot.  So if you know how to play the game you can get anything reasonably made passed.  Did you know that the writing of the operating manual is about 50% of the whole process?  It is there that the game is played.  Sure there are certain standards of FCC parameters for spectral purity that have to be met but just about any half way decent amp can pass that test at some level of "stated output".  The loophole is that the amplifier only needs to adhere to the standards as stated in the manual.  The manual only has to refer to the limits of the standards as the unit adheres to at that given level of output.  Under the law you have to operate the equipment in the parameters of which the equipment adheres to the standard.  Once you go beyond the output to which the amplifier is not compliant, it is your responsibility not the manufacturer.  So you see the easy way to get an amplifier to reach full compliance at full legal limit is to use a big tube rated at 2X or more of the legal limit and write the manual to say that all FCC requirements are met at full legal limit.  Which would most likely be the case.  When the user realizes he can put in 2X the recommended drive and get 3X the legal limit well you get the point.  And for the OP, The OM-4000 is FCC type accepted.  The old fashioned "export only" usually referred to amps that had factory enabled 10 meters.  Some of the old Henry amps that had 2 8877 tubes were considered "export only" probably because of the 15db gain issue.
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N3QE
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« Reply #12 on: November 20, 2016, 06:45:04 AM »

Many single-8877 amps can do 2.5KW out no problem.

For a long long time legal limit was 1kW DC input. And 8877 amps capable of 4kW DC input were widely homebrewed and also commercially available at the same time. FCC never blinked an eye at the manufacturers, but did occasionally make measurements and raid users of these "California Kilowatts".
« Last Edit: November 20, 2016, 06:51:04 AM by N3QE » Logged
N3QE
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« Reply #13 on: November 20, 2016, 06:55:03 AM »

Its more of a matter that no one is producing new designs in the USA using the current popular tetrode - the FU-728F.

Once you figure in costs of quality control for imported Chinese tetrodes, I'm not surprised that many makers continue to use the good old triodes which only cost a little more. (These triodes are also made in China today.)

The EU manufacturers that make FU-728F amps, just moved to Chinese tetrodes once the ex-Russian tetrode stock became sparse.
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KM1H
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« Reply #14 on: November 20, 2016, 06:59:41 AM »

Quote
Ameritron have a few offerings that will easily exceed the legal limit.

Its more of a matter that no one is producing new designs in the USA using the current popular tetrode - the FU-728F.

The FCC lets Alpha get away with a pair of 4CX1000A's.

Exceeding the limit by a few hundred watts doesnt enter the equation. While the AL-1500 can get into the 2200W area it becomes PS limited for any more. Put in the separately sold AL-82 RF deck with a pair of 8877's and an outboard transformer and you can get some serious power... or buy  a AL-82 or AL-1200 with bad tubes and iron and do similar; it is all interchangeable.
How do you think W8JI did so well even before he built the BIG amp hidden away in another room and driven by an AL-600. His TX antennas are nothing special but he hears exceptionally well with low nose RX antennas.

The old Alpha 77DX and 77SX could only be called real QRO with an outboard aftermarket transformer. And the Amp Supply LK-800A and C required the LK-550 outboard transformer to break the 3000W barrier and with an even bigger aftermarket transformer and 3CPX800's could be pushed to 5KW PEP; that is a reason they sell for more than new today.
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