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1-7 of 7 messages
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RM Italy HLA-150 QRP amp page
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by KG0WX on February 14, 2006
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I tried to create a new topic in the reviews about
this great little amp but the staff killed the topic
because besides selling clean, bandswitched amps (2),
the manufacturer also unfortunately sells what are
in the USA illegal CB amps. I understand their point
but the HLA-150 & 300 are bandswitched and very clean,
unlike their CB amps. These are nice!
Anyways, with no Eham review on this great little
amp, I decided to create my own review page:
http://hla-150.50megs.com
73's de Ken KG0WX
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RE: RM Italy HLA-150 QRP amp page
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by WB2WIK on February 14, 2006
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Well, I went to your site and read your writeup.
That an amplifier doesn't generate RFI isn't any indication of how "clean" the amplifier really is. Most of the problems with amplifiers like this, bandswitched or not, is the close-in distortion products (IMD) that you cannot see on a broad spectrum sweep at all -- they simply won't show up.
Bandswitched filters can reduce harmonics, and that is one kind of "distortion," but don't do anything for IMD.
One fault in your test process is evident, and that is that at some intermediate power levels (between lowest input power and highest input power), you observed a positive change in amplifier gain -- I don't believe that's possible. The amp is in serious compression at 14.5W drive power, and I certainly wouldn't use it there. (Although I think that's above RM's rated power level, too.)
I think eHam.net, the ARRL and other conscientious providers are correct in not publishing reviews of equipment that is not legal for sale in the United States. We do have foreign subscribers and readership for sure, and this amp may well be legal for sale in some of those countries, but this service is based here and to review products unlawful for sale here is promoting an illegitimate activity.
If RM wants to make an amplifier that can be certificated for sale in the U.S., I'm sure that once such an item does complete FCC certification, reviews on that product would be acceptable.
WB2WIK/6
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RE: RM Italy HLA-150 QRP amp page
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by W8JI on February 14, 2006
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Hi Ken,
There is nothing at all unique in that circuit. It is a simple push-pull amplifier. There isn't any possible way that amp has anywhere near 80% efficiency. There might be something odd going on with your RF power meter or dc supply metering.
The theoretical limit for a class B amplifer is in the mid 70% range. Conduction angle would have to be well under 180 degrees to get 80%, and the individual RF pulses nearly square.
You can do about 70-75% with class B if things are just perfect, but nothing more than that.
Gain compression tests also do not indicate linearity on voice very well. Two-tone tests barely provide any useful information. Once again we are at the mercy of your power meters, and the results are somewhat suspect since you are measuring 80% efficiency.
I'm not sure how linear that amp is because something appears to be drastically wrong with your dc power input/ RF power output measurements. I'd expect efficiency to be more like 40-50% at the upper end of the power curve's linear portion and significantly less as power is reduced.
73 Tom
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RE: RM Italy HLA-150 QRP amp page
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by K7VO on February 15, 2006
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Further to Steve's point, eHam.net does allow reviews of amplifiers that were legal to sell in the U.S. prior to the change in FCC rules (i.e.: the Yaesu FL-110), certain monoband low power kit amps that cannot be modified for CB use (i.e: those from Ramsey and Mizuho) which have been sold in the U.S. legally, amp kits internal to a radio which are legal (Elecraft K2/100), and certain Tokyo Hy-Power triband amps that have narrow filtering and can't be modified for CB use (i.e.: HL-710 and HL-750).
The FCC had an NPRM last year which would allow amps that are RF switched and can be used with QRP rigs to be sold and imported. The requirement for certification would remain. If a Report & Order is issued making the proposed changed official certain manufacturers may indeed bring such amps into the country, most likely including Tokyo Hy-Power. I really wonder if RM Italia, who flagrantly violate existing rules by selling cheap CB amps in this country, will be able to receive certification. I personally hope not.
Bottom line: RM Italia makes cheap CB amps and to me that makes all their products suspect.
Finally, a QRP amp is an amp that puts out no more than 10W. A Mizuho PL-21S (2W in, 10W out, 15m only) could legitimately be called a QRP amp. An amp that can driven by a QRP radio is not QRP. Semantics, I know, but that one bugs me.
73,
Caity
K7VO/9
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RE: RM Italy HLA-150 QRP amp page
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by KA8OCN on December 4, 2006
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Boy I wish eham would have allowed a review of these amps, they could have placed the information that has been supplied on this thread and I would have not purchased one.
I purchased one to use with my Yaesu 817D on eBay. I seems to work but I am no expert with amps.
I have a Ameritron 811 for home but I wanted a solid state amp for my truck and Ameritrons are a little high to say the least
This is not the dark ages, information is not bad, There are mods in the download section that can make a rig operate out of band but they are not blocked (There are not that many people in MARS)
Now I have to worry about causing interference, or selling the amp (and it sounds like only a CB'er would want it and I will Throw it away before I sell it to a CB'er).
I LOVE eHams reviews, I always check out the reviews before I buy anything.
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RE: RM Italy HLA-150 QRP amp page
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by KC9OFX on October 7, 2008
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I couldn't get to the home page either. The PEP of this amp is 250 watts on SSB or CW. AM/FM is 150 watts. This amp is CE approved and used all over Europe. Band pass filters for 160, 80, 40, 20-30, 15-17, 10-12 meters. My spectrum analyzer is on it's last legs but I don't see any out of band garbage except that the 10 to 12 meter filter passes the CB band. Might need an add-on output filters for 15,17,20 or 30 meters. I'm new to ham radio and wouldn't operate on these bands without knowing the technical limits. My amplifier is new and looks preliminarily usable. Others in this group have described this amp as dirty and a cheap CB amp. It ain't cheap and I'm still investigating dirty. Dean KC9OFX
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