Even though the BLA-703 is in fact an "FCC-Approved" linear-amplifier (ie: went through 10s of thousands of $$$$ and many months of time for FCC approval)., it is NOT "full-HF" in its capabilities (ie: 1.8 Mhz / 160M to 54 Mhz / 6M) as their other Ham / Amateur units are.
One MUST remember., that the reason why ALL of the full-HF range amplifiers (regardless of brand-name), and even just the 1.8 Mhz / 160M to 30 Mhz / 10M amplifiers are SO much more expensive., is caused by the complexity of the many input and output tuning networks required to cover so many HF bands, AND to keep all those bands BOTH linear AND "clean" enough in their input to output specifications, in order for the American FCC to "approve" them...
The BLA-703 base-station amplifier has an "RF-deck" that is "based" on their KL-703 mobile-amplifier., but as can be CLEARLY seen by its internal photos AND the owner's manual (posted in other articles on the FaceBook, RM "page"), virtually the only thing they have in common, is the use of sixteen (16) of their "proprietary" RM-3 MOSFETs, as do all their KL-xx3 units.
The RM3s they incorporate are VERY different in their internal specifications (specifically their Vgs/th and their Gm ratings) from ALL other such TO-220 case-style MOSFETs used in ALL of those "semi-fake" 10-meter / CB radios which have become SO popular on-the-market for the last decade.!
While their KL-505 and KL-805 (10/11 meter units) and ALL their mobile, multi-band HF., VHF., UHF units do in fact incorporate true "RF-devices".!
The main reason for the use of their specialty MOSFETs in their KL-xx3 series of amplifiers, is to simply "accommodate" the Folks out there, which are only interested in the 10/11 meter band, AND are NOT willing to spend the extra $$ to purchase the VERY high-quality KL-xx5 series of 10/11 meter-band amplifiers.! :-(
Below is a web-link to a detailed article I had written, to address the issue of why Folks who abuse their amps (causing MOSFET failure) can NOT just simply use some generic / popular TO-220 case-style MOSFETs as proper replacements when making their own repairs to the KL-xx3 series of RM amplifiers...
Please read:
"Regarding the best MOSFETs to use for repairing any of the KL-xx3 series of amplifiers"
*Below (at the bottom) is a web-link to the 1st page (of 7 pages) of products and accessories that RM Italy produces.
FYI: be sure to "click" on the English language "button" (shown as a British "Union-Jack" flag in the upper right corner), that is, if the page "defaults" to Italian.
There's a total of about 75 products., which includes about a dozen or so, of individual RF, mechanical, and accessory type parts.
*However., that list does NOT include the "specialty" RF-units they design, produce and sell to larger, "high-end" companies to be incorporated into those other company's "finished-products".!!
Also., most all RM units / equipment have a "PDF download link" for a user / operator manual, with a number of them also containing some sort of schematic diagram (and / or PCB layout) therein.! 
RM Italy Products are high quality devices for Radio Transceivers: DC-DC converters, power supply, linear amplifier and accessories.
www.rmitaly.com
Regards / 73
Eric Klein
Klein Communications
Also as KY8E
The BLA-703 does not have an FCC ID number affixed to its back like the BLA-600... Meeting FCC specifications for second and third harmonics while locking out 11 meters, does not imply FCC type approved equipment.
Broadband solid state amplifiers do not typically require individual input circuits for each band. All band HF output filters are available, already assembled for around $130.
The RM-3 is not a real transistor number. It's a fabricated number used to hide the datasheet, which would expose why it takes sixteen 31.25 watt transistors to produce 500 watts. Literally the only reason to use lots of "RM-3" transistors is because they cost pennies rather than tens of dollars.
The drawback here is extremely inexpensive transistors. However, that's also the advantage of being able to hit a $750 price target. Adding a 30 MHz low pass filter, gives it a very clean output. Adding overdrive and SWR protection has a chance of making inexpensive transistors operate reliably.
Time will tell if it's reliable. Claiming that it's FCC type accepted requires publishing the FCC ID number. Claiming that it uses real linear RF transistors requires publishing a part number, that has a data sheet attached to it.
PS: I'm sorry if I sound too critical on this amp Eric. I believe it's a lot of watts and features for the money. Even though it uses inexpensive transistors, only asking each one to produce 31.25 watts, may be the saving grace.
RM makes a wide range of equipment. The fact that they can even produce a 500 watt base amplifier in this price range today, is somewhat astonishing. The fact that it has some nice features, makes it attractive. I think you'll sell lots of them.
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