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Reviews Categories | Amplifiers: RF Power - HF & HF+6M | Communications Concepts Help


Reviews Summary for Communications Concepts
Communications Concepts Reviews: 13 Average rating: 4.3/5 MSRP: $(missing—add MSRP)
Description: These guys supply all of the design and parts to build any kind of solid state amp. From 12volt versions running from 140 watts to 1kw, 50 volt versions runing the same power to VHF and UHF amps. All of the designs are from Motorola. For example I priced the parts to build a 1KW 12volt amp using there design and parts but replacing the MRF421 they use with the 2CS2879 and found it to be just under $500. You SAVE A LOT OF MONEY by doing the assembly work yourself. Check out the site and see for yourself.
Product is in production.
More info: http://www.communication-concepts.com
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KG7RS Rating: 5/5 Jan 18, 2001 09:23 Send this review to a friend
AN-762 is a Winner!  Time owned: 0 to 3 months
After some satisfying experiences with the EB-63 design, I opted to build the AN-762 design. This again, is based on an older Motorola Applications Note for HF mobile amplifiers. The AN-762 parts and circuit board are available from Communication Concepts and is a major improvement over the EB-63. The downside is that the '762 does not include a carrier-operated relay circuit, so the builder will have to supply his/her own. My COR design was based on information contained in the 2001 ARRL Handbook, has only about 10 parts, and uses the same open-frame relay that the EB-63 calls for, available at Communication Concepts. It is built on a separate small board that is easily homebrewed and works very, very well. Switching and hang-time is a great improvement over the circuit included in the EB-63. I would be happy to provide circuit details, just email me (email on QRZ.com).

The AN-762 features regulated, adjustable bias and negative feedback to compensate for amplifier gain variations over its broadband operating range of 1.8-30mhz. The idle current is much lower than the EB-63 with simple diode clamp bias circuit, 200-400ma vs nearly 2A on the EB-63. This results in a much cooler heatsink! Gain is not so wild as on EB-63 either. Mine will output approx 160-watts on 80/40, dropping only slightly to 130 watts on 10m. There are some surface mount components, only about 10 chip capacitors, but it is very easy to install them and they add greatly to repeatability, ie: less stray capacitance, etc.
Most other components are installed through-hole as opposed to bending and surface soldering on the EB-63, so very easy to build.
Don't forget to used the lowpass filters to keep the FCC folks happy (and our fellow hams). All in all, a great design that is super-easy to build and has the operating feel of a factory amp.

By the way, this same circuit design is the basis for higher power amps designs offered by Communication Concepts. There is a 300-watt version that is nearly identical, just different transistors (it requires 28VDC) and component values.

Have fun with 'em. 72/73, John, KG7RS
 
WB2WIK Rating: 4/5 Dec 21, 2000 13:30 Send this review to a friend
Excellent  Time owned: more than 12 months
Okay, I hardly give anything a "5," it would have to be flawless. Never having met God, I guess nothing rates a "5" for me, but the CCI EB-63 amp is close. I built an EB-63 back in 1989, and it's performed perfectly for 11 years of occasional use. I intended this to be a "mobile" amplifier, and as such built it into a small but rugged aluminum chassis with a "swap meet found" extruded aluminum heatsink. The heatsink is too small to run the amp continuously at full power without additional cooling, so I installed a 125mm muffin fan in the car's trunk, blowing across the heatsink fins and activated by the same switch which powers "on" the amp. The only trouble found was the original design used a lousy RF sensing circuit for the T/R function. I changed that entirely to a homebrew circuit on a small piece of PC board stock, and now it works fine. Puts out about 200W on 3.5 through 14 MHz, and 130-140W on 21/28 MHz. Since I use it only mobile with a whip antenna and constantly moving location, I was not terribly concerned about how clean the xmit signal really is...no RFI/TVI etc. possible for more than a few seconds, since I'm using the amp in a moving vehicle; and with small whip antennas, I'm not too concerned about QRMing other hams or services, at least not for more than a few seconds, hi. As such, I did not use any of the recommended output filters. However, I would recommend they be used, especially if the amp will be installed at a home station or other permanent location, or if used with "real" antennas. After 11 years of taking harsh bounces in the trunk of my car, it still works perfectly.
 
KG5BV Rating: 5/5 Dec 20, 2000 15:24 Send this review to a friend
Highly recommended  Time owned: more than 12 months
I have built two of the AN-762 amps, one I gave to my son and I use the other. The only problem was the bias circuit didn't operate (using a current limited DC supply saved the RF transistors). Replacing the Motorola regulator IC with an SK equivilent solved the problem in both cases, and I understand that CC is now supplying another type of IC.

The amps have worked fine on all modes from 160-10 meters. I also built a switched low pass filter for them, and everything works great. The MRF-454 transistors are tough and cheap, and you won't blow them unless you really try. It's a great value for the money. Now I want to try the 600 watt MOS-FET amp, but first I have to build a 50 volt DC supply!
Dwight
 
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