External 2 meter amplifier alternatives

[sm7vzx]

Hello,

Look at this, http://www.eham.net/reviews/detail/6437:
http://www.rlham.com/cgi-bin/shop/modellookup.dbw?MODEL=1410G
maybe little over your $400 but much better quality then others

maybe best quality you will get from TOKYO HY-POWER, but you need to pay
little more...

Best Regards
Samir, 7S7V (SM7VZX)
www.qsl.net/7s7v




Message: 19
Date: Sat, 20 Feb 2010 20:35:58 -0800
From: Lew Phelps K6LMP <[hidden email]>
Subject: [Elecraft] External 2 meter amplifier alternatives
To: [hidden email]
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=us-ascii

I have on order -- and hope to receive in about 3 weeks -- Elecraft's K144XV
2 meter internal transverter module for my K3. I'm beginning to look at
available alternatives for an external 2 meter amplifier, and would
appreciate any experience anyone on the list has with any of the following:

1. Communications Concepts 875A (10 watts in, nominal 75 watts out, $120 for
a complete kit, $160 assembled)
2. Mirage B1018G (10 watts in, nominal 160 watts out, $350 new from some
dealers)
3. Maha MH-A103 (5 watts in, nominal 50 watts out, several used units
currently available on eBay under $100)
4. KLM PA 2-70BL (4 watts in, nominal 70 watts out, one used currently
available on eBay, BIN of $100)

Any other amps I should be considering?

"Must have" criteria: will operate on 13.8VDC power, requires no more than
10 watts input to achieve maximum rated output, interface easily with
K144XV.

Nice to have criteria:  compact, quiet, less than $400 street price.

Max power output isn't all that critical to me; this will be used for VHF
contesting, not EME, so I don't need or want a 1KW or 1.5KW tube-based
amplifier. Based on my experience in VHF/UHF contesting, I think that either
75 or 150 watts out would be a big improvement over 10 watts, but that there
wouldn't be all that much difference in results between 75 and 150 watts.
Yes, I'd love to have 500 or so watts, but the price tag is too high for my
budget at the moment, given what I need to add to my K3.  

Based on specs and price (that is, most watts output for the buck) I'm
leaning toward the CC 875A kit, but I can't find any reviews that discuss
its performance and reliability. It's uses a Motorola MRF247 MOSFET, and is
based on a circuit design in Motorola's Application Note AN791.  CC has
added some features to the basic design published by Motorola, but the basic
amp is what's described in AN791. I like the fact that it's compact (6 x 3 x
4.25"), and that it draws only 9 amps at maximum output.  The cost per watt
of output is $1.60 for the kit. The lack of a pre-amp doesn't seem too
significant to me, given that the K144XV specs show -144 dB sensitivity (14
dB improvement over the main rig's  -130 dB specs). Is anyone familiar with
this product?

The Mirage B1018G has a lot more output when driven by 10 watts in, and it
includes a receive pre-amp with jumper-selectable gain ranging from 2.5 to
14 dB -- duplicative of the receive amplification in the K144XV --   but
it's also more expensive, and a lot bigger and heavier (12 x 3 x 5.5, 5
lbs.) The cost per watt of output is $2.19 given the best dealer price I can
find (which isnb't Mirage itself). Given that Mirage is owned by MFJ, I'm
also a bit leery of construction quality and reliability. At full output
this unit requires 30 amps, which is a minus factor for me. The amps/watt is
about 1.5 times the power supply requirement of the 875A.

The used units mentioned have their own attractions, but both are long out
of production, and thus support would be zilch, so they are lower on my
list, subject to input from this group.

Comments and "user reports" welcome.


Lew Phelps K6LMP
Pasadena, CA DM04wd
Elecraft K3-10 (160-6 meters, soon to be 160-2 meters, all modes)
Yaesu FT-7800 (2m and 70 cm, 50 watts FM only)


 

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[VK4DD]

Hi,

I have build my own solid state amplifier with the BLF248.
ROCK SOLID ! Nice linear and better than commericial solid state.
It is the only FET I am aware of which does VSWR 50:1.

Have a look at the feedback from a user... who melted the coax cable to his antenna :-)
and was pleased to see that the amp was still fine.

If you are after low cost than consider the BLF278 amplifier.

Both PCB's are for sale via my web site.

www.vk4dd.com
Look in the forum for documentation.
www.vk4dd.com/forum

I also have a sequencer, watt meter, SWR meter PCB including protection for sale.

Off course this is only for people who have the skills to home brew.

73 Ron
VK4DD