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Author Topic: Ramsey Amplifier Kits  (Read 753 times)
G0WSP
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Posts: 3




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« on: November 25, 2006, 01:52:03 AM »

Hi - I am consedering a Ramsey 20 mtr Amp as a first amp project for use with an FT817. I would appreciate any advice / tips or comments on building or compatibillity of this equipment.
Mni tnx
Phil
G0WSP
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KA5N
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Posts: 4380




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« Reply #1 on: November 25, 2006, 07:52:36 AM »

The FT817 runs 5 watts (or 2.5 when batt pack is used).  The Ramsey amp requires 1-2 watts input for 20 watts output.  So you may have to pad down the output of the FT817. While this is a 6 dB increase I wonder if it is worth the aggravation.  Also it is a single band amp.  If you are going to use it for a home (base) station getting power will be no problem, but for portable use you will have to lug extra batteries or a power supply along.  
If you expect that the power increase will make all those difficult contacts a breeze I feel you will be disapointed.  A better antenna system would be a better investment.
The kit should be easy to assemble if you have good soldering skills as poor solder joints are the most common problem with assembled kits.  You will need some kind of enclosure to protect the amp from inadvertent shorts etc.
Good Luck Allen KA5N
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AI4NS
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« Reply #2 on: November 25, 2006, 09:11:17 AM »

How about one of the amp kits from Communication-Concepts?
Here is a 140W one that requires 1-5W input power:
http://www.communication-concepts.com/an762.htm
It is a 160-10 amp that would be great for a QRP rig.
It is a fairly simple build. I am currently building one along with a K5OOR filter board for my K2. I have about $200 in my amp.

They have several other amps as well.

Mike
AI4NS
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KA3NXN
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« Reply #3 on: December 01, 2006, 10:11:15 AM »

Do your home homework. The ramsey kits have gotten a real bad reputation. Check out the reviews here on eham. I highly recommend the HFPacker Amp by Virgil Stamps K5OOR I build the complete kit for 10-160 meters I think it will handle 1-5 watts input with about 35-40 watts output. Also the kit is only about  $129.00. It is a really detailed kit and fun to build. go here:
http://www.hfprojects.com/hfprojects/

Good luck

Jaime
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5R8GQ
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Posts: 203




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« Reply #4 on: December 02, 2006, 06:15:13 PM »

I too recommend the HFPacker Amp by Virgil Stamps K5OOR. The Ramsey kit is $50 now and is junk. With the HFPacker Amp you will get a nice amp with case, heat sink, and low pass filters for all the HF bands.
They use the same low cost power MOSFETS as the Ramsey kit, but at a higher voltage and better bias regulation.

I also have built the Communications Concepts 140 watt amp. It's a fine amp with a carrier operated relay circuit, but no adjustment on the bias. It is just a circuit board kit. You have to supply a heat sink, fan, case, and low pass filters.
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SUPERHET
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Posts: 16




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« Reply #5 on: January 27, 2008, 06:59:18 AM »


   on my concept communications 140 watt amplifier,
 i cannot get the relay carrier circuit to work on transmit???  so i just installed a switch to operate the amplifier circuit when i transmit.
   all in all though...i have had good reports on the quality of RX from other stations.
  i will be adding a low pass filter anyway.
     KC2SPU
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