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50
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eHam Forums / Amplifiers / RE: Keeping a clean signal
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on: February 15, 2013, 08:52:47 AM
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In addition to what others have said, Use only as mush grid current as necessary for your power output. Grid current in excess or near maximum specifications is what causes the tube to deteriorate in performance over time. Tubes like the 811’s do not much reserve grid current dissipation.
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51
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eHam Forums / Amplifiers / RE: New QRO 8877
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on: February 15, 2013, 08:46:52 AM
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I understand the reason for not bothering with the WARC bands. The input tuning matrix board looks to be the same as what Ray has used on other grounded grid designs. This was probably a cost saving decision. Big gun DX stations don't do contesting on the WARC bands. With the exception of 17 meters the other bands for all intensive purposes are QRP operation.
I don't know what the "reduced output" on 17 meters is but I'll bet it still makes 1500 watts instead of 2500 watts on 20 meters. Nobody will miss the illeagle 2.04 dB when you are using a 4 element monoband er at 100 feet with 1500 watts.
As for input tuning on 17, use the transceivers antenna tuner once you get the output tuning set.
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52
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eHam Forums / Amplifiers / RE: Amp/Ant
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on: February 15, 2013, 08:25:36 AM
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Only true in some cases.
If the person has a high noise floor and is having a hard time hearing you, by you using an amplifier, you enable him to complete the QSO.
Most hams live in a city or suburban areas and as a result of the many microprocessors in a typical home have very high noise floors on receive.
Having a 10-14 dB stronger signal doesn't mean you signal is polluting the air waves. It is a matter of settin you station up properly. I have heard many broad band splattering signals running just 50 watts.
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53
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eHam Forums / Amplifiers / RE: Molly has resigned.
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on: February 12, 2013, 08:56:31 AM
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I was contacted by RF Concepts and was assured by their owner that they are not having finical problems of any kind.
Gordon is still on staff and will be writing the code along with others.
The antenna tuner project is doing fine.
I apologize for any misunderstanding my previous post might have caused.
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54
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eHam Forums / Software Defined Radio / RE: Flex 1500 Amplifier Recommendations ?
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on: February 11, 2013, 03:58:24 PM
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I have a RM Italy HLA-300V. With 5 watts in it produces 250 watts PEP at 14.4 VDC. The two tone IMD is about 34dB with two exciters on 20 meters. Did not check it on other bands for that is good enough. Harmonics are better than 43 dB of the log power. Push it to 300 watts and the harmonics start to rise. The fan noise is a bit high while transmitting. About 70 dBa at 12 inches with a A weighted meter.
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56
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eHam Forums / Amplifiers / RE: Molly has resigned.
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on: February 08, 2013, 08:53:30 PM
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This is interesting. Their new CEO has an advanced license but has never been active. They have been trying to produce an antenna tuner for three years, is it out yet?. It looks like this is a cost saving maneuver. It is just a guess but I suspect financial problems.
I wonder who is going to write their future code? Molly was a very good programmer.
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57
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eHam Forums / Amplifiers / RE: Molly has resigned.
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on: February 08, 2013, 03:54:41 PM
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For those of us not familiar with the inner workings of RF Concepts, who is Molly and what does her resignation have to do with anything?
You must not be active in HF operations. Molly was the heart and soul of Alpha Radio Products.
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59
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eHam Forums / Amplifiers / RE: Need Lil Help
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on: February 04, 2013, 08:34:04 PM
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Why not buy a SPDT relay from radios shack and connect the relay coil from the + 12 out on the radio to the relay and the cold end of the coil to the radio key line. Then connect the N/O relay contacts to the amplifier. No battery, key any voltage and the relay only cost under $2.00.
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