For the first time since my Argonaut 505 days, I have been thinking
about adding an amplifier-- to my Omni6+. What benefits derive from
purchasing the Hercules over Ameritrons far cheaper 500w 12v
all solid state amplifier?
k7puc
-----Original Message-----
From: John - G3JAG <patents@dx0man.prestel.co.uk>
To: Jim Reid <kh7m@hsa-kauai.net>
Cc: M. Clark <rudder@gulfcoast.net>; tentec@contesting.com
<tentec@contesting.com>; Greg Hodsdon <k7kj@teleport.com>
To: <tentec@contesting.com>
Date: Friday, December 31, 1999 6:10 PM
Subject: Re: [TenTec] Hercules II Power Source
>
>The power gain is not necessarily exactly the same for different Herc
>IIs. The final transistors are matched by TT, but two sets may well not
>have the same gain. TT can and do adjust the gain, but only into the
>same ballpark, not to complete identity.
>
>It is also affected by the actual voltage reaching the finals, as
>opposed to what the PSU puts out. When you say 14 volts from the 9420,
>that is the voltage each rail should be set to internally, at the
>respective capacitor terminals. TT say not to set it any higher (to
>compensate for voltage drop in the cables) as that will upset the
>control circuitry. It follows that the voltage at the finals will
>always be less than 14. How much less depends on the resistance in
>circuit. In my case, I discovered that there was at least one
>intermittent dry joint in the Herc II distribution/relay board. The
>effect was to create a spectacular imbalance in the amplifier, one pair
>of finals getting practically no power under load.
>
>Incidentally the dry joint was apparently not a recent development; it
>may have been responsible for the self-destruction of two finals some
>time back.
>
>If you see low gain, then it may be worth opening the Herc up and
>checking carefully for any problem in this area. I re-soldered all the
>rivetted connections, relay terminals etc. on the control board after
>measuring some strange variations in standing current (I think it
>should be exactly 1/2 amp per set of two finals - the individual DC bias
>voltages are NOT a reliable guide to actual idling current). I also had
>this intermittent and humongous voltage drop for one pair under load.
>
>Its a tedious job and needs a large soldering iron, but in my case it
>was well worth the effort.
>
>John G3JAG
>
>On 31-Dec-99 Jim Reid wrote:
>>
>> Gregg, K7KJ wrote:
>>
>>> Jim:
>>> Just checked my 10 year old Hercules II/9420 PS on 7.025 into a
>>> dummy
>>> load using a VFD wattmeter: 26w in/ 540w out, 35w in/ 600w out, and
>>> will
>>> put out well over 600w (with the red LED on!). Keep in mind the 9420
>>> puts out 14.0 vdc, no load.
>>
>> Now that is interesting, Gregg. That is exactly 13 dB gain on the
>> first pair, and 12.3 dB on the second. My numbers show my
>> solid state amp is producing only about 8 dB gain, hmmmmm?
>> Yes, 84 in, 570 out is only a numerical gain of 6.8x's, or some
>> 8.3 dB. I can crank the Astrons up to 14 vdc, but probably won't.
>>
>> Herc. II typicals from the TT web page:
>>
>> "RF Power: 1000 watts input. 500/600 watts output, depending
>> on frequency and load impedance.
>>
>> Drive Power: 65 to 80 watts typical for 500 watts output.
>>
>> (Or a typical Herc. gain of around 9 dB down to only 7.9dB,
>> with 80 in and 500 out)
>>
>> Primary Power: RF deck, 12 to 14 volts at 100 amps, maximum"
>>
>> Your Herc. II at 13 dB gain is a real "hot one", Gregg, hi.
>>
>> Does the 9420 PS have a current meter, if so, how much
>> current is being drawn?
>>
>> Happy New Year and 73, Jim, KH7M
>> On the Garden Island of Kauai, temp outside: 75 F.
>>
>>
>> --
>> FAQ on WWW: http://www.contesting.com/tentecfaq.htm
>> Submissions: tentec@contesting.com
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>> Problems: owner-tentec@contesting.com
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>
>----------------------------------
>E-Mail: John - G3JAG <patents@dx0man.prestel.co.uk>
To: <tentec@contesting.com>
>Date: 01-Jan-00
>Time: 01:44:06
>
>This message was sent by XFMail
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