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SILVER STREAK 150 (2 X MRF455) ?

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Old 03-31-2008, 01:04 PM
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Default SILVER STREAK 150 (2 X MRF455) ?


What is it about these little amps ? IM sure I've had 1/2 a dozen of these things over a few decades it would seem. (They work ! and whomever builds them ,IM guessing they have been building them for a long time)Seems like 1 watt DK usually does the trick on these little guys. IM getting to my question , (without using a cap resistor mod or not) Will use a 1 to 4 watt pep at 100% modualtion into this little guy . My numbers are ballpark 20 to say 60 audio watts on low (I could whistle 80 but that don't count) , 80 to say 120 audio watts on high (I could whistle 160 watts but that don't count either) . On just about anyone of these boxes I've had over the years they always seem to DK bigger numbers then I would expect on the high side of these little guys , IM guessing this is normal for these ? Keeping in mind, IM only talking about a 1 watt drive ? 80 seems like alot ? or is it just the way the box is built ? Thanks



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Old 04-02-2008, 05:55 PM
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30 views and no clue ? hmmm

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Old 04-02-2008, 07:16 PM
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Quote:
Originally Posted by Switch Kit View Post
30 views and no clue ? hmmm
The mrf455's are meerly 60 watt transistors so anything over 120 or so is fluff.

Data sheets don't lie, http://datasheets.foxdelta.com/mrf455.pdf

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Old 04-02-2008, 08:54 PM
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My question is why the high DKs on these with only 1 watt , the many I've had over the years all acted that way. Your data sheet means nothing to me unless you explain it ? why the high DK's on these little boxes at 1 watt compared to many others is the question. As far as fluff goes , I already said that didn't count. No offence to you Mack , but folks tend to ask simple questions (or look for simple answers) and I could drop a data sheet on somebody any day of the week weather i understood it or not ....kind of like this past thread ......"Pill" questions... Thanks for the reply all the same Mack , the data sheet doesn't tell me why these little amps key higher then I personally would think they would on the high side of a 2 x 455 amp. I can believe the low side at 20 to 60 but 80 to 120 audio pep seems strange to me ? Is when a radio is perfectly tuned at 1 to 4 into this box , what happens to the 4 to 1 ratio from the box , this is why I "think" 80 watt DK would be high on this one ? NO ?

Last edited by Switch Kit; 04-02-2008 at 09:07 PM.

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Old 04-02-2008, 10:32 PM
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simply compare the 455 to another popular 60W transistor to answer your ?.

http://www.firecommunications.com/trdbase/2sc2290.pdf
2SC2290....1 in 20 out, 13db., 12.5vdc @ 28mhz.
Ref: Po - Pi Graph, end page.
db = 10LOG(Pout/Pin)
db = 10LOG(20/1)
db = 10LOG(20)
db = 10(1.301)
db = 13.010

http://www.firecommunications.com/tr...mrf455rev0.pdf
Ref: Po - Pi Graph, mid page.
MRF455.....1 in 50 out, 17db., 12.5vdc @ 30mhz.
db = 10LOG(Pout/Pin)
db = 10LOG(50/1)
db = 10LOG(50)
db = 10(1.698)
db = 16.989

the increased gain of the 455 allows it to produce (2.5X) more power output with the same amount of drive at the lower input levels.. the information is in the spec. sheets.

also, if we move both devices to 27mhz. the gain of both increase still further, the gain of the 455 increasing even still more than the 2290.

the Silver Streak 150 is an extremely drive sensitive Class C Amplifier.

Last edited by freecell; 04-02-2008 at 11:29 PM.

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Old 04-03-2008, 04:38 AM
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hey freecell whats the specs on the 2879?just curious to see the gain on those.

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Old 04-03-2008, 05:21 AM
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http://www.firecommunications.com/trdbase/2sc2879.pdf

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Old 04-03-2008, 07:47 AM
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the increased gain of the 455 allows it to produce (2.5X) more power output with the same amount of drive at the lower input levels.. the information is in the spec. sheets.

also, if we move both devices to 27mhz. the gain of both increase still further, the gain of the 455 increasing even still more than the 2290.

the Silver Streak 150 is an extremely drive sensitive Class C Amplifier.


That would explain the higher DK's on the high side on these with such a low input into them , thank you Freecell .

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