>
>On Fri, 06 Jun 1997 23:34:55 GMT wrt@eskimo.com (Bill Turner) writes:
>>On Fri, 06 Jun 1997 10:36:03 EDT, km1h@juno.com wrote:
>>
>>>I guess the question I have is why anyone would wish to give up a
>>bullet
>>>proof workhorse amp such as the AL-1200 for something completely
>>unknown
>>>with no track record such as the QRO?
>><snip>
>><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
>>"Bullet proof" is in the eye of the beholder I suppose, but my
>>experience would rate it a bit more tender than that.
>>
>>The AL-1200 is probably fine for CW/SSB operation, but running it at
>>full power on RTTY will overheat the tank coils on 80 and 160 meters.
>>There is nothing in the manual to caution you against this. During a
>>recent contest, mine got hot enough to melt the solder connecting the
>>80 meter tap. The plastic support rods also melted and the coil
>>twisted itself into a pretty good slinky imitation. It needs more
>>cooling air in the tank area. Cost about $25 for a replacement coil.
>>
This isn't surprizing to me, Bill. The designer of the AL-1200's tank
has made some eyebrow-raising statements regarding RF skin-effect.
Consider the ratings of the E.F Johnson (now made by Multronics) roller
inductors. (silver-plated) #12 wire is rated at 5a. 1/4" by 1/8" bar
stock is. rated at 10A. 1/2" ribbon is rated at 15A.
I chuckled when the AL-1200's designer recently criticized the SB-220's
cooling system. Heath had enough smarts to direct cooling airflow at the
tank inductors. He did not.
Rich---
R. L. Measures, 805-386-3734, AG6K
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