[AMPS] Electronic Bias Switching

[km1h@juno.com]

On Mon, 28 Dec 1998 10:03:02 -0800 Rich Measures <measures@vc.net>
writes:

SNIP

>€  However, some various fault possibilities.  
>1.  A gas flashover in the tube due to a leaky seal.
>2.  The anode touches the grid (some 3-500Zs)
>3.  An intermittent vhf parasite generates a large burst in 
>grid-current. 
> 
>-  -  Each of these faults makes the grid dangerous to an EBS, so 
>rugged 
>protective measures would still be necessary.  //  Another issue is 
>RF-input actuated transmit/receive bias switching.  A friend recently 
>purchased such an amplifier (a 91B), and it generates a pecuilar type 
>of 
>IMD as the amplifier rapidly switches from Tx-bias to Rx-bias between 
>syllables of speech.    At the risk of being boring, I believe it is a 
>
>mistake to allow the bias to switch to Rx (cut-off) mode at any time 
>when 
>the amplifier relays are in Tx mode.  

So what do you think, specifically and not rhetorically, about the EBS in
the MFJ  AL80B? 
Any hard data such as measurements to share with the reflector?

BTW, I agree that EBS systems as implemented in ham amps are inherently
IMD and splatter producers. Just wondering if anyone has some hard facts.

73  Carl  KM1H




>
>-  later, Paul.  
>
>
>Rich...
>
>R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  
>
>
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