[Central-Electronics] Central Electronics 200V

[GRANT YOUNGMAN]

You’re absolutely right.  Sorry.  My meager brain was stuck on the 100V.

With the 200V, you use LSB on the emission switch and adjust the A/B null controls for minimum output as measured on an external meter or your receiver.  In any case, you should not use the internal “power input” scale to do this.  Other comments apply.

Grant NQ5T


On Aug 20, 2014, at 12:04 AM, Mike Saeger <mike at thesaegers.com> wrote:

> My Emission switch on the 200V has no NULL position just FSK/CW/PM/AM/USB/LSB. The 200V manual that came with it says to use the LSB position.
> 
> Mike
> 
> 
> On Tue, Aug 19, 2014 at 11:56 PM, GRANT YOUNGMAN <nq5t at tx.rr.com> wrote:
> Hold the Emission switch in NULL (the position is spring loaded) and only THEN adjust the carrier balance pots for zero.  If you can’t get a 0 reading on the meter this way, then there may be other issues (see my earlier email for a webpage with places to look)
> 
> The meter reading you are seeing in LSB/USB with PTT invoked is only the RESTING PLATE CURRENT of the finals.  This “input” power meter is something of a misnomer.  You are seeing resting plate current, which should normally show around 50-60 watts on the meter scale with no output.  So that actually sounds about right.  You can’t null the carrier by the method you’re using.
> 
> So I’d suggest using the correct method in the NULL position, and then look at the actual power output.  If you can’t get a null in the NULL position,  then there are likely some aged components causing a problem with balance.  It could even be from a hum in the audio chain, for example, which can look like the carrier isn’t nulling out.  If the radio hasn’t been electrically restored, then you likely have some fun ahead in any case :)
> 
> There are some smarter people on the 100/200V here than me, so maybe they’ll chime in at some point …
> 
> Grant NQ5T
> 
> 
> On Aug 19, 2014, at 11:20 PM, Mike Saeger <mike at thesaegers.com> wrote:
> 
>> Hi, I put the Emission switch in either LSB or USB and adjust the carrier pots for minimum after pressing the PTT on the D-104. The lowest carrier output as measured on my watt meter occurs when both pots are at full CCW. At that point I have a bit over 5 watts out. The 200V meter shows 50 (unsure of the scale).
>> 
>> 
>> Mike N9MS
>> 
>> 
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>