[DSP-10] Another step of progress

[Bob DeVarney W1ICW]

Hey Don,
  be VERY careful using the small metallic screwdriver in those slugs. 
It is very easy to break the slug and then you are in a bad way.

I once spent a couple of weeks repairing a Yaesu FRG-7 in which someone 
had broken EVERY slug in every coil using the wrong tuning tool. I had 
to pull every coil out and remove the slug from the bottom as the broken 
pieces had seized the slug in the core.

Just saying... Good progress and keep the reports coming. I just got a 
DSP-10 from a friend and am close to incorporating it into my 2-meter 
EME station.

73 de Bob W1ICW

On 4/14/2013 1:53 PM, Don AE5K wrote:
> On 04/14/2013 11:48 AM, Don AE5K wrote:
>> OK Mike, will do the coil peaking in transmit -- L8, L9, L10, L11, 
>> L12, L13.  But this will probably not solve the intermittent problem 
>> of the output level jumping around from -0.6 to +3.6 dBm and point in 
>> between.  So it could be the output will increase with coil peaking 
>> and that could be one problem we're seeing, but the other seems to be 
>> in the tx chain around U5.
>
> Started the DSP-10 up from cold, output read +2.0 dBm. (By the way, 
> all this is at 144 Mhz. frequency, not the center of the 2 meter band, 
> since ultimate use is 1296 transverter with frequencies 1296.0 to 
> 1296.4 or so corresponding to 144.0-144.4 on the DSP10)
>
> I do not have the proper tuning tool for the coils/inductors, finally 
> used a metallic screwdriver, moving core a little at a time and 
> observing power output.  About half the inductors made a little 
> difference, the other half made quite a difference!  These are L8, L9, 
> L10, L11, L12, L13.  With the clumsy tuning tool, I was able to get 
> the output up to +8.0 dBm at 144 and +9.6 dBm at 146 MHz.  (This is 
> read from the ANT connector, not TX out)
>
> This still does not solve the erratic power out problem, but goes a 
> long way to confirm the tx chain seems to all working.
>
> I'll push on to try to find the cause of the erratic output, may 
> solving this will increase the power even more (since usually have 
> started with +3.6 instead of +2.0 dBm that I did with today).
>
> Next step, try to pin down the erratic output to a single stage or 
> between stages.
>
> Thanks to much Mike and all the others who have offered suggestions.  
> Still working on it.  Hey, I might have a good working DSP-10 soon 
> without taking Bob up on his offer made a while ago to fix DSP-10's.
>
> Don AE5K
>
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