[DSP-10] sequencing and control question

Courtney Duncan cbduncan at earthlink.net
Sat Nov 20 00:22:48 EST 2010 

On Nov 2, 2010, at 9:14 PM, Bob Larkin wrote:

> Hi Courtney -
>
> If one uses the DSP-10 built in sequencer, they have the two external
> lines that can have their times adjusted, and then the time to the
> actual start of RF is also adjustable.  I doubt that anyone really  
> needs
> any more than that.  At most one would want to get the antenna relay  
> in
> the correct state before turning on a power amplifier.  Than another
> delay and apply drive.  I have seen provision for more lines, but it
> seems unneeded.
>

I just ordered some boxes and connectors and cables and things from  
Mouser so I could finish this up.

I think I'll have the first sequence signal activate the relay and de- 
power the preamp then the second signal will apply bias to the  
amplifier (all through buffer transistors to adjust the sense  
appropriately).  I have just been running with the preamp on at the 3  
watt level and probably don't need to go to the trouble to turn it off  
at the 35 watt level either, but while I'm in there building stuff  
I'll just take care of it.  And... someday if I want to or think I  
need to go to a third control line, it will be separable.

> If you remote the microwave gear, it always seems to need some DC or
> control/measurement lines.  Our house is sort of down in the trees,  
> but
> about 125 feet away is a decent place for microwave gear (clear of
> trees). So I built a box out there, and ended up running about 30
> wires.  It started with just coax and 115V, and I think a rotor cable,
> but there always seemed to be a need for more.  I bring a RF power
> detector pair of wires in to see if the transmitter is doing its  
> thing.
> And then a couple of wires for a PLL sense.  And on and on.  So a few
> more for controlling anything would not be noticed.  I like the multi
> conductor wire they sell for lawn and garden irrigation.  It is about
> #18 and intended for burial.  They come in various sizes, like 9- 
> conductor.

I once remoted an OSCAR station that way, at a distance of 300 feet  
from the shack.  If I remember correctly I ran two eight conductor  
rotator cables, one for the two rotators and the other for control  
wires.  Didn't run AC, but operated remotely from a battery that was  
trickle charged over the cables.  When the trickle charge was turned  
off, an FET at the remote end powered up the equipment, so there was a  
limit to operating time (albeit many hours, plenty for the OSCAR  
passes of the old days).

Ini the present project, I had thought to remote the microwave  
equipment and control it via ethernet but have decided it is too much  
trouble.  For now (the foreseeable future) I'll just run the L-Band  
box within a cable's length (three feet) of the DSP-10.  If I do  
remote L-Band closer to the antenna one of these days, first choice  
will be to just run a longer 2 meter IF cable and a longer 8 conductor  
control cable, as you and I have both done before.  Will still have to  
do something about remote power.  For all the effort and expense, one  
could just invest in 100 feet of really good coax!


>
> I am interested in getting a 432 high side transverter one of these
> days.  Mike, KD7TS has been playing with this, as well.  He is farther
> along than I am.
>

Mike sent me his schematic but I don't yet have the software to read it.

The very next step on L-Band is to design the control board and use PC- 
Express or something like it (very first time for me) to produce it.   
In the process of doing that, I may gain the ability to generate and  
read schematics like Mike's.  I also plan to sketch out 432 ideas  
while I'm thinking about all the issues.

> We did not make it to Marys Peak.  The rain and wind were excessive,  
> and
> then they closed things for maintenance.  The road is sliding down the
> hill in places.  So, a couple of weeks later K7ITA and I went up  
> Bunker
> Hill in CN85.  We worked W7SZ easily on 10 and 24 GHz.  he is about 35
> miles, and may be LOS.  KD7TS and W7GLF were up by Mt Rainier, and we
> worked them on a mountain bounce with SSB signals on 10 GHz.  But on  
> 24
> GHz, we never saw a sign of anything on the waterfall, and they never
> heard us.  We are going to pursue the why of this, one of these days.
>

The reason I'm going to ~30 watts on L-Band is because I plan on  
mostly home use.  I do have enough equipment to go remote, at least  
vehicle remote, however, and will probably mountaintop a little one of  
these days.  Right now the antenna is still the medium gain (8  
element) beam you suggested I build.  The medium term plan is a 4 foot  
dish on az/el mount.  Then I'll be back to EME2.  The schedule on this  
is only constrained by my need to work for a living, so it's still  
measured in years rather than months.  <sigh>

> 73,  Bob  W7PUA
>

73, Courtney N5BF
>
>
> On 11/01/2010 09:07 PM, Courtney Duncan wrote:
>> Hi Bob,
>>
>> Yes, it continues to be very educational getting the 1296 station
>> running the way I want it to.  The good news is that I think I
>> understand the transverter issues well enough now to attempt to  
>> design
>> and homebrew the 432 to 144 version that we talked about (576 LO).
>> The bad news is that I don't have any more spare time than before, so
>> it will take a while to "get to it."
>>
>> For sequencing I've decided for this rev to bring out all 8 lines  
>> from
>> the DSP-10, go ahead and use the two that are already supported as  
>> you
>> describe, but design my interface board to where it will take
>> additional inputs should I want to increase the number of sequencing
>> points in software later, just wiring logical ones together for now.
>> This means keeping the 23 cm stuff in the same room with the DSP-10
>> for now, i.e., not remoting it closer to the antenna, but that's OK
>> for now due to the educational nature of the whole project.  I want  
>> to
>> keep my eye on it while it's working.
>>
>> I visited KB5MU over the weekend.  He and W5NYV are working on a 10
>> GHz project.  We swapped war stories.  He also brought me up to date
>> on the Microwave Update held near here last month.  Didn't make it to
>> that but might make it to a San Bernardino Microwave Society meeting
>> sometime soon (like maybe even this Thursday!).
>>
>> How did the Marys Peak 24 GHz work go?
>>
>> 73, Courtney, n5bf/6
>>
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"It's science. They don't know anything; they just make a lot of  
educated guesses."  -- Viannah Duncan

Courtney Duncan, n5bf/6
cbduncan at earthlink dot net
1296.100, 1.810.
n5bf at amsat dot org

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