[Elecraft] P3TX questions

[Alan Bloom]

Hi Mike,

I don't believe there are any plans to display the transmitted envelope 
on the external SVGA monitor.

The way the SVGA works is the I/Q data for the spectrum/waterfall 
display are streamed continuously to the SVGA via an SPI bus.  The SVGA 
then basically duplicates everything the main processor is doing for the 
main display in order to display the spectrum and waterfall on the 
external monitor.

The issue with displaying the power information is that it does not 
exist in the SVGA module.  The main processor would have to somehow send 
the information in real time to the SVGA, which would then display it. 
There is an I2C bus between the two modules that is used for 
communications and control, but I don't think it would have enough 
bandwidth to handle real-time power data.

Perhaps the main processor could pre-process the data and compress it 
somehow for transmission, but it would not be a simple task.  Perhaps 
not impossible - I'll have to think some more about it.

Alan N1AL


On 05/16/2015 05:48 AM, Mike K2MK wrote:
> Hi Alan,
>
> Are there plans to display the transmitted envelope on an SVGA monitor in
> the future. Would it require a different SVGA board?
>
> 73,
> Mike K2MK
>
>
> Alan Bloom-2 wrote
>> On 05/15/2015 12:34 PM, Jeff Stai wrote:
>>> 1. What about digital modes like RTTY and PSK at least? How will they
>>> display? For these modes determination of good TX quality will be huge.
>>
>> The P3 screen shows the modulation envelope, so flat-topping of a PSK31
>> signal, for example, should be obvious.  RTTY is constant-envelope
>> modulation so you shouldn't see any amplitude changes.
>>
>>> 2. Distance from the sensor. In the FAQ the distance supported is 5'6"
>>> but
>>> longer is hinted as being possible. What are the considerations for a
>>> longer run (say 20 feet)? For example, bigger conductors, or shielding,
>>> or...?
>>
>> I'd say go ahead and try it.  I haven't tested longer cables but I can't
>> think of any reason they wouldn't work.  All the input pins on the RJ-45
>> have pi-type R-C filter networks.
>>
>>> 3. Switching sensors. I see that mechanical RJ45 switches are available
>>> for
>>> low prices, what are the considerations for using a switch? Also, is it
>>> strictly necessary to switch all 8 lines?
>>
>> I suppose you could just leave the +5V (pin 1) and ground (pin 3) lines
>> connected to both sensors all the time, but a mechanical LAN switch
>> probably switches all 8 wires anyway so it's a moot point.
>>
>>> 4. Meter display. This might be my favorite feature to have power/SWR
>>> right
>>> there at the P3, but the meter display to my eye is at least twice as
>>> tall
>>> as it needs to be. For digital contesting especially I live and die by
>>> the
>>> waterfall and hate to give up any real estate. Will the meter display
>>> height be adjustable? (I'd be happy with just the numbers down in a
>>> corner,
>>> like:
>>
>> We're still tweaking the design so a shorter meter face is a
>> possibility.  You can also gain some display space by turning off the
>> function key labels with the LABELS key or changing to a smaller type
>> font with the "Font" menu selection.
>>
>> Alan N1AL
>
>
>
>
>
> --
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