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How susceptible is the DRAWS board to RFI? Metal Case required?


Charlie Hein
 

Just askin'.  Is an acrylic case suitable, or should the Pi and DRAWS be housed in a metal case to help prevent RFI?

Charlie


 

Acrylic cases are suitable with a couple of caveats:

Be mindful of Temperature rise, probably not suitable for Pi4

One customer had RFI issues and fixed them with a grounded metal plate on top of their acrylic case

C4Labs makes acrylic cases for DRAWS both versions 1 with the SMA on the side and version 2 with the SMA on the end. They are working on a new version for the current rev, which has the Barrel Connector for DC.


Bryan K7UDR

On Jul 28, 2020, at 6:33 AM, Charlie Hein <chein@...> wrote:

Just askin'.  Is an acrylic case suitable, or should the Pi and DRAWS be housed in a metal case to help prevent RFI?

Charlie


Charlie Hein
 

Thanks Bryan - I'm running a Pi 3 B+ and right now just idling and running off of the buck booster on the DRAWS board, the temperature on the Pi is holding steady at 56° C.

I have an email out to C4 Labs on the new design, waiting for a reply from them.  For now the Pi is sitting on the baseplate from its old case, which will work until I have to actually deploy the thing in the field.

Now I need to figure out the pin-outs on the connectors and build a cable to interface with my HT so I can test without tearing any of my existing setup down.  Is there a diagram posted somewhere for this?  Would save a lot of time.  If not, I'll post one once I figure out how to build a good working cable.

Charlie


Basil Gunn
 

Now I need to figure out the pin-outs on the connectors and build a
cable to interface with my HT
Which HT?
Trying to make digital modes work on most (all ?) Chinese HT's is not
recommended.


 

There are two types of RFI to consider. 

RFI from the Pi + HAT, which are generally not a problem. 

Then there is RFI to the Pi.  Some ham installations have lots of RF in the shack.  This can lead to interference with the operation of the Pi and potentially the HAT.  If you encounter this problem, then shielding and other mitigation steps may be necessary, including ferrites and shielded cabling, shielded case, and proper grounding.

On Tue, Jul 28, 2020 at 6:51 AM Bryan Hoyer <bhhoyer@...> wrote:
Acrylic cases are suitable with a couple of caveats:

Be mindful of Temperature rise, probably not suitable for Pi4

One customer had RFI issues and fixed them with a grounded metal plate on top of their acrylic case

C4Labs makes acrylic cases for DRAWS both versions 1 with the SMA on the side and version 2 with the SMA on the end. They are working on a new version for the current rev, which has the Barrel Connector for DC.


Bryan K7UDR

On Jul 28, 2020, at 6:33 AM, Charlie Hein <chein@...> wrote:

Just askin'.  Is an acrylic case suitable, or should the Pi and DRAWS be housed in a metal case to help prevent RFI?

Charlie



--
John D. Hays
Kingston, WA
K7VE

 


Chris Doutre <c@...>
 

And keeping the antenna as far away from the Pi as possible. Sometimes tricky using an HT.

 


Charlie Hein
 

I have two that are available for this, a Baofeng BF-F8HP and an ancient Icon IC-2AT, both of which I have hand mics for that can be sacrificed for their nice pre-molded cables.

Charlie 


Kevin K. - N7KJK
 

I share this image of a custom case which includes dual fans.. I also wired two AAA batteries to the clock backup.


I used a gpio riser to make room between the PI and the DRAWS for heat syncs and a center fan.  Simply bought two PI stack style cases and modified one for the DRAWS connects.

I've been running it for a couple days now as APRS tracker with no temp issues.

Kevin/N7KJK


On Tue, Jul 28, 2020, 6:51 AM Bryan Hoyer <bhhoyer@...> wrote:
Acrylic cases are suitable with a couple of caveats:

Be mindful of Temperature rise, probably not suitable for Pi4

One customer had RFI issues and fixed them with a grounded metal plate on top of their acrylic case

C4Labs makes acrylic cases for DRAWS both versions 1 with the SMA on the side and version 2 with the SMA on the end. They are working on a new version for the current rev, which has the Barrel Connector for DC.


Bryan K7UDR

On Jul 28, 2020, at 6:33 AM, Charlie Hein <chein@...> wrote:

Just askin'.  Is an acrylic case suitable, or should the Pi and DRAWS be housed in a metal case to help prevent RFI?

Charlie


Jim Erickson
 

I’ll share this image, a metal case from amazon that I customized to accommodate the 2 mini-din and sma connector.  Temperature sits around 55-60 with the fan which is using the accessory pins on the draws hat.  I’ve been using this daily for 6+ months with no temperature issues or RFI issues.



------
73,
Jim
VA7SHG - Phone
VE7TGZ/VA7TGZ - Other

On Jul 28, 2020, at 10:06, Kevin K. - N7KJK <kkutzera@...> wrote:

I share this image of a custom case which includes dual fans.. I also wired two AAA batteries to the clock backup.


I used a gpio riser to make room between the PI and the DRAWS for heat syncs and a center fan.  Simply bought two PI stack style cases and modified one for the DRAWS connects.

I've been running it for a couple days now as APRS tracker with no temp issues.

Kevin/N7KJK


On Tue, Jul 28, 2020, 6:51 AM Bryan Hoyer <bhhoyer@...> wrote:
Acrylic cases are suitable with a couple of caveats:

Be mindful of Temperature rise, probably not suitable for Pi4

One customer had RFI issues and fixed them with a grounded metal plate on top of their acrylic case

C4Labs makes acrylic cases for DRAWS both versions 1 with the SMA on the side and version 2 with the SMA on the end. They are working on a new version for the current rev, which has the Barrel Connector for DC.


Bryan K7UDR

On Jul 28, 2020, at 6:33 AM, Charlie Hein <chein@...> wrote:

Just askin'.  Is an acrylic case suitable, or should the Pi and DRAWS be housed in a metal case to help prevent RFI?

Charlie



<IMG_20200715_062609.jpg>


Stuart Longland VK4MSL
 

On 29/7/20 2:30 am, Chris Doutre wrote:
And keeping the antenna as far away from the Pi as possible. Sometimes tricky using an HT.
Even harder on a bicycle… In my situation, it'll be mounted beside my
FT-857D which is inside a 44L motorcycle plastic top-box. I do
sometimes run 100W on SSB on the 80m, 40m, 20m, 15m, 10m and 6m bands.

The antenna mounts are to the sides of that same top-box (with an earth
strap for the HF antenna). So in that situation, the RPi will be
mounted barely 30cm from the base of the HF antenna (and maybe a little
further away from the 2m/70cm antenna).

Keeping RF out of the microphone (in my helmet) has been a challenge,
particularly on lower bands.

My plan is, when the case finally arrives, to earth that to the antenna
ground system, possibly even double box the thing in another case so I
can put some cable retention in as I can guarantee those mini-DIN6
cables will just shake themselves loose.

(We'll see how WiFi range goes, I only need it to reach about 10m.
There are ways to replace the on-board antenna with a socket. FCC be
damned, they aren't in charge in this country.)
--
Stuart Longland (aka Redhatter, VK4MSL)

I haven't lost my mind...
...it's backed up on a tape somewhere.


Mitch Winkle
 

Just last week, I took an RPi4 with the tiny fan in the lid of the plastic case (from CanaKit) out into the wilds of a military installation in the heat and humidity (and it rained almost the whole time).  I had it running for many hours shuttling data between HF radios in different places.  No issues whatsoever. They are a bit tougher than we give them credit for.  The thing bounced around in my car all the way there for hours of driving multiple times.

On 7/28/2020 9:51 AM, Bryan Hoyer wrote:
Acrylic cases are suitable with a couple of caveats:

Be mindful of Temperature rise, probably not suitable for Pi4