[hfsig] soliciting advice regarding 30m HAT

[Bruce Raymond]

Hi Chris,

On 40m the second harmonic is -23 dBc and the third harmonic is -44 dBc. 
With 200 mW that's about 1 mW for the second harmonic. Not perfect, but 
not likely to cause too much interference, especially as the 40m second 
harmonic doesn't fall in the 20m WSPR subband.


Hi Bryan,

The problem with WSPR and the Pi 3+ board is incompatible software in 
the current build (wiringPi and WsprryPi don't recognize the Pi 3+). 
I've put together a new build using Raspbian Stretch instead of Jesse 
and the updated versions of wiringPi and WsprryPi and am in the process 
of checking it out (been out of town last week ...). We'll put it up on 
the TAPR website as an experimental build to try out. I don't have a Pi 
3+ to verify it with, so I'm hoping that you'll check it out. I'm still 
working on fixing a couple of bugs. I'll keep you apprised of my progress.

73 Bruce/ND8I




KB3CS - Chris wrote on 2/10/2019 7:56 PM:
> yes, i know it will put a signal out on the airwaves on 40m if you ask 
> it to ... but i'd prefer knowing if the harmonic emission is too 
> strong to be permissible without getting a QRPLabs transmit filter first.
>
> i started off with a 3B+ with rpitx already installed and tested, so 
> instead of using the WWoT image, i loop mounted it and made a tar file 
> of the user directory, then extracted that in a working directory on 
> my Pi. if you're having boot problems, you may have to carefully check 
> the partition table to see if you've gotten bitten by the "GB or GiB" 
> problem - not all "32G" SDCards (for instance) have the same number of 
> bytes in total. for example, i got a SDCard from Elektor with a 
> Raspbian image on it and it had an impossible partition table (more 
> blocks defined than the total number of block available on the 
> device). had to work out how to resize a filesystem, then write a 
> sensible (and correct) partition table.
>
>  - \0111 -
>
> On Sun, Feb 10, 2019 at 7:49 PM Bryan Corkran <bcorky at gmail.com 
> <mailto:bcorky at gmail.com>> wrote:
>
>     Just tried it for a while here in VK .
>     Got spots from nearby states immediately ( 400 to 790 Km )
>     Would need to to take to our radio club to properly check for birdies.
>     By the way the 30m Hat and SW wont boot on my  Pi 3b + , its fine
>     on my  3b
>
>     Bryan Corkran, VK3KEZ
>
>     > On 11 Feb 2019, at 6:52 am, KB3CS - Chris <kb3cs at arrl.net
>     <mailto:kb3cs at arrl.net>> wrote:
>     >
>     > unlike the 20m HAT, there are no frequency selective elements
>     before the RF amp.
>     >
>     > has anyone tested (or could test) the 30m HAT output when
>     instead a 40m band excitation frequency is used?  would the output
>     be to horrible to inflict on the airwaves?
>     >
>     > also, if i'm not mistaken, the latest rpitx release uses GPIO4
>     for all output modes.
>     >
>     > comments?
>     >
>     >  - 0x49 -  chris  KB3CS
>     >
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