[hfsig] soliciting advice regarding 30m HAT

[KB3CS - Chris]

Bryan,
  with rpitx built and installed from the repo at
https://github.com/F5OEO/rpitx.git , you need only the user files from the
WWoT image on your 3B+ (this is the configuration i have been using).   i
can make the tar file i made of the user files available to you, if you
need it.

Bruce,
  how do the 40m harmonic levels ( -23, -44 dBc ) compare to the 30m
levels? the 40m levels indicate at the very least a 2nd harmonic notch is
needed to conform to the minimum -43 dBc harmonic supression specification.

 - 3g (base 19) -


On Sun, Feb 10, 2019 at 9:35 PM Bruce Raymond <bruce at raymondtech.net> wrote:

> 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> 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> 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
>> >
>> > _______________________________________________
>> > hfsig mailing list
>> > hfsig at lists.tapr.org
>> > http://lists.tapr.org/mailman/listinfo/hfsig_lists.tapr.org
>>
> _______________________________________________
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>
>
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