[CQ-Contest] ICOM 7610 & C31XR

[David Siddall]

Years ago I worked an op on 7 MHz CW that turned out was located at a hotel
about 5 blocks away.  When we got together for drinks and QSL exchange, it
turned out that he was transmitting QRP to a wire on his balcony ... but on
21 MHz.  I was hearing him weakly but clearly, and exactly on my 7 MHz
frequency.  So he was hearing my 7 MHz CW exactly on his 21 MHz frequency,
and vice versa.   My radio was a Drake C-line, I forget his radio.  He
could have been hearing my 3rd harmonic (although I think we concluded that
it was several hundred kHz from 3X freq.), but how was I hearing his
signal?  These sounded like regular discrete signals, not covering the band
or anything like that.

Maybe a hidden feature of (some?) SDRs is more unintended cross-band QSOs?

73, Dave K3ZJ


On Wed, Mar 21, 2018 at 11:11 AM, Terry Zivney <n4tz at arrl.net> wrote:

>
> <  >
>

BUT, this past weekend at N1UR for RDXC. Ed had monobanders withadjacent
> bands on separate towers. We had Dunestar 600s band passfilters. He had no
> problem with his FT1000Mk5 Field but I hadproblems with the new Icom 7610.
> In particular, I needed thepreamp on 15 meters. But, that brought the
> overload light on.When the ICOM 7610 goes into overload, things fall apart
> prettyfast.  Also, you cannot use the DIGI-SEL to add some badly
> neededextra front-end selectivity when you want to use the preamps.
> BTW, the 7610 (and undoubtedly other radios with the samearchitecture) has
> a new type of second radio problem not foundin traditional superhet radios.
> When listening on 3505 you willhear the second radio on 7010.  The 1/2
> harmonic!  Again, Dunestars in line.  This is apparently due to the
> decimation process of the SDR.
> Good luck.
> Terry N4TZ