[RRDXA] RFI

[ulf schneider]

Mahlzeit,

trotz dem Einsatz von Mantelwellensperren an allen Ein- und Ausgängen, 
Verdrosselung aller Zuleitungen mit ordentlichen Ringkernen hatten wir 
im RDXC in HB0 erhebliche (Audio-)Probleme beim Microham "USB micro 
KEYER". Das war mit vertretbarem Aufwand durch 2 erfahrene HF-Ingenieure 
und einem Doktor der HF-Technik auch nicht in den Griff zu bekommen. Die 
Probleme konnten in einem anderen Setup verifiziert werden, das Gerät 
wurde in der Zwischenzeit an Jemanden verkauft der wohl kein QRO macht ....

Der unten angesprochene "USB MK2R+" lief am Wochenende bei DL0TUM 
allerdings problemlos .. trotz Alpha 91b und maximal 6-7 m Abstand zu 
den Antennen. Hier waren allerdings auch Mantelwellensperren und 
Drosseln massivst im Einsatz.

73 Ulf DK5TX


Juergen Henneke, DF1DX wrote:
> Guten Tag,
> 
> aus gegebenem Anlass einige Hinweise zur Entstörung
> von der microHAM-Liste.
> 
> 73 Jürgen, DF1DX
> 
> [snip] ----------------------------------
> 
> b. Re: MK2R+ and 20m Interaction
>      Posted by: "Joe Subich, W4TV" w4tv at microham-usa.com k4ik
>      Date: Sun Oct 28, 2007 10:47 pm ((PDT))
> 
> If you have a problem that is related to transmitting on
> one band, I would look for common mode RF issues ("hot"
> feedline) and/or radiated RF on that band.  The most
> common issue is a hot feedline that places MK2R at the
> "wrong" place.
> 
> I strongly recommend the writings by W1HIS and W9YC on
> common mode chokes and RFI suppression.
> 
> W9YC:  www.audiosystemsgroup.com/publish.htm
>         www.audiosystemsgroup.com/SAC0305Ferrites.pdf
>         www.audiosystemsgroup.com/RFI-Ham.pdf
>         www.audiosystemsgroup.com/CoaxChokes.pdf
> 
> W1HIS: www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf
> 
> 73,
> 
>     ... Joe Subich, W4TV
>         microHAM America
>         http://www.microHAM-USA.com
>         http://groups.yahoo.com/group/microHAM
>         support at microham.com
> 
> 
>>> -----Original Message-----
>>> From: microHAM at yahoogroups.com
>>> [mailto:microHAM at yahoogroups.com] On Behalf Of py2ny
>>> Sent: Sunday, October 28, 2007 7:59 PM
>>> To: microHAM at yahoogroups.com
>>> Subject: [microHAM] MK2R+ and 20m Interaction
>>>
>>>
>>> Good Evening...
>>> I am suffering a lot on this CQ WW SSB !! I have
>>> MK2R+ with a FT1000 Field plus Alpha 91B
>>> with no more than 500/600w all the time.
>>> I have no reason, but it's impossible to work
>>> with this setup on 20m with more than 200w...
>>> A very strange interaction specially while
>>> using ProSet Heil HC-4 (boomset) and MK2R,
>>> is happening, only on 20m...
>>> You can go to 10m, use everything there with
>>> no problem, and then to 20m. After few minutes,
>>> transmissions seems to be overloaded and some
>>> times (VOX operation) the TX stay transmiting
>>> after you stop to talk, with noise into in the
>>> microphone...
>>> I have NO PROBLEM if I take of 8pin cable
>>> in front of the radio and attach there, directly,
>>> Proset, but I loose DVK...
>>> If you have any hints about that let me know:
>>> grounding MK2R box? Changing something
>>> in the cables?
>>> Only on 20m !!
>>> Thanks in advance...
>>> Vitor PY2NY
> 
> _______________________________________________
> RRDXA mailing list
> RRDXA at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/rrdxa
>