[1000mp] Relay thing..deaf receiver

[Garry Shapiro]

Thomas,

I am glad to hear the problem has not reoccurred for you. But please be
advised that, after the return of my unit from Yaesu, it worked fine--for
about two years. The problem then returned, although not as severe. I
frequently notice it after certain band changes also, so there may be
another relay involved,as well.

Garry, NI6T

-----Original Message-----
From: 1000mp-bounces at mailman.qth.net
[mailto:1000mp-bounces at mailman.qth.net]On Behalf Of Thomas Otterbein
Sent: Monday, September 18, 2006 9:57 AM
To: 'All about Yaesu 1000mp'
Subject: [1000mp] Relay thing..deaf receiver


Hello,

I watch the thread long time and I had also the described problems of the
RX muting with my MkV in the past.
My transceiver (FT1000MP MkV Field) were two times at the Yaesu repair shop
in the Netherlands. They exchanged the relays RL1002 and RL1005 at the
RF-Unit and did some modification (as they described in the
repair report).  Unfortunately I couldn't get any information what kind of
modification they did.

In the meantime I read several articles about electrostatic and thunder
storms close to antenna systems.

With the knowledge which voltage loads can occure during thunderstorms and
caused by electrostatic charges at antenna systems I now always disconnect
the antenna cables from the radio when I leave the shack.
And since that time I had now more than 1,5  years no problems with the
mentioned relays and RX muting anymore. Not one single time the RX was muted

due to relay problems.

Beside this I read also an interesting article in a German ham magazine
about coax cable and its electrical behaviour as a capacitor.
The author wrote that he measured at a open coax feed line of a antenna
system  (without earthing) after several days thousands of volts capacity.
When you connect in this case the coax direct to the transceiver the ´stored

voltage´ will be grounded over the radio
and the related relays.
I think no good conditions for the front end to survive :-).

Be careful, not all coax switches connect the unused antenna port to
ground. For example the DIAMOND antenna switches CX-310, which I use, didn't

ground the unused port.

Some Balun/UnUn systems are DC grounded and with this the above described
´earthing´ will not happen. But for example direct feeded dipoles will act
with its coax line as a big capacitor (for example RG213 101 pf/meter).

With all this information I disconnect now always the feed line from the
transceivers and ground it to avoid high voltage groundings over the radio.
And up to know it helps and I hope it will keep it like it is :-).


In my humble opinion the mentioned relays at the RF-unit are too sensitive.
And when I see how many OMs wrote about their experience it is not a
individual case but a common problem besides this in other respects fine
transceiver.

I would therefore recommend all MkV user, disconnect the antennas from the
transceiver when not used and ground the coax feed line.


73
Thomas
DG8FBV
---
www.dg8fbv.de

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