[1000mp] Re: Mark V high SWR with amp

Sat Feb 12 22:52:13 EST 2005

Cool, glad it was that easy to take care of.

Happy DXing,
Bob
KB4CL

----- Original Message ----- 
From: "Michael W Elliott" <kq0b at sbcglobal.net>
To: <1000mp at mailman.qth.net>
Sent: Saturday, February 12, 2005 10:29 PM
Subject: [1000mp] Re: Mark V high SWR with amp 

> For all those who answered my post I wish to thank
> you.
> I got some great advise and used them as part of my
> problem resolution.
> 
> PLEASE EXCUSE ANY GRAMMAR OR SPELLING ERRORS.
> 
> Short recap:  My Yaesu Mark V had high (full scale)
> swr while my Alpha 99 output and Bird Wattmeter showed
> good swr.
> 
> Here is the outcome.
> 
> 
> I eliminated the Nye Viking tuner to make the testing
> simple.  Basically had the rig to amp to Bird
> wattmeter.  When I felt I had determined the problem
> solution I finally re-introduced the Nye Viking Tuner.
> 
> 
> 
> 
> 
> So here goes.
> 
> 1. I talked to Yaesu and because the rig was ok in
> normal power output the problem pointed to the amp or
> another place in my set-up. 
> 
> 2. I next talked to Alpha and explained my situation
> on the Alpha 99.  I talked to Glen at Alpha.  He
> indicated there was a 50 ohm resister located
> underneath the bottom of the amp and to start there.
> You take the bottom cover off underneath and you will
> see it immediately.   This resistor is connected to
> the SO-239 for the input side.  This resistor is about
> 3 to 4 inches long (black) (you can't miss it).  It
> seems one end of the clips holding the resistor in
> place completely came off.  Now the clip was still
> attached to the resistor but not to the chasis. This
> would be the end opposite of the SO-239.  This may
> have happened in transit last September when I shipped
> the amp back to Alpha for a problem that was under
> warranty and fixed. For whatever reason the clip was
> dangling or hanging down on one side. Again, the
> resistor was still in the clips on both ends but only
> one end was held by a ceramic standoff on the end of
> the SO-239 and not grounded or connected directly to
> the chasis.  I tested the resistor to be certain the
> value was still good and re-attached the clip with
> resistor in place to the chasis.  
> 
> 3. I grounded all equipment to the tuner. The tuner to
> a number 4 wire to my ground rod.
> 
> 4. I am awaiting a Line Isolator from Radio Works
> coming in on Monday 2/12/05 to be sure to eliminate
> the  possibility of stray rf on the coax.  Guess I am
> going all out now.
> 
> Post testing:
> I tested the Alpha 99 and it appears to be doing ok
> with the Mark V.  Mark V shows low swr as it should
> with matched antenna set-ups or by using the Nye
> Viking tuner for 75/80 meters sloper. 
> 
> Now on the Alpha 89 I believe I also helped eliminate
> some marginal jumper cables and it also appears
> happy..
> 
> Thanks to all who responded.  I got a lot of great
> info from you guys.
> 
> INCIDENTLY:  In talking to Yaesu you Mark V guys who
> run an amp using the Alpha 99 or 87a might want to
> check your output power from the transceiver and move
> it down to 100 watts max output from the rig. The menu
> option values are 10/75/200 watts but my Mark V puts
> out 25 watts more than what the menu says.  Look in
> your Alpha 99 / 87a Manuals to see the caution about
> running anything over 100 watts through the 99 or 87a
> because of damaging the resistor - even if it is in
> stand-by.  My Mark V puts out 250 watts with no
> modification done on the transceiver.  I have even
> called Yaesu and it said it is not uncommon for the
> Mark V to put out 225-250 watts out from the box.
> 
> 
> 73s
> Mike
> 
> --- Michael W Elliott <kq0b at sbcglobal.net> wrote:
> 
>> I have started to notice a high swr reading on the
>> input side (transceiver) while running with amp.
>> This
>> problem is becoming more persistent.  The SWR meter
>> goes full scale on the Mark V.  Rig internal tuner
>> is
>> off in the menu so that is ruled out.  This does
>> does
>> not happen using 200 watts output. I have checked
>> the
>> swr with 250 and all is fine.  Once I turn the amp
>> on
>> and transmit I get the swr problem in the rig - does
>> not matter if cw or ssb.  
>> 
>> I see no problems on the outboard meters with a
>> Bird,
>> Nye Viking or even on the amplifier output meters
>> indicating output swr problems. Everything looks
>> normal  there.  
>> 
>>   
>> I seem to remember a thread sometime in the past
>> about
>> a similiar problem.  Can someone recall or give me a
>> clue to the problem.
>> 
>> So that I do not waste a lot of time on the
>> reflector
>> please respond directly.
>> 
>> Thanks
>> Mike
>> 
>> 
>> 
>> 
>> =====
>> Michael W. Elliott
>> THE INSIDE ADVANTAGE -
>> RETIREMENT - LEISURE, REST and ONLY ELECTRONIC MAIL
>> PAYMENTS
>> Servant to Bridgett, Collin and all my Creditors
>> St. Louis County Missouri
>> 
> 
> =====
> Michael W. Elliott
> THE INSIDE ADVANTAGE -
> RETIREMENT - LEISURE, REST and ONLY ELECTRONIC MAIL PAYMENTS
> Servant to Bridgett, Collin and all my Creditors
> St. Louis County Missouri
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