Topband: Re: K9AY beverage transformers - did I fry them? -- results

[Dave NØRQ (lists)]

Thanks to half a dozen of you that replied.

I put a good DX Engineering 470 Ohm bev resister across the two terminals,
and tested with an MFJ-259B.  To my surprise, all 4 transformers tested 
fine!
(R was 43 to 48 across the lower bands, X was 2 to 5, SWR very low.)
I was sure I had fried at least one of them.

Last winter, the feedpoint of 3 of my 4 Beverages was at the same ground 
rod,
with all 3 K9AY transformers mounted next to each other.  Reading
http://www.w8ji.com/beverages.htm , I found out that that arrangement is
a no-no   :-(   -- but that might explain why they didn't perform as 
expected.
So, I'm off to reroute some wires...  ;-)

Thanks! & 73,
Dave NØRQ



----- Original Message ----- 
From: "K9AY"
To: "Dave NØRQ (lists)" <n0rq-lists at sbcglobal.net>; "Topband Reflector" 
<topband at contesting.com>
Sent: Monday, October 25, 2004 1:10 PM
Subject: Re: Topband: K9AY beverage transformers - did I fry them?


> Dave,
>
> The TRX-9 XFMRs should handle 100W briefly without problems -- the cores 
> are
> quite large and the surge protector has 85V breakdown and 20A continuous
> current rating.  At 1 kW, it's all different -- it would be sheer luck if
> the units survived a brief blast at that power level.
>
> To test the transformers, put a 470 ohm resistor across the binding posts
> and check the SWR at the coax connector with an antenna analyzer -- You
> should see an SWR of 1.3:1 or less.  If it is higher than 1.5:1, there are
> probably shorted turns or a change in the magnetic properties of the 
> ferrite
> and it should be considered "broken" !
>
> Also, check your terminating resistors -- the surge protector may have 
> saved
> them, but no guarantees at 1 kW.
>
> If the XFMRs test OK with the above method and the terminations are OK,
> reinstall the XFMRs and check signal levels as a final test.
>
> 73, Gary
> K9AY
> ___________
>
> My IC-746PRO does not have a receive antenna port, so last season I
> had to manually flip an antenna switch between xmit and rcv antennas.
> (Yes, I know, I need to resolve that situation, one way or another.)
>
> In the process, I inadvertently dumped some RF into my beverages, and
> am wondering if I damaged/ruined my K9AY beverage transformers.  (It
> was 100 watts briefly several times, and 1kw briefly once, into different
> units.)
> How can I tell if they are functioning properly?  I disconnected them
> and brought them inside, but the case is sealed shut, and I don't know
> the correct way to determine if they still work.  Advice appreciated!
>
> --
> Dave NØRQ
>
>