[TenTec] Eagle problem?

Wed May 14 22:17:24 EDT 2014

Sure, the ground cable was acting as an antenna in the presence of an RF field.  Therefore the radio was above RF ground. 
Due to the Z of the ground it only provides a DC ground.  
With coax fed antennas the RF should be on the inside of the shield. 

73
Bob, K4TAX

Sent from my iPhone

> On May 14, 2014, at 8:46 PM, José Félix Ballester <jfballester at gmail.com> wrote:
> 
> All,
> 
> My antenna is close to the shack and I had RFI issues with my Eagle.   Tried many things and removing the ground connection from the equipment solved it.  I had a ground rod with 6 gauge wire connected to everything.   No ground, no RFI.   Can someone on the know explain this to me?
> 
> 73 de Pepe WP3HW
> 
> 
> On May 14, 2014, at 6:32 PM, Rick - DJ0IP / NJ0IP <Rick at DJ0IP.de> wrote:
> 
> Carter,
> 
> Most of the time this type of problem is caused by common mode current.
> I don't think the 25' away from the house is the problem.
> The problem would be an imbalance in the current on the feedline.
> 
> I can't say whether or not something is wrong with your OMVI.
> Of course it is possible.
> 
> However my recommendation is an RF choke on the openwire.
> YES, there is such an animal!
> 
> I don't know if you can buy them ready-built in the states but you can buy
> them here.
> They are also very easy to build if you can't buy them.
> What you do is build a short thin openwire using two 18" pieces of Teflon
> insulated wire secured side by side.
> Use heat shrink tubing to secure them.  They will have about 100 Ohms, but
> that doesn't matter for just 18 inches.
> Then slip a string of ferrite beads over them.  Best would be #43 material.
> You can use the same ones used for RG-213.
> Use wire ties each side of the stack of toroids to prevent slippage.
> You can then place a large heat-shrink tube over the thing to make it look
> neat.
> 
> Run your openwire into one end of this just before the matchbox.
> The connect the other end directly to the JV matchbox.
> 
> There is a good chance that this will solve your problem, but of course I
> can't promise it.
> With just 100w, Teflon insulation may not be necessary but it should be
> something that can withstand a little bit of heat without melting.
> 
> 73 - Rick, DJ0IP
> (Nr. Frankfurt am Main)
> 
> 
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Carter
> Sent: Wednesday, May 14, 2014 10:36 PM
> To: tentec at contesting.com
> Subject: Re: [TenTec] Eagle problem?
> 
>> On 5/8/2014 6:51 PM, Stuart Rohre wrote:
>> 
>> These types of problems usually  indicate that there is RF leaking
>> back to any any transceiver he might try, because his antenna is too  >
> close to the shack ...
> 
> An interesting thought, but can we always blame the "antenna being too close
> to the shack"?
> 
> I bought my Omni VI new in 1994 and have never been able to operate SSB or
> PSK31, SSTV or any other mode that required the use of the mic jack. 
> (Good thing I am 99% a CW and RTTY guy.  <grin> ) Anything over about 10
> (ten) watts of power seems to cause the problem, utter and complete
> distortion of the radiated signal.
> 
> The shack is in the basement, the antenna is a 132' long dipole about 25
> feet high and fed with ladder (window) line to a Johnson KW Matchbox tuner.
> The length of the window line between the Matchbox and the hole in the wall
> where it exits the basement is no more than five feet. Yes, when I measure
> the RF current in each leg of the window line they are different -- to be
> expected as this is not a perfect world and the dipole is not in free space.
> The coax cable to the Centurion / Omni VI has a multiple ferrite bead balun.
> 
> After years of unsuccessfully chasing around with ferrite beads and chokes,
> I was finally told [by ******] that my dipole was "too close to the house".
> Unfortunately, because of the shape of the lot, the location of trees and
> zoning/deed restrictions, the antenna HAS to be where it is.
> 
> So...problem occurs at around 10 watts of output, the antenna can't be moved
> and I don't think I am the only ham in the world using a dipole close to the
> house fed with window line.
> 
> This leads me to do the unthinkable and to ask about the elephant in the
> room. Rather than everyone saying the antenna "is too close to the house",
> is it possible that this particular vintage of Omni VI option 3 is just
> particularly sensitive to RF getting into the mic jack (or other ports)???
> Is this unique to my radio? Do Yaecomwoods suffer from the same issue?
> 
> The reason I ask is that I am getting into PSK31, JT9 and JT65-HF (and yes,
> I realize these are "low power" modes), but I wouldn't mind going up to 20
> or 25 watts -- or  SSTV at (gasp!)100 watts.
> 
> I would appreciate any thoughts or suggestions. New /different radio or
> fixing this radio (how?) is OK, but a 100' tower 300' away is just not an
> option.
> 
> 73,
> Carter   K8VT
> 
> 
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