I have had good luck with the line isolators I referred you to some time
back. I'm fairly certain they're just farite beads over coax, but
solved my problem, magic.
73
Butch
WA0VJR
Node 3148
Wallace, ks.
On Sun, 21 Feb 2016, Tom Fowle wrote:
> tom,
> Remember this gizmo is just a hypothesis based on guess work?
>
> When you can get to putting common mode chokes on your feed lines, you have
> the choice of making them from turns of coax if you have extra length of
> cable or of putting on a bunch of appropriate ferrite beads over the
> feedline near the antenna. The beads are more expensive but if you don't
> have extra feedline maybe easier to accomplish. Suppliers of antenna
> accessories should be able to help you find the correct ferrites for your
> feedline.
>
> Nothing from my friend yet. I'm not mentioning his name with out his sayso
> since he's not a ham.
>
> good luck
> Tom Fowle WA6IVG
>
> On Sun, Feb 21, 2016 at 12:09:44PM -0500, Tom Behler wrote:
>> Tom:
>>
>> Thanks for the clarification. ... It helps a lot.
>>
>> I don't know if I'll get to it today, but this is certainly worth a try.
>>
>> If you get any thoughts from your engineer friend, please pass them along.
>>
>> If you want to write to me privately, my address is:
>>
>> [log in to unmask]
>>
>>
>> Tom Behler: KB8TYJ
>>
>>
>> -----Original Message-----
>> From: For blind ham radio operators [mailto:[log in to unmask]]
>> On Behalf Of Tom Fowle
>> Sent: Saturday, February 20, 2016 11:52 PM
>> To: [log in to unmask]
>> Subject: Re: Next RFI Update, and question for Tom: WA6IVG
>>
>> tom,
>> My thought is this thing would replace the ground wire from the common shack
>> point or the outside ground point on your window panel, going to the ground
>> rod.
>>
>> If I were going to mess with this, and it is purely hypothesis, I'd make the
>> common mode chokes maybe 8 turns on a 6 or 8 inch diameter form.
>>
>> At the ground rod end, I'd connect the center and shield together and to the
>> ground rod.
>> At the top, just the center conductor to the ground on your window panel.
>>
>> Again this is perhaps nonsense. purely hypothetical, my vague theory is the
>> chokes would keep common mode current off the outside of this new type of
>> "shielded ground"
>>
>>
>> I'd much rather see you put common mode chokes in the feeds near your actual
>> antennas, but understand the weather makes that difficult.
>>
>> Gaads Tom, you might just have to turn off the "boots" <HORRORS!>
>>
>> I've written to my engineer friend discribing the aforementioned shielded
>> ground, we'll see if he has anyting to say.
>> Tom Fowle WA6IVG
>>
>>
>> On Sat, Feb 20, 2016 at 11:30:06PM -0500, Tom Behler wrote:
>>> This is a multipart message in MIME format.
>>>
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>>> Hi, all.
>>>
>>>
>>>
>>> I thoroughly checked all of my coax jumpers in the shack for
>>> continuity, and all looked good. But, RFI issues still occurred.
>>>
>>>
>>>
>>> I then found a few small RG9913 jumpers I had lying around, and
>>> actually had two snap-on RF chokes that could accommodate that size of
>>> coax. Put one at the output of the TS590, and the other between the
>>> output of my MFJ998 auto-tuner, and the common connector on my
>>> six-position Alpha Delta antenna switch. Still no joy.
>>>
>>>
>>>
>>> Now, I have a question for Tom: (WA6IVG):
>>>
>>>
>>>
>>> In your last post with the subject of "shielded ground", you posed a
>>> possible solution for an in-the-shack common ground. You said:
>>>
>>>
>>>
>>> How about a piece of coax as ground wire with center conductors used
>>> as the actual ground.
>>>
>>> Now take the coax and wind a common mode choke in it at each end, but
>>> do nothing with the shield at the top and ground the shield at the
>> bottom."
>>>
>>>
>>>
>>> I'm a bit confused: where exactly would you connect both ends of this
>>> new grounding cable made out of coax? Obviously, one end would go to
>>> the common ground connection on my feed-through panel, but I'm not
>>> sure where the other end would go. Also, how would you ground the
>>> shield at the other end of the cable? And, what would you recommend
>>> for the size of the common mode chokes on each end?
>>>
>>>
>>>
>>> I have some extra coax here that I'd be willing to try this with
>>> sometime tomorrow.
>>>
>>>
>>>
>>> Tom Behler: KB8TYJ
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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>>> class=3DMsoNormal>Hi, = all.<o:p></o:p></p><p
>>> class=3DMsoNormal><o:p> </o:p></p><p = class=3DMsoNormal>I
>>> thoroughly checked all of my coax jumpers in the = shack for
>>> continuity, and all looked good. But, RFI issues still =
>>> occurred.<o:p></o:p></p><p class=3DMsoNormal><o:p> </o:p></p><p =
>>> class=3DMsoNormal>I then found a few small RG9913 jumpers I had lying
>>> = around, and actually had two snap-on RF chokes that could
>>> accommodate = that size of coax. Put one at the output of the
>>> TS590, and the = other between the output of my MFJ998
>>> auto-tuner, and the common = connector on my six-position Alpha Delta
>>> antenna switch. Still no = joy.<o:p></o:p></p><p
>>> class=3DMsoNormal><o:p> </o:p></p><p = class=3DMsoNormal>Now, I
>>> have a question for Tom: = (WA6IVG):<o:p></o:p></p><p
>>> class=3DMsoNormal><o:p> </o:p></p><p = class=3DMsoNormal>In your
>>> last post with the subject of “shielded = ground”, you
>>> posed a possible solution for an in-the-shack common = ground.
>>> You said:<o:p></o:p></p><p = class=3DMsoNormal><o:p> </o:p></p><p
>>> class=3DMsoPlainText>How about = a piece of coax as ground wire with
>>> center conductors used as the actual = ground. <o:p></o:p></p><p
>>> class=3DMsoPlainText>Now take the coax and = wind a common mode choke
>>> in it at each end, but do nothing with the = shield at the top and
>>> ground the shield at the = bottom.”<o:p></o:p></p><p =
>>> class=3DMsoPlainText><o:p> </o:p></p><p =
>>> class=3DMsoPlainText>I’m a bit confused: where exactly
>>> would = you connect both ends of this new grounding cable made out of
>>> = coax? Obviously, one end would go to the common ground
>>> connection = on my feed-through panel, but I’m not sure where
>>> the other end = would go. Also, how would you ground the shield
>>> at the other end = of the cable? And, what would you recommend
>>> for the size of the = common mode chokes on each end?<o:p></o:p></p><p
>>> = class=3DMsoPlainText><o:p> </o:p></p><p class=3DMsoPlainText>I
>>> have = some extra coax here that I’d be willing to try this with
>>> sometime = tomorrow.<o:p></o:p></p><p
>>> class=3DMsoPlainText><o:p> </o:p></p><p =
>>> class=3DMsoPlainText>Tom Behler: KB8TYJ<o:p></o:p></p><p =
>>> class=3DMsoPlainText><o:p> </o:p></p><p =
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>
>
|
