When i tried to connect my equipment with the ground rod, i have major
problems, with pll's lock and the modulation. I have grounded my equipment
to public power's corporation ground.
On Sun, Oct 31, 2010 at 3:08 AM, W5CUL <w5cul@sbcglobal.net> wrote:
> Jim,
>
> You may have missed it, but his diagram shows his 1M ground rod directly
> connected to his antenna, with no grounding for his equipment. I certainly
> hope the diagram is incorrect and he is not depending upon his 2.5M coax
> shield for station ground. Since the antenna is on the roof, he may be
> better off connecting the ground to his station, and use raised radials for
> his antenna.
>
> Placing a bunch of ferrites on the coax feedline will go a long way to
> solving the symptom, RF riding the coax, but not the underlying issue;
> impedance mismatch at the feed point. The elegant way of resolving the
> issue
> is to build a Unun to transform the feedline impedance to the antenna
> impedance, interface the output of the Unun to a 1:1 Balun, and then
> connect
> the output of the Balun to the antenna. This will resolve the impedance
> mismatch and definitely cut back on the reflected RF from riding the cable
> back to the shack. The only caveat with this is that you are now locked
> into a mono-band antenna for the most part. Given his antenna is on a roof
> with coax in the near field on its short run to the shack, I would put the
> ferrites on the shack end to keep the induced RF at bay.
>
> Your friends M2 Balun sounds like a "dirty balun" gone wrong ;-) It is not
> the amount of turns that really matters, it is the length of the coax used,
> and the turns have to be a consistent radius touching only the two windings
> adjacent to it in order for it to work properly. Scramble winding will
> work
> in a quick pinch, but without a form it has a tendency to fall apart over
> time. If it is to be permanent, and you really want to use a dirty balun,
> then you should use some kind of PVC form to wind it on.
>
> 73,
>
> Mike
> W5CUL
>
> -----Original Message-----
> From: Jim Thomson [mailto:jim.thom@telus.net]
> Sent: Saturday, October 30, 2010 5:44 PM
> To: W5CUL; amps@contesting.com
> Subject: Re: [Amps] use or not coaxial audio cable to transmitter's
>
>
>
> --------------------------------------------------
> From: "W5CUL" <w5cul@sbcglobal.net>
> Sent: Saturday, October 30, 2010 3:15 PM
> To: <amps@contesting.com>
> Cc: "'Jim Thomson'" <jim.thom@telus.net>
> Subject: RE: [Amps] use or not coaxial audio cable to transmitter's
>
> > Tzikas,
> >
> > A Balun at the antenna end and Ferrite at the shack end should help with
> > RF
> > riding the coax cable into the shack. Build the balun to transform the
> > impedance at the antenna feed point to that of the impedance of the coax.
> > I
> > don't understand what is meant by "metal house", but a 2.5M coax puts the
> > equipment kind of close to the antenna though. Don't know if that would
> > be
> > a part of the issue or not. Last observation would be 1 ground rod. May
> > not
> > be enough for a good RF ground, but should work great for DC. One
> > question,
> > how is the PLL, Amp & Power supply grounded?
> >
> > I think someone already mentioned a good type of audio cable to use, one
> > with a braided shield and or foil wrap. I use a cable that has two
> > twisted
> > pairs surrounded by a very heavy braided shield for all of my audio
> > connections between gear. Here is a hyper-link, maybe you will be able
> to
> > find a distributor in your location:
> >
> > http://www.canare.com/ProductItemDisplay.aspx?productItemID=53
> >
> > 73,
> >
> > Mike
> > W5CUL
>
> &&&&& That 9M of grnd wire from roof to the dirt is probably causing him
> more problems than
> it solves. That's 31' of grnd wire , to get to grnd. Meanwhile, his
> vertical ant is radiating into both the
> shack, and the 31' of grnd wire as well.
>
> &&& My buddy who had the RFI problem with his new m2 80m yagi, also has a
> 6m RFI problem now. The 80M
> RFI problem was cleared up by installing 20 x type 43 beads slid over
> coax...at the output of his HF amp. Before that,
> he was knocking his dsl modem offline, and RFI from one end of the house to
> the other. The m2 supplied 80m balun,
> was just some rolled up coax, inside the switch box. Clearly it does not
> have a high enough Z.
>
> && The 6M RFI problem was a doozy. Distorted audio, that gets really bad
> when 6m yagi pointed over top his house.
> The tower is right behind the house too. 6M coax is separate from HF
> coax...and 6m coax is routed directly from 6m yagi
> to the output of the dedicated 6M amp. I suggested a bare min of 10 x
> type 43 beads [ he has lots of large beads in his junk box]
> and he installed 23 of em, slid over RG-213, right at the output of the 6m
> amp. Problem solved on 6M. No more distorted
> audio, and very clean. The 6m yagi was a case of yet another m2 balun
> being used, the 6m one is a short, cylinder type of thing.
> All the other hf ant's used 17 x large type 43 beads slid over coax, zero
> problems with all of those ant's.
>
> && I would suggest that Tzikas 1st try a load of ferrite at the feedpoint
> of his vertical. If that doesn't completely solve the
> problem, then install another load of ferrite on the output of his 500W
> amp. If his Mic is generic, unbalanced type, like most stock ham gear,
> then plane RG-58/59 will work just fine for a mic cable.. All you need
> for the mic is hot audio and grnd.
> RG-58/59 will fit the bill..and do the job nicely, and it's readily
> available. If you need PTT, then use a footswitch......and use more
> RG-58
> from footswitch to back of xcvr. Sure, the radio comes with a 8 x pin mic
> connector/cable, but who needs the up/down junk?
>
> &&& I think the above will solve most of his problems. One other thing
> he
>
> could try is to temp disconnect that 9M grnd wire. His 9M
> grnd wire is longer than his 2.5 M coax to base of vertical. That 9M
> long grnd wire is parallel to the vertical. My guess is the vertical is
> radiating loads of RF into the 9M grnd wire..which is coming right back up,
> and into the 500w amp + xcvr.
>
> Jim VE7RF
>
>
> >
> > -----Original Message-----
> > From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On
> > Behalf Of Jim Thomson
> > Sent: Saturday, October 30, 2010 12:20 AM
> > To: amps@contesting.com
> > Subject: Re: [Amps] use or not coaxial audio cable to transmitter's
> >
> >
> > ### He posted a diagram in his 4th posting. His coax to vertical on
> > roof
> > is just 2.5M long.
> > He also has 9 M of grnd wire from metal to the dirt. He has a xcvr +
> > 500
> > w amp. He probably
> > requires ferrite at both the base of the vertical..and also in the
> > shack....
> > IE: both ends of the coax.
> >
> >
> > http://tzitzikas.site90.net/files/installation.JPG
> >
> > Jim VE7RF
> >
> >
> > On 10/29/2010 9:20 AM, tzikas tzik wrote:
> >> pll= phase lock loop . This equipment keep the frequency of oscillator
> >> stable
> >
> > Understood. But more questions.
> >
> > You say 500 watt transmitter. Most ham transmitters are 100W output, and
> > if you want more power, you add a power amplifier. Is this a 500W
> > transmitter all in one box, or two boxes?
> >
> > Where does this cable run? Inside the transmitter, from one point to
> > another, or outside the transmitter, between boxes? What is the
> > transmit frequency?
> >
> > What kind of cable is it? Coax or two conductors plus shield? What
> > kind of shield? What kind of circuit is connected to the cable at each
> > end? Balanced or unbalanced? Where is the shield connected?
> >
> > 73, Jim K9YC
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
> >
>
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