Here is a link to the BOG in action;
https://www.facebook.com/272355476187337/posts/2140150649407801/
Brent Scott
WR5O
> On Feb 5, 2019, at 3:18 PM, k8mp@aol.com wrote:
>
> Thanks Jay.
>
>
> -----Original Message-----
> From: Jay Terleski <jayt@arraysolutions.com>
> To: k8mp <k8mp@aol.com>
> Cc: wr5o <wr5o@icloud.com>; antennaware <antennaware@contesting.com>; Ward
> Silver <hwardsil@gmail.com>
> Sent: Tue, Feb 5, 2019 01:57 PM
> Subject: Re: [Antennaware] Antennaware Digest, Vol 117, Issue 1
>
>
> There are other products.
> ARRL reviewed the Array Solutions RX-FEP front end protector and found it
> excellent.
> https://www.arraysolutions.com/as-rxfep
>
> Try it out if it doesn't do the job send it back for a refund. No kidding.
> Jay, WX0B
>
> Jay Terleski
> Array Solutions
> 214 954 7140
>
>
>
> On Tue, Feb 5, 2019 at 12:42 PM Joe via Antennaware
> <antennaware@contesting.com> wrote:
> Thanks Brent
>
>
> -----Original Message-----
> From: Robert Scott <wr5o@icloud.com>
> To: k8mp <k8mp@aol.com>
> Cc: hwardsil <hwardsil@gmail.com>; antennaware <antennaware@contesting.com>
> Sent: Tue, Feb 5, 2019 12:58 pm
> Subject: Re: [Antennaware] Antennaware Digest, Vol 117, Issue 1
>
> There are products to protect your receiver that are available from DX
> Engineering however,depending on your radio,it might have the option to
> switch between antennas automatically. The big issue is the passive coupling
> between the two. The transmit antenna is receiving noise and when coupled to
> the BOG will transfer this noise to it. That being said you need at least a
> wavelength of separation to avoid this. I know that is not possible in most
> situations including mine so I live with it. The benefits of the beverage are
> still good even in this situation. Here is my BOG on 160 last night. This
> beverage is approximately an eighth of a wavelength separated from my
> inverted L and lays across the street and into a neighbors yard when I have
> it deployed.
>
> Brent Scott
> WR5O
>
>
>
> > On Feb 5, 2019, at 9:45 AM, Joe via Antennaware
> > <antennaware@contesting.com> wrote:
> >
> > Hey Ward, et al,
> > This is not related to the original topic but you mentioned BOG antennas
> > and I have a question.Is installing a BOG near the ground system of an
> > Inverted-L dangerous for a receiver? Separation between them would be about
> > 1/8 wavelength, perhaps less, from the nearest radial.
> > In my situation, there would be radials and the BOG(s) in the same body of
> > water. I have no clue how much RF current and voltage would be in there.
> > Thanks, Joe, K8MP
> >
> > -----Original Message-----
> > From: Ward Silver <hwardsil@gmail.com>
> > Cc: antennaware <antennaware@contesting.com>
> > Sent: Tue, Feb 5, 2019 09:57 AM
> > Subject: Re: [Antennaware] Antennaware Digest, Vol 117, Issue 1
> >
> >
> > I would suggest that you contact K9AY directly about the impedance mismatch
> > - k9ay@k9ay.com
> >
> > From my experience and in reviewing a lot of literature, unless the loop is
> > *really* small, preamplifier noise figure is not significant on the lower
> > HF and MF bands. I suppose it might be an issue for desktop rotatable
> > loops or "Beverage on Ground".
> >
> > 73, Ward N0AX
> >
> > On Tue, Feb 5, 2019 at 5:43 AM Andrew Ikin <andrew.ikin@btopenworld.com>
> > wrote:
> >
> >> Hello Ward,
> >>
> >> I think I need to rephrase my email. What I am trying to say is, a small
> >> terminated antenna e.g. a Flag or a Waller Flag is noise limited by the
> >> termination resistor. This is because the resistor has a 3dB noise figure.
> >> The antenna loss or low radiation resistance doesn't matter so much as this
> >> loss can be made up with an LNA. The issue is made worse because most
> >> practical
> >> designs have the matching transformer z that is the same as the termination
> >> resistor. Now if we use amplifier with high input z of say 30k Ohms; using
> >> chemandy.com Return loss and mismatch loss calculator
> >> the resistor noise is miss-matched to the amp. by approx. 10dB.
> >>
> >> Thus the antenna noise floor should be lower. However, I am assuming that
> >> the LNA has negligible noise when terminated with the antenna. This could
> >> be
> >> a design issue to get the noise figure down to less that 0.5dB!!!
> >>
> >> The example I gave using a high z amp. with the K9AY suggests that there is
> >> no loss in gain by using increasing the input z.
> >>
> >> 73
> >>
> >> Andrew G8LUG
> >>
> >> -----Original Message-----
> >> From: Ward Silver
> >> Sent: Monday, February 4, 2019 7:50 PM
> >> To: antennaware@contesting.com
> >> Subject: Re: [Antennaware] Antennaware Digest, Vol 117, Issue 1
> >>
> >> A flux-coupled transformer with separate windings provides galvanic
> >> isolation between the feed line shield's outer surface and the loop.
> >> Coupling from the loop to the feed line can upset the pattern and couple
> >> noise on the feed line into the antenna.
> >>
> >> It is also a good idea to add a choke of several thousand ohms on the feed
> >> line at the antenna to prevent common-mode current on the outside of the
> >> feed line shield from getting into the cable and becoming differential-mode
> >> signals. Same concern at the receiving end although most receivers are
> >> well-shielded.
> >>
> >> 73, Ward N0AX
> >>
> >> On Mon, Feb 4, 2019 at 11:00 AM <antennaware-request@contesting.com>
> >> wrote:
> >>
> >>> Send Antennaware mailing list submissions to
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> >>> Today's Topics:
> >>>
> >>> 1. Fw: source impedance of resistor terminated antennas (Andrew Ikin)
> >>>
> >>>
> >>> ----------------------------------------------------------------------
> >>>
> >>> Message: 1
> >>> Date: Sun, 3 Feb 2019 23:04:32 -0000
> >>> From: "Andrew Ikin" <andrew.ikin@btopenworld.com>
> >>> To: <antennaware@contesting.com>
> >>> Subject: [Antennaware] Fw: source impedance of resistor terminated
> >>> antennas
> >>> Message-ID: <2E4939776E6344ECB4242B584629630C@DESKTOPCPQEP29>
> >>> Content-Type: text/plain; charset="UTF-8"
> >>>
> >>>
> >>>
> >>> From: Andrew Ikin
> >>> Sent: Sunday, February 3, 2019 10:38 PM
> >>> To: antennaware@contesting.com
> >>> Subject: source impedance of resistor terminated antennas
> >>>
> >>> Is there any reason why most resistor terminated antennas like the K9AY
> >>> and the Flag use a matching transformer to the Rx feed line that has the
> >>> same impedance as the termination resistance. The reason for the question
> >>> is, such antennas have a ideal match to the 3dB noise generated by the
> >>> termination resistor and this resistor has no radiation resistance.
> >> Hence,
> >>> for antennas like a small size Flag, the performance could be limited by
> >>> the resistor noise.
> >>>
> >>> However, if the antenna is connected to a high zin amp., then the
> >> resistor
> >>> noise should be reduced by the miss-match and if the amp. noise figure is
> >>> very low, then it may be possible improve the antenna performance?
> >>>
> >>> Winding the clock back 20 years I noticed that the K9AY Rx matching
> >>> transformer could be replaced by a high zin amp. with a voltage gain of
> >>> 11dB. The overall gain increase compared to using 9:1 z transformer was
> >>> 20dB. This increase in gain is what would be expected (11dB amp. plus 9dB
> >>> by replacing the 9:1 transformer). Thus, the antenna gain compared to one
> >>> without the amp. had not been degraded by using high zin amp.. However,
> >>> then I didn?t consider the effect of resistor noise, but this wouldn?t be
> >>> an issue with the K9AY.
> >>>
> >>> Is there something else I need to consider?
> >>>
> >>> 73
> >>>
> >>> Andrew Ikin
> >>> G8LUG
> >>>
> >>> ------------------------------
> >>>
> >>> Subject: Digest Footer
> >>>
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> >>>
> >>>
> >>> ------------------------------
> >>>
> >>> End of Antennaware Digest, Vol 117, Issue 1
> >>> *******************************************
> >>>
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