re: "Tuned loops did not work well obtaining a heading on the signal
because tuned loops have very little directional properties for high
arrival angle signals which we were often encountering on 40 meters."
I see this complaint all the time. Consider the below as a method to avoid that
issue.The video was on 80 meters, but, I have used the same technique for 40
meters.Rapid back and forth motion while listening to the audio level is the
key to this
technique; one is looking for the usual null when the loop plane is normal(at
90 degs) to the incoming signal's AZ and EL angles. IF you also know
how high the reflective layer is, one can also make a distance estimation given
the elevation angle.
https://rumble.com/vo0ao5-looking-at-incoming-angle-of-80-meter-signals.html
de AA5CT Jim
On Monday, January 30, 2023, 6:50:56 PM GMT-6, Don Kirk <wd8dsb@gmail.com>
wrote:
Back in April 2022 there was a carrier on 40 meters for many weeks as I
recall. TDOA was said to not work well because the carrier was constant
whereas they said you needed the carrier to be on and off (I have no idea
when TDOA works well and when it does not work well). I was able to
provide a heading from Indiana using my portable flag that turned out to be
within +/- 5 degrees of the actual location which turned out to be in Alma
Colorado and it turned out to be a summer home of a ham who had remote gear
located at his cabin and somehow the transmitter got locked on. Another
ham actually took to the sky in his airplane trying to DF the signal using
DF gear in his airplane but it was the FCC that actually located the
source. Tuned loops did not work well obtaining a heading on the signal
because tuned loops have very little directional properties for high
arrival angle signals which we were often encountering on 40 meters. My
portable flag did the best because it still provided reasonable front to
back properties at the high arrival angle we were often dealing with.
I just did a quick check of the 7.195 MHz carrier at about 7:30 pm EST with
my portable flag and I can actually hear it with the portable flag just
fine without any preamp from my home in Fishers Indiana. I used a preamp
to get enough signal strength so I could use the crude S meter on my
portable receiver, and doing a very quick reading I obtained a heading from
Indianapolis of approximately 265 to 270 degrees give or take a little
bit. It's very cold outside right now so I did not spend any time trying
to get an accurate heading, I just wanted to see what general direction it
was coming from. I was not totally out in the open (I was standing pretty
close to my house), so I will try and get a better heading when time and
weather conditions permit.
Just FYI,
Don (wd8dsb)
On Mon, Jan 30, 2023 at 6:06 PM Don Moman VE6JY <ve6jy.1@gmail.com> wrote:
> the source is likely from North America (or any other country that uses 60
> hz power) as the carrier has 120 hz power supply sidebands...
>
> On Mon, Jan 30, 2023 at 3:59 PM Michael Carter <Mike.Carter@unh.edu>
> wrote:
>
> > If my reading of that table from the source
> > Joe linked is correct, the China transmitter
> > on 7.195 MHz has a TX power of 50 watts.
> > Seems unlikely to provide S9 + 10 dB signal
> > or larger in west central US......
> >
> > Mike, K8CN
> > ________________________________
> > From: RFI <rfi-bounces+mike.carter=unh.edu@contesting.com> on behalf of
> > David Eckhardt <davearea51a@gmail.com>
> > Sent: Monday, January 30, 2023 5:52 PM
> > To: Joe <nss@mwt.net>
> > Cc: rfi@contesting.com <rfi@contesting.com>
> > Subject: Re: [RFI] CARRIER ON 40-METERS
> >
> > CAUTION: This email originated from outside of the University System. Do
> > not click links or open attachments unless you recognize the sender and
> > know the content is safe.
> >
> >
> > I would rule out either of these two sources. It is strong with slow
> > ionospheric fading indicating only one skip zone. Certainly not
> > characteristic of Chinese or German signals in the middle of the
> afternoon
> > on 40-Meters.
> >
> > Dave - WØLEV
> >
> > On Mon, Jan 30, 2023 at 10:42 PM Joe <nss@mwt.net> wrote:
> >
> > > According to these folk it's Germany or China.
> > >
> > >
> >
> https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.freqspotter.com%2Fsearch.php%3Fsearch_for%3Dguide%26q%3D3%26order_by%3Dcallsign%26page%3D45%26order_direction%3DASC&data=05%7C01%7Cmike.carter%40unh.edu%7C26a8ef3f122e41c3051a08db0314c5e6%7Cd6241893512d46dc8d2bbe47e25f5666%7C0%7C0%7C638107159972664361%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=mxIzPgYi3nT84MZeuzbbeK3zX3BKeJujf%2Fs8blpDi28%3D&reserved=0
> > >
> > > Joe WB9SBD
> > >
> > > On 1/30/2023 4:36 PM, Wes Stewart via RFI wrote:
> > > > Using my Perseus it's peaking -70 dBm on my 40-meter inverted-vee
> > with
> > > 30 dB fades here in Tucson at 2225Z.
> > > > I have no idea what it is.
> > > >
> > > > Wes N7WS
> > > >
> > > > On Monday, January 30, 2023 at 03:06:28 PM MST, David Eckhardt<
> > > davearea51a@gmail.com> wrote:
> > > >
> > > > Strong here in N. Colorado. 7.195 MHz. It is being heard at least
> > > from E.
> > > > Texas to Kansas and, of course, here in N. Colorado. It is a clean
> > > > unmodulated carrier and has been present for 3 to 4 days. I've heard
> > it
> > > > typically during daytime hours, but not tried during the evening.
> > > >
> > > > Does anyone have information on what it may be?
> > > >
> > > > Dave - WØLEV
> > > >
> > > _______________________________________________
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> > >
> >
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> > >
> >
> >
> > --
> > *Dave - WØLEV*
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