[Lowfer] Lowfer JH Loop Experiment

Tue Nov 30 15:38:59 EST 2021

Mike,

My mica's should be in this week and I think that will solve the tuning
issue. I bought some old 4ls style ones and some standard through hole
ones. They range from 500V to 5KV.

I will try the led trick tonight. That will be really cool if it works for
me. I have never heard of that. I think I have some pretty high turn CT's
somewhere, so I will build a current meter when I come across them. I need
one for this type of stuff anyways.

Yes, Your capture does seem to match up. I used the same frequency counter
to tune it, so it should be at the same place.

John Hamer

On Tue, Nov 30, 2021 at 3:04 PM N8OOU <n8oou at meekfarm.us> wrote:

> John,
>
> I have used Mylar and polystyrene caps for determining the values needed
> to tune the loops. They seem to do ok, but after getting pfff's needed I
> have always put Mica HV caps and Air variables on the air.
>
> I use a simple LED - Diode as an rf detector with one lead connected to
> a loop end. The other hanging in free air. Tune for max brightness.
>
> I also put up this 2020 capture of JH. I was comparing the frequency
> from it to last night. Last night the noise level was a lot higher.
>
> qsl.net/n8oou/JHbeaconJan152020.jpg
>
> 73   de   N8OOU - Mike Meek
>
> On 11/30/21 9:11 AM, John Hamer wrote:
> > Mike,
> >
> > Thanks for looking last night. There is definitely something there. It's
> > hard to tell if there is a JH in there, but it definitely looks like it
> > could be.
> >
> > I am using some met poly capacitors I had right now for tuning the loop,
> > but I have some mica's on order. I also have a 900pF tuning cap for fine
> > tuning. Do you have any experience with Met Poly caps with something like
> > this? They claim to be pretty stable. Something is changing after the
> > transmitter cuts on. I am tuning the antenna using a nanoVNA. The current
> > on my final looks exactly correct for the 50Ohm load every time the
> > transmission starts, but over the next 30 seconds to 1 min the current
> > slowly drops. I'm not sure if the capacitors are warming and changing
> value
> > or if there is just a connection issue with them in a breadboard. I will
> > remove one of those possibilities when I solder everything together, but
> it
> > kinda looks like it's just coming out of tune. I also need to build
> > something to measure antenna current. I should have it all next week
> > sometime.
> >
> > Finals are staying cool and frequency is stable.
> >
> > The link below has some pictures.
> > http://jwhamer.me/lowferJH/Loop2021/
> >
> > John Hamer
> >
> > On Tue, Nov 30, 2021 at 7:55 AM N8OOU <n8oou at meekfarm.us> wrote:
> >
> >> John,
> >>
> >> Thanks for the info, I can relate your results to the tests I made using
> >> Quad Shield RG6 and RG8.
> >>
> >> I shut down WM to listen overnight. Nothing seen until Gray Line this
> >> morning. See the first capture at;
> >> http://qsl.net/n8oou/nov29210006.jpg
> >>
> >> I have a second screen comming, it looks like you went qrt at 06:30 CST.
> >> The filename will be nov29210007.jpg when it's ready.
> >>
> >> 73   de   N8OOU - Mike Meek
> >>
> >> On 11/29/21 8:58 PM, John Hamer wrote:
> >>> Mike,
> >>>
> >>> I actually have some pretty good size litz wire. It looks to be around
> 3
> >> or
> >>> 4mm diameter.  Ill see if there is a label on spool with more
> >> information.
> >>> I'm not sure if the spool came with the wire.  I got it from my last
> job
> >>> years ago when they were trashing it.
> >>>
> >>> I still have everything breadboarded, so I'm not sure if that is
> causing
> >>> any issues,  but I will solder it all together in the next few days
> >>>
> >>> John
> >>>
> >>>
> >>> On Mon, Nov 29, 2021, 9:52 PM N8OOU <n8oou at meekfarm.us> wrote:
> >>>
> >>>> John,
> >>>>
> >>>> Good to have another loop experimenter. I am curious about what you
> are
> >>>> using for the loop conductor. My experiments have shown the larger the
> >>>> conductor, the better.
> >>>>
> >>>> Good Luck
> >>>>
> >>>> 73   de   N8OOU - Mike Meek
> >>>>
> >>>> On 11/29/21 5:17 PM, John Hamer wrote:
> >>>>> I have a 12'x12' square loop setup. I am transmitting my usual mode
> of
> >>>>> qrss60 and a graphic on 181.818KHz. I just got it going tonight and
> >> still
> >>>>> have some work to do, but if you are looking for a challenge, give
> it a
> >>>>> shot! It is aimed in the N/S direction.
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