In our present definition of seasons, this is the first day of summer.?

In a few hours, we will have the shortest night of the year.? Long time ago, it would have been called "Mid-Summer's Night".? Summer was once defined as beginning half-way between the equinox and the solstice. That would a better match to when the weather changes in CA.? It would also require someone to do a little arithmetic.

Some countries just say summer is June, July and August.?

Anyway, if Shakespeare was alive today, he might have used a different name for his play.

On Thursday, June 20, 2024 at 01:51:11 PM PDT, HOWARD POMERANTZ <howpom@...> wrote:

Today at 20:51 UTC (13:51 PDT) will be the June Solstice. The first day of summer. Day length here is ~14hrs 47min. which is the longest period between sunrise (05:45 PDT) and sunset (20:33 PDT) of the year.

So HAPPY SOLSTICE

73

Howard

N6POM

On Jun 19, 2024, at 4:48 PM, Cliff Sojourner K6CLS via <cls@...> wrote:

---

From:

Cliff Sojourner <cls@...>

Sent: June 19, 2024 4:43:01 PM PDT
To:

[email protected]

Subject:

Re: [QRPops] I’m doing a little survey of people that have rotatable antennas.

That's funny!? Exactly what paint was it?? They make so many.

On June 19, 2024 4:01:19 PM PDT, HOWARD POMERANTZ <HOWPOM@...> wrote:

Hi Cliff,

As you say it depends on what you are using the paint on. I have an Ed Fong (TJB-1) contained inside a piece of PVC pipe. It was working great until I painted it with a Rust-Oleum spray to blend in and guess what? It stopped working. When I removed the paint it worked as advertised. The product I used had metal in the paint matrix.

Moral of the story: caveat emptor

?

73

Howard

N6POM

On Jun 19, 2024, at 11:42 AM, Cliff Sojourner K6CLS via <cls@...> wrote:

I'm going to be a wet blanket here.? There's a lot of superstition and folklore but very few objective measurements about metal in paint being RF effective.

This matters a lot to hobby rocketry, using 434MHz and 915MHz trackers and telemetry, inside painted airframes.

My practical experience is: very little effect of paint.? Experiments include white paint (titanium dioxide), heavy build primer (lots of zinc), black (carbon for color), and lots of combinations in between.? Not much 70cm signal attenuation, nothing really measurable.

We've also done experiments with airframe materials, including cardboard, FR4 fiberglass (similar to the pultruded dowels for hex beams), epoxy and E glass layups, not colored and colored, and carbon fiber layups.? Of those, only real carbon fiber showed any attenuation.

None of the paints or airframe materials showed any DC conductivity (ohms) at all.


Some years ago, a ham 3D printed a small microwave (mm wave actually) dish, and used a special expensive high-metal paint.? That worked, to the limit of the 3D printed shape.? The paint layer was very thin and I'd expect because of surface effect it would not be effective at lower frequencies.

So yeah very special high metal paints can have some RF effect if you go to enough trouble.


Next step:? trying to organize some calibrated test equipment and both an anechoic chamber and outdoor range.

Cliff K6CLS CM87

On Jun 19, 2024, at 11:42 AM, Cliff Sojourner K6CLS via <cls@...> wrote:

I'm going to be a wet blanket here.? There's a lot of superstition and folklore but very few objective measurements about metal in paint being RF effective.

This matters a lot to hobby rocketry, using 434MHz and 915MHz trackers and telemetry, inside painted airframes.

My practical experience is: very little effect of paint.? Experiments include white paint (titanium dioxide), heavy build primer (lots of zinc), black (carbon for color), and lots of combinations in between.? Not much 70cm signal attenuation, nothing really measurable.

We've also done experiments with airframe materials, including cardboard, FR4 fiberglass (similar to the pultruded dowels for hex beams), epoxy and E glass layups, not colored and colored, and carbon fiber layups.? Of those, only real carbon fiber showed any attenuation.

None of the paints or airframe materials showed any DC conductivity (ohms) at all.


Some years ago, a ham 3D printed a small microwave (mm wave actually) dish, and used a special expensive high-metal paint.? That worked, to the limit of the 3D printed shape.? The paint layer was very thin and I'd expect because of surface effect it would not be effective at lower frequencies.

So yeah very special high metal paints can have some RF effect if you go to enough trouble.


Next step:? trying to organize some calibrated test equipment and both an anechoic chamber and outdoor range.

Cliff K6CLS CM87

On Jun 14, 2024, at 7:57 AM, Peter Mahowald <petek6tj@...> wrote:

Consider grey paint, less visible

On Jun 14, 2024, at 7:44?AM, Cliff Sojourner K6CLS via <cls@...> wrote:

Joy, about painting;

Any kind of enamel will work to protect the fiberglass rods from UV.

Go to OSH and get a big can of their brand spray black enamel.? Gloss or flat, your choice; heck you can use white or green or brown if you want.

Details:

If you are not comfortable with spraying and the resulting over spray, get an 8oz can of enamel and a brush.

The fiberglass likely has some mold release (PVA) on it from the factory.?? You can feel it, it's a little slippery.? It?? is best removed chemically, I use Zep brand orange degreaser spray.? The fiberglass will be squeaky clean.

If the rods have any splinters (be careful!) those can be tamed.? use a green Scotch Brite scrubby and some water.

Cliff K6CLS CM87

On June 14, 2024 7:10:03 AM PDT, Joy Rabins <doghouse3@...> wrote:

Paul, The way my "MacLogger DX" logging program works is, it gives you a spreadsheet like list of spots from its spot cluster. When I select a spot from this list, it tunes the radio to the selected frequency and mode that is displayed on the cluster list. I think the way it works is if you have a third party controller connected, in addition to switching to the correct band and mode it would also turn the rotor to that spot information listed as their address from the spot. I think it gets most of the ?information from QRZ. Now, if the cluster spot that is selected ?is the home address coordinates, and they are working portable somewhere, all bets are off and it won't work because the rotor control will be turning the antenna to the home address ?coordinates listed in QRZ which will be wrong........unless of course, they are working portable from their backyard ;)?

This is more than I probably need to get started and can always add it later.?

This is all new to me. I have never even seen a station that has rotor set up in action, hence all the questions.?

The hex beam arrived yesterday. I don't know exactly what I was expecting but i thought it would be in a lot bigger package. But most of it is air when it's deployed.

Dick told me to make sure I painted the spreaders before it goes up. The KIO website suggested Rustoleum black flat spray paint- two coats. Have you ever looked at the Rustoleum ?website? Even if I choose black for a color, they have a gazillion choices of products. Everything from painting motors to plastic. I sent their product support a message asking which product to use to paint fiberglass, so I'm waiting for their responce. Once this baby goes up......it is not coming down because I used the wrong paint.?

Expect more questions.
Joy
N6GO