What may be the clearest pictures of our sun have been taken by an amateur astronomer named Andrew McCarthy. He used a technique called image stacking to bring out an incredible amount of detail in his images. Click on the images below to see a larger version. Hope he tries this again at the height of the solar cycle.
I have redesigned and printed in PLA a few parts to accommodate the Fiberglass fishing poles. These were namely the pole adapters and the pole tips to eliminate the need for steel hooks. This time of year the weather changes almost daily. It was cool in the 70’s on Tuesday and today it supposed to be hitting the 90’s again before the next frontal passage tonight. Unfortunately, this will bring fairly breezy conditions to the QTH through Saturday. I will target testing the Moxon on Sunday afternoon so that I can keep it deployed a few days to run WSPR and other experiments. I am a bit concerned over the strength of the fiberglass pole bases as I have had a few split during experiments with verticals. I may use the time between now and Sunday to print some reinforcements and perhaps even print the pole adapters in PETG.
A bit breezy today but tried to test at least the structural aspects of the Moxon 2.0 design. Pole adapters worked as planned as did the hub. I am having trouble keeping the antenna from swinging in the wind again even though I have a locking point on the hub. Probably the poles themselves are turning as I don’t have the Spiderpole fully extended. First issue I had was with the hooks on the pole tips. Simple loops would slip through and slide up the poles. I had to just tie some knots which is a pain. The new wire clamps worked great but the wire layout is a bit finicky to set. I set everything up and only dared to raise the antenna up about 20 feet for initial testing.
First issue was tuning. Min SWR was around 20.3Mhz. Seriously off from before using the same set of wires. I brought it down to square it up a bit more and found the same issue. Don’t have any more time this afternoon to adjust but I suspect one of the following:
Carbon fibre spreaders are detuning the design. I used fibreglass before without issue.
The distances / wire lengths are off. on the bends.
The antenna is too low and I am having ground effects.
I suspect the issue is likely the spreaders in which case…sigh. Long Fibreglass fishing poles are gettin hard to find. I have enough to try them as spreaders but they are not as strong or as long. I’ll have to print new pole adapters and may still have issues getting a 20m Moxon working. Anyway I’ll give it a rest today and do some more testing tomorrow if the wind dies down.
Update 12/6/2021: I have redesigned the pole adapters and pole ends for the fiberglass fishing poles. I have also eliminated the need for a separate hook for the pole ends as the Kevlar cord keep slipping off. Also thought of a way to mark the wire end points for easier setup in the field using cable ties to create a stop point for the wire clamps at just the right position. I will try the carbon fiber poles one more time then switch to the fiberglass poles. I am finding the 7.2m fiberglass poles are getting more difficult to find. I couldn’t find any on Ebay but I did find some on Aliexpress and ordered four.
Here’s the parts for my fishing pole version of the Moxon antenna. I have redesigned the wire stops to allow them to slip over the wire. Will structural test tomorrow.
Update 12/5/2021: Here are the parts to setup the Moxon on 15m. I am going to go ahead and set it up today for 15m and test the structure.
Looks like I have largely sorted the problems with the Ender 3 and PETG. The only upgrade which did not work in my case was the solid bed mounts which caused endless first layer headaches. After making all new adjustments I am able to print nicely albeit with a brim to ensure parts aren’t warped. Here is the PLA Moxon hub with the PETG fishing pole adapters.
With this I can try some structural tests with the poles extended to configure a 20m Moxon.
I replaced the two 10Ahr LiFePO4 Batteries in my portable solar generator with a single Miady 12V 20Ahr battery. This should take care of any balancing issues between the two 10Ahr batteries in parallel as was noted this year during field day. These have been tested and reviewed by KM4ACK. Check out his YouTube site for more info.
I am struggling a bit with the Ender 3 printer which I need to print some PETG Moxon parts. I recently installed several upgrade parts that changed the z-axis settings. After readjusting everything I started having problems with warping and first layer issues. Even a 20mm calibration cube was showing warping. After going through the setup and calibration procedures for the capacitive leveling sensor, I started noting that repeatability was way off when the printer bed was heated to 90°C. The TH3D unified firmware has a command called M48 which homes the machine, and then takes 10 Z- height readings at the same spot and displays the standard deviation of the 10 readings. A reading of less than 0.01 mm is expected with the bed at temperature. I was reading ~.4 most readings. I noticed that this worked fine when the bed temp was at room temp. I heated the bed up again and found the same behavior but then turned off the bed heater and repeated the M48 command and found it to be OK. It appears that the bed heater is causing some sort of interference with the sensor.
I am testing a fix now where I modified the starting Gcode to turn off the heater when ready to probe the bed. It doesn’t take long for the probing and the bed remains hot. I then turn on the heater and wait for it to get back to temp before starting the print. I have tested this on two cubes with a brim and found them to come out perfect. I am currently printing the fishing pole adapters so I’ll know if this is working the way I want in about an hour or so. So far so good.
UPDATE 12/2/2021: I did manage to print one set of pole adapters and they fit perfectly. Next time around I was not as fortunate with all sorts of 1st layer issues again. I replaced the EZABL sensor with a newer one I had waiting to install on the CR-10S. This time it calibrated perfectly and I had a .005 standard deviation with the heated bed on. Looks like maybe the sensor is faulty. Back to printing calibration cubes…
UPDATE 12/3/2021: Arrrgh! Despite getting good readings with the replaced leveling sensor I am still having severe issues with the 1st layer. I now believe the problem is that the solid bed mounts I installed leave the bed badly out of level. I ran several probing tests and found good repeatability between readings but the flatness of the bed was off by quite a bit. Here is a view of one set of readings with the bed cold:
I replaced the springs and manually leveled the bed. Here is the plot using the same scale:
Needless to say a big difference. So Now I need to heat up the bed and adjust the z-offset, level the bed and recheck the z-offset. I suspect this will fix my 1st layer issues as the sensor could not compensate for so much variation. I liked the idea of the solid bed mounts but their use would require a bunch of fiddling with shims. I think I will stay with springs. I have some stronger springs for the Ender 3 coming in as the stock ones are notorious for being a bit on the loose side.
I see some more calibration cubes in my immediate future…
Adventures in Amateur Radio 