Electronics > RF, Microwave, Ham Radio
CB and Ham Radio Techs Love Their Bird Wattmeters
xrunner:
Some iterative design here. I almost got it right the first pass. But that's only good for horseshoes and hand grenades.
When I measured the slot spacing in the original case I came up with 26.0 mm spacing. However, the panel had to be bent a small bit as you can see in the pic, to get it to fit. I could tell the ribs were not exactly spaced right. I turned on more lighting and inspected the measurement again. It turns out the spacing on the case is closer to 25.8 mm. Who spaces things at 25.8 mm rather than 26.0 mm? OK fine whatever - fixed in the drawing.
I added a horizontal rib on the inside surface for stiffening. However I realized also that the front and back faceplates will prevent the riser from being pushed in at the ends. So that's all good and works.
The last problem was when I designed the part where the screw goes through, it was glaringly off center from the case screw hole on the 3D printed part. That was simply a matter of me not dimensioning the spacing at all - I just forgot and probably got distracted. So that's now fixed.
That black filament was near the last on the roll, which was called "Deep Black". I will switch to the new roll which is called "Jet Black". It's supposed to be a better black. So I can compare it to this last print.
joeqsmith:
I hadn't thought about the two ends of the spaces resting against the front and rear face plates. That should prevent the condition I mentioned. Planning to use N bulkheads for the main connections?
xrunner:
N bulkheads - no. Standard SO-239s. Hams and SO-239s go together like peach pie and vanilla ice cream. ^-^
joeqsmith:
I would have guessed that the manufactures would have changed to N for their 2M and up. That old Drake I have uses the 239 but that radio is limited to about 30MHz.
xrunner:
--- Quote from: joeqsmith on September 26, 2023, 01:15:36 am ---I would have guessed that the manufactures would have changed to N for their 2M and up. That old Drake I have uses the 239 but that radio is limited to about 30MHz.
--- End quote ---
The manufacturers of ham equipment have used N connectors on some transceivers in past years that were for 144 / 440 MHz bands, but mostly don't anymore. For example the IC-7100 can use the HF, 144, and 450 MHz bands, but doesn't have N connectors. However the IC-9700 which can use the 144, 440, & 1200 MHz ham bands has three RF outputs. The 144 MHz band has an SO-239, but the 440 and 1200 MHz bands have N connectors. But again most 144/440 MHz transceiver don't have N connectors.
So for the 440 MHz band, why does one radio use an N, and the other doesn't? Don't ask me.
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