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uBITx Antenna Pins Connector

Martin Hickey
 

Please forgive me, I am new to building and I am ignorant.
I am building my uBITx.  I see from the previous posts here that it may be normal to have continuity between the pins in the antenna jack but, both pins in my antenna jack are continuous with ground too.  Is this normal?
Also, I'm putting the uBITx in the amateurradiokits.in enclosure and I notice that builders use a small piece of coax to connect the antenna output  pins to the UHF SO-239 connector.  How do you put the center conductor and braid into the two-hole plug that slides onto the pins on the board? Or should I just use the brown and black wires that came already installed in the plug and call it "goodenough?"
Regards,
Martin

MVS Sarma
 

Yes. It is normal. Mixer input winding is brought  thro rx low pass filter to ANT pins in Rx mode. and

 PA OUT at the secondary is brought thro low pass filter concerned in case of Tx .

You may connect Brown to center pin of rf connector and bl k wire to body of that connecto
Aall the best 


On Wed, 11 Sep 2019, 10:19 pm Martin Hickey via Groups.Io, <hickmodawg=googlemail.com@groups.io> wrote:
Please forgive me, I am new to building and I am ignorant.
I am building my uBITx.  I see from the previous posts here that it may be normal to have continuity between the pins in the antenna jack but, both pins in my antenna jack are continuous with ground too.  Is this normal?
Also, I'm putting the uBITx in the amateurradiokits.in enclosure and I notice that builders use a small piece of coax to connect the antenna output  pins to the UHF SO-239 connector.  How do you put the center conductor and braid into the two-hole plug that slides onto the pins on the board? Or should I just use the brown and black wires that came already installed in the plug and call it "goodenough?"
Regards,
Martin

Paula Bailey-Stine
 

Re how to get the RG-174 cable to connect gracefully with the SO-239 and the little Molex/Relimate plug for antenna on the uBITX board:

Strip outer coating of RG-174 about an inch (2-3cm to strip for those of you outside the States and Liberia). Gently separate ground braid and twist together.  Strip just enough of the center connector to make contact with center of your SO-239 connector.Center pin on the coax goes to center pin, ground braid goes to ground lug.  Solder.

There's really two ways to set up the other end:

a) Cut the brown and black lead close to the plug, leaving JUST enough both to strip and a bit more to fit some heat-shrink tubing on (so about 2 inches or 5 centimeters or so).  Strip and tin ends.  Strip RG-174 outer coating like noted above, though probably just need to strip to about 3/4" or 2cm.  CAREFULLY solder center wire to brown wire, then cover with heat-shrink.  CAREFULLY solder braid to black wire and cover THAT with heat-shrink.

b) Carefully strip about an inch of external insulation off the RG-174 and prepare as above.  Take a short length of wire (preferably something solid and around 20 to 22ga--basically about 1 1/2 times the length of the braid).  Cut off about half the braid, twist it with that wire, solder;  wrap the remaining wire around just beyond your insulation about 2-3 times and cut (this makes a strain relief).  Strip just enough of the center conductor to make good connection to the little connectors that go in the plug that came with Sunil's kit, crimp, optionally solder, stick in at the appropriate points where the black and brown cables would go.  (A good *pictoral* example of this (for a different radio) is at http://www.wb5rvz.com/sdr/RXTX_V6_3/13_ext_conn.htm and yes, I've done this with Relimate/Molex connectors rather than soldering connectors directly to board.)

(That said--generally you do need special crimp tools to really get those Molex/Relimate female connectors crimped right--Radio Shack did sell a hand tool to do this once upon a time, hobby stores tend to have them, and both the usual Chinese sources (Banggood/Aliexpress/etc.) and Amazon tend to have the tools that are actually an improvement over the old RS kit (https://smile.amazon.com/gp/product/B00OMM4YUY/ref=oh_aui_detailpage_o02_s01?ie=UTF8&psc=1), or if you already have a crimping tool like this for RG-58/RG-8X cable just get the die sets...but honestly the die sets are nearly as expensive as the crimper itself, so might as well get the dies with bonus crimper. :D  And I do recommend getting a good ratcheting crimp tool or two with interchangeable dies; one of the decidedly more useful tools in the ham shack, especially if one messes with Relimate or Molex crimp pins or if one makes one's own coax runs for antennas and prefers not to use clamp connectors.)

-KI4QGJ

hickmodawg@...
 

Thanks to Paula and MVS Sarma for your replies!  I really appreciate your help.  I will proceed and assemble my radio using your wise information and recommendations.

73,

Martin