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DC Grounded Base Load Antenna vs 1/4 Ground Plane mobile antenna

jr26

Active Member
May 5, 2022
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Is there any advantage of a DC grounded base load over a 1/4 ground plane for mobile use? I read the DC grounded base is good if lack of ground plane, I would like to learn more about them. Sorry if this has been covered I have searched several times but would like some more knowledge on the subject.
 

Big advantage of DC grounded antennas is that they are a LOT quieter when it comes to noise and RFI because static charge is drained to ground.
Much better in lightning-prone areas too...
 
Is there any advantage of a DC grounded base load over a 1/4 ground plane for mobile use? I read the DC grounded base is good if lack of ground plane, I would like to learn more about them. Sorry if this has been covered I have searched several times but would like some more knowledge on the subject.
Try searching shunt fed, vs. end fed.
 
I think the OP was asking whether it was more advantageous to use a 1/4 wave antenna (no DC ground), or a 5/8 type antenna with a tapped coil (DC grounded).
 
I think the OP was asking whether it was more advantageous to use a 1/4 wave antenna (no DC ground), or a 5/8 type antenna with a tapped coil (DC grounded).
Yes exactly primarily for mobile installation. Like to compare 1/4 top load like firestick, middle load like HQ27 to something like Laird C27, PCTEL MLB2700. Larsen NMO27. Mostly what I find on the subject is for base antennas, I do understand they share a lot of similarities.
 
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Ok Thank you I think I am getting DC grounded at base confused with DC grounded. From what I understand Browning Br140 has shut in them not sure about the others. I currently run a Browning Br140 on a small car I may try a PCTEL or larsen 30-34 mhz coil with longer whip. Also wondering if this would work better on the fender mount of my pickup replacing a Hustler Hq27.
 
Ok Thank you I think I am getting DC grounded at base confused with DC grounded. From what I understand Browning Br140 has shut in them not sure about the others. I currently run a Browning Br140 on a small car I may try a PCTEL or larsen 30-34 mhz coil with longer whip. Also wondering if this would work better on the fender mount of my pickup replacing a Hustler Hq27.
The Browning is a copy of the Maxrd/Pctel. The higher freq coil and longer whip is a headache and little benefit. I have tried every coil you mentioned and best result with shunt fed 26-30 MHz coil with long whip, like Wilson 1000 style antenna.
 
I think the OP was asking whether it was more advantageous to use a 1/4 wave antenna (no DC ground), or a 5/8 type antenna with a tapped coil (DC grounded).
I think you just pointed out the main difference there, wavelength.

The 5/8 will have more radiation resistance than the 1/4. Instead of 36Ω typical of 1/4 antennas, it could be closer to 45Ω for the 5/8 if I go by the ideal charts in the ARRL antenna book. There is also a point between 1/4 and 5/8 that would have the same radiation resistance as the 5/8, somewhere around 100°, but it would require a series capacitor to tune it and that would isolate the antenna from DC ground even with the resistor in the radio, so the 5/8 is better because it can be tuned without cutting off the DC ground and because of the ease of shunt tuning using a tapped inductor..
 
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I think another difference is in the pattern. The 5/8 will have a pattern closer to the horizon compared to the 1/4 where a good portion of the signal goes off at higher takeoff angles into shorter distance skip land that the ionosphere may not be capable of refracting back down. For local, I would definitely go with a 5/8.
 
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So it sounds like next to impossible to have a 64" shunt fed with NMO mount. My Choices are 30-34mhz end fed with 64" whip PIA to tune, little benefit and more noise, BR140 shorter lower quality, PCTEL MLBDC 2700 slightly better than BR140, change nmo to uhf for a wilson 1000, or search ebay for a Laird CW27.
 
Ahh, yea at 11m, 5/8 is huge. Not sure what I was smoking there. You sure can shunt feed a 64" whip. Would work good, I think thats about how long mine is
 

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