I have been looking for a 5/8ths wave design to build. Any pointers???
On Fri, Nov 28, 2025 at 1:46 PM Chris Boone via BVARC <[email protected]> wrote: > A 5/8 wave is not 50 ohms and has a lot of reactance present...thus a > matching coil is needed for proper matching to 50ohm feed. The coil makes > the 5/8 wave look like a 3/4 wave electronically thus presenting a 50ohm > feed point. It also allows it to operate as a 1/4 loaded on 6m. I've done > this with NMO150s for decades..of course a decent groundplane is required > for proper operation > > *Chris WB5ITT* > *Trustee W5APX* > *WRXZ789 GMRS* > *Society of Broadcast Engineers Vice Chairman and Frequency Coordinator, > SBE134 SE TX and SW LA* > > > > On Friday, November 28, 2025 at 11:50:18 AM CST, Gary Sitton via BVARC < > [email protected]> wrote: > > > On 11/28/2025 10:35 AM, Daniel Poirot via BVARC wrote: > > I tried the 5/8ths wave and couldn’t get it to tune until it was cut down > to 1/2 wave!!! > > :-/ > > > > On Fri, Nov 28, 2025 at 10:29 AM Gary Sitton via BVARC <[email protected]> > wrote: > > Dan: > I made both a 2 mtr and a 20 mtr version of the flower pot vertical. > There's also a 5/8 wave version using both 50 and 72 ohm coax. > > Gary, K5AMH > > > > On November 28, 2025 9:22:05 AM Daniel Poirot via BVARC <[email protected]> > wrote: > > Howdy y'all, > > Thinking of our new friend Jose and all of the folks with constrained > spaces, I have just the thing! > > The 'flowerpot antenna' is an end-loaded, half-wave vertical. It takes up > no space at all, may be deployed for use and hidden away after, is easy to > build, and is cheap! > > The parts list is simple: > 10' or longer 1/2" PVC pipe > 10' or longer 50 Ohm RG-58 coax patch cable > electrical tape and box cutter knife. > > The antenna itself may be threaded inside the PVC at the end load coil, or > just taped to the outside, depending on just how stealthy you need to be. > > The wavelength of 2 meter frequencies is 2 meters. A half wave is 1 meter, > and a 1/4 wave is 50 cm. Simple math! > > A premade coax feedline is a great way to start, as the pesky BNC is > already fitted. Lop off the end you don't need. > > Measure down 1/4 wavelength. almost exactly 50 cm. Longer is better. We > will tune for length. Cut around the outside and through the braid, and > strip off 50 cm of the shield braid and the 'outside'. Leave the inner > insulator for protection from the elements. > > Tape the stripped end to the end of the PVC, leaving 3" or so for tuning. > Tape along the length of the stripped portion and the next 50 cm. Make > several turns of tape 1 meter down to anchor the antenna part of the coax. > > At this point, wrap nine (9) turns of coax tightly for the end load. Wrap > this all in plenty of tape to keep the turns from separating. Add several > turns of tape at the end of the coil to anchor the coil. > > Done. That was easy. It actually took longer to read than it does to make. > > Using our handy, dandy SWR meter, tune the stripped portion to length. > Mine ended up shorter than 50 cm. but with a nice 50 Ohm matching > resistance. > > The 10 feet of PVC makes for a suitable mast, the tail of the coax can > reach the HT, or you can extend EACH as necessary. > > The performance easily beats the antenna shipped with the HT. I hope it > lights a fire in you to build another antenna! ;-) > > For a video of the exercise, see the YouTube: > https://youtu.be/4EhUau841jk?si=LWWBV8fhqdQ4zYjX > > 73, y'all > Dan KJ5IZK > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > Publicly available archives are available here: > https://www.mail-archive.com/[email protected]/ > > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > Publicly available archives are available here: > https://www.mail-archive.com/[email protected]/ > > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing > [email protected]http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > Publicly available archives are available here: > https://www.mail-archive.com/[email protected]/ > > > -- > Gary Sitton, K5AMH > [email protected] > SDR/DSP Consultant, > "Have FFTs, Will Travel." > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > Publicly available archives are available here: > https://www.mail-archive.com/[email protected]/ > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > Publicly available archives are available here: > https://www.mail-archive.com/[email protected]/ >
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