Thanks all for the feedback. No chance to work on it today, even if the weather had cooperated.
I can get it to work fine on 20M and up, and since the trip starts soon, I'm going to try it again when we get back. Going to try another testing location to rule out interference that only seems to affect 40M, since the current location is fairly near the house (stucco with metal lath), and buried electric lines. Also will try different coil settings and grounds. I will try to elevate it too, but since this is my hiking antenna I'm not sure I want to add a tripod LOL. Andre W4SFZ On Wed, Jun 19, 2024 at 4:09 PM John Denison via BVARC <bvarc@bvarc.org> wrote: > Hi Andre > > I was going to mention the 33' counterpoises, but I see that you have done > that already. I've used a single counterpoise on 40 meters with various > coil antennas. One thing I didn't see in any of the emails is... where are > you setting up your antenna? Is there anything metallic nearby? > > I have a Wolf River Coils Take It Along mini which is good for 40 meters > and up, and I found that I can tweak the resonant frequency by rotating the > sleeve around the coil rather than just moving it up and down. I use either > the stock WRC telescopic whip or a Buddipole extended length whip used for > 80 meters. Both are roughly 10 feet long. > > I typically achieve better results with vertical antennas when they are > elevated above the ground. i.e. 4-5 feet vs .5 foot above the ground, > though I was never able to get any results comparable to an inverted V. > With a manual tuner I was able to make the transceiver happy while still > being able to use the antenna to some degree of success, but it took a > steady hand and very miniscule changes in the capacitance knobs. > > 73 > John Denison > KD5YOU > > On 6/18/2024 4:19 PM, Andre Pollard via BVARC wrote: > > I need one of our antenna gurus to give me some input- > > I have an 18'-4" telescoping antenna I have been using when camping. By > adjusting length, I can get it to tune at <1.5 SWR on all bands 20M and > above. So far so good, but when do we ever leave well enough alone. > > I'm getting ready to travel for a while, and wanted to extend the range > down to 40M. So I used the calculators at Coil-Shortened Vertical Antenna > Calculator (66pacific.com) > <https://www.66pacific.com/calculators/coil-shortened-vertical-antenna-calculator.aspx> > to > determine the necessary coil. It said I need 4.9 mH. I made the coil per > the calcs one the same site, using a 1.9 inch diameter PVC pipe. I'm > running it bottom-loaded. > > By tapping the coil a couple of turns down, I can get it to tune to 7.2 > mhz, but the SWR is >6. If I put my hand very close to the coil , the > frequency shifts (expected), and the SWR drops to 1.2. So I tried adjusting > the length and tapping different turns, never better than 4 SWR on any > frequency around 7 mhz. However, if I get my hand near the coil, SWR drops. > > Thinking this meant I needed capacitance, I tried a hat to the whip, with > several different designs and sizes. Changes frequency, but horrible SWR > still. > > Bypassing the coil I can adjust the whip and get great SWR on 14 mhz and > above. So, I don't think it's a problem with the coax (20 feet of RG8X) or > nanoVNA. > > Google shows up all sorts of sites showing making a coil loaded shortened > vertical like i'm trying. None mention the issue I'm seeing as a problem. > > I'd appreciate any input, I've been 'learning' on this for a couple of > days now and haven't gotten it to work yet. > > Thanks, > Andre > W4SFZ > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing > listBVARC@bvarc.orghttp://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > Publicly available archives are available here: > https://www.mail-archive.com/bvarc@bvarc.org/ > > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > BVARC@bvarc.org > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > Publicly available archives are available here: > https://www.mail-archive.com/bvarc@bvarc.org/ >
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