Your suggestion of a hairpin is a high-pass. Herb's suggestion for a series-L shunt-C L-network is a low-pass. Sometimes you might prefer one over the other.
Or choice might be entirely driven by parts on hand. I happen to have some big old variable capacitors so all my tuners use them. But a younger ham probably wouldn't and might rediscover the variometer or other solution. Tim N3QE On Wed, Sep 19, 2018 at 1:46 PM Clive GM3POI <cl...@gm3poi.com> wrote: > What I don't understand is why would you use more components than needed. > Why a capacitor (possibly vacuum). What is wrong in using a hairpin which > also DC shorts the vertical to ground. A combination of hairpin size and > top loading will give you 1:1 at your favourite 1.825 or anywhere else. > Perhaps WX0B's article needs a reprint in the NCJ. It really is simple just > a few microhenries of inductance and you are done. > 73 Clive GM3POI > > -----Original Message----- > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Don > Kirk > Sent: 19 September 2018 17:29 > To: Herbert Schoenbohm > Cc: topband; ash.kf5...@gmail.com > Subject: Re: Topband: Toploaded vertical - SWR > > > > > Herb (KV4FZ) mentioned an L network, and that is what I always use. Very > > simple, and you just plug you're measured complex impedance values (at > the > > frequency you want to be resonant) into one of the many online L network > > calculators to determine the amount of inductance and capacitance > required > > for the L network. I normally just wind my own coil for the inductance, > > and use high voltage silver mica caps for the capacitor. > > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband