Cecil Moore wrote:
Lushy wrote:
Can anyone point me to a site that shows how to build a multi freq hf
vertical, thanks in advance

The easiest system is to cut the vertical for 5/8WL on your highest
frequency of interest and feed it at the base with an SGC-230 autotuner.

Agreed - for example, about 10m (33ft) high will nicely cover
7-10-14-18MHz. You're only highly dependent on grounding at 7MHz or
below.

But as you rightly say, beyond 5/8 wavelength the high-angle lobe grows
very rapidly and the low-angle lobe shrinks rapidly too. By 21MHz, a 10m
high vertical is noticeably beginning to "lose it", for example in terms
of cracking pileups.

It's only a few dB, but if you "need" to work certain specific stations
- like DXpeditions and contest multipliers - then those few dBs make a
big difference to how long it takes. On the higher HF bands, stations
with verticals are already one layer below the stations with beams, so
unless your vertical is the best it can possibly be, you'll be at the
bottom of the second layer too.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek