Marcel Pertus F5DQK has compiled A comparison of 4m yagis using the MMANA simulator.
Vine Antennas is now back in full production of the 4m and 6m antenna ranges, and in summer 2008 they will also be manufacturing combined (on one boom) 6 & 4m antennas, and introducing new models. Check their web pages for the latest information.
Sandpiper Aerial Technology is a family-run business operating out of Aberdare in South Wales, who have been designing and manufacturing aerials for over 25 years. They produce a range of 4m antennas, including dipoles, yagi arrays, an HB9CV, and a 5/8 ring-base vertical.
Trident Antennas offer a UK-made and rather nice-looking 4-ele for 4m, which claims 11dBi gain.
Moonraker sell a range of antennas for the 4m band, including 3 and 5-element yagis, an HB9CV compact 2-element, a halo loop and an end-fed half-wave vertical. Several stations have commented that the mechanical design of this antenna leaves it prone to the ingress of rain, and so its performance is degraded in wet weather!
Nevada sell the Trident V4M half-wave vertical for 4m, rated at 200W PEP, and fitted with an N-type connector.
CB37 Communications of Crewe can supply the Sirio CX4-71 vertical antenna, as reviewed by Ian G6TGO elsewhere on this site.
For those with only space to put one (large) aerial on the mast, Waters & Stanton are offering two different multi-band log-periodic dipole arrays:
The ASL-670 from Cushcraft has 14 elements, and provides 6.5dBi gain over 50-450MHz. Power rating is 300W, boom length 1.9m, turning radius 1.9m, weight 5.15kg.
The 5130-1N from Create is a 25-element design offering 10-12dBi gain across 50-1300MHz. Power rating is 500W, boom length 3m, weight 5kg (Nick M1DDD uses one portable!).
The same vendor also supplies a Watson 4m half-wave vertical claiming "3.5dB gain" with a length of 2m and weight 1kg. This is reputed to be a re-badged Moonraker antenna (see above).
Until a few years ago Jaybeam of Northampton produced amateur band antennas, including a four-element yagi which was rugged and is still used by many stations today. They also produced a trapped dual-band 4m / 6m yagi which was useful for those short of space and wishing to be QRV on both bands. Surplus or used Jaybeam PMR Low-Band yagis work well in the 4m band, and are exceptionally rugged.
If you're handy with a hacksaw, there are some useful designs including the G3FDW log-periodic yagis in the book VHF/UHF Antennas by Ian Poole, G3YWX, available from the RSGB bookstore.
It is quite easy to scale antenna designs for the 6m or 2m bands. Another option is to cut down an existing 6m antenna for use on 4m. As well as yagis, quad beams for 4m are still quite managable, and even the humble half-wave "halo" loop may be useful for mobile operations.
There are details of some of these designs on the Technical and Links pages.