Editing Chain Home (section)

==Comparison with other systems==
Modern texts are often dismissive of Chain Home, viewing it as "dead end technology with serious shortcomings".{{sfn|Clark|2010}}

In many respects, CH was a crude system, both in theory and in comparison with other systems of the era. This is especially true when CH is compared with its German counterpart, the Freya. Freya operated on shorter wavelengths, in the 2.5 to 2.3&nbsp;m (120 to 130&nbsp;[[MHz]]) band, allowing it to be broadcast from a much smaller antenna. This meant that Freya did not have to use the two-part structure of CH with a floodlight transmission, and could instead send its signal in a more tightly focused beam like a searchlight. This greatly reduced the amount of energy needed to be broadcast, as a much smaller volume was being filled with the transmission. Direction finding was accomplished simply by turning the antenna, which was small enough to make this relatively easy to arrange. Additionally, the higher frequency of the signal allowed higher resolution, which aided operational effectiveness. However, Freya had a shorter maximum range of {{convert|100|mi|km|abbr=on}}, and could not accurately determine altitude.

It should be remembered that CH was deliberately designed specifically to use off-the-shelf components wherever possible. Only the receiver was truly new, the transmitter was adapted from commercial systems and this is the primary reason the system used such a long wavelength. CH stations were designed to operate at 20–50&nbsp;MHz, the "boundary area" between [[high frequency]] and [[VHF]] bands at 30&nbsp;MHz, although typical operations were at 20–30&nbsp;MHz (the upper end of the HF band), or about a 12&nbsp;m wavelength (25&nbsp;MHz).{{sfn|Neale|1985|p={{pn|date=April 2024}}}} The detection range was typically {{convert|120|mi|km nmi|abbr=on}}, but could be better.{{sfn|Pritchard|1989|p=49}}

The main limitation in use was that Chain Home was a fixed system, non-rotational, which meant it could not see beyond its sixty-degree transmission arc or behind it once the targets had flown overhead, and so raid plotting over land was down to ground observers, principally the Observer Corps (from April 1941 known as the [[Royal Observer Corps]]). Ground-based observation was acceptable during the day but useless at night and in conditions of reduced visibility. This problem was lessened on introduction of more advanced surveillance radars with 360-degree tracking and height-finding capability and, more importantly, aircraft fitted with Airborne Intercept radar (AI),<ref>{{cite web |url=http://www.r-type.org/articles/art-036.htm |title=The First Airborne Radar |publisher=R-type.org |access-date=10 February 2013}}</ref> which had been developed in parallel with Chain Home from 1936 onwards. This new equipment began to appear in late 1940 fitted to [[Bristol Blenheim]], [[Bristol Beaufighter]] and [[Boulton Paul Defiant]] aircraft.

Even as the CH system was being deployed, a wide variety of experiments with newer designs was being carried out. By 1941 the Type 7 [[Ground control intercept|Ground Control Intercept Radar]] (GCI)<ref>{{cite web |url=http://www.winkton.net/RAF%20Sopley%20pages/sopleyww2.htm |title=Starlight, Southern Radar and RAF Sopley |publisher=Winkton.net |access-date=10 February 2013 |archive-date=26 November 2020 |archive-url=https://web.archive.org/web/20201126073822/http://www.winkton.net/RAF%20Sopley%20pages/sopleyww2.htm |url-status=dead }}</ref> on a wavelength of 1.5&nbsp;m was entering production, and reached widespread service in 1942.<ref>{{cite web |author=Dick Barrett |url=http://www.radarpages.co.uk/mob/gci/type7.htm |title=Type 7 air defence search radar |publisher=Radarpages.co.uk |date=22 September 2003 |access-date=10 February 2013}}</ref>