aerial for NAT 01

Is Ron Smith still around? I heard his son runs the company now (based in luton area if i remember right)? He was always the go-to guy for serious aerial work. Maybe they can recommend something?

You can go for some extravagant  piece of metal work, or if you are effectively line of sight with no electrically noisy industrial factories around you,  a 3 element Yagi antenna should be fine, offer sufficient gain, provide some back to front rejection, a modicum of directionality and not too sharp a resonance across the FM broadcast band (gain reasonably consistent across band)... if you can ask for it to be fitted with a BalUn this  will optimise impedance conversion, strengthen the receiving field pattern and potentially most importantly help reject interference from the downlead coax coming from Electronics in the house. The BalUn will add a bit of loss so that is why I say you'll need at least three elements and good quality coax. If mounted on the side of the house, do try and have the antenna raised above the roof line for optimum performance and reduced issues with reflections. Do use an experienced fitter, and for consumer radio work there are less of them around now, so do check specifically, but they should have the right test equipment to validate the installation including SWR and gain.

Ron Smith Aerials (Luton) is now run by Rons son George.  That said RS aerials are all big beasties, the smallest on offer is the 'Circular 5' & although they say its a 5 element it's effectively a 3 element yagi.  But its still based on the Ron Smith 'circular' driven element & with its 3 element rear reflector,  it is 68 x 33 inches WxH & the usual 3 element 44 inches long.   Go to www ronsmithaerials . com.   it is a big bugger but If you can fit one OK it is the best for old Naim NAT's.     

Apart from that,  I agree with Simon, a simple but good quality 3 element (Blakes or Antiference)  will be OK.  Especially so if you are line of sight - i.e. you can actually see the transmitter at Ashkirk - its aprx 10 miles from Galashiels & that is very close in FM radio terms as its transmitting 50kW on the BBC's.  The one problem with Ashkirk is it's BBC only,  Classic FM & Radio Borders transmissions come from (the area's main TV transmitter) at Lindean Moor, Selkirk with 10kW & 5kW respectively.   Selkirk (as you obviously know) is closer to you at only just over 5 miles away & almost exactly dead in line between you & Ashkirk,  fortunate indeed - on beam reception for everything.   

If you wish, I can sound you a FLAC sound clip of what the NAT01 sounds like using the G17 vs a long piece of wire (5m of NACA5) as an antenna. Although both gave hiss free, full strength signals, the Ron Smith G17 was 'simply better' in all the ways that make the tuner special. Its a rip from a single jazz track where I A/B swap in the two antennas every 10 or 15 seconds. At the time I lived within a few miles of the transmitting towers, so having a large antenna was not for the signal strength. But the multipath rejection that only a multi-element antenna can do goes a long way to adding stability and definition to the reproduced sound. In some ways having a strong signal makes multipath more evident as the reflected signals may be stronger in amplitudes. 

You could look at the Magnum Dynalab ST 2. I bought one a few years ago and very happy with it given my constraints around mounting space.

rjfk posted:

You could look at the Magnum Dynalab ST 2. I bought one a few years ago and very happy with it given my constraints around mounting space.

Sorry, unless you really have no other choice this is not going to provide optimum results for a quality tuner... there is no gain as it is essentially a whip antenna balanced against a lossy coil, with no reflection rejection ... so for it  to have any chance of supporting a stereo decoder at all with descent  accuracy it will need to be mounted well high up and in the clear... and I suspect using this sort of antenna most will put it in the loft which could make matters worse on what is already a very compromised antenna. If you really want circular gain then the best bet will be a vertically mounted dipole.. no multipath rejection but you will get unity gain (as most quality antennas have gain referenced to the dipole gain)

Ron, there is a bit of difference between a piece of non resonant piece of wire and a resonant antenna so not sure what it is really  demonstrating .. so to the OP's question we have recommended at least three element Yagi which provides directionality and rear rejection... it's a balance though... the more directional and higher the gain (which will help severe multipath rejection from the sides and rear ) the more resonant the antenna will be and the more it's performance will fall away as you move from the point of resonance... so unless you have obstacles or surrounded by tall buildings in an urban setting the multipath issue will tend to be less prominent. I suggest there are advantages in not having too high a gain especially if you want optimum reception across the band. However the more you are relying on the antenna gain response the more crucial the BalUn will be (if using coax). But I guess it's worth remembering  for the stereo to image accurately on decode we need a clean low noise signal as the left-right signal is transmitted in AM centred on  a carrierless frequency of 38kHz offset to the base FM carrier frequency.