NAT01 - Why is it flipping to mono?

RonToolsie one of the side benefits of my love of music is that it has brought me into contact with a number of wonderful people - Julian Vereker and Kit among them. I owe them all a huge debt of gratitude for the enrichment they’ve brought to my life. And the pleasure continues to spread - a close friend of mine took delivery of a delicious pile of Naim boxes this morning, although he’s fully gone over to the streaming side, and is not tempted by the old glories of FM.

I’m going to explore whether the BBC might be willing to send out text alerts, to those that want them, when engineering work causes a drop in output at one of their masts. My “stereo dart” has been coming and going this morning, and sure enough the “Check transmitter faults” site has logged engineering work today, although the timing they give doesn’t coincide with the output here.

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The link below will take you to a picture of my Galaxie 17 vertically aligned to receive the signal from the nearby vertically polarised relay station.

The signal I receive from the relay station is much better than what I was getting from Wenvoe.

Cleaner than mine, which has been up a quarter of a century this summer - almost first job after a move. Rather think RS encouraged me to bring it from my previous house, since it hadn’t been up long and he rigged it and a new digital tv aerial.

Pleased the OP is making progress with tracing the stereo issue.

Thanks Neil, much apprecaited.

I remember the dark brown van very well. I witnessed around five rigs I was fortunate to acquire, starting early eighties. It was still a decade away from NAT02 joining my system, ultimately moving over when I located a mint 01. Proms on the horizon and nightly treats with NAT01.

Check with the Broadcaster if they have changed the polarity.

BBC stations (apart from Radio Solent) and Classic FM off air today for this Soton listener, due to ‘essential engineering works’ on Rowridge transmitter.

What’s the latest @Charlie177 on the flipping?

Edit: Classic FM has just come back.

2nd edit: All stations now back with stereo beacon lit on my NAT :slight_smile:

Sounds like that engineering works was indeed essential.

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It’s been an interesting journey.

On the NAT01 side, most of the time it’s delivering perfect stereo. I don’t know a lot about the insides of tuners, but the pattern of behaviour doesn’t seem to be compatible with an intermittent fault in a component. I could send it down to Salisbury for a full service, only to find that the problem wasn’t in the tuner.

So there’s been a sequence in trying to identify where the problem might be. One contributor mentioned that, by comparison with my Creek tuner, Naim made some compromises over sensitivity in order to maximise quality.

My suspicion is that the signal from Rowridge varies – perhaps during engineering work – taking the level at my distance just below the Naim threshold, but not below the Creek threshold for stereo. I’ve asked the BBC if they could issue text alerts when the signal is reduced, to those that want them, but I suspect that very, very few listeners are affected by this. If the signal flips to mono, I do go online to see if engineering work is scheduled. There is some correlation, but not a perfect match.

So I have a reel of new WF100 which I’ll hitch to the four element aerial and run through the loft hatch direct to the NAT01. If I still get the problem, I’ll assemble my G17 and try that on a temporary basis. If I still get the problem, the NAT01 goes to Salisbury.

The intriguing thing is that since I started this thread, and particularly since I contacted the BBC about sending out alerts, my NAT01 has delivered stereo. Who knows? Maybe the BBC didn’t think anyone was affected by an occasional reduced signal, and now they keep the signal at full strength as much as they can. They might have thought that 20th century dinosaurs still listening to FM were virtually extinct. I wonder if some of those who’ve discovered vinyl for the first time might at some point realise that a half decent FM tuner with a good aerial can deliver real treats.

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I’m facing the Wrotham transmitter and about 22 miles distance. This is my aerial

I had been getting stereo but recently it dropped to mono so I’ll be getting it checked.

A brief search for better aerials doesn’t give much in the way of options nowadays sadly.

Ron Smith aerials - a search for “ronsmithaerials . com” (without the gaps) should take you to their web site.
(I hope this doesn’t fall fowl of the forum rules)

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Agree with Ron Smith aerials. I have the smallest Galaxie type; a Circular 5 in my loft. However, has your Nat 01 been recently serviced? As a student my aerial was two feet of co-axial cable stuffed into the aerial socket of my Armstrong tuner and I had no problems getting stereo reception!

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If you are only 22 miles from the 125kW Wrotham transmitter, you really do not need anything better than the Antiference FM1083Tthat you have.

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That was my thinking/hope. It was fine up until recently. I suspect some wear to the connection or maybe wind damage, although nothing visibly apparent. The NAT01 was serviced at Naim when I bought it about 7 years ago, so it should be ok.

I’ll get the installer to check the signal strength and then the aerial if necessary. It is quite a long cable run from the aerial to the outlet. Hopefully no issues with that as it’s not something that’s accessible. Out if interest does anyone know what level of signal is required to get good stereo on the NAT01?

I understand. I had, in essence, a similar problem with my glorious NAT05. See thread: ‘Yagi goes snaggy’.

Both my aerial and tuner had faults.

I sorted the aerial first and I think you are right to do the same. Then Naim serviced the tuner for a fixed fee. This covered the eventual replacement of the tuning head, so in effect a new tuner. All good now.

Hope you can get it sorted.

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