Nat 05 query

Hi, first time post here. Just become turned onto Naim through a recent interest in FM radio and tuners (getting into training for retirement ?) so I bought a few to audition including a red light Nat 05. I am using a homemade dipole in the loft (what’s left of it as part of a dormer room) which sounds pretty good to me although I’m sure it could be improved on. I am on the Crystal Palace transmitter facing towards it so there is a very good signal. It’s also amplified as I am splitting one cable between upstairs and downstairs and between VHF and UHF. The Nat 05 seemed fine when I got it a couple of weeks ago but just yesterday the scanning has gone haywire. It works from the top of the “dial” down to around 100 MHz then doesn’t pick up anything (i.e. all BBC stations) until it stops again at the top of the range (Radio Jackie 107.8 where I am in London). This is also connected to picking up stereo as all of the stations not picked up on the scan are now showing in mono when you tune into them (I assume scans only pick up stereo ?). Wondered if anyone had any ideas on what is causing this ?

Welocme to Naim ‘mathutchinson’, & welcome to the forum, nice place & nice people.
I have a NAT-05, yellow LED (ALPS head unit)
I have it on a Ron Smith G-14 thats mounted in the attic & my main (BBC etc) 46kW regional TX is just 3.5 miles distance. I also get other transmitters with surprisingly low power & far away. Meaning I don’t see the need for an amplified aerial, plus an aerial amplified will also amplify cross channel reflections & other nasties. So I would think about getting the signal from the dipole without the amp., maybe try a passive splitter. I have a suspicion the amp might be causing your scanning & mono issues, head unit overload maybe.

Re scanning; I’ve noticed my NAT-05 can pass by a station when scanning in one direction, but it catches it going back the other way; so although it works, its not perfect.

This is ringing a bell - having said that …

There is a very long thread on the NAT05 (I have a NAT 03) and I think I have read something like that before . I think (and as I said I am racking my brain) that you may have inadvertently set the tuner to Japanese settings .

As I said I am 99% certain that I have seen a similar problem on the 05 .

Sorry if this is as much use as a chocolate tea pot.

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… hmmm yes limited to 100MHz, Japanese format … me too have a memory bell ringing.
I’ll go looking to see if I can find something.

Ah-ha, I’ve found a previous thread (now closed) with the same problem, the poster contacted Naim & they said it would have to go back to HQ.
Then another message from Naim …
Power off the unit, hold the down button in and then power back up while continuing to hold the down button. Give it a few seconds. This might reset the ranges.

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Thanks for the prompt responses. I did find the thread about holding the button down and tried that but to no avail (unless I was doing it in the wrong order so will try again). It is also skipping the channels in both directions. The reason for the amplification was because I didn’t want to install a separate FM cable all down the side of the house and I am splitting it between UHF and VHF at both ends, in the attic room and living room, so I thought it would be beneficial given the loss in gain at both ends. I will try getting rid of it and see what happens. At any rate all the playing around with aerials and cables is quite interesting and educational too though the wife would beg to differ. I will report back on my findings.

Is it possible to tune incrementally up and down from 88 to 103 using the buttons and then save the stations you want as presets? If so, the Japanese thing is a red herring. A proper aerial on the roof is a good idea regardless.

I have taken away the amplification and also tried resetting again with the button method but no joy so far. I don’t have a remote so not sure I can save stations ? What’s confusing me is that the stations not being scanned now are not shown as stereo when I tune to them. Does that just signify that the scanner doesn’t recognise them ?

If they are not stereo it means the signal is too weak. That’s probably why they are not found during a scan. I’d suggest you need a roof aerial or at least a decent proper aerial in the loft, and the remote so you can save presets. When fed properly the 05 gives fantastic sound quality.

HH reminds me, i had one a long while back and it needed a whopping signal if memory serves etc.

If it was working fine… then unless the ‘05 has gone duff, I think you’re looking at an aerial or wiring fault. Has anything else changed?

Not in my experience, the NAT-05 is as sensitive as any modern tuner.
I regularly listen to a jazz program on a local station thats pushing out only 3.0kW & is 56km distant, my NAT-05 is on full stereo & only a slight hint of hiss. Whereas I’ve had Audiolab & Arcam tuners on it that although they picked it up, both had more hiss.
The older Naim’s - the NAT-02 is the only one I’ve compared on my aerial - do need a lot more signal & although it did pick up that station, it was unlistenable.

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Thanks Mike, just a memory from living in an awkward spot in rural Gloucestershire


I am struggling a bit with the signal/aerial as the issue simply because all stations were working fine recently on the same aerial. I am getting a strong reading on an FM4 which I think also requires a good signal ? The fact that only stations from around 100 MHz downwards are affected (actually seems to be Smooth 102.2 where the problem starts) is a bit inexplicable. Perhaps the amplification permanently affected something ?

If it’s working with an FM4 then my bet is your NAT 05 has developed a fault. I don’t think an aerial or feeder fault that only affects stations below 100 MHz is at all likely, especially as the FM4 is ok.



To be sure, do you have a basic ribbon dipole aerial you can plug in as a test. That way you may discover whether it’s the aerial amp.


Are you thinking that your aerial amp puts phantom power on the lead and might have affected the NAT05?

As HH has mentioned, certainly set the tuner to frequency mode and step down in increments by using the up and down buttons… does it cycle through from 87.5 to 108.5? If so and you are on 88.8 that should give you Radio 2 as a test from Crystal Palace. You certainly should be able to pick up the main transmitter at Wrotham from which Radio 2 transmits at 89.1. If you see the stereo light on and hear nothing then I suspect a fault. I have an early Nat05 tuner originally with a red light indicating a Philips tuning head, it is just back from Naim HQ fully serviced now with a green stereo light (at my request to match all the other green lights) and sounding magical.

OK, if that’s the case that’s disappointing after such a short time. Also I do not know whether I have caused it or whether I can justify sending it back.

I really doubt that a faulty aerial amplifier would actually damage the NAT 05 and then still work with an FM4. The electronics just doesn’t work that way. Anyway by all means try the tests that have been suggested in the earlier postings. But if all of this points to a tuner fault, you probably do have a tuner fault and it won’t have been caused by anything you did or your aerial amplifier.



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OK, I found an internal aerial with a coaxial end and that works perfectly so it looks like the signaI/aerial lobby was correct and apologies for casting doubt on that theory. I am not getting any signal on the UHF side either (pretty sure I was before) so there is some problem along the line somewhere. On the plus side looks like the tuner is fine. Bank holiday has almost gone so this may have to wait until the weekend…