Radio Caroline 648 khz test transmissions

In case you haven’t found this on the Radio Caroline website – here is feedback on our reception reports sent to them

Reception Reports Round-up

Thank you to everyone who has sent in reception reports. We have literally been inundated with them, and will try to reply to those who asked for replies over the coming weeks, but it will be a slow process.
Our best reports so far have been from keen DX’ers in Finland and Italy, although one report did come from Japan from a listener using an on-line radio receiver much closer to us! Whilst we appreciate all reports and understand the excitement of radio DXing, it is the reports from within our local target area where you are almost all reporting good and excellent reception on all types of radio which are the most important to us. Comments such as “no fading while passing under bridges on A12” are very informative, as are “signal is good enough in my kitchen that my wife doesn’t switch it off”
One or two comments seem to be frequently occurring and we will try and respond to those here. It is good to know our listeners are knowledgeable and care enough to bring these to our attention.
Frequency accuracy. Yes, we are approximately 3Hz low, on 647.997. Although our transmitter was fully tested and setup before it was shipped to our transmitter site, for some reason when it was installed, it was running slightly low. It is adjusted to its maximum, but we appreciate the need to be more accurately on channel and reduce the night-time flutter experienced in fringe areas. This will be attended to in due course though the OFCOM and ITU limit is for 10Hz, so we are well within the required specification.
Audio processing. Thank you for all your comments on audio processing. Reports vary from “best AM audio I’ve ever heard” to “very tiring to listen to after a few minutes”. Although we are running our permanent audio processor, we are currently using a temporary programme feed to the transmitter site. Once we have the permanent connection to our main studio we will adjust the processing carefully. The most common comment is that the bass is a bit light and the treble a bit crushed. We will address this once we have a good quality source to find the best compromise to suit the multitude of different radios in use as we can.
We’ve received many comments on audio bandwidth. Our brand new state of the art DSPx digital audio processor (kindly supplied by our friends at Broadcast Warehouse) allows us to run audio to +/- 7khz, yet still be better than 30dB down at 7.5Khz, which is well within the required limits. On a good quality radio many have said that we sound very bright. However, with some mid-band pre-emphasis to suit the filtering in the majority of radios, some of you have said we are too bright. We will keep an eye/ear on this and carefully adjust the processing during these tests transmissions to arrive at a best compromise.
We received a lot of comments over the weekend of 25/26th stating that our signal appeared weaker than the previous tests over the 11/12th although a few commented that it was stronger. We can confirm we did not make any substantial changes during this period and are curious to establish whether this is accurate or just perceived. We are investigating this.
We can also confirm that all test transmissions have come from our new land based transmitter site. The broadcasts over the weekend of 25/26th, although originating from the ship were not broadcast from the ship.
As expected, those of you in fringe areas can get a good daytime signal but find the signal is over powered at night time by other stations. We share the channel with stations in Spain and Slovenia, so there is not much we can do to improve this other than suggest you listen online or via a mobile app, or try adjusting the position of your radio to minimise the other stations.
Modern houses often contain foil-lined insulation in the cavity walls. In these circumstances you will likely find reception better by placing the radio close to a window. Modern houses also contain a lot of computer and switching-power supplies which can generate a lot of interference. Try moving a portable radio around, or rotating its direction to improve reception.
There is a lot of difference between different radios, particularly as manufacturers may not put much effort into providing good performance for AM nowadays. If you have several radios then try them all.
Some cars can have truly awful AM reception – again manufacturers often do not put effort into obtaining good performance. The old fashioned spark plug ignition and alternator interference may not be as much a problem these days as interference generated by all the computer modules in a modern car. Generally a car with an external roof mounted antenna will be better than one which uses elements in the rear windows or a small “shark fin” type antenna.
If you are thinking of buying a new car (either new or second hand) be sure to check the radio performance on AM. You may find it only picks up very strong stations so make sure you try some weaker frequencies. In and around Suffolk and Norfolk try signals like Spectrum Radio from London on 558Khz, or Radio 4 on 720Khz. Tune them in, then start the engine. If performance is not good, ask the salesman why it is so poor! Easy for a new car – not so easy for a second-hand one.
It’s good to hear about the variety of radios you are using – from vintage 1933 sets to the latest software defined internet connected systems. For those who posted your age in the comments it is good to know how many of you have followed us since 1964. So far the ages admitted to range from 13 to mid 80’s and it is reassuring to know we cross so many age groups.
Thank you to those who have offered to send in mp3 recordings of reception. This is very kind but we would get swamped by the number of submissions. We are just glad that you are able to hear our signal. We have listened to our signal on a number of web connected SDR radios in various locations so have a good idea of how much interference there is and what reception is like.
Thank you all for making the effort and taking the time to provide reports and feedback. We really have read and studied every one of them.

Image result for radio caroline 648


Author: wirelesswaffle

A radio enthusiast from the UK - but also includes humour and comments on a wide variety of subjects including music and photos. A hobby site

8 thoughts on “Radio Caroline 648 khz test transmissions”

  1. Great daytime reception, great music… what a variety! On 8.12.2017 just before 15.00 hrs and the track before the beach boys you spun a track…… fab. who was it, please?

    1. Not sure maybe a blog visitor can give us an answer John. I heard a track, when the tests were audible here, and used the app Soundcloud to identify it. Maybe if you hear the song again hold your phone to the radio and you will identify your tune? Sorry I could not be more helpful

  2. Good reception in my radioshack in north of France. Good modulation, listening whith my hamradio rig (kenwood TS2000) and a vertical HF antenna. I enjoy your musical programs.
    Greetings to the team and good luck.
    Best regards and 73’s



  4. As 648 was used by the BBC at up to 500Kw to cover Europe ,can Radio Caroline request to use higher power , say 50Kw to cover most of England?

    1. Sadly the licence is only for 1kw. The signal of 500kw was beamed away from the UK. I agree though that the site is unique in that it was designed to broadcast at high power and there is not problem with objections from neighbours as it is on an established site away from housing. It does seem a waste only to broadcast 1kw from that site. Unless of course they used it for national security or other sorts of broadcasts still?

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: