TMC miniscan signal strength

ijhill · Posted: Wed Apr 09, 2008 11:34 am Post subject: TMC miniscan signal strength

I have used a miniscan arial, although, brought from Rocketradio.net it covers the FM band and goes down to 25Mhz.

After connecting it the signal strength on the hidden screens drops from around 37 to 22 in Wolverhampton, however, the frequency never changes from 97 and receives traffic really well.

Is this normal, I can imagine that the increased cable length +5m increases signal loss but the external aerial improves signal quality. In any case I now receive traffic information on my drive and in a couple of seconds which is great, waiting to see how this works elsewhere.

mikealder · Posted: Wed Apr 09, 2008 11:47 am Post subject:

If it works better with the aerial connected than without simply ignore the hidden menu's and any signal strength meter on the device, they are meaningless at best, misleading at worst.
I have used a Mini-Scan and Sky-Scan aerials to great effect in the UK with various RDS-TMC receivers, far better than the cr*ppy bit of shoe lace they all seem to like supplying - Mike

PaulB2005 · Posted: Wed Apr 09, 2008 11:56 am Post subject:

Any chance of some part / stock numbers for places like Maplin etc for this sort of item?

Also how did you connect the shoe string to the antenna?

Some sort of idiots guide to doing this? I've read a few threads on this and because i've never done anything like this before it goes a bit over my head..... Embarassed

ijhill · Posted: Wed Apr 09, 2008 11:57 am Post subject:

Thanks Mile, I did disconnect the aerial and although the signal increase I got a yellow flashing light so the signal quality has definitely improved. a rival now for tomtom traffic.

ijhill · Posted: Wed Apr 09, 2008 12:02 pm Post subject:

PaulB2005 · Posted: Wed Apr 09, 2008 12:11 pm Post subject:

Ah, thanks.

Ok stupid question(s). The antenna on the end? Absolutely necessary of can a length of suitable cable be used - got plenty of 16/0.2 wire lying around.

BNC Connectors necessary or could you use this and this to make the join?

mikealder · Posted: Wed Apr 09, 2008 12:37 pm Post subject:

The Mini Scan only goes down to 100MHz but it works very well for RDS-TMC, better still it doesn't look like an aerial farm stuck on the roof see Mini-Scan for more details.

If you don't mind drawing attention to the vehicle consider the Sky-Scan, this goes down to 25MHz and is therefore more suitable for the FM band 87 - 108 MHz Sky-Scan

On either case you are better to connect the aerial to the RDS-TMC via a decent connector, the 50 ohm BNC connector isn't costly and will offer less attenuation than banana jacs see
BNC Socket
Mike

PaulB2005 · Posted: Wed Apr 09, 2008 12:50 pm Post subject:

So the "Round BNC Chassis Socket" HH18U just literally solders onto the end of the TMC antenna (after removing the end block and striping the insulation) at the centre pin (the gold spike top right of the picture?)

The antenna BNC connector just twists on and off the other end?

mikealder · Posted: Wed Apr 09, 2008 12:56 pm Post subject:

What you describe is exactly what I have done with the Garmin RDS unit and the TomTom units I use, the BNC socket makes it easy to remove to transplant the kit to another car as I use Hire cars with work quite often - Mike

PaulB2005 · Posted: Wed Apr 09, 2008 1:15 pm Post subject:

Thanks. I'll have a think about it....

ijhill · Posted: Wed Apr 09, 2008 3:07 pm Post subject:

The link I gave was the only demountable one I could find that covered all of the fm spectrum, as stated the mini scan doesn't. The aerial should be slightly longer than the mini scan; the price is around the same.

I now pick up a signal on my drive, previously I had to drive a couple of miles to civilisation before I got any traffic.

PaulB2005 · Posted: Sat Apr 12, 2008 11:40 pm Post subject:

Parts now ordered from Rocket Radio. Maplin were out of stock of antenna.

I noticed on this thread davawt states

mikealder · Posted: Sun Apr 13, 2008 7:12 am Post subject:

The alternative is to get the crimp type connector but the crimping tools cost a small fortune, for a good reliable connection soldering the joint is best - Mike

PaulB2005 · Posted: Sun Apr 13, 2008 2:15 pm Post subject:

I found a PDF on a website that shows how to dismantle the plug / socket and how to solder using the solder hole, then put the plug / socket together.

This is it

I'll have to wait for my order to arrive from Rocket Radio and then i'll either borrow or buy a soldering iron....

PaulB2005 · Posted: Tue Apr 15, 2008 12:53 pm Post subject:

Antenna arrived from RocketRadio and so did some random bit i don't recognise.

I ordered

	PocketGPS
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