Confused about cable.. HELP please :)

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MarkRennie
Posts: 28
Joined: Wed Apr 08, 2015 6:51 pm

Confused about cable.. HELP please :)

Post by MarkRennie » Fri Apr 17, 2015 4:11 pm

Hello,

I started to fit my new antenna to my chimney which has a great 360 deg view and I realised the 2m of cable I bought is WAY too short. I need about 7m and I am going to buy a pre-made cable. I can only get RG-58 Coax cable 10 Metre Lead BNC to N type. I am going for RG-58 as it is 50 Ohm, as this is what i think need.

I am using ADS-B using dump1090 on a Raspberry Pi with DVB receiver dongle and a Short pigtail 25cm long mcx to BNC

Since I am fairly new to all of this, will I have signal loss with a 10m cable?

Anyone give me some advice please?

Cheers
Mark

jonfear
Posts: 365
Joined: Sat Feb 09, 2013 12:15 pm
Location: Wick St Lawrence
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Re: Confused about cable.. HELP please :)

Post by jonfear » Fri Apr 17, 2015 6:10 pm

Hi Mark

No! Do not use RG58. It is no good for the frequency you are dealing with here.

Get some Satellite TV cable and some F type connectors off of eBay or from Maplins.

Ebay: http://www.ebay.co.uk/itm/100m-RG6-Blac ... 3ef2f8567b

AND http://www.ebay.co.uk/itm/F-type-connec ... 5665a552dc.

Then get a BNC to F type adapter http://www.ebay.co.uk/itm/BNC-Plug-to-F ... 35e3013085
This gets you down to the receiver.
Then either:
an F type to SMA adapter http://www.ebay.co.uk/itm/F-Type-Female ... 4d14a92192

and finally an SMA to MCX: http://www.ebay.co.uk/itm/GlobalSat-MCX ... 2a4f228753.

OR

F type to MCX http://www.ebay.co.uk/itm/F-female-to-M ... 35e2dba02d

Although this might be too inflexible.

I use Satellite cable on three out of my four antennas and it works fine. It works well at 1GHz unlike RG58. Get self amalgamating tape to seal the joints outside the house, again from eBay.

Note, there are other providers of these parts out there but I have used most of who I listed and found them to be good.

HTH

Jon
http://www.360radar.co.uk, the new name for MLAT Radar in the UK and Western Europe.

Former PP feeder Bm. No longer feeding. I do not have time to sort out imaginary problems with NTP
when it has been working fine for 2+ Years.

MarkRennie
Posts: 28
Joined: Wed Apr 08, 2015 6:51 pm

Re: Confused about cable.. HELP please :)

Post by MarkRennie » Fri Apr 17, 2015 6:32 pm

thanks for the really detailed reply Jon. I need to go from a N type connector, as that is what the antenna I have bought has. I will look to go into a homemade one in the future, but for now I would like to use this one :oops: :oops:

could I use one of these
http://www.ebay.co.uk/itm/Adapter-Conne ... 51c6fe29ef

then BNC onto the cable? etc etc

Cheers
Mark

PS being on the roof was NOT fun :D lucky it isn't a standard shaped house, so wasn't too bad :lol:

jonfear
Posts: 365
Joined: Sat Feb 09, 2013 12:15 pm
Location: Wick St Lawrence
Contact:

Re: Confused about cable.. HELP please :)

Post by jonfear » Fri Apr 17, 2015 10:34 pm

HI Mark

The cable is the problem. It has a VERY high loss at 1GHz which is what you are receiving.

You must use cable suited to the frequency otherwise all your hard work on the roof is for nothing.

Most pre=made cables are for radio scanners that work at much lower frequencies.

You could buy a pre-made satellite cable and then buy the adapters...

Jon
http://www.360radar.co.uk, the new name for MLAT Radar in the UK and Western Europe.

Former PP feeder Bm. No longer feeding. I do not have time to sort out imaginary problems with NTP
when it has been working fine for 2+ Years.

MarkRennie
Posts: 28
Joined: Wed Apr 08, 2015 6:51 pm

Re: Confused about cable.. HELP please :)

Post by MarkRennie » Sat Apr 18, 2015 8:55 am

thank you Jon, I hate the Internet at times, as I read/was told to use RG58 cable. Anyway I have now bought some satellite cable and connectors. Hopefully by Tuesday night I will be back up on that roof!

Have a great weekend!

k5ted
Posts: 10
Joined: Fri Dec 25, 2015 2:53 am

Re: Confused about cable.. HELP please :)

Post by k5ted » Fri Dec 25, 2015 3:01 am

LMR240 is better

jonfear
Posts: 365
Joined: Sat Feb 09, 2013 12:15 pm
Location: Wick St Lawrence
Contact:

Re: Confused about cable.. HELP please :)

Post by jonfear » Sat Dec 26, 2015 12:16 pm

Agreed that LMR240 is better however here in the UK it is 10 times more expensive than simple satellite cable such as RG6. The difference in attenuation is just not worth the price difference for those running the RTL dongle. It "may" show some benefits when using a Beast or similar however the difference still would be minimal. However if you have a Beast and want every available ounce of signal out there then buy the LMR240!

The main comment still stands that RG58 is completely unsuitable at this frequency and is subject to massive losses.

Jon
http://www.360radar.co.uk, the new name for MLAT Radar in the UK and Western Europe.

Former PP feeder Bm. No longer feeding. I do not have time to sort out imaginary problems with NTP
when it has been working fine for 2+ Years.

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