Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 10-11-2016, 10:37   #1
Registered User

Join Date: Jan 2010
Boat: Allied Seawind 30
Posts: 121
VHF cable connection

So I think I have RG8 cable going from my VHF to antenna ( based on 0.4" OD) and I need to connect two ends together before it goes in mast. There is an old screw type connector on one side that I snipped off (see pic)...what type of connector is this? How else could I connect some RG8 coax cable??

Thanks!Click image for larger version

Name:	1478799418008.jpg
Views:	106
Size:	322.4 KB
ID:	135732
__________________

__________________
Sailor Keddy
http://sailorkeddy.com/
SailorKeddy is offline   Reply With Quote
Old 10-11-2016, 10:40   #2
Registered User
 
transmitterdan's Avatar

Join Date: Oct 2011
Boat: Valiant 42
Posts: 5,562
Re: VHF cable connection

The connector is type PL-259. It is also known as a "UHF" connector. There are various types such as crimp or solder. Which type you need depends on the skill and tools available. Solder takes the most skill. Crimp requires the right tools and some training.
__________________

transmitterdan is offline   Reply With Quote
Old 10-11-2016, 11:10   #3
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 14,159
Re: VHF cable connection

Hi SK

Everything you need to know to do this job is at this link. Easy VHF Connections Photo Gallery by Compass Marine How To at pbase.com

Compass Marine is on this forum under username Maine Sail. Expert in things marine electrical and more.
__________________
The water is always bluer on the other side of the ocean.

Sometimes it's necessary to state the obvious for the benefit of the oblivious.

Rust is the poor man's Loctite.
skipmac is offline   Reply With Quote
Old 10-11-2016, 12:31   #4
Registered User

Join Date: Jan 2010
Boat: Allied Seawind 30
Posts: 121
Re: VHF cable connection

So all I see are male connectors....are there female PL-259 connectors? Or do I need two make and a female-female??
__________________
Sailor Keddy
http://sailorkeddy.com/
SailorKeddy is offline   Reply With Quote
Old 10-11-2016, 12:44   #5
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 14,159
Re: VHF cable connection

Quote:
Originally Posted by SailorKeddy View Post
So all I see are male connectors....are there female PL-259 connectors? Or do I need two make and a female-female??
Don't know about where you're located but in FL to get a "good" marine electrician to come to your boat and do a simple job would probably set you back $100 at least. I emphasize good as this isn't an area where you want to cut corners.

You can buy antenna cable with one end already attached. If you're reusing old cable it might be worth investing in new, low loss cable like RG-213.
__________________
The water is always bluer on the other side of the ocean.

Sometimes it's necessary to state the obvious for the benefit of the oblivious.

Rust is the poor man's Loctite.
skipmac is offline   Reply With Quote
Old 10-11-2016, 12:54   #6
Registered User

Join Date: Jan 2010
Boat: Allied Seawind 30
Posts: 121
Re: VHF cable connection

I have rg-213 going from my VHF to the base of my mast, then more rg-213 going up the mast to the antenna. I need to connect the two bare ends at the base of the mast. I've seen male connectors I can splice/solder on but no female. Do I need two male ends and the a female-female in the middle?
__________________
Sailor Keddy
http://sailorkeddy.com/
SailorKeddy is offline   Reply With Quote
Old 10-11-2016, 13:48   #7
Registered User
 
tkeithlu's Avatar

Join Date: Feb 2012
Location: Carrabelle, Florida
Boat: Fiberglas shattering 44' steel trawler
Posts: 1,262
Re: VHF cable connection

It's called a double female PL259. Here's a link, although Google will take you to many other sources, including Amazon.

PL-259 Connectors, Adapters & Reducers | Amateur Radio Supplies
tkeithlu is offline   Reply With Quote
Old 10-11-2016, 14:48   #8
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 14,159
Re: VHF cable connection

i believe the female version of the PL 259 is an SO 239 and yes they are available for the cable but I used used PL 259s on both ends of my cable with a double female SO 239 the middle. The signal loss is almost zero if you use good connectors. Spend the money for Amphenol
__________________
The water is always bluer on the other side of the ocean.

Sometimes it's necessary to state the obvious for the benefit of the oblivious.

Rust is the poor man's Loctite.
skipmac is offline   Reply With Quote
Old 10-11-2016, 15:04   #9
Registered User
 
transmitterdan's Avatar

Join Date: Oct 2011
Boat: Valiant 42
Posts: 5,562
Re: VHF cable connection

Quote:
Originally Posted by SailorKeddy View Post
I have rg-213 going from my VHF to the base of my mast, then more rg-213 going up the mast to the antenna. I need to connect the two bare ends at the base of the mast. I've seen male connectors I can splice/solder on but no female. Do I need two male ends and the a female-female in the middle?
Any ham radio shop will have what you need. Generally you put male connectors on the cable. If you need to join 2 pieces of cable together use a so-called "barrel connector" which is 2 female connectors back to back.



You can get them here and many other places:

Female UHF barrel
transmitterdan is offline   Reply With Quote
Old 11-11-2016, 10:11   #10
Registered User

Join Date: Apr 2011
Location: Northport, Michigan
Boat: Trailerable cruising boat
Posts: 412
Re: VHF cable connection

Quote:
Originally Posted by SailorKeddy View Post
So I think I have RG8 cable going from my VHF to antenna ( based on 0.4" OD) and I need to connect two ends together before it goes in mast. There is an old screw type connector on one side that I snipped off (see pic)...what type of connector is this? How else could I connect some RG8 coax cable?...
The connector you show is some variant of the PL-259 connector, part of the UHF-Series. I believe the nomenclature PL-259 was the USA Army part number, probably a holdover from wartime production in the 1940's. The series designator UHF is a bit misleading, as today no one would use a PL-259 connector at UHF frequencies. The PL-259 is a PLug and it makes with the SO-239, a SOcket.

To connect a PL-259 to another PL-259 requires an ADAPTOR, not a connector. The nomenclature used is sometimes 83-1J, the part number of a major manufacturer (Amphenol) for an in-series plug-to-plug PL-259 adaptor. The Army part number is PL-258, but this is not in common use in my experience (which goes back to the 1950's).

You mention two generic types of coaxial transmission line, RG-8 and RG-8X. Both these designators are now generally meaningless as there are no military specifications for them. You can buy coaxial cable marked RG-8 or RG-8x and get a wide variety of products of various quality.

In general, the RG-8/U Mil-C-17 specified cable was a single-shielded 0.5-inch OD 50-Ohm impedance cable with a contaminating black vinyl outer jacket. This has now long been superseded by RG-213 cable, a similar cable except the outer jacket is a non-contaminating black vinyl, often called a Type-II. In coaxial cable to be used outdoors in weather and sunlight, it is much preferred to use cables with non-contaminating jackets. There are also many very similar cable to RG-213 made by many cable manufacturer with their own designations. Cables with contaminating outer jackets tend to see increases in loss as the outer jacket vinyl contaminates the copper shield conductor.

The RG-8x cable was something of a hybrid cable in which the general dimensions of RG-59/U, a 75-Ohm cable were used, but the dielectric was changed to a foam instead of polyethylene and the center conductor diameter increased to get the cable impedance back to 50-Ohms. There has never been, to my knowledge, any Military Specification for an RG-8x cable. This cable is often seen in marine applications and comes is a very wide variety of quality. In my experience RG-8x is not a good cable to use--unless you buy it from a major cable manufacturer--as it has a non-contaminating jacket and the foam dielectric must not be subjected to any sharp bends. Migration of the center conductor in the foam is a problem with this cable, and particularly in hot climates. No professional antenna installer would ever use this cable.

In general for installing a VHF Marine Band antenna atop a tall mast, the transmission line loss should be carefully considered. A typical goal in any transmitter installation is to limit transmission line loss to less than 1-deciBel.

Here are some typical characteristic transmission line losses at 150-MHz for 100-feet of line for several grades of cable:

RG-58/U = 6.2 dB
RG-8x = 4.7 dB
RG-213 = 2.8 dB
LMR400 = 1.5 dB

With this data we find the maximum length at 150-MHz for a loss of 1-dB to be:

RG-58/U = 16-feet
RG-8X = 21-feet
RG-213 = 35-feet
LMR400 = 67-feet

If you want an optimum installation, choose the transmission line accordingly.

For connectors, the transmission line at the antenna must be fitted with the appropriate mating connector for attaching to the antenna. It sounds like a PL-259-type connector must be used in the situation under discussion.

There are many choice for a PL-259-type connector, depending on what transmission line you choose. Get a quality connector that is specifically designed for the transmission line. I am old-school and prefer solder connectors for the center conductor. Center contacts should also be captivated so they do not retract in cold weather and break contact.

If you buy transmission line from a vendor who offers a service to install connectors, I recommend taking that option. Most boaters do not have specialized tooling for installing modern connectors using crimps, and solder connectors can also be a problem, as they require some skill and possession of proper soldering irons.

If there is any weak point in a boat radio system, it seems like the transmission line connector is the number one suspect. In the case of a connector installed at the top of a tall mast, make every effort to use a proper connector, to remove strain from it, and to protect it from ingress of water.
continuouswave is offline   Reply With Quote
Old 11-11-2016, 19:00   #11
Registered User

Join Date: Apr 2011
Location: Northport, Michigan
Boat: Trailerable cruising boat
Posts: 412
Re: VHF cable connection

Oops--meant to say that many RG-8x cables have a contaminating jacket. This really varies with the brand of cable.
__________________

continuouswave is offline   Reply With Quote
Reply

Tags
vhf

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
SH Matrix AIS VHF connection to Humm 999 pdurdon Marine Electronics 3 09-03-2014 10:43
VHF remote mike connection RDW Marine Electronics 0 08-11-2012 10:07
ICOM M710 Connection Cable sailordiver Marine Electronics 11 09-08-2012 20:48
Want To Buy: Icom 710 RT Connection Cable Alecadi Classifieds Archive 5 12-10-2011 19:06
For Sale: 50' Telephone/Cable TV Combo Cable off-the-grid Classifieds Archive 5 27-10-2009 13:00

Advertise Here


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 06:40.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
×

ShowCase vBulletin Plugins by Drive Thru Online, Inc.