Tuner Location vs Long Cable Run ?

[atoll]

i am in the process of rebuilding the nav station on a 63ft alu yacht.
the question is where to mount the tuner,icom at-120 in relation to the transmitter icom m-700.

i can easily mount the atu below the backstay,but this would require about 40 ft coax and control cable run to the transmitter located in the nav station.

alternatively mount transmitter and atu in the aft cabin 5ft apart.

or mount atu and transmitter in the nav station and run a40 ft sheilded cable to the backstay.

advice much appreciated

[colemj]

Don't mount the ATU a large distance from the antenna. The wire from the ATU to the antenna is part of the antenna, and you do not want this transmitting 40' through your boat.

The cable run from the transceiver to the ATU is inconsequential, so mount the ATU as close to the antenna as possible and the transceiver wherever it is most convenient to use.

Mark

[btrayfors]

Exactly right (what Mark said)!

Sometimes the location of the transceiver will also be a function of how easy it is to run the needed AWG6 or AWG4 12V DC cables directly to the house batteries.

One other point: I've found it's best to use the heavier RG-213 or, better, double-shielded RG-214 coax between the transceiver and the ATU. Insofar as possible, keep the coax away from other electrical and signal wires.

Bill
WA6CCA

[atoll]

thank you makes a lot more sense than the manual,which is very non specific about distance between atu and transmitter,apart from the interference issues.

next challenge is to find a route away from the existing conduiting,carrying all the domestic ac/dc cables.
assume rg-214 cable will screen out most rf interferance at aprox 1 ft away from other cables?

[btrayfors]

Originally Posted by atoll

thank you makes a lot more sense than the manual,which is very non specific about distance between atu and transmitter,apart from the interference issues.

next challenge is to find a route away from the existing conduiting,carrying all the domestic ac/dc cables.
assume rg-214 cable will screen out most rf interferance at aprox 1 ft away from other cables?

It will help. If problems persist, it's always possible to add ferrites both to coax and to the control cables -- at both ends -- and, in difficult cases, an isolator such as the ones made by Radio Works can be helpful as well.

Bill

[Mambo]

Originally Posted by btrayfors

Exactly right (what Mark said)!

Sometimes the location of the transceiver will also be a function of how easy it is to run the needed AWG6 or AWG4 12V DC cables directly to the house batteries.

Hi Bill -
What sort of fusing do you recomend on the power feed. I have been thinking about installing one of the blue seas safetyhub fuse blocks for all of the direct feed items. Would you run through the fuse block or install a separate fuse?

Originally Posted by btrayfors

One other point: I've found it's best to use the heavier RG-213 or, better, double-shielded RG-214 coax between the transceiver and the ATU. Insofar as possible, keep the coax away from other electrical and signal wires.

Bill
WA6CCA.

So, I guess my plan to go through the hole in the bulkhead that every otherwire routes throughand then past the charger and over both battery banks ... is probably a bad idea, eh? -)

Thanks!

[atoll]

just got a quote for rg-214 about $5 a meter,see they can also supply a screened 4wire cable for the control wire to tuner is this a good idea or over kill,and also would it be best to run the control cabel in existing conduiting with domestic wiring,since it is only carriyng dc?

[btrayfors]

Originally Posted by Mambo

Hi Bill -
What sort of fusing do you recomend on the power feed. I have been thinking about installing one of the blue seas safetyhub fuse blocks for all of the direct feed items. Would you run through the fuse block or install a separate fuse?

So, I guess my plan to go through the hole in the bulkhead that every otherwire routes throughand then past the charger and over both battery banks ... is probably a bad idea, eh? -)

Thanks!

Both the positive and negative DC cables for the radio need to be fused close to the batteries. Under current ABYC guidelines, only three types of fuses have a sufficiently high AIC (ampere interrupt capacity) for wires connected to the house batteries: ANLs, Class-T's, and the new terminal fuses by Blue Sea Systems. I like the terminal fuses: they can connect directly to the battery terminals, or to the nearby busses. You can also get a 30A fuse for them, and that's the correct value to use for SSB radios.

Run the AWG6 (or AWG4 if the one-way distance is more than 20') cables up to a terminal block near the battery. Install an ON-OFF switch if you like; I favor the Blue Sea Systems #6006 mini battery switch...it's robust, compact, and inexpensive. Then, cut the transceiver power cables to a length sufficient to connect to that terminal block. Leave a bit of a "service loop".

RE: routing of wires,yeah...best to physically separate them IF YOU CAN...but don't be paranoid about it :-)

Bill

[btrayfors]

Originally Posted by atoll

just got a quote for rg-214 about $5 a meter,see they can also supply a screened 4wire cable for the control wire to tuner is this a good idea or over kill,and also would it be best to run the control cabel in existing conduiting with domestic wiring,since it is only carriyng dc?

Not a bad price. RG-214 here is about $1.25 per foot for the tinned variety, and $2.25 per foot for the MILSPEC silver-coated variety, viz: RF Connection Coaxial Cable

Separating the control cable from other wiring is desirable, too, though not critical so long as you use ferrites at both ends.

Bill