Can you mix coax types?

[groundwire]

Is it ok to use a different size coax for jumpers than the main antenna line?
For example: lmr-400 from my radio to my amp, then lmr-600 between amps and for antenna line.

 

[sp5it]

Sure you can

 

[groundwire]

Ok, great. I was kinda thinking that. I was thinking of those 30kw etc broadcast radio stations, im sure they are not using that 6 inch hardline that goes to the antenna for jumpers as well lol.

 

[Captain Kilowatt]

Ok, great. I was kinda thinking that. I was thinking of those 30kw etc broadcast radio stations, im sure they are not using that 6 inch hardline that goes to the antenna for jumpers as well lol.

Wanna bet? My 20Kw on 94.9 and my 7 Kw on 97.7 ran 3 inch hardline, that's REAL solid pipe hardline from the tx output to the patch bay to the combiner then 3 inch heliax up the 300 foot tower to the wideband 12 bay antenna. Broadcast gear runs considerably different switching and patch bay systems. There are no flexible jumpers at that power level. The BIG stuff I have seen at CBC Halifax runs NINE INCH solid hardline and nine inch heliax to the tower.

 

[543_Dallas]

Starting at the exciter I have lmr 240 flex, then a run of lmr 400 through the attic to the amplifier, a patch cable of rg213 (that gets disconnected when not in use) and a finally LMR 600 to the ant.

 

[groundwire]

Wanna bet? My 20Kw on 94.9 and my 7 Kw on 97.7 ran 3 inch hardline, that's REAL solid pipe hardline from the tx output to the patch bay to the combiner then 3 inch heliax up the 300 foot tower to the wideband 12 bay antenna. Broadcast gear runs considerably different switching and patch bay systems. There are no flexible jumpers at that power level. The BIG stuff I have seen at CBC Halifax runs NINE INCH solid hardline and nine inch heliax to the tower.

Ok. But im starting with a 30w transmitter to amplifier, not 30kw transmitter to everything else. I understand though, at those power levels you have to. I was just wondering because the lmr-600 from the radio to the amp is a tight fit between the back of the radio and the floor ( in my mobile). Its the heatsink on the back of the radio thats causing the headache. Its totally in the way. Oh well

 

[543_Dallas]

im starting with a 30w transmitter to amplifier, not 30kw transmitter to everything else.

That's where you went wrong. Think BIG.

 

[Slowmover]

Nine inches better be enough.

 

[FredTx63]

Starting at the exciter I have lmr 240 flex, then a run of lmr 400 through the attic to the amplifier, a patch cable of rg213 (that gets disconnected when not in use) and a finally LMR 600 to the ant.

That's a lot of extra impedence dickering and losses. What kind of amp you run in a Texas attic?

 

[543_Dallas]

That's a lot of extra impedence dickering and losses. What kind of amp you run in a Texas attic?

The amp is in the garage. The coax runs from the radio room to the garage and then to the antenna. The amplifier has a pair of 8877 tubes. It's nice to have the blower noise and heat somewhere else.

There are only 4 pieces of coax in the whole system. They are just longer than most. The average joe with a cb set, driver, big amp, and watt meter has the same amount of connections. Mounting a line section to the amp saves a jumper. With quality cable the losses on HF frequencies are negligible.

 

[Captain Kilowatt]

As long as the impedances are the same, 50 ohms, you can have as many different types of cable as you want. My station uses LDF4-50 as the main feedlines but Belden 8214 (RG8 type) and RG-8X is used as jumpers. I think there is still some old RG-8 type and possibly some RG-58 in there somewhere as well.

 

[Tallman]

Nine inches better be enough.

JUST BARELY!
The lights in Texas flash with the Captain's modulation.

 

[Slowmover]

JUST BARELY!
The lights in Texas flash with the Captain's modulation.

Oh, I needed that. Thx!

.

 

[543_Dallas]

JUST BARELY!
The lights in Texas flash with the Captain's modulation.

That's the 50kw suburban south of Dallas.

 

[AudioShockwav]

Real hardline is a lot of work.


73
Jeff