On 5/24/2011 6:11 PM, Jim Lux wrote:
On 5/24/2011 2:54 PM, Dave Platt wrote:


I'm using 75' of
professionally assembled RG8X which is required to get from the radio to
the antenna.

That's probably costing you about half of your power (assuming a
typical RG8X-type coax). Some lower-loss types (e.g. LMR-240 are
better than this.


The results are all over the map. A piece of Cable TV cable might not be
a bad choice, if you can scrounge one. The 75 ohms probably isn't a big
deal.

At 144 MHz, bigger in diameter almost always beats fancier dielectric
(that is, the .405 inch RG-8, RG-213 flavors will usually beat any of
the quarter inch cables (RG-6, RG-8X, LMR240, etc.) because dielectric
losses aren't a big driver.. it's the IR loss in the center conductor.
RG-11, for instance, has less than 1.2dB loss for a matched 75 foot
line, and for the 1.5:1 mismatch, the loss only goes up 0.1 dB. (RG-11
type coax has a solid dielectric, and is pretty darn rugged stuff)

75 feet, at 144 MHz
LMR240 - 2.2 dB
Belden 8215 (RG-6A) - 2.5 dB
Belden 9258 (RG-8x) - 3.0 dB
Tandy RG-8x - 3.1 dB
Belden 8267 (RG-213) - 1.9 dB
Wireman CQ110 (RG-213) - 1.6 dB
Belden 8237 (RG-8) - 1.7 dB
belden 8213 (RG-11) = 1.2dB


Huh? 75 ft of RG-11 has almost 8dB of loss at 146MHz. 75 ft of LMR240
has 9.7dB of loss at 146 MHz.

I won't go through your entire list.

Check out http://www.vk1od.net/calc/tl/tllc.php

Cheers,
John

"John KD5YI" wrote in message
...

75 feet, at 144 MHz
LMR240 - 2.2 dB
Belden 8215 (RG-6A) - 2.5 dB
Belden 9258 (RG-8x) - 3.0 dB
Tandy RG-8x - 3.1 dB
Belden 8267 (RG-213) - 1.9 dB
Wireman CQ110 (RG-213) - 1.6 dB
Belden 8237 (RG-8) - 1.7 dB
belden 8213 (RG-11) = 1.2dB


Huh? 75 ft of RG-11 has almost 8dB of loss at 146MHz. 75 ft of LMR240 has
9.7dB of loss at 146 MHz.

I won't go through your entire list.

Check out http://www.vk1od.net/calc/tl/tllc.php

Cheers,
John


John you need to see where you went wrong. The numbers Jim listed are
either correct or very close. I did not bother to do the calculations, but
looking at a 100 foot chart, the numbers are very close and no where near
the numbers you have.

I thought you may have looked at the web page and missed it defauls to
meters, but that does not seem to be the case to me.

On 5/24/2011 8:08 PM, Ralph Mowery wrote:
"John wrote in message
...

75 feet, at 144 MHz
LMR240 - 2.2 dB
Belden 8215 (RG-6A) - 2.5 dB
Belden 9258 (RG-8x) - 3.0 dB
Tandy RG-8x - 3.1 dB
Belden 8267 (RG-213) - 1.9 dB
Wireman CQ110 (RG-213) - 1.6 dB
Belden 8237 (RG-8) - 1.7 dB
belden 8213 (RG-11) = 1.2dB


Huh? 75 ft of RG-11 has almost 8dB of loss at 146MHz. 75 ft of LMR240 has
9.7dB of loss at 146 MHz.

I won't go through your entire list.

Check out http://www.vk1od.net/calc/tl/tllc.php

Cheers,
John


John you need to see where you went wrong. The numbers Jim listed are
either correct or very close. I did not bother to do the calculations, but
looking at a 100 foot chart, the numbers are very close and no where near
the numbers you have.

I thought you may have looked at the web page and missed it defauls to
meters, but that does not seem to be the case to me.

You are correct, Ralph, and I apologize to the group for my error. I did
indeed put meters rather than feet into the calculator.

Again, my apologies, and thanks, Ralph, for correcting me.

Cheers,
John

On 5/24/2011 8:08 PM, Ralph Mowery wrote:
"John wrote in message
...

75 feet, at 144 MHz
LMR240 - 2.2 dB
Belden 8215 (RG-6A) - 2.5 dB
Belden 9258 (RG-8x) - 3.0 dB
Tandy RG-8x - 3.1 dB
Belden 8267 (RG-213) - 1.9 dB
Wireman CQ110 (RG-213) - 1.6 dB
Belden 8237 (RG-8) - 1.7 dB
belden 8213 (RG-11) = 1.2dB


Huh? 75 ft of RG-11 has almost 8dB of loss at 146MHz. 75 ft of LMR240 has
9.7dB of loss at 146 MHz.

I won't go through your entire list.

Check out http://www.vk1od.net/calc/tl/tllc.php

Cheers,
John


John you need to see where you went wrong. The numbers Jim listed are
either correct or very close. I did not bother to do the calculations, but
looking at a 100 foot chart, the numbers are very close and no where near
the numbers you have.

I thought you may have looked at the web page and missed it defauls to
meters, but that does not seem to be the case to me.



According to the loss calculator at Times Microwave the loss at 144 MHz
for a 75 length of LMR 240 is 2.952. 100 METERS is 9.687.

Perhaps you misread.

tom
K0TAR

On 5/25/2011 8:44 PM, tom wrote:
On 5/24/2011 8:08 PM, Ralph Mowery wrote:
"John wrote in message
...

75 feet, at 144 MHz
LMR240 - 2.2 dB
Belden 8215 (RG-6A) - 2.5 dB
Belden 9258 (RG-8x) - 3.0 dB
Tandy RG-8x - 3.1 dB
Belden 8267 (RG-213) - 1.9 dB
Wireman CQ110 (RG-213) - 1.6 dB
Belden 8237 (RG-8) - 1.7 dB
belden 8213 (RG-11) = 1.2dB


Huh? 75 ft of RG-11 has almost 8dB of loss at 146MHz. 75 ft of LMR240
has
9.7dB of loss at 146 MHz.

I won't go through your entire list.

Check out http://www.vk1od.net/calc/tl/tllc.php

Cheers,
John


John you need to see where you went wrong. The numbers Jim listed are
either correct or very close. I did not bother to do the calculations,
but
looking at a 100 foot chart, the numbers are very close and no where near
the numbers you have.

I thought you may have looked at the web page and missed it defauls to
meters, but that does not seem to be the case to me.



According to the loss calculator at Times Microwave the loss at 144 MHz
for a 75 length of LMR 240 is 2.952. 100 METERS is 9.687.

Perhaps you misread.

tom
K0TAR


Oops, needed to do this one level up. Should have responded to John.

tom
K0TAR

On 5/24/2011 5:17 PM, John KD5YI wrote:
On 5/24/2011 6:11 PM, Jim Lux wrote:
On 5/24/2011 2:54 PM, Dave Platt wrote:


I'm using 75' of
professionally assembled RG8X which is required to get from the
radio to
the antenna.

That's probably costing you about half of your power (assuming a
typical RG8X-type coax). Some lower-loss types (e.g. LMR-240 are
better than this.


The results are all over the map. A piece of Cable TV cable might not be
a bad choice, if you can scrounge one. The 75 ohms probably isn't a big
deal.

At 144 MHz, bigger in diameter almost always beats fancier dielectric
(that is, the .405 inch RG-8, RG-213 flavors will usually beat any of
the quarter inch cables (RG-6, RG-8X, LMR240, etc.) because dielectric
losses aren't a big driver.. it's the IR loss in the center conductor.
RG-11, for instance, has less than 1.2dB loss for a matched 75 foot
line, and for the 1.5:1 mismatch, the loss only goes up 0.1 dB. (RG-11
type coax has a solid dielectric, and is pretty darn rugged stuff)

75 feet, at 144 MHz
LMR240 - 2.2 dB
Belden 8215 (RG-6A) - 2.5 dB
Belden 9258 (RG-8x) - 3.0 dB
Tandy RG-8x - 3.1 dB
Belden 8267 (RG-213) - 1.9 dB
Wireman CQ110 (RG-213) - 1.6 dB
Belden 8237 (RG-8) - 1.7 dB
belden 8213 (RG-11) = 1.2dB


Huh? 75 ft of RG-11 has almost 8dB of loss at 146MHz. 75 ft of LMR240
has 9.7dB of loss at 146 MHz.

I won't go through your entire list.

Check out http://www.vk1od.net/calc/tl/tllc.php


That's what I used..
Sure you got feet and not meters?

B9219, 75ft, 146 MHz = 1.811dB

On 5/25/2011 3:51 PM, Jim Lux wrote:
On 5/24/2011 5:17 PM, John KD5YI wrote:
On 5/24/2011 6:11 PM, Jim Lux wrote:
On 5/24/2011 2:54 PM, Dave Platt wrote:


I'm using 75' of
professionally assembled RG8X which is required to get from the
radio to
the antenna.

That's probably costing you about half of your power (assuming a
typical RG8X-type coax). Some lower-loss types (e.g. LMR-240 are
better than this.


The results are all over the map. A piece of Cable TV cable might not be
a bad choice, if you can scrounge one. The 75 ohms probably isn't a big
deal.

At 144 MHz, bigger in diameter almost always beats fancier dielectric
(that is, the .405 inch RG-8, RG-213 flavors will usually beat any of
the quarter inch cables (RG-6, RG-8X, LMR240, etc.) because dielectric
losses aren't a big driver.. it's the IR loss in the center conductor.
RG-11, for instance, has less than 1.2dB loss for a matched 75 foot
line, and for the 1.5:1 mismatch, the loss only goes up 0.1 dB. (RG-11
type coax has a solid dielectric, and is pretty darn rugged stuff)

75 feet, at 144 MHz
LMR240 - 2.2 dB
Belden 8215 (RG-6A) - 2.5 dB
Belden 9258 (RG-8x) - 3.0 dB
Tandy RG-8x - 3.1 dB
Belden 8267 (RG-213) - 1.9 dB
Wireman CQ110 (RG-213) - 1.6 dB
Belden 8237 (RG-8) - 1.7 dB
belden 8213 (RG-11) = 1.2dB


Huh? 75 ft of RG-11 has almost 8dB of loss at 146MHz. 75 ft of LMR240
has 9.7dB of loss at 146 MHz.

I won't go through your entire list.

Check out http://www.vk1od.net/calc/tl/tllc.php


That's what I used..
Sure you got feet and not meters?

B9219, 75ft, 146 MHz = 1.811dB

Yes, Jim, Ralph pointed that out to me yesterday and I posted an apology
to him. I see that I should also analogize to you for my mistake.

Thanks to you both.

John

On 5/25/2011 5:17 PM, John KD5YI wrote:
On 5/25/2011 3:51 PM, Jim Lux wrote:
On 5/24/2011 5:17 PM, John KD5YI wrote:
On 5/24/2011 6:11 PM, Jim Lux wrote:
On 5/24/2011 2:54 PM, Dave Platt wrote:


I'm using 75' of
professionally assembled RG8X which is required to get from the
radio to
the antenna.

That's probably costing you about half of your power (assuming a
typical RG8X-type coax). Some lower-loss types (e.g. LMR-240 are
better than this.


The results are all over the map. A piece of Cable TV cable might
not be
a bad choice, if you can scrounge one. The 75 ohms probably isn't a big
deal.

At 144 MHz, bigger in diameter almost always beats fancier dielectric
(that is, the .405 inch RG-8, RG-213 flavors will usually beat any of
the quarter inch cables (RG-6, RG-8X, LMR240, etc.) because dielectric
losses aren't a big driver.. it's the IR loss in the center conductor.
RG-11, for instance, has less than 1.2dB loss for a matched 75 foot
line, and for the 1.5:1 mismatch, the loss only goes up 0.1 dB. (RG-11
type coax has a solid dielectric, and is pretty darn rugged stuff)

75 feet, at 144 MHz
LMR240 - 2.2 dB
Belden 8215 (RG-6A) - 2.5 dB
Belden 9258 (RG-8x) - 3.0 dB
Tandy RG-8x - 3.1 dB
Belden 8267 (RG-213) - 1.9 dB
Wireman CQ110 (RG-213) - 1.6 dB
Belden 8237 (RG-8) - 1.7 dB
belden 8213 (RG-11) = 1.2dB


Huh? 75 ft of RG-11 has almost 8dB of loss at 146MHz. 75 ft of LMR240
has 9.7dB of loss at 146 MHz.

I won't go through your entire list.

Check out http://www.vk1od.net/calc/tl/tllc.php


That's what I used..
Sure you got feet and not meters?

B9219, 75ft, 146 MHz = 1.811dB

Yes, Jim, Ralph pointed that out to me yesterday and I posted an apology
to him. I see that I should also analogize to you for my mistake.
^^^^^^^^^
Thanks to you both. Apologize

John

On 5/25/2011 3:17 PM, John KD5YI wrote:
On 5/25/2011 3:51 PM, Jim Lux wrote:

Yes, Jim, Ralph pointed that out to me yesterday and I posted an apology
to him. I see that I should also analogize to you for my mistake.



Darn newsreader that didn't have all the messages loaded.. I saw Ralph's
comment and your reply. Such is life..

Now, if you want some high loss coax.. can I interest you in some tiny
coax made of stainless steel? It's for cryogenic applications so it has
very, very low thermal conductivity, but it also has really high loss. I
don't think you want to be running kilowatts (or even watts) through it.

On 5/25/2011 7:37 PM, Jim Lux wrote:
On 5/25/2011 3:17 PM, John KD5YI wrote:
On 5/25/2011 3:51 PM, Jim Lux wrote:

Yes, Jim, Ralph pointed that out to me yesterday and I posted an apology
to him. I see that I should also analogize to you for my mistake.



Darn newsreader that didn't have all the messages loaded.. I saw Ralph's
comment and your reply. Such is life..

Now, if you want some high loss coax.. can I interest you in some tiny
coax made of stainless steel? It's for cryogenic applications so it has
very, very low thermal conductivity, but it also has really high loss. I
don't think you want to be running kilowatts (or even watts) through it.

Well, thanks, Jim, for your kind offer. However I have plenty of lossy
cable now. I only use in the lab because other options are difficult to
handle.

Cheers,
John