Coax upgraded

[gdotts]

Previously allways used regular RG8X coax in going from antenna to shack now receintly switched to Shireen 400 flex cable. The Shireen flex cable did cost less than the LMR400UF although the manufacturer said it was the same but sometimes a manufacturer can... "creatively truth bend"!!. Is it the LMR 400UF same as the Shireen 400 flex? PLease advise..thank you.

 

[jonwienke]

Connect your watt meter directly to a transmitter and take a reading.

Insert the Shireen cable between the same transmitter and watt meter and take a second reading. You can calculate the loss in dB/foot at the TX frequency by comparing the before and after readings and the length of the cable, and see if it matched the manufacturer specs.

Even crappy a LMR400 clone will still likely perform better than RG8X.

 

[cmdrwill]

Even crappy a LMR400 clone will still likely perform better than RG8X.

There is a whole lot of 'crappy' LMR xxx knock-off coaxial cables out there. Even crappy RG8X.

We have pulled out a lot of so-called LMR xxx and replaced Times LMR cable. Not to mention lots of really crappy connectors, and connectors not properly installed.

The Shireen 400 flex seems to be a much up-dated construction. We have not tried it yet.

 

[Rred]

Is the attenuation the same?
Is the water absorption the same?
Is the flexibility the same?
Is the UV resistance of the jacket the same?
Will the jacket break down or bleed plasticizers the same?
Is the capacitance the same?

So many things to compare, but since the OP already bought it...unless he's going to scrap it, that doesn't matter right now, does it?

 

[prcguy]

Last time I did research on LMR400 type cables the attenuation was nearly identical for all brands and the internal dimensions must be the same to qualify as LMR400 type. There is a slight difference between the flex types and regular due to the stranded center conductor and different materials in the outer covering to make it more pliable.

Since the center conductor and outer braid must be the same dia in all cases the capacitance per foot should be about the same in all brands, otherwise it would not be 50 ohms. The difference you will find is the way the aluminum foil is attached, how thick and how much extra shielding the braid has and the outer covering characteristics.

Some brands will last longer outside than others due to UV. Some have stiffer had harder plastic coverings and others are more pliable. Some are designed for direct burial but most are not. Times is always a good default but I have some LMR400 made by Commscope that is really durable and looks like it will survive a nuclear hit.

I usually buy LMR400 off Ebay in 1,000ft spools when it gets down below $200. I also get lots of free LMR400, 500 and 600 left over from large satellite installations I work on.
prcguy

Is the attenuation the same?
Is the water absorption the same?
Is the flexibility the same?
Is the UV resistance of the jacket the same?
Will the jacket break down or bleed plasticizers the same?
Is the capacitance the same?

So many things to compare, but since the OP already bought it...unless he's going to scrap it, that doesn't matter right now, does it?

 

[lmrtek]

I learned decades ago that generic coax is a crap shoot as to what you get but many use cheaper jacket materials that deteriorate rapidly outdoors and use lesser quality control

For the cost difference, going with genuine Times Microwave or Belden coax is the only sure thing

In professional service I would never take the chance due to the loss of life law suits that could result but for amateur use they are likely good enough

 

[cmdrwill]

Correction: replaced with genuine Times cable(s),