Cable types and losses

[JohnE]

been meaning to put this out there for a while,since I have had a few conversations about this w/various members.
first pics,cables from L-R w/associated N male connectors.
RG8/213 LMR400 type, 1/2Inch superflex, 1/2inch hard line also known as Heliax, 7/8inch hard line.

 

 
[ MyGMRS STAFF EDIT:  3 Photos no longer available from linked source.]
 

 

now lets talk about the losses in Db and how much power that is.
Cable type                                  loss at 100Mc                          400Mc


RG8/213                                      2.0dB/100'                              4.7dB/100'
LMR400                                       1.2                                         2.5

Hardline type                                       150Mc                              450Mc

1/2" superflex                                    1.3dB/100'                         2.3dB/100'
LMR600                                             1.0                                   1.7
1/2" Heliax                                         0.85                                  1.5
7/8" Heliax                                         0.44                                  0.8
1-1/4" Heliax                                      0.3                                    0.6

dB loss            power loss in %
0.5                        10                        100W in 90W out
1.0                        20
1.5                        30
2.0                        37
2.5                        44
3.0                        50
3.5                        56
4.0                        60

all of the above loss specs are manufacture specs, I strongly suggest that you measure your line loss w/watt meter if possible to know exactly what you are getting at the antenna.
IME most of the book specs are on the money for hard line ,RG8/213 can be a crap shoot depending on manufacturer. I've had some really bad and some pretty good.
LMR I've had a love/hate relationship w/, good cable but seems to be prone to moisture issues. wish I had pic of the 7yr old cable that pretty much self destructed.
hope this is of some help to those looking to put up a machine or control station in the future.
JE

***EDIT***

found this very useful

http://www.arrg.us/pages/Loss-Calc.htm

Edited March 12, 2022 by JohnE

[MarkInTampa]

Stupid question....

I picked up 300ft Commscope LDF4-50A Andrew HELIAX at heck of a deal for a new antenna and 40ft tower. The tower is approx 100ft away from the radio room on the other end of the house. I can run the coax under the eave of the roof or underground but part of the roof is flat so no attic access. Distance would be equal. The game plan is to run two lines to the tower just incase or future use (I see a beam coming from Santa).

In looking at Commscopes spec sheet for the cable it doesn't mention anything about being under ground rated. Looking at retail shops online at the cable I see this statement:
"All HELIAX® coaxial cables are jacketed for direct burial or for corrosive environmental conditions."

I'd like to bury it for aesthetic reasons but would like to confirm if it is really rated for direct burial. Can anybody confirm?

Thanks!

[gortex2]

I have never done direct burial on LDF. I always run it in conduit. 1/2" is pretty stiff so I'd use at least 1 1/2 or 2" conduit and I'd probably load as I go vs trying to pull after especially if you have any bends. Also remember LDF doesn't bend tight so if you have turns use a couple 45' angles vs a 90. 

[Doggorunning1]

 Messi & Paoloni Ultraflex 7 verse Messi & Paoloni Ultraflex 10

Seems 7 would be easy to work with on a 45 foot run what are we talking in the real world anyone have experience in this?  

Why I'm considering 7? Cheaper, more flex, and in stock, in stock....that 10 Im looking for 

[Doggorunning1]

I just ordered directly from M&P 

Ultraflex 10 Pre assembled factory, tested, PL 259 connectors, Silicon Sealed from the factory , anyone needing info just contact me 

https://messi.it/en/messi-calc.htm

[WRYN359]

On 1/24/2024 at 9:01 PM, Doggorunning1 said:

I just ordered directly from M&P 

Ultraflex 10 Pre assembled factory, tested, PL 259 connectors, Silicon Sealed from the factory , anyone needing info just contact me 

https://messi.it/en/messi-calc.htm

I've been looking at this cable. Let me know how you like it.

[SteveShannon]

5 minutes ago, WRYN359 said:

I've been looking at this cable. Let me know how you like it.

It’s very good cable. I’ve used it and M&P Broadpro 10, which only differs from the Ultraflex by having a solid inner conductor. 
If you intend to shorten it be sure you can get the Evolution connectors. The very similar XCRD connectors from Amazon have too small of a hole to accept the stranded center conductor of the UltraFlex. 
Two US dealers carry it: Gigaparts and Buytwwayradios.com. Or you can get it directly from Italy. 

[Doggorunning1]

Gigaparts and Buytwwayradios.com.  has been out of stock for awhile, these are the same company I think as I went to Gigaparts next and talked to the same rep...  I ordered direct from Italy and had them install  the weather proofing, on 3 of the pl259 fittings, one fitting I was going to disassemble/shorten anyway, and was to be indoors unlike the other 3 end pieces.  received in 3 days WOW! 

[Doggorunning1]

50 foot run and VERY flexible, the fittings are such high quality and dissemble in seconds, It you order from Messi Italy they can also weather proof the ends.  Im hitting all the repeaters in my area 

link goes to my video, its 9 min, I also have a YouTube SHORT thats 1 min that is essentially the same. 

 

[Doggorunning1]

It's one minute and shows a VERY basic set up that allows you to talk all over Southern California.  It shows you Grounding which is the most difficult aspect of set up.  

[SteveShannon]

1 hour ago, Doggorunning1 said:

Gigaparts and Buytwwayradios.com.  has been out of stock for awhile, these are the same company I think as I went to Gigaparts next and talked to the same rep...  I ordered direct from Italy and had them install  the weather proofing, on 3 of the pl259 fittings, one fitting I was going to disassemble/shorten anyway, and was to be indoors unlike the other 3 end pieces.  received in 3 days WOW! 

I bought 50 feet of Ultraflex 10 just last week from Gigaparts. It’s popular. 

[Doggorunning1]

Yes, 50 foot sections are in stock, matter fact never went out of stock; but thats about it, I needed a 12 and 25 foot premade. 50 feet is still in if thats what's needed.  

https://www.buytwowayradios.com/messi-paoloni-mp-uf10-jmp-uhfm.html

 

[SteveShannon]

7 minutes ago, Doggorunning1 said:

Yes, 50 foot sections are in stock, matter fact never went out of stock; but thats about it, I needed a 12 and 25 foot premade. 50 feet is still in if thats what's needed.  

https://www.buytwowayradios.com/messi-paoloni-mp-uf10-jmp-uhfm.html

 

I got the 50 foot one and I’ll cut it where I need it and put two new ends on. That’s where I put the alpha delta lightning arrester. Then the remaining piece runs up the mast to the feed point. 
The ends are in stock at Buytwowayradios, but they’re almost twice the price there compared to Gigaparts. As far as I can tell I got the last ones Gigaparts had in December. 

[Doggorunning1]

If you watch my video, you can see the nice job they do at the factory with the silicone sleeves.  Very thick silicon, really thick, when ordering it gives you this option.  Very impressed; think the option is around $7 

 

The fittings are very easily removed, sure its not your first time, it was for me, just a great design 

https://messi.it/en/messi-calc.htm 

[LeoG]

I just did a real world test of some RG58/U cable.  Why? Because that's what I have kicking around unused LOL.

Using my little TD-H3 radio at 467.625MHz going into a 50ohm dummy load through my Mcbazel Surecom SW-102 SWR/Power meter.  The 1st connection is an SMA-F to PL259F and then a PL259M-M, 1 ft RG58 jumper cable to the meter.

The output on the meter was 4.69 watts

I then switched out the RG58 jumper cable for 50' of RG58/U cable (Retevis) and checked the output and it was 1.48 watts.  Pretty significant.

[LeoG]

Anyone know how to calculate the dB loss with those numbers

 

And yes, I'd like to see the math.

[SteveShannon]

1 hour ago, LeoG said:

Anyone know how to calculate the dB loss with those numbers

 

And yes, I'd like to see the math.

1.48 watts = 31.7026171539 dbm 

4.69 watts = 36.7117284272 dbm 

The difference is 5.009 db

Use an online calculator:

https://www.rapidtables.com/convert/power/Watt_to_dBm.html
 

[LeoG]

Little bit better than spec-ed.  I'm using a higher frequency so the loss would be slightly more than shown in the table.

 

[LeoG]

So 7.89 watts out of my repeater through 50' LMR400 is 5.78 watts into the antenna.  Nice to be able to figure that out.

[dosw]

19 hours ago, LeoG said:

So 7.89 watts out of my repeater through 50' LMR400 is 5.78 watts into the antenna.  Nice to be able to figure that out.

I like this one: https://kv5r.com/ham-radio/coax-loss-calculator/

And it agrees with your calculation, assuming a 1:1 SWR. As I tinker with different antennas and cables, I find that I get 1.1-1.5 SWR with all of my antennas when properly mounted with a ground plane. So if you have a perfectly acceptable 1.5SWR your power to the antenna is estimated to be 5.7 on that calculator.

The calculator doesn't take into account loss through connectors. There will be a little, there.

If you put a 5.1DBd antenna on there you would have an ERP of about 18.5, again minus a little for connectors.

[LeoG]

Yup, not accounting for connector losses and SWR.  But at the shop mine is about 1.04 so close enough to 1:1 to not worry about it.

[SteveShannon]

Measure SWR right at the antenna instead of at the radio to see what it really is. 

[LeoG]

My arms aren't long enough to reach the 40' up.

[SteveShannon]

4 minutes ago, LeoG said:

My arms aren't long enough to reach the 40' up.

Here’s why it’s important:

SWR is calculated based on the relationship between forward power and reflected power. Higher SWR by definition means higher reflected power relative to the forward power. 
When you measure it at the radio, you’re seeing all of the forward power, but you’re only seeing some of reflected power. So, measured at the radio you always see a lower SWR. 

One of my RigExpert analyzers has Bluetooth so we connected it directly to ann antenna before raising the antenna. We could see that SWR was 1.6:1.  Measuring at the radio end of the cable using the same analyzer the SWR was 1.1:1.  That was with 50 feet of M&P UltraFlex 10, which is as good as LMR 400. It was also at 2 meters where the cable performs even better than on GMRS. 

[Lscott]

19 hours ago, SteveShannon said:

SWR is calculated based on the relationship between forward power and reflected power. Higher SWR by definition means higher reflected power relative to the forward power. 
When you measure it at the radio, you’re seeing all of the forward power, but you’re only seeing some of reflected power. So, measured at the radio you always see a lower SWR. 

You can get a reasonable estimate for the SWR at the antenna end of the cable if you know the coax losses, from a chart of loss verses frequency for a known length of cable, and the forward and reflected power. You can calculate the loss for the exact cable length one is using at the frequency of interest. 

The cable loss allows one to calculate the power delivered to the antenna based on the forward power measured at the radio end. 

Also the reflected power measured at the radio end allows one to calculate the reflected power at the antenna end based on the cable losses.

With both the calculated forward and reflected power at the antenna end of the cable is now “known” it’s now possible to calculate the SWR of the antenna itself. This saves the trouble of having to stick the SWR meter up at the antenna, which in many cases isn’t a realistic possibility. While not likely as accurate as a real reading it’s better than nothing.

[LeoG]

So............   Is it worth it to go from M&P Airborne10 to Hyperflex13.  I have two applications.  1st is at home and will be with a 20watt transmitter with a 7.2dBi antenna.  2nd will be at my shop with a 7.8 watt RT97S with a 7.2dBi antenna.  The shop coax run might be 50' instead of 65'.  Cost isn't really a huge factor even though the cables are 2x the price from each other.  There are fittings to buy and have installed which tacks on another $50 and shipping for $20 or so, but is it really worth the 0.3dB?

What would you do?