Mini COAX - Is It Limiting Your Portable Radio Operating?

[@VE6LK]

Mark, you've concisely explained a difficult concept around how much power actually makes it to the antenna. Bravo!

[@aa3konthego]

@@VE6LK Thank you for the complement and watching. And I'm really enjoying finding out all of Rig Expert's capabilities.

[@billryland6199]

I use RG-8X for portable ops. You don't want to lose most of your signal in lossy coax. Using BNC connectors saves some weight.

[@EvanK2EJT]

Overall, a well thought out video and I agree with your assessment. If I'm going to be operating near my vehicle, I generally run 50' of ABR 281XATC. Hiking in though? Definitely RG316 with BNC connectors. The longest section I have is 30'. I normally use 25' or 15' though. If I'm hiking up to a mountain top do a SOTA activation, every ounce is probably going to make a difference. In real world use, I get insane pileups on 5w or less, even with compromised antennas and lossy coax. That being said, if band conditions are lousy (like they have been lately) squeezing every bit if power out of the rig and into the antenna helps, and using good coax will most definitely make a difference.

[@aa3konthego]

@@EvanK2EJT Thank you for watching Evan! My QRP backpack is way too heavy and I need to look at trimming it down as I'm thinking of a POTA-Pseudo SOTA activation. It's probably close to a mile hike on a well defined trail but a mile up hill is a mile up hill!

[@EvanK2EJT]

@@aa3konthego You should be able to get it pretty light. My entire pack, including food, water, enough stuff to spend the night if I get stuck during warm weather, and my entire radio kit comes in around 10-12lbs

[@BikingHikingRadio]

Nice review. I use RG 174 as you saw last month, but I only use 20 ft. Since in my mind POTA and SOTA is portable operating, so I don't carry RG 8X, it takes up too much space in the pack and heavier. 72 Scott

[@aa3konthego]

@@BikingHikingRadio I have a 20 foot pre-made length of 316 which will cut the losses in half but I do rely on the coax to be the counterpoise. I'll need to pop it on a EFHW and see how the tuning goes. The RigExpert makes that so easy!

[@timg5tm941]

Good quality rg58 is fine into a resonant antenna throughout HF. RG174 into a dipole or resonant vertical is ok from 40m band and below with a 50ft run.

[@garycowger9579]

I run RG-6 75ohm on My QRP and worked very well for Me and have WAS, Master of Europe and other Awards As long as you have a resident antenna the coax doesn't affect it that much, I have found that out.

[@aa3konthego]

@@garycowger9579 interesting. Have you ever compared SWR and/performance between 50 & 75 ohm coax?

[@garycowger9579]

@@aa3konthego Yes and there was not much Difference between the 75 ohm and the 50 ohm with SWR I use a QRP tuner from MFJ and it works out very well a matter of fact with the 75 ohm I can use universal adapters to connect to the QRP rigs Wherewith the 50 ohm cable you can only use a limited amount of adapters and 75 ohm on cable is everywhere all the hardware stores carry it and all your TV manufacturing stores carry it that's the reason why I use 75 ohm cable

[@aa3konthego]

@@garycowger9579 and with cable going to higher frequencies, much of the 75 Ohm stuff is quad shielded. Also useful for runs from satellite dishes.

[@samallan6616]

Nothing wrong with RG-6 and RG-11 for HF work as long as you avoid the CATV stuff if you plan to solder it. I have cables using real honest RG-6 and RG-11 with all copper braids which is easy to put a PL-259 on. They are used on my flat-top dipoles since 75-ohm coax matches to the antennas better than 50-ohm coax does. 75-ohm coax was used by hams long before 50-ohm coax became the norm. If you look hard enough, you can still find old SWR meters designed for 75-ohms. I have one you can switch between 50 and 75 ohms. 73!

[@vladtepes481]

In my opinion, there is no reason for a 50ft length of RG-174 to exist particularly when running QRP into an inefficient antenna. I use about 25 ft of LMR 240. For SOTA on the low bands maybe 10ft or less of RG174 would be OK. Generally I use LMR 400 or equivalent on HF through VHF. I got a little over 200 QSOs on Field Day running 5 watts. Worked HI too from WPA.

[@aa3konthego]

@@vladtepes481 I've often used the whole 50 ft when the best antenna location is not cooperative with the shady spot to operate from. And it's my counterpoise where for 40m you need about 33 feet. You can get away with less especially with good ground conductivity.

[@mikemcdonald5147]

LMR400 the world!!!! LOL. I use that for most stuff because I want the best amount that I can afford.

[@aa3konthego]

It is good stuff and I use it at home to my tri-bander beam.

[@toddlafon4700]

YES !

[@williamkizer3445]

Ultra flex 7

[@aa3konthego]

@@williamkizer3445 I looked at the specs for that and see that it is similar to POTA-Flex 7 but not as heavily built. The POTA-Flex 7 build is sturdy but also springy when rolling it up. Unless you maintain some tension, the first coils want to jump off the reel.

[@Philip-KA4KOE]

RG-316 is just hard to handle.

[@kk6onl]

wat? how so?

[@Philip-KA4KOE]

​@kk6onl wants to kink very easily even though I roll up using over/under method.

[@aa3konthego]

The over/under method may be better suited to the RG-174. It has the stiffness of wet spaghetti and as I mentioned, I do find it getting tangled. The RG-316 is just stiff enough that I roll it up and unroll it out with little if any issues. Thank you all for watching!

[@kk6onl]

@@Philip-KA4KOE ohh ok, want thinking that way...

[@moselblues8694]

One S-Step is still 6dB so don't take it so serious😂

[@bob-N4REE]

Sez the guy who runs ??? watts. One S-level often means the difference of actually being heard or not.