POTA Question

[SteveShannon]

2 hours ago, TNFrank said:

What about 2M? I was under the impression that RG8x gave less signal loss across all frequencies. I'm still learning this stuff though.  What would be better then, RG58?  Also, I know shorter is better but I wanted enough length to get the antenna out and away from any tables I'd be sitting at. 

Losses through any coax go up as the frequency goes up. RG-58 is terrible for UHF. RG8x is better than RG58 but still poor compared to something like LMR400.  Each person must calculate what the actual losses will be and decide whether they can afford that amount of losses. What’s worse, the losses are expressed in decibels which can be confusing until you become familiar. A loss of 3 decibels means you lost 50%.  A loss of 6 decibels means you lost 75%.  
Every coax company has charts that show us how much loss they have at a particular frequency, usually for 100 feet or 100 meters. Be careful not to compare the two. A meter is more than three feet. 

Losses increase with length as well but that’s a linear relationship: twice as long equals twice the losses if the frequency is the same.

Most of us find a calculator online to calculate the losses at the exact frequency and length of the type of cable you’re looking at. Just google “coax loss calculator“ and you’ll find one. This is the most common one:

https://kv5r.com/ham-radio/coax-loss-calculator/

 

[TNFrank]

LOL, test questions, yep, I know. A lot of stuff I learned in Tech School at DeVry is coming in handy now. Also, that's one reason I'm sticking at 2M, it's the lowest my radio will do and there's quite a few repeaters here for 2M. I'll need to see just how far from the tripod I'll actually be and see how close I can cut the distance. 

 

[TNFrank]

https://www.amazon.com/MOOKEERF-KMR400-PL259-Male-Cable/dp/B094D3DFG3

There's also a KMR400 cable too.

[SteveShannon]

5 minutes ago, TNFrank said:

https://www.amazon.com/MOOKEERF-KMR400-PL259-Male-Cable/dp/B094D3DFG3

There's also a KMR400 cable too.

Personally I wouldn’t use either one of those. I would buy a better known brand such as ABR, M&P, DX Engineering, Times-Microwave, Belden, etc. The way to make certain you’re getting a quality product is to buy from a vendor you trust to provide quality products. If you buy an unknown cable from an unknown vendor on Amazon you’re completely responsible for assessing the quality. 

[WRUU653]

2 hours ago, SteveShannon said:

Personally I wouldn’t use either one of those. I would buy a better known brand such as ABR, M&P, DX Engineering, Times-Microwave, Belden, etc. The way to make certain you’re getting a quality product is to buy from a vendor you trust to provide quality products. If you buy an unknown cable from an unknown vendor on Amazon you’re completely responsible for assessing the quality. 

This ^^^ 

I would add also that a lot of people assume Amazon will be the cheapest but many things like radios, cable, antennas, and other things you’ll find are less from places like DX Engineering, Ham Radio Outlet, Gigaparts… it’s definitely worth shopping around and comparing from reputable places.  Make sure you factor shipping cost though but sometimes you’ll find what you want is cheaper at one place over two or three others for whatever reason and it doesn’t always seem to be the same place that’s cheaper… just my two cents, that I saved lol. 

[Davichko5650]

On 4/7/2025 at 10:05 AM, SteveShannon said:

And Walmarts on the air!  

The best is still John Kruk of Yaesu's PPOTA. Porta Potties OTA. He has cups and T-Shirts etc. that he hands out to in person visitors at Ham Fests.

[Davichko5650]

Somehow posted the PPOTA reply twice.

[WRYZ926]

13 hours ago, TNFrank said:

What about 2M? I was under the impression that RG8x gave less signal loss across all frequencies. I'm still learning this stuff though.  What would be better then, RG58?  Also, I know shorter is better but I wanted enough length to get the antenna out and away from any tables I'd be sitting at. 

You will not see any loss or gain on 2m using 25 feet of RG8X. You will see a loss of 1-2 watts ERP (output at the antenna) using 25 feet of RG58. You would be okay with either coax as long as you stay at 35 feet or less. This was figured using an antenna with only 1 dB of gain. The more gain the antenna has the higher the ERP will be.

The https://kv5r.com/ham-radio/coax-loss-calculator/ is an excellent source to figure out line loss with the different types of coax.

Using any type of portable J pole or similar antenna up high will help extend your range when using a hand held radio. I have built a 2m j pole using faraday cloth and getting it up at 20-25 feet above the ground made a vast improvement. I can get into the local 2m repeater that's 22.5 miles away with a 5 watt HT but there is some noise on my transmission. I was told that I sounded like I was on my base radio when using the same HT connected to the faraday j pole. 

[TNFrank]

Awesome link, thanks. Looks like LMR-400 would work well. At 220MHz and 20ft@10W I'd only get a 26% power loss so I'd still be putting out over 7W of power. 

[WRXB215]

10 hours ago, Davichko5650 said:

The best is still John Kruk of Yaesu's PPOTA. Porta Potties OTA. He has cups and T-Shirts etc. that he hands out to in person visitors at Ham Fests.

LOL!!! And here I thought "Patio On The Air" was funny.

[Northcutt114]

Can someone explain to me the purpose of POTA? I've been watching Mike on Ham Radio Tube and he's had several videos up where he is using various objects as antennas for his G90. I understand that there are "hunters" and "activators" and that the goal is for the activator to go into a park of some sort and get a certain amount of contacts in a certain amount of time and then that is plotted into an app of some sort?

Simple question, is this just for the gamesmanship of saying "I can do it!" and it's something HAM guys do for fun? Or is there a broader sense to it in that they creating a map whereby other HAM people will know that contact can be made from this location to that location? And in that regard is it prep for a grid down situation? Or am I reading too much into it? I've been all over their website and still don't really "get it."

 

[hxpx]

1 hour ago, Northcutt114 said:

Can someone explain to me the purpose of POTA? I've been watching Mike on Ham Radio Tube and he's had several videos up where he is using various objects as antennas for his G90. I understand that there are "hunters" and "activators" and that the goal is for the activator to go into a park of some sort and get a certain amount of contacts in a certain amount of time and then that is plotted into an app of some sort?

Simple question, is this just for the gamesmanship of saying "I can do it!" and it's something HAM guys do for fun? Or is there a broader sense to it in that they creating a map whereby other HAM people will know that contact can be made from this location to that location? And in that regard is it prep for a grid down situation? Or am I reading too much into it? I've been all over their website and still don't really "get it."

 

I don't have a POTA rig, but there seems to be two purposes:

1. You get to operate your mobile radio away from a permanent location so if you're into emergency or off-the-grid communication, this is gamified practice.

2. Playing with radios outside is more fun than playing with radios inside.*

*weather permitting

[Northcutt114]

23 minutes ago, hxpx said:

I don't have a POTA rig, but there seems to be two purposes:

1. You get to operate your mobile radio away from a permanent location so if you're into emergency or off-the-grid communication, this is gamified practice.

2. Playing with radios outside is more fun than playing with radios inside.*

*weather permitting

OK, so it's about what I thought. Do you have any insight into the "app" they use? 

[WRYZ926]

1 hour ago, Northcutt114 said:

Can someone explain to me the purpose of POTA? I've been watching Mike on Ham Radio Tube and he's had several videos up where he is using various objects as antennas for his G90. I understand that there are "hunters" and "activators" and that the goal is for the activator to go into a park of some sort and get a certain amount of contacts in a certain amount of time and then that is plotted into an app of some sort?

Simple question, is this just for the gamesmanship of saying "I can do it!" and it's something HAM guys do for fun? Or is there a broader sense to it in that they creating a map whereby other HAM people will know that contact can be made from this location to that location? And in that regard is it prep for a grid down situation? Or am I reading too much into it? I've been all over their website and still don't really "get it."

 

All of the above.

POTA allow one to enjoy the outdoors while being on the air at the same time. One benefit is that those living in noisy RF environments can get away from all the noise by going to a park.

Some will take a 100 watt radio and some will even take amplifiers. Others like using QRP radios (10 watts or less) to see how far away they can be heard and make contacts. I like using my 20 watt Xiegu G90 and keeping my antennas light and simple.

Mostly it is a way to get out of the house and have fun.

[WSEZ864]

10 hours ago, TNFrank said:

Awesome link, thanks. Looks like LMR-400 would work well. At 220MHz and 20ft@10W I'd only get a 26% power loss so I'd still be putting out over 7W of power. 

LMR-400 is an excellent VHF/UHF cable, but has a solid center conductor and is very stiff. LMR-400 should not be unrolled/rerolled/bent/unbent very much due to damaging the dielectric. A better choice for portable with similar loss figures is LMR-400 Ultra-Flex, which has a stranded center conductor which tolerates handling much better.

I use LMR-400 for my base/home installations (even HF) and LMR-400 UF for temporary/portable/mobile use like Field Day setups, etc..

[Northcutt114]

1 hour ago, WRYZ926 said:

All of the above.

POTA allow one to enjoy the outdoors while being on the air at the same time. One benefit is that those living in noisy RF environments can get away from all the noise by going to a park.

Some will take a 100 watt radio and some will even take amplifiers. Others like using QRP radios (10 watts or less) to see how far away they can be heard and make contacts. I like using my 20 watt Xiegu G90 and keeping my antennas light and simple.

Mostly it is a way to get out of the house and have fun.

As someone whose end goal is to RV full time in retirement, I feel like this might be my focus when I enter the world of HAM. I appreciate the insight.

 

[WRXB215]

@Northcutt114 if you're not against climbing some hills, you might also look into SOTA, Summits On The Air.

I don't have a portable rig yet but I just ordered a QCX-mini today. I'm hoping to do some SOTA this fall when I go out to west Texas. It appears that there is 5 summits on the ranch where I go.

[hxpx]

2 hours ago, Northcutt114 said:

OK, so it's about what I thought. Do you have any insight into the "app" they use? 

Hopefully someone who's done POTA activations can chime in with the software side of things. I know of pota.app which lets you spot activators (report their location and frequency so others can try to contact them) but AFAIK logging is done with whatever software you want as long as it outputs ADIF.

I've used kiwisdr to listen in on activations. Sounds fun.

[WRYZ926]

I use the HAMRS app for logging my POTA contacts. HAMRS will automatically upload my POTA logs to the POTA website and to my QRZ logbook. I log into the POTA website to spot myself along with see sign who else is working POTA. I try to work park to park as much as possible. And I will answer POTA stations when at home to help them active the parks.

[Davichko5650]

14 hours ago, WRXB215 said:

LOL!!! And here I thought "Patio On The Air" was funny.

I did tell JK that if he heads down under, he could work it as PLOTA Porta-Loo OTA...

[TNFrank]

RG-8x seems to be pretty good especially if I keep it at 10 feet.

 

[Northcutt114]

18 hours ago, WRXB215 said:

@Northcutt114 if you're not against climbing some hills, you might also look into SOTA, Summits On The Air.

I don't have a portable rig yet but I just ordered a QCX-mini today. I'm hoping to do some SOTA this fall when I go out to west Texas. It appears that there is 5 summits on the ranch where I go.

I appreciate the sentiment, however this ole boy is done summiting. I spent the better part of my early 20's on the Appalachain Trail and a large portion before and after that climbing. I'm more looking for Beaches and Plains on the Air at this point. 

[Northcutt114]

18 hours ago, WRYZ926 said:

I use the HAMRS app for logging my POTA contacts. HAMRS will automatically upload my POTA logs to the POTA website and to my QRZ logbook. I log into the POTA website to spot myself along with see sign who else is working POTA. I try to work park to park as much as possible. And I will answer POTA stations when at home to help them active the parks.

I watched an HRCC video last night and he talked about HAMRS. Thanks for the info.

You mentioned "park to park." I've overheard Mike on Ham Tube Radio use that language to. The idea being that you aren't talking to a base station in someone's home? Helping activate from another park is preferable than getting a contact from someone at home? Is that the gist?