Coaxial Cable: How Long Is Too Long?

Рет қаралды 13,396

Күн бұрын

Can Coaxial Cable Be Too Long? What Is The Best Size Battery For Portable Ham Radio? How Can You Increase The Bandwidth Of HamStick Antennas?
**Save 5% Off Messi & Paoloni at Gigaparts OR DIRECT FROM M&P with code K8MRD
~Gigaparts Link: www.gigaparts.com/nsearch/?lp...
~Messi & Paoloni Link: messi.it
**Save 15% off your Coax order at ABR Industries. Use code K8MRD at checkout.
abrind.com
Coax Loss Calculator: kv5r.com/ham-radio/coax-loss-...
Consider becoming a Patron @ / k8mrdradiostuff
Follow me on Twitter. / k8mrd
Links to many of the things I use can be found here:
www.amazon.com/shop/k8mrdradi...
As an Amazon Associate I earn from qualifying purchases.
Big Geek Battery Box, k8mrd.square.site
Watch the video here: • Big Geek 12V Ham Radio...
Tri-Lam BuddiStick Pro Counterpoise Support: k8mrd.square.site
K8MRD Radio Stuff Shirts:
Happy Skull Guy: grapevineamateurradio.com/col...
Tower of Terror: grapevineamateurradio.com/col...
Parks On The Air Merch (non affiliate) www.clubgearonline.com
Links to other stuff (affiliate where possible)
**Save 15% off your Coax order at ABR Industries. Use code K8MRD at checkout.
abrind.com
The SkyHook Portable Mast Antenna Mount (non affiliate)
www.thehamstop.com/
Use code K8MRDRADIO for 20% off
Save 5% Off At Gigaparts With Code K8MRD:
www.gigaparts.com/nsearch/?lp...
5% off Messi & Paoloni Coax
Use code K8MRD for 5% off.
messi.it. (or you can order from Gigaparts)
Signal Stuff Signal Stick Antennas:
BNC Antenna: signalstuff.com/super-elastic...
SMA Female Antenna: signalstuff.com/super-elastic...
SMA Male Antenna: signalstuff.com/super-elastic...
Signalstuff Antennas: signalstuff.com/?ref=4089
~~~$15 off most purchases over $65 at Radioddity:
radioddity.refr.cc/mikedahlhofer
#hamradio #k8mrd #parksontheair

Пікірлер: 68

@btaylor1948 Жыл бұрын

Thanks for responding to my POTA email. I gave you half the info though. They are on a mag mount on the hood of my truck since I have a fiberglass shell in the back. I did get 80m to Rez at 3860 with chokes on the coax. I added a 15 in. extension to the whip and got it to Rez at 3580 for digital and some cw. Still the bandwidth is small @ about 100kc for 2:1 or less. I will try your stake and short radial method for 40m and report back. Really want to keep things as compact as possible. Thanks for all your information. Bob WB6TIS

@user-xr5se2ib6g Жыл бұрын

mike from kb9vbr its a mad genius. he was my first ham video i ever watched

@Aimsport-video Жыл бұрын

Great info on Ah required. I built a 50Ah in that smaller gigaparts explorer battery box (after I found a short enough battery lol) with genasun controller and measured consumption Buddipole Powermini2 matches your data. Great videos.

@dougdaniels Жыл бұрын

Coax length can depend on what antenna you are using. While shorter is usually better, it is recommended by some (including the TennTenna designer) that 50' is the sweet spot for EFHW antennas, as it acts as it's own counterpoise.

@N2YTA Жыл бұрын

I've seen several end fed antennas that had minimum recommended coax lengths. The braid acts as a counterpoise.

@danikl.st-amour8385 Жыл бұрын

Thanks for sharing your knowledge, always great content. PS. 👍on the Armalite style antena in the background lol😂

@hamradiotube Жыл бұрын

Ha, yeah that's just a .22LR. Neat for plinking.

@rftech1608 Жыл бұрын

Great video Mike, you look very happy these days! 73s Don

@hazratmuhazmat8831 Жыл бұрын

It just needs to be long enough to reach your antenna.

@geod3589 Жыл бұрын

you beat me to it lol

@washingtonstatepicker3460 Жыл бұрын

Yup

@chrisnmichelle0218 Жыл бұрын

Custom built my own 42ah lifepo4 battery with a Daly bms that has Bluetooth so I can watch my usage on my phone, throw out 200 watts of solar power and I can run my Dx-10, tablet plugged in, and a desktop fan without any issues all day even with overcast. Battery is mounted in ammo can, works amazing and love being able to see real time draw and remaining capacity on the battery from my phone.

@hamradiotube Жыл бұрын

Oh yeah, that'll do it. I've got a Daly BMS on my 10AH that I built years ago. Don't have all that fancy bluetooth stuff though.

@chrisnmichelle0218 Жыл бұрын

@K8MRD real time readings make all the difference, no guessing on remaining power 😉

@GreggK6EGG Жыл бұрын

hey mike i went from 100ft of RG8X to 90ft of LMR400, I noticed a pretty big differences, less RFI in the shack more power to the end of the coax

@hamradiotube Жыл бұрын

Oh for sure, LMR-400 is like 9 billion times better than RG8X.

@Macrosill Жыл бұрын

@@hamradiotube Inconceivable!

@orlandostevenson7214 Жыл бұрын

Hi - just jumped on.. buying pieces and planning to get my used IC-7300 with MFJ tuner setup on long wire (running 100w).. 10-160meter and purchased 100ft coax to help it tune vs adding counterpoise. I have no tower or tree, just fence and house.. might try the gutter too :) 73s K90S

@kd5you1 Жыл бұрын

The thing about coax and coax loss is that the incoming signal is going to be much weaker than the outgoing signal, so you could lose any incoming signal before the outgoing signal is completely lost. Also part of the coax length is used on the tower itself, and there is a good reason why Hexliax or hardline is used on long coaxial cable runs. :) Obviously for portable use no one would need to make a very long run of coax, but in the end it all depends on whether contacts can be made with a given setup. This is a really great video & lots of great content! 73 KD5YOU

@donfritto-iu8mm 5 ай бұрын

on a long run it is the opposite unless you using something like LMR 400 at like 100 feet of coax it has almost no losss!!! people complain they lose modulation on longer runs with other coax like rg8 or 58

@kevingaukel4950 Жыл бұрын

I have a 40 Amp-Hour Battery, and I did 100W CW for hours. It was overkill, but I'm very happy with it. Did a 6 hour solo Field Day/POTA activation and it was great.

@hamradiotube Жыл бұрын

Better to have it and not need it. I've never ran my 30aH down in the field but it's comforting to know I have the capacity.

@rafaelgcpp Жыл бұрын

Awesome t-shirt Mike!

@hamradiotube Жыл бұрын

Baby-Ruth!

@j.p.thearmoredchef 3 ай бұрын

Yes. Here’s how you fix the bandwidth on your ham stick. It’s a mod called the DX Commander with an 80m 1/4 wave inverted L😂 I get the entire band without an external tuner. Oh. And it gets you everything else up 2m (or at least 10m which you will have to pick a portion of that giant band)

@robertmeyer4744 Жыл бұрын

interesting. wire mesh from home depot or so . works with long wire antenna either end fed 1/2 wave or random length . just roll it out put some blocks on it. clip to counterpoise on antenna .also I found it helps with noise floor . with battery I say how big can you bring ? leave the lead battery home. I bring a few LiFePO4 ones with me. run laptops charge phone. re charge HT . run led lights . recharge drowne .keep camcorder going. ETC . I make coffee ,RV coffee pot. powerqueen LiFePO4 50Ah is great for IC 7300. what I use. 73's

@ahoward2kable Жыл бұрын

I use my 7300 for POTA and I have great luck with a 15ah. I have 2 but I've never run one all the way down in my activations

@KC2BKM Жыл бұрын

Bioenno has a nifty handy dandy chart on their website to give you a basic idea of the load vs time for their batteries. I went with the 20 amp hr.

@unwin42 Жыл бұрын

Metal screen is the Hot Girl Summer counterpoise of 2023.

@hamradiotube Жыл бұрын

haha!

@n0vty873 Жыл бұрын

2 hamsticks for same band as radiating elements can increase band width

@johnclark2149 Жыл бұрын

I tried chicken wire and construction cloth and when it starts to rust you can hear it corroding when the ground is moist.

@davenewmyer3735 Жыл бұрын

At some point, 250 ft or greater, you might want to look at 600ohm balanced feeders as an alternative to coax.

@lyfandeth Жыл бұрын

I keep 100x of cable in my go kit. I know it is unlikely I will need more to use an antenna outside of a shelter, but if I'm lucky I know 50' of cable will be enough. Instead of worrying about which choice, I carry two 50' runs and join them with a double female connector if needed. More importantly, carry a couple of rubber door wedges to prevent the foam from being crushed in doorways. And some bright gaffers tape for trip hazards.

@aa3konthego Жыл бұрын

When I first looked at LiFePO batteries I wondered if the 16 Ah I saw was going to be enough for a 100 W SSB activation. It is more than enough! The laptop's battery taps out at about 2.5 hours and the 16 Ah LiFePO still has easily another 2.5 hours and probably more.

@ChuckBigbie Жыл бұрын

Ground the ecm on the cummins ecm unit

@BLACKHEAT1028 Жыл бұрын

Any Biker knows the destination is the excuse for the ride, field day is the excuse to get together and play just a little radio. If you have no choice but to have a long run then buying good coax and an amp help say 500 watts should help compensate

@ronlewis6394 3 ай бұрын

Looking to use a

@bigchew3149 Жыл бұрын

i would be Curious to What Coax You Would run on HF 100ft MAX But Probably 75ish ft is about what i need..I run M&P Ultraflex 10 Sahara For my VHF/UHF @ 65ft But i am getting Redy to start HF & i am just doing my homework so to speak ! I Was Thinking About 213 or ultraflex 7 but i still dono but them 2 are on my short list

@wesKEVQJ Жыл бұрын

They sell what they call Faraday fabric, they are advertising it as a conductive material that shields wifi, cellular and gps. I am assuming the screen reflects wavelengths larger than the mesh size of the material. Anyway that might be more convenient than a window screen to fold up and stow. I wanted to ask this, is it a better idea to put a usb dongle right on the antenna and use usb cable? Is it easier if you want to do a long run to the antenna to use usb repeaters than an amplifier for the coax like the cable tv companies use? I am new to the hobby and I am leaning toward sdr for reception.

@giulianoggg2035 4 ай бұрын

I have a G5RV full size, how long does the coax have to be? is there a minimum or maximum suggested? should I use a Balun? many Thanks

@AlvinMcManus 11 ай бұрын

More counterpoise! Is that like more radials (in number) on a DX Commander antenna? Similar yes, but not exactly the same.

@TheRetiredtech Жыл бұрын

The better the ground plane the higher the Q. The only way to increase band width is to add loss some way but that isn't a good idea.

@NICKENAQ Жыл бұрын

i saw your video about the GPS dongle i cant get that one in the UK

@hamradiotube Жыл бұрын

Really? At all? That sucks.

@richarde735 10 ай бұрын

if you need a counterpoise for a mobile, connect a 25 foot extension cord and let it dangle it out of the trunk going down the road 👍

@jerryKB2GCG Жыл бұрын

Will counterpoises help if it’s a mag mount on my car?

@hamradiotube Жыл бұрын

I can't see it not helping though I've never tried counterpoise on the car.

@btaylor1948 Жыл бұрын

@@hamradiotube how would you connect the counterpoise with a mag mount. String them out under the mag mount?

@jerryKB2GCG Жыл бұрын

should one coil the extra coax or “snake” it?

@hamradiotube Жыл бұрын

It really doesn't make any bit of difference, though you would gain the added benefit of creating somewhat of a choke if you coil it.

@jonthebru Жыл бұрын

Taking it to extreme again! Why not give a practical run, maybe 200 ft.

@hamradiotube Жыл бұрын

That wasn't the question.

@mine99759 Жыл бұрын

I love the goonies shirt

@hamradiotube Жыл бұрын

Hey you guys!!!!

@johnclark2149 Жыл бұрын

Ahhhh, the age old question…. 😂 How long is too long….

@Kody10538 Жыл бұрын

So what I've learned today...is I can run a kW a mile up a to a tower on top a mountain and still have 900 watts to spare lol

@Mr4Brown Жыл бұрын

That's what she said.

@jakep5121 Жыл бұрын

I like using 2 -12 AH. Then I know exactly when I'm half way out of battery. I almost never use the 2nd one. but I'm not all that hardcore. most pota contacts (SSB) was like 30. so there ya go. ya comment readers.

@truckinguy92 Жыл бұрын

No matter what you do you’re never going to gain a worthwhile bandwidth increase on 80m with a ham stick. Even with a dipole you don’t get a whole lot of bandwidth. I get 4 hours with a 15aH Bioenno and 8 hours with a 30aH doing SSB @100W.

@willian.direction6740 Жыл бұрын

If the ham of 60 yrs wants to operate POTA on 80m tune the antenna to the frequency he wants to operate on and stay there he will be the one calling CQ. I use 3.680 on SOTA the best VSWR depends a bit on the ground or mounting position on different summits but is usually ok. Spot my activation on SW3 and call on 3.680 on either SSB or CW, the Chasers have a bit more flexibility with their antennas usually.

@btaylor1948 Жыл бұрын

POTA is not the priority for 80m. I am part of a EmCom group with people I know in CA and OR. Our schedules are around 3680 after grey line. I would like to start using my POTA go box to start hooking up with them instead of the base just as a POC.