Best coax feedline for Ed Fong vertical Dipole 2m-70cm. I will be running about 80 feet
- Thread starter K4MKF
- Start date
kayn1n32008
ØÆSØ Say it, say 'ENCRYPTION'
Find a coax loss chart, the smaller the loss per 100 feet of coax @450MHz, the better.
The 'best' is going to be the lowest loss feedline you can afford.
The 'best' is going to be the lowest loss feedline you can afford.
devicelab
Whacker Extraordinaire
100ft of Times Microwave LMR240 will be a good choice -- as long as you're using lower power. Should be fine up to 400w.
What? There is around 5dB loss in 80ft of LMR240 at 70cm.
devicelab
Whacker Extraordinaire
And?? He's putting up a HAM antenna. Yes LMR400 is better but it's twice as thick and heavier.
So then why not RG-174? It’s even smaller and lighter. And even more loss. I imagine you don’t do many antenna installations for other people.
@K4MKF - 100’ of LMR-240 will lose 70% signal on both TX and RX. 80’ of LMR-400 has 40% loss. An antenna with “gain“ will help to make up for losses. I encourage you to compare that Ed Fong antenna to any other amateur dual band antenna, like a Diamond X50 or better.
Also remember when you are reviewing gain numbers that 2.15 dBi = 0 dBd. Thus, 5.15 dBi = 3 dBd. If the antenna mfg. uses (dB) they are probably referring to dBi in order to show a higher gain number...if you trust their numbers.
Also remember when you are reviewing gain numbers that 2.15 dBi = 0 dBd. Thus, 5.15 dBi = 3 dBd. If the antenna mfg. uses (dB) they are probably referring to dBi in order to show a higher gain number...if you trust their numbers.
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Ubbe
Member
I'm trying to find any dipoles by him but only see j-poles. But anyhow both antenna types are balanced antennas and coax are unbalanced so be sure that you use a balun or the whole coax will work as an antenna.
/Ubbe
Firth I'd throw the antenna in the trash then buy good cable and a real antenna...
Blackswan73
Active Member
His antennas are made by students. They are based on a J pole design and have built in matching stubs. He has two basic models, but they are basically the same. Just the permanent ones are designed to be put in a PVC pipe, 3:4” if I remember correctly
B.S.
B.S.
Belden 8214, 9913
80ft is quite long for
LMR400 has replaced those in most cases with lower loss and 9913 is notorious for filling up with water in the air dielectric.
