i got a nagoya 771 antenna will this make a big difference in transmit power? these radios are nee 358 off ebay and also fdy off ebay both uhf 5 watt.
also is there a cannel you can test distance on?
What country are you in? First, we need that, plus more detail on the exact model number of radio you have.
Then we need to determine if the radios you have are legal in your country. Also, is a license required, and do you have one if so.
I found these radios… totally illegal for use in the USA. Nonetheless. no antenna will improve your transmit power…
Insofar as range, a better antenna can help.
Looking at your antenna, I see it is a dual band antenna. As such, it “compromises” between VHF and UHF… as such… performance will suffer, compared to a single-band antenna.
I have used 5 watt uhf radiios… I have onw for amateur use. I can tell you honestly, do not expect point to point (hand held) communications over 3 miles or so…
If you are talking to a base station, then this performance increases greatly.
The height of the antenna is the answer.
My hand held will make ot over 10 miles if the receiving antenna is 200 feet up. If it is 6 feet up… 2 or 3 miles.
Hope this helps
hello thanks fr the input, i did a little test with these nagoya arials on and got 3 miles my wife had one in the house and i was in a car. i kept losing signal as i went downhills this was expected, but clearly we both comunicated at three mile, i used google earth to gain a line of sight to give me distance, however i aint tried it with the little stubby ones i got with them, i am using them for flying so i am assuming 10 mile should be fine?? as no obstructions?
what arial would you recomend that are solely uhf which are the best for hand helds? i read on some forum the nagoya duel band is a great ones and greatly increased range which is why i bought them, but i understand the compromise in both vhf and uhf, so need to know which is best to buy,
i fly micro light and have lincences relevant for airband, but i am not in to radios so ariela and such i dont know about, these radios are for a different form of flying which involves hand held to hand held, no base station involved, regarding the licence for these there isnt an issue with gaining the apropriate licence but this will be once i find the range and clarity i need, i am presently testing these rather than uhf as i was made to believe the distance is further line of sight on these
hello again just trying to get a thorough understandin , ya mention arials wont make much difference?? how can this be when the higher the db the further the signal will travel? apparently power only plays a part the biggest factor is arial so i have read, so what i am wondering is can i get the highest gain possible for my hand held, i am using a nagoyya 771 3db gain it is claimed, but this arial is uhf vhf, so i need one which wont compromise the signal, uhf only with the highest gain possible?? can someone recomend?/
hello no one know an answer then? i would have thought you boys would know
Hi there-
keep in mind in USA this is a big holiday time so forum traffic is of course reduced.
antenna gain (dB) and transmitter power (watts) both work together to create a stronger signal. A bigger antenna will also help you on the other end, receiving the signal.
And in terms of the radiated signal power, a better antenna DOES make a bigger difference than transmit power.
The problem is, once you get to a certain distance your problem becomes the local geography, not signal strength. You could be running 50 watts into a ten foot long perfectly resonant antenna, and that wouldn’t help you if there is geography between you and the other guy.
This is also how the consumer radios get their absurd ‘23 miles’ range numbers- if you have perfect line of sight, 5 watts into a half decent antenna will work (somewhat) at 23 miles. I’ve seen it happen- two guys on the roofs of tall buildings could talk to each other at ~25 miles running 5 watt radios.
However for average use, you won’t be ~200 feet in the air, you’ll be on the ground. And when you’re on the ground, small changes in terrain affect you. even small hills will get in your line of sight and block your signal.
Now this isn’t to say that more power or better antennas do nothing. They do increase the strength of your signal, so if conditions are marginal but not completely blocked they will make a difference.
Now as for flying, airband (in the USA at least) is around 108-137MHz, well below the UHF band. For this you’ll want a VHF antenna specifically designed for airband use.
Now if I’m getting you right, you are a pilot and are personally flying (IE not remote control flying) what we’d (USA) call an ultralight aircraft and want something to communicate with your flying buddies. I’d suggest you should use your airband radio for this, unless you specifically want to keep it OFF the airband.
If that’s the case, the antenna and radio you have should be quite sufficient- since you’ll be in the air, geography isn’t an issue. What you have should (in the air) go for at least ~20-25 miles, probably more. The only real way to figure that out is to test it in the air.
If you still need more range, you’ll want to switch to mobile (not portable) radios. Mobile radios are larger, heavier, and require an external 12v power supply- they are designed to be mounted in a car, not carried on a person. However a mobile radio (depending on which radio you get) can put out up to around ~50 watts, which (when fed into a good antenna) should take your signal for maybe 50-100 miles, maybe more. Note that if you go this route, you’ll have to make sure your aircraft is capable of putting out the required power, and more importantly you’ll have to make sure you have EXACTLY the right antenna.
An antenna is ‘tuned’ for a particular frequency, the farther away from that you get, the more of the RF energy bounces off the antenna and is fed back into the transmitter (this is called SWR or Standing Wave Ratio). At small power levels (2-5w of portable radios) this isn’t as much of a problem, but at higher power levels you have to be careful, as a high SWR can damage the radio. Thus you must get an antenna designed for the specific band you’ll be in, IE your transmit frequencies must fall within the antenna’s rated frequency range (not be ‘close to it’).
Hope that helps…
yes brilliantly explained thankyou. what i am flying is what is known here as a paramotor, paratrike in usa, but no room for a heavy 12v supply, but if these radios with the antenna i got will do 25 mile then i am happy with that, just one curious thing i have whizzin around is , is there a anntenna any stronger than the one i have on my radios? that is solely uhf? if not its no prob as i think the range of what is said is plenty.
Ah yes, I think we are starting to understand each other better 
From what I understand of your aircraft, it’s basically a go kart with a lawn mower engine and propeller hanging underneath a parafoil type parachute.
Does it have any 12v generator from the engine at all? If so you can use that- even if the generator doesn’t put out 50w of power. Get a mobile radio and a small 12v battery (the type used for alarm systems or motorcycles will do nicely), and just wire them all up together. The battery will supply the extra power needed for transmitting, and be charged when you aren’t transmitting, it acts sort of like a buffer. This all won’t weigh much (maybe about 10 pounds / 5 kilograms) and when combined with a proper mobile-type antenna will give you excellent range (25 miles minimum thru open air, most likely quite a bit more).
With a good 5w portable (handheld battery power) radio and a good antenna you should get about 20-25 miles range but you’d really have to test that in the air.
I’ve been trying to find this ‘nee 358’ radio to figure out what frequency it transmits on so I can see if the antenna will work. As a general rule, antennas will have a rated frequency range, you’re only going to get the stated dB gain inside that range because outside you start to lose more power due to SWR and such.
What frequencies are you using? Let me know this and I can get you a better answer…
hello the frequenzies are 440 up to 470 uhf
if it helps the radios are fda 450, and a nee 358 both uhf
Remember that an antenna will not help you if your problem is interference. It will just pick up more interference. Of course it may help you to pick up specific frequencies better. Just pointing out that a better antenna is only an improvement in a specific environment.