Should I use more Power on VHF or UHF? (
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- Опубликовано: 13 сен 2024
- Andy, KC3SRU, is currently living on a second floor, in a wooden house, with neighbors he doesn't want to upset, and he is using a 18" pizza pan as a ground plane with a mobile antenna. Quite the situation. He asks, "Is there or what would be the maximum PEP at the antenna [that] would not interfere and keep me a good neighbor?"
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Like OG said, if you’re hitting the target repeater then you don’t need more power. On 70cm you’ll bleed into you and your neighbors electronics, even at low power, and even with your antenna outside. Your kind of limited in an apartment dwelling but do with what you have. You can also find an echolink repeater in the area and talk all over the world. You can also test your audio on an echolink repeater ex: tx on HT and rx on your mobile app to hear yourself. It also helps to ground your HT and it’ll make your antenna more efficient. Use the screw that holds the belt clip in place. You can google how to ground your HT. Good luck and welcome to the ham community. OG is a very informative channel you’ll learn a lot from him as I did when I was new.
On VHF and above height, to clear obstructions and obtain line of sight, is everything. If you can't access the roof. raising the antenna with a telescopic painters pole or such tied to the railing will improve distance and reduce RFI.
I have mine on a 20-foot pole that itself is mounted 15 feet up in a birch tree!
Great video.
Sir,please tell me,which one best bands vhf or uhf,for the TV
Tim Taylor: "More power!"
The trouble I have is that my buddies all have dual band radios and I have a VHF only. So their antennas are not as tuned to VHF due to some sacrifice to UHF. I must talk them into having a VHF tuned antenna so that they can hear me better from further away.
Sounds to me like the PERFECT installation scenario for a flowerpot dual band antenna. I made one and covered it with plastic Holly leaves, left over from a Christmas decoration, it just looks like a plant in a pot in the corner, but I can easily hit repeaters 70Klms away no problem with the antenna only 1 foot off the ground using 0.5w power. A portable J-Pole would also work fine. I think my flowerpot cost me about eight bucks, maybe ten with the PL259 tossed in......a pretty good use of about 3m of RG58 and a plug.
All things being equal spending 50% of your ham radio budget on an antenna, 40% on the receiver and 10% on the transmitter will usually give you the most bang for the buck. Remember 3db of gain from the antenna is the same as doubling your transmitter power and 6db of gain will be equivalent to four time the transmitter power. So bottom line go with the directional antenna if you have the option.
The short answer is “no”. If I can (and have) talked to the International Space Station with a 5 watt handie-talkie and an Arrow antenna, while you need more than 10-20 watts for anything but EME, you’re doing it wrong.
@@ZAR66 The Arrow antenna proves the point that power isn’t everything, and sometimes it isn’t anything compared to height and gain. Please, feel free to throw off enough VHF and UHF microwave radiation to cook a chicken off of the roof of your car to hit a repeater 20 miles away if you like. I don’t care. But, I would advise most hams to skip the power (it won’t help you on receive anyway), and have fun building and raising VHF and UHF antennas for long-distance contacts. The great thing about the 2m/70cm portions amateur band is that you can easily build or buy antennas with 6-12 dB gain that turn any vhf/uhf rig into a flamethrower. 5w + 9dB gain = 40w ERP, and you’ll be able to actually hear the station/repeater you’re pointing at!
Dave: Here in rural America, we do not have a repeater in every town and sometimes not in a county. Here at my house and at our farm, active repeaters are over 40 miles away. So higher power is a necessity. Here at the house, in a HOA, I cannot have outside antennas. At the farm you need stacked antennas to reach a repeater because of all of the hills and trees. But most of my VHF/UHF activity is on CW and SSB and most of my contacts are over 100 miles away, so lots of elements, height, and power are a necessity. Most of my FM activity is on DMR these days through a HotSpot, so there are no needs for running more than a watt of power!
I'm also living in a remote area, so I know the problem. I have outdoor antennas and a UHF beam to get to Grand Junction, about 80 miles to the NW.
@@davecasler Do you have elevation in your favor? Here in the “Lowlands” we have to contend with very tall and thick trees, along with rolling hills. When we lived in Oklahoma, a tall tree was 20 feet tall, here in SE MS, trees are 120 feet tall. At the farm, 56 elements at 115 feet do the trick.
On VHF get it up as high and above any obstruction as you can. 50 watt radio and the antenna high as you can will work wonders
I made the M0MSN 'coat hanger' antenna on YT but used copper wire precisely cut. A dual band vertical dipole, which I put in the loft. I bought a Retevis RT-95 and used 5M of old satellite coax from my dish (75 Ohm?).
I tried it on 2 Web SDR receivers. VHF was strong, S9 +10 and more, but on UHF only S6 and nothing on the furthest SDR. UHF was like my UV5R-TP so I assume 6 Watts. The plastic looking roof tiles probably don't help.
It has better reception than my HT being higher up, but doesn't seem much better at reaching the repeaters (mostly UHF).
There's probably some stray RF and my HP server PSU when close to the radio also lost one side of someone's VHF QSO.
A YT video used a Marconi Test Set and the true power was L: 4-4.5W, M: 12-13W, H: 20W. Not far off the 5, 15 & 25 as claimed.
Using just a single element gave a small improvement. Using a very short feedline made it worse, so I guess the coax acts as part of the antenna? Or SWR issues.
My PC Nvidia card wipes out PMR446 CH4 until the screen output sleeps, even with the monitor unplugged.
On TX the radio knocks out TV reception of my UHF Yagi (for DVB-T Freeview) a metre away, but not another 3M away. It also briefly triggered a mains powered smoke alarm at higher power 2M away but I rerouted it's wires.
Before boosting power, I'd just look into a directional antenna. I was able to cleanly hit a repeater 132 miles away on UHF, 38 feet of old, water damaged RG8 with 10 watts, on a stacked Yagi. I was opening it, but barely audible on 5 watts, on a 2 foot run (for testing purposes, to zero in the antenna). So a good antenna will make a huge difference.
Yes! There are usually two ways to solve this kind of engineering problem -- throw more "horsepower" at it, or see where you can optimize the power used. This solution falls in the latter category and is much more efficient imho - 73 de W3DJS in Dacula, GA
Not bad advice but remember VHF and UHF are line of sight so the height of the antenna is as important if not more important then power.
I am in the same situation. I put a 3 element yagi on a 6 foot coat stand and I hit all the repeaters I couldn't. I run a ht thru a amplifier set a 20 watts only when I need to.
What is the picturer over your left shoulder ?
Thank you. N0QFT
That's vary good content. I'm just starting this hobby you help me a lot. I have question but am not sure how to get my question to "Ask Dave" section. I live in apartment on the 3rd top floor of the building and want to work on hf 40 and 20m bands. I was thinking of running DX-EE antenna along the shoulder of the roof (along the wall under the gutter) but I need to talk to my neighbor to use their part of the roof too because my apartment is not long enough to fit 40' antenna. It would take about 10 feet of their space.
Is it a good idea to do so? We are very good neighbors and I do not doubt they will allow me to do so but I'm afraid of causing and receiving RFI. So I would like to know if it makes any sense to even start this project. I'm going to use 100w output power.
73, VA7IGR.
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