SWR is important though it shouldn't be an obsession. Anything less than the start of auto power fold back should work well. Even if you are at VHF, good quality low loss coax will not have that much increase in loss. Kind of a rule of thum, less than 1.5 is fine. On HF I might even let things go as high as 2.0 before I would worry. The reflected power is reflected back added to the radio output. The biggest problem I find with antenna to coax mismatch is that it makes the impedance that appears at the radio vary with distance from the load.
Nice video. I sure wish RU-vid was around when I first started in the ham world. Then again , that was before PCs even existed. When I recently heard the expression “dummy load”, I immediately thought of the Sniffer in Chief’s Dementia Diaper. 🤣 Thanks again.
For those who dont know, a dummy load is basically a resistor that has an ohm rating matching an antenna. Thats how its able to virtually be an antenna
Yes, the meter must be recalibrated when changing frequency and most especially when changing power levels. Setting the calibration level (essentially a relative forward power reading) at high power and then keeping that same level when switching to a lower power output will result in an inaccurate (artificially low) SWR reading. Remember that SWR is a function of pure resistance along with inductive and capacitive reactance. Those values change with frequency but not with power level. Therefore the SWR of an antenna system will remain the same at a given frequency regardless of power output and thus one should expect to see the same SWR value on the meter no matter what power level is used.
@@BrianEsche The difference in in SWR when recalibrating between 148 and 144 is pretty nominal. I could see if you needed a precise reading, but when judging resonance and seeing how out of whack it is, it works fine. I did remove the section on power levels though, given your feedback, Brian. Thanks for posting!
Cos my field is in computers and being a semi-pro, i have some idea, , your wondering, what the hell is an SWR, SWR stands for "Standing Wave Ratio", the transmitting signal travels along the antenna (FORWARD) and refects at the end, returning down the antenna (REFECTED), the forward signal interferes with the reflected signal causing constructive or deconstructive interference, differant lengths create differant phases along the antenna, when a peek meets a peek there is max emission, and when a peek meets a trough there is zero emission, an SWR ratio of 1:1 is perfect constructive interference, where the cycle appears STATIONARY on the antenna, creating a perfect waxing and waning electo-magnetic field, as the electric field collapses, the magnetic field increases and vice versa, , ,Without that load absorbing energy, the energy instead appears as a high voltage or high current somewhere which may not be equipped to handle it, , So basically, an ideal 1:1 SWR will produce a low 50ohm resistance match where the antenna does work, the SWR is relatively constant along the feedline, the impedance will vary along the line unless it is perfectly terminated (that is, the SWR is 1.0 : 1). This is an important concept for impedance matching, because with a high SWR, the impedance at the final output transistor load inductor could be lower than 50 ohms, and produce a high current that damages the finals, , , PS - a 1:1.5 SWR = just a 4% loss \ a 1:2 = 11% loss \ and a 1:3 = 25% loss
@@K0LWC - the cheap eBay low power ones shipped from China are $20. If you are careful that can do the job. I tend to borrow expensive $200 meters from clubs or club friends.
So if you're antenna tuner is situated at the rig end, rather than at the antenna end of the system, then although your xmitter thinks it is working into a resonant antenna, it may not be, in which case a lot of power will be lost because of standing waves on the coax cable. So I guess that this is why it is better to install the tuner at the antenna end of the system? I guess that the whole idea is to maximize standing waves on the antenna, and nowhere else?
The SWR meter is also very important, when choosing a antenna for your HT. I have the Abbree 18.8 inch version, and on my TYT UV8000E, with the frequency set to 146.000, I have a SWR of 1.0, and all 10 watts of power from the radio. So yes if your SWR's are bad, it can damage your radio, be it a base station, mobile rig, or a HT. Stay Safe and 73's, KI7BSL, I'm out.
Shouldn't it be that it should be at the FORWARD mode when you calibrate and when reading your SWR then switch it to REFLECT to read how much reflected power in WATTS is going back to your radio?
I have 40w coming out to antenna! Swr 1.10 and power 37. 1 and reflected power .113 Is this good?what is more important Swr or reflected power? * ** YOU GUESSED IT MY FRIEND IM NEW! WILL WAIT FOR YOUR REPLY!THANKS EVER SO MUCH!!!
Thank you. Great info for us new guys. So if you are just about ready to hoist the antenna up onto the roof, can you test the SWR and resonance with a HT before tightening things up, or is it best to use the radio you plan on using for said antenna?
HT could complicate things. I would use the radio you’ll use everyday on the antenna. Either set it up temporarily in open space (PVC pipe is one idea) - or just know what once it’s up to test before tearing down your ladder etc. where you place it permanently could impact the SWR - so just be sure to test once it’s mounted, but be prepared to head right back up if needed.
@@paulm0hpd319 try spelling. I say it's vague for one reason, the old then instead of than. And it's still outside the scope. I'm a CBer and know more than most hams anyway.
