In 2 1/2 years of trying to radio your's is the 1st vid I've watched that made me understand forward and rf. Now I get it. I was already thinking about getting a cross needle meter, now I am sold. I'am saving this page. Thanks.
Nice video. But people need to remember, you can have a good SWR and not get the power out because of line loss. For these VHF/UHF radios, please get a high quality feedline like LMR-400. You don't need true LMR but an equivalent low loss line is imperative.
I wish I could... However, I did make it out last weekend with the Moscow Prepper to a local range and we shot some AKs there (he did a small vid). Thanks for the feedback and support. 73s CommsPrepper
Properly tuned AT the ANTENNA. Yes. NOT at transmitter. BUT...the meter is NOT reading reflected power bc line losses are much greater across a line when out of tune. That just amplifies the REQUIREMENT to check AT the antenna, not transmitter. Worse than just extra heat, mismatch causes very high voltages or currents into the TX and that also can damage the transmitter. PS thats not a VSWR meter.... VSWR is voltage at two different pounts on the line. These meters measure reflected current. All in all, good video.
Thanks, that is very well explained. Now this topic is much clearer to me than before watching this video. Two remarks: the close-up video of the SWR-meter is a bit blurred. And ... did I miss the explanation what the difference is between "AVG" and "PEP"? Would be good to know what is is about.
+Thomas Gärtner Thomas sorry about the blue but the video is posted and I cannot correct it. I have since tried to do better with how I shoot the videos. Average setting will slow the swing of the needles and allow them to hang momentarily to give you time to see the reading. Avg will also show lower power because it's an average of RF energy. Peak Envelope Power (PEP) is a real-time reading of power, which includes the peak of the transmission. In PEP mode the needles move fast in response to present RF energy. When in PEP mode and side-band mode on the radio I whistle see peak power on the needles.
SOrry during measure VSWR, does it matter if the antenna is not set up in open area (direct to the wall of the room)? Is the signal reflect from the wall will cause VSWR higher than usual?
So what can you do when a test of a new antenna and a new radio produce super high SWR? Can you do a video on how to address undesirable readings? I can understand not using the rubber duck antenna, but what if it's a brand new EFHW antenna and a new HF radio? Do I send it all back?
What is an EFHW antenna. Things to look at if your SWR is bad. Cable problems (short, open, bad connectors, bad cable). Antenna problems - not tuned or cut for the operating frequencies, shorts/open, bad coils/balums, etc.
If there's reflected power back at the radio that doesn't trip the protection circuit of radio what happens to it, it gets reflected back to antenna, how much that gets back to antenna is down to feeder, the lossy it is the less that gets back to antenna
Thanks for the video but im confused because there are many videos about how to check but how to fix? You have one antenna thats wrong, ok how to fix it?
cvcoco At first I would look at the antenna length. If the antenna is a match at a lower frequency - it's too long and needs to be trimmed. If the antenna is a match at a high frequency - it's too short. If the antenna is not at match at any frequency around the frequency you cut it for then you should look at the following: 1. Connectors (properly made, no shorts and no opens) 2. Coax check (no cuts or shorts) Hope this helps.
Commsprepper Ok thanks, understood. Are you ever going for an average length? Once I read that the ideal length for a car FM antenna was 37 inches but that length doesnt match 88 or 108, its somewhere in the middle so something is always being lost, yes? In other words, do you need a separate antenna for every frequency band? How can 2M and and 400 band use the same length of antenna in one radio? SWRs wouldnt ever match right?
cvcoco Never seeking and average length. Frequency wave lengths are specific and must be correct to have a resonant antenna which will result in low or no VSWR. This is said - antenna length is less critical for receivers since they are passive devices (i.e. car stereo or coat hanger on the back of an old TV). Different antennas are needed for different bands. However, there are many multi-band or dual-band antennas. For multi-band antennas designers use traps and coils to manipulate the antenna's impedance (resident wave length) and take advantage of fractional wave lengths of an antenna. For example 145mHz wave length is roughly 2 meters long and will have low or no VSWR. But you can also achieve the same VSWR with fractions. 1/2 wave length and 1/4 wave length. The fractions are also resonant and will have low or no VSWR but are less efficient. Another example: the antenna length for 14.24 mHz is roughly 21 meters long, At 21 meters this antenna is too short for 7.25 mHz for a full wave antenna - BUT - is almost perfect at a half-wave. Add a coil or choke and you have a single antenna that works on two very different frequencies. One of the more popular antennas that does this is the G5RV (names after the British ham's call sign that designed the antenna). Hope this provides some insight. CommsPrepper
Cool wish I had watched this before I went for my test Sunday, I would have got one more question right. I passed anyhow but it is nice to learn a bit more anyhow before my radio arrives and my name gets in the database. So what could you do with that little rubber ducky to get the SWR down to a good rating in VHF?
+Jerry Ericsson Congratulations on getting your ticket! Handheld rubber ducks - nothing. They are what they are. However, if you make an antenna then you can do more.
does the watt meter you show here perform the same task as your radio tuner did in another video… without the ability to TUNE… would the tuner replace the need for the watt meter? also what does a dummy antenna mean? is it just a teaching antenna for classes?
Yes the meter in this video performs the same task as the meter built into my tuner. I have this meter for testing my VHF/UHF antennas that do not use/need a tuner. A "dummy antenna or dummy load" is large resister that absorbs all of the power transmitted by a radio. They are used for testing and trouble shooting. They simulate a perfect antenna that has zero reflected power. All the power sent to a dummy antenna/load is absorbed and none of that power is radiated into free space.
the watt meter as you refer to it is a SWR meter that measures standing wave ratio hence "SWR" they are not the same, nor do they do the same however what I watched of the video did not explain impedance good video but I found it boring, sorry
AA1PR I know for the Boeing aircraft I work on, we use the wattmeter. If output is 30 watts, you turn a crystal around and check to see reflected power. it should be no more than 10% or 3 watts in this example.
With my Yaesu 7900R, I'm getting good readings in front and reflected values, but the needles aren't crossing, so I can't read a SWR. This happens in 2m only, not 70cm. What's happening?? If the needles don't cross, then what is my SWR value?
What the hell is "R3CU"? As long as you are going to do all of this prepper work in comm, you might as well get your tech or general amateur license. You (and the others) most likely have the intelligence and iniative to easily study for and pass the tests. Also, other hams will be glad to assist you with your technical and operating skills.k Otherwise, your video is very good simplified explsnation of VSWR and how to measure it. 73 de K6WHP
William - R3CU is my call sign here in the Russian Federation. It's a CEPT Class I license (same as a U.S. Extra class license). I also have a U.S. Extra class license and have been licensed since 1988. Thank you for the feedback on this video. 73's Hank
Commsprepper Well, don't I feel the fool? Congratulations on getting a license in another country! Quite an accomplishment.Did you have to take the test in Russian? Anyway, the advice still stands for other preppers who want to become proficient in comm. Hams are more than happy to help folks study for their tests as well as share their knowledge and experience in technical areas. (As your fine video demonstrates.) 72/73, K6WHP
k6whp I did not need to take the test here. There is a reciprocal agreement between the U.S. and Russia for radio licensing. I agree 100% that preppers who seek a solid communications plan should get licensed. I have a few videos on the topic, providing guidance on where to start and walking through the process. Again - thanks for commenting. Hank
