Part Four Antenna Tuners: RF Man Discusses Long Wire Antennas, Unun's, RF Chokes, & Antenna Tuners.
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- Опубліковано 5 вер 2024
- This is part 4 of a 4 part video that discussed how to build and test a multiband long wire antenna, a 9:1 Unun, a 1:1 RF choke, and an antenna tuner. Part 4 focuses on the construction and test of the Antenna Turner. Please visit my web site at: rflinear-amplifiers.com for more info. on my LDMOS HF Amplifiers.
I really enjoyed your videos, looks like you spent a lot of time researching, thank you! Very helpful 💯👍👍👍👍👍
Nice job on the tuner. Even though your tuner is matching the transceiver you still have significant coax loss between the antenna and the tuner due to High SWR on the feed line. You are likely loosing 30-40% of your power in feed line loses due to the mismatch. You should see how you can mount the tuner remotely with remote stepper motor control. If you can get a 1:1 match at a remote tuner your feed line loses will only be those shown in coax attenuation charts.
Beautiful method of coil construction.
This is BEAUTIFUL!!!! This is exactly what I am missing. Im working with an L Network and I am unable to catch all that I am wanting to catch...So I need to simple modify what I have now with another Capacitor to convert it over to a 🥧 Network like you have here :) well talk about it sometime but for now I'm taking notes from this video.
Thanks for taking time to do this :) Your friend GK said that and im gone for now.
Hey Tom, thanks for your comments my friend!!
Howdy.
Just two words: Absolutely awesome.
Regards.
Thanks for more good info Rob. Another great video brother
Thanks for your positive feedback!
Enjoyed videos. Very good dem of the different tuners which has helped me understand them better. One critique though, on at least two bands you were actually your going outside of our allotted frequencies because of bandwidth of your signal. A.M. has a fairly broad bandwidth and when you tuned up on 7.00 mhz, 14.00 mhz, etc., Half your signal was going outside the band. Not a terribly big deal, but it could get you noticed by the wrong people. Still very informative videos. Thanks, Ralph, N4CFX, Northport, Alabama.
Will try this out with my antenna. Also should give really nice static sparks from the charge collected on the variable capacitor!
RF MAN, MERRY CHRISTMAS and HAPPY HOLIDAY’S to You and Your Family. Thankyou
I ask Dave question : what govens the height of the antenna off the ground at different Frequencies ? By the way Dave cannot tell me
Where did you get the grommet strips?
Question: what wire antenna thickness that restricts maximum RF out put from transmitter be it 50 watts output?
I can't wait for you to start playing with open wire balanced line and link coupled tuners on the low bands. Link coupled is like magic to most people. No physical connection between input and output. What? I will tell you this open wire feed line and 136' of dipole will get you talking on every freq. from 3.5Mhz to 30Mhz and with very little compromise other than the radiation pattern of the antenna can be out of favor on some freq. Another thing that's hard to imagine for cbers as well as many hams is the fact that I can use all frequencies between 3.5 and 30 Mhz with good efficiency and always have a perfect SWR. You never tune or touch the antenna length at all but you may have to adjust the feed line length according to the tuner you use. Hams call the antenna the doublet. The only coax I own is in jumpers. The problem with using coax with an antenna tuner, the places you need the tuner the most are also the places you have the most loss. This isn't the case with open wire line. We tune out reactance capacitive or inductive and we are left with resistance and the power is transferred to the load where it is radiated no matter how long the antenna is. Balance is key though with my setup. 73
great video. Still don't know why people test at "low" power of 10 or 20 watts, when all you need is a couple milliwatts! Antenna analyzer puts out a couple mW and allows adjustment of tuner. Change from analyzer to rig, then apply full power (5 watts, who needs more?).
Dave WA4NID
Why not just use a resonant circuit with link coupling to antenna? link coupling was used a lot in early radio transmitters in ARRL hb
Will it matter to have a variable inductor of higher inductance instead of 25uh? I know the capacitor values on MFJ tuners are enough for 160-6 meters. Thanks.
Yes, the wider the range of L and C the wider the tuning range will be. Regards
Great series. Thanks. I was wondering if you find the end-fed random length wire antennas with the 9:1 noisier than a standard dipole or even an EFHW? I noticed you have S9 noise level on 20m. That's seems pretty high.
Yes, you do hear a higher noise level. It's a design tradeoff. Regards
shortcutting sections of the inductor, it increases losses and lowers the quality factor
VK2SS has a point! If I understand correctly, you have your Tx attached to the pi tuner, which is connected to an unknown length of 50 ohm cable . The cable leads to a 9:1 unun which feeds the random length long wire. At any frequency, the random wire presents some impedance which is reduced by a factor of 9 to the far end of the 50 ohm transmission cable. What happens at the tx end of the cable is unknown, but is matched to 50ohms by the tuner. So you are in fact matching feedline impedance discrepancies and not tuning the radiation element. Where is the energy going? I suspect it is absorbed by the various matching components rather than launching into the air via the radiating element. Providing a good load match to the transmitter, but not necessarily the radiator. VK4bAC
Sorry to disagree but the so called antenna tuner does not tune the antenna to resonance . It just presents a 50ohm load to the transmitter and there is still a high swr from the coupler to the antenna . VK2SS Chuck
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TERRIBLE CAMERA WORK, motion sickness plus
Thanks for sharing the useful informations via these video's! 73 de SV3GLJ
stop moving the damn camera around!!! get a tripod!!!
Fully agree 👍