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Fact or Fiction ... Antenna tuners/meters for dummies (please help) Thanks

Road Squawker said:
"Tuners" do not tune the antenna. the SWR "looking into the antenna" doesn't change.

they also do not tune your radios output, it is a constant 50 ohms (+/-), they only allow your radio to load into an approx 50 ohm load.



If that is the case, why do you have a tuner in line?
The "tuner" is just "seeing" the meter, not the antenna. take that meter out and see what the antenna impedance really is.

Doesn't your MFJ tuner have an SWR meter built in?
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Thanks for the replies guys ! I keep the tuner inline for my dipoles mostly, I got the Maco pretty much dead flat on my first shot using the wire on the match ring about 12' off the ground and it did change a tiny bit once I had the bucket truck here and mounted it on the chimney . The dipoles are both less than ideally mounted so I could not get either of them flat with just length adjustment so that's where the tuner really comes in to play for me . The tuner does have a cross needle meter in it and to the best of my knowledge its pretty darn accurate I have just put other meters inline after the tuner to make sure it was reading properly and they all read the same (+/-.1-.2.)

Thanks , Brian
 
fourstringburn said:
Tuners don't really tune antennas, they compensate for any mismatch in or along the antenna system.

Your Maco antennas is tuned by lengthening or shortening the antenna to the closest resonate point ideally where you operate at. You then rely on the antennas bandwidth to operate on either side of that.

A tuner can lower the SWR outside of the antennas sweet spot so it looks good on a SWR meter, but the actual SWR at the antenna never changes.

We Hams use tuners on multiband antennas so we can operate our radios safely beyond the resonate point on many of those multibands.

On 80 meters with my multiband wire antenna, my actual SWR at the antenna feedpoint is as high as 10:1 or more. The ERP (effective radiated power) isn't very good and my radio's high SWR protection circuit will kick on if I tried to operate it like so.

But because I use a tuner, I can get a low SWR so my radio will transmit full power but the true radiated power out the antenna is about a 65% power loss due to in-efficiency losses. So, on 100 watts, I still can transmit 35 watts with an inefficient antenna. I also use an amp to boost the power so my approximated ERP is increased before any other typical losses are calculated. There are always other some losses in your antenna system but many are small.

Your SWR meter can show full power out from your radio and a flat SWR on the tuners meter. All this means is that you have a nice match in your antenna system before the antenna and your radio will be capable of full output power. However, it doesn't mean your transmitting full power out the antenna. The losses are dissipated out the antenna as heat and not effective radiating RF.

Ideally, tune your antenna with a analyzer at the antenna feedpoint for the best ERP and you shouldn't need a tuner with a monoband antenna. Tuners can have losses in them too.
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Very well put and extremely understandable ! Thanks for not bashing and being constructive! As a CB guy I understand why hams get annoyed with guys running radically mismatched gear or dirty class C high power gear and splattering all over the bands and I like to think I am NOT one of "those guys" lol . I think we need a few more hams to be accepting of us 11-meter guys and we can become more educated , better informed and less annoying to the hams out there . Cant we all just get along lol
Thanks again for all the great info , Brian
 
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wa373 said:
One question posed by the poster is how accurate are "affordable" swr/power meters? I would consider "affordable" as between $100 to $150. :cautious:
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That's a good number for "affordable" considering most CB guys I know have 3-4 $25-$50 meters lol but most guys start off slow and cheap . I guess the cheapies will keep you in the ballpark and keep your radio safe but are not ideal for fine tuning or building antennas . My next move will be A Digital antenna Analyzer from MFJ added to my "stable" I like the tuner and another small meter I have from MFJ but nothing seems quite as accurate as those digitals bad boys so its on my wish list .

Thanks for getting back to me and helping the CB guys and the Hams come together and talk about things !

Thanks , Brian
 
kopcicle said:
For relative measurement (fwd/rev) , just build it . $5 , maybe less. Depends on your junque boxx
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That was one of my first scratch built devices and a great learning tool ! If I can find my diy meter I will post pics (she is an ugly duck) in an old Sony Walkman case I hollowed out !
Thanks as always kopcicle ;)
 
Unit 75 said:
I can understand you using a tuner on your wires. Is there a reason your using the tuner with the Maco??
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The Maco does sit pretty flat (on any meter lol) the tuner is mostly for the wires but since I cannot reach the Maco (3 story house chimney mount sitting atop a fence top rail 51-52' ish to base , and my buddy sold his bucket truck) to dial it in any better , I do use the tuner to dial it dead on 1:1 but I have ran it for years without the tuner with no problems at all !

Thanks , Brian
 
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binrat said:
I treat anything past the output of the radio jack a part of the antenna. Here is a video for your viewing pleasure. Lengthy but some good info.
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Awesome video thanks binrat , well worth the time to watch ! Even us single band guys can wrap our heads around that .

Thanks a lot , Brian
 
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hotrod said:
on your wire antenna..definately... on ya maco no.. just tune the antenna
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Tru indeed Sir The Maco changed a tiny bit from being ground tuned to its current 3 story chimney mount barley makes a needle move , Im sure I could get it perfect if I could reach it but not without the bucket truck ;( But yes Its really for the wires buddy !

Thanks , Brian
 

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