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Viking II to tune or not to tune




 
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Author Topic: Viking II to tune or not to tune  (Read 11955 times)
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Steve - WB3HUZ
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« Reply #25 on: July 29, 2009, 11:51:37 AM »

Some good info on the various losses here.

http://www.vk1od.net/balun/W2DU/index.htm


Even in the second scenario, the coax and the tuner accounted for far more loss than the balun.
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K3ZS
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« Reply #26 on: July 29, 2009, 01:35:36 PM »

Please, I said about the W2AU Unadilla balun I tried heating up, not Walt's W2DU
choke style balun.    This seems to be resulting in a pissing contest rather than a good conversation.    In my 50 years of hamming, I have used only one balun and I am not obsessed with them or against them.    Just another useful thing to use at times.   I am sure, just like the Bible, you can find somewhere on the internet to support whatever viewpoint you have about something or another.   I usually consult with an older ARRL Handbook or Jasik Antenna Engineering rather than yahoo when looking for answers.   Most of these antenna problems were solved before I was ever around.

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N4LTA
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« Reply #27 on: August 03, 2009, 04:56:30 PM »

I don't use tuners unless I am forced to.  I 'd rather use a separate resonant antenna for each band. I realize this is limiting, but I have not had good luck with using open line fed dipole variants and tuners. Things heat up and power is lost. I use a current balun on all my antennas at the feed-point.

When I got active again on multiple bands I spent $600 on a new Palastar Tuner and put up a open wire fed  dipole up about 70 feet. Figured I was ready to go. What a dissapointment. The tuner was not impressive and had problems loading on quite a few bands.

I now have a resonant dipole on 30, 40 and 80 plus a 1/4 wave vertical on 40 with 60 1/4 wave radials. I am underway installing a 160 meter inverted V up about 90 feet. I'll have to live with 4 or so 1/4 wave radials and some shorter ones. I work mostly QRP and the last thing I need is sending what little power my trusty K3 can generate into heat in a tuner/balun.
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ka3zlr
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« Reply #28 on: August 03, 2009, 05:19:25 PM »

Please, I said about the W2AU Unadilla balun I tried heating up, not Walt's W2DU
choke style balun.    This seems to be resulting in a pissing contest rather than a good conversation.    In my 50 years of hamming, I have used only one balun and I am not obsessed with them or against them.    Just another useful thing to use at times.   I am sure, just like the Bible, you can find somewhere on the internet to support whatever viewpoint you have about something or another.   I usually consult with an older ARRL Handbook or Jasik Antenna Engineering rather than yahoo when looking for answers.   Most of these antenna problems were solved before I was ever around.



That is a Fact and I agree whole heartedly alot of antenna issues have already been discussed and documented the older manuals are the bees knees....Good Info.

73
Jack.

 
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Jerry-n5ugw
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« Reply #29 on: August 04, 2009, 06:43:33 AM »

Well.. lots of opinions... I was asking in the condition of non-res antenna application wether most Viking II users used a tuner or not. The balun question is more about the antenna and not the transmitter. In my case I have to have a balun to match the 50ohm coax to the 450ohm ladder line. Have you ever tried to put ladderline into a tin can trailer and control the RF. So I really can figure out the antenna issue and for my application I have to use one antenna in the RV park, I'm lucky I was able to throw up a diapole. I'll do some test runs and see what I like best. Thanks for all the bandspace.
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The Slab Bacon
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« Reply #30 on: August 04, 2009, 08:48:46 AM »

Well, being the troll that I am (I pride myself on being an ornery bastard) It is a good time to chime in with my $.02 worth.

Many people come on here looking for advice, they get plenty of it, but wont take or do any of it. Especially on the subject of antennas, tuners, feedlines and/or baluns. these are some of the most hotly argued items in ham radio. especially when the person asking for the advice knows very little and is prone to some of the old "superstitions" of antennas.

Some of it (like the coax vs open wire thing) is one of those Ford vs Chebbie deals. There are some people on here that know more about this stuff than I have brain cells left to learn or remember. The trick is that when they are talking (or typing) keep your mouth shut and your ears open. If you know anything about radio theory, it doesnt take very long to figger out who is who. And who knows what they are talking about and who are just bullshitters.

Whith a lot of advice from some of the others, I have figgered out what works for my "worst case scenario" of small lot / need antenna issue. To those of you who helped me figger it out (you know who you are) I offer many thanks. It was a lot of fun to prove some of the others wrong. This stuff aint rocket science! ! !

The bottom line of this post is not to flame anyone, but to slap you in the face with: When you ask for advice, go out and try it if it comes from the right people.
Dont stand around with your thumbs up ur butt complaining ur stuff doesnt work. Go out and try something and you may be pleasently surprised. Take some of the advice from the ones in the know and simply try it!

                                                 The Slab Bacon   
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"No is not an answer and failure is not an option!"
ka3zlr
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« Reply #31 on: August 04, 2009, 09:52:10 AM »


I Dunno, to much fooling around for me, First Drop the g5rv ladder line balun coax deal thing.. run the coass straight up build a fan dipole check for fare resonance on all the bands you want covered cut an trim as needed and build ya an air core coaxial balun at the feedpoint of the antenna and run the damn thing...if your gona use one piece of wire for all bands your gona need some type of antenna coupling... it's just that simple...The outpoot section of the VII is very hardy with antennas in close resonance it was designed to take in not so perfect Hammy Hambone Designs.....If I remember isn't there a small section in there about this in the manual I'll have to look at mine i forget...

As I understand your question about not using a tuna..

73
Jack.


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The Slab Bacon
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« Reply #32 on: August 04, 2009, 10:15:52 AM »

As I understand your question about not using a tuna..
73
Jack.

Just FWIW, many people worry about tuner losses. If you have a really good tuna (preferably homebrew) the losses are pretty low, almost unnoticable. I have run as low as 7w into my short small lot antenna on 3.885 and been heard all up and down the east coast when condx was favorable. However, you wont see this with a storebought tuna.

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k4kyv
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Don
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« Reply #33 on: August 04, 2009, 10:25:22 AM »

If you are going to use a dipole on multiple bands, balanced line with a balanced tuner IS THE BEST SETUP! Do not even think of coax and a balun. I have put in 100's of hours testing the differences. I am not one for trusting what I hear or read. Coax is ONLY good in a 50 ohm environment. If you are happy with 9 s unit signals, then run coax. If you are interested in 20 over 9 signals, then do it right the first time. That statement only applies to using an antenna on multiple bands!

What kind of insulators are those holding the wires?
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Don, K4KYV                                       AMI#5
Licensed since 1959 and not happy to be back on AM...    Never got off AM in the first place.

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This message was typed using the DVORAK keyboard layout.
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ka3zlr
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« Reply #34 on: August 04, 2009, 10:42:28 AM »

 As stated the gentleman Asked " I was asking in the condition in non-res antenna application whether most Viking II users used a tuner or not".....and my answer is was within band at fairly close resonance No the PI network will handle quite a bit.  You start multi-banding with one wire the need for a coupler is needed..that's it for my part.

I seen nothing about Tuna losses in the paragraph or assumed any. there was talk about a balun and ladder line and a trailer...now I can't read...right... Grin

73
Jack.


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The Slab Bacon
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« Reply #35 on: August 04, 2009, 12:00:52 PM »

Run the balun on the OUTPUT of the tuner, and it's a piece of crap, no matter the feedline length, even if you run ladder line to the antenna....  The balun will always see a variable impedance, and NOT work.
Hope that helped to clarify what I was trying to say.
--Shane

this one also caught my eye as i also run a short (about 8') run of coass between the tuna and the laddah line. I had no choice since i had too much wire, metal and other crap behind the wall where the feeders had to run.

After either setting them on fire or blowing them to bits I decided to do some experimenting with home brew baluns. Especially after being told by many "baluns dont work" or "they're all junk" I wound many different varieties of 1:1 and 4:1 designs. One constant became vary apparent quickly. Just about all of the 1:1 designs were very impedance specific, especially depending on the test frequency. Most all of the 4:1s weren't.

the input / output impedances would get pretty squirrely on the 1:1s the farther I deviated from 50 ohms (either direction). However the 4:1s stayed pretty much a 4:1 impedance ratio no matter what the operating impedance was. I tested from 5 to 500 ohms and 1.5-15Mhz.

Once I came up with a design that could handle 15 minute key downs with my 4x1 rig and didnt heat up (at all) I was good to go. Always remember that heat=loss.

                                                                 The Slab Bacon 
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WA1GFZ
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« Reply #36 on: August 05, 2009, 09:56:58 PM »

Frank, I suspect the 4:1 worked better because of extra turns giving better coupling primary to secondary. I never played with transmission line transformers until I bought the ERBTEK amps. This configuration gives you much broader frequency response due to improved coupling. A good 1:1 transformer would be Teflon coax wound in a core. The shield would be the primary and the center conductor the secondary. The turns required at 50 ohms would be enough to give you 200 ohms reactance on the lowest frequency. A 50 ohm transformer would be wound with 50 ohm coax. A 25 ohm transformer would have 2 50 ohm windings in parallel. a 35 ohm would be two 70 ohm windings in parallel.
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w4bfs
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more inpoot often yields more outpoot


« Reply #37 on: August 05, 2009, 10:13:37 PM »

Hmmmm ...is that ERBTEK or DERBTEK ? irquiring minds want to know...73...John
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