Author Topic: Antenna help  (Read 17840 times)

Offline JustinBoots

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Antenna help
« on: April 23, 2015, 08:11:42 PM »
i doubt that I am the only one when has questions about antennas, so I a, starting this so that those who know better can help those of us who don't. I'll start.  I was trying to figure out the connection of a balum, Smurf hunter was kind enough to show me his balum and I thought mine had different connections.  I was wrong. Is there any tricks or tips to connection to a balum?

Offline JustinBoots

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Re: Antenna help
« Reply #1 on: April 23, 2015, 08:13:46 PM »
Second question, is it possible to make your own balum or coils?

Offline cpf240

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Re: Antenna help
« Reply #2 on: April 23, 2015, 08:29:46 PM »
I'll show you mine if you show me yours?   ;D

... and its BalUn... no m... as in Balance/Unbalanced

Sorry, that's all I have on that... actually wondering if I'll need a balun for my G5RV and FT-857...

Offline JustinBoots

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Re: Antenna help
« Reply #3 on: April 23, 2015, 08:45:54 PM »
Oops, my eyes are tired and I am on my tablet.  I will get a picture up soon

Offline jerseyboy

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Re: Antenna help
« Reply #4 on: April 23, 2015, 09:04:54 PM »
http://vk5ajl.com/projects/baluns.php

Here is a detailed page about current and voltage BalUns.

Jerseyboy

Offline Carl

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Re: Antenna help
« Reply #5 on: April 24, 2015, 06:26:59 AM »
i doubt that I am the only one when has questions about antennas, so I a, starting this so that those who know better can help those of us who don't. I'll start.  I was trying to figure out the connection of a balum, Smurf hunter was kind enough to show me his balum and I thought mine had different connections.  I was wrong. Is there any tricks or tips to connection to a balum?



A typical BALUN has connections for a PL-259 coax and TWO wires...you TIE your antenna wires to eyebolts physically to the balun and make the electrical (radio signal) connection with the wire coming out of the balun to avoid stress on the balun internals.This balun has 3 inverted V antennas connected(you can do that) 10 - 20 - and 40 meters are primary and 6 through 80 meter can be tuned on this setup.

You also want to support the coax to avoid stress on the connectors by tieing (taping) the coax to the balun,also note water proofing of PL 259 with tape.The balun support rope can hang below the balun to be used as support for the coax.The coax will survive much longer with support every 5 to 10 feet down the tower or support rope used to pull the feed point into your tree...you don't want free hanging,blowing in the wind coax.
« Last Edit: April 24, 2015, 06:33:59 AM by Carl »

Offline Carl

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Re: Antenna help
« Reply #6 on: April 24, 2015, 06:29:44 AM »
Second question, is it possible to make your own balum or coils?

YES,a balun can be hand made:(but I don't as I have little hand dexterity)

http://vk5ajl.com/projects/baluns.php

Offline Carl

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Re: Antenna help
« Reply #7 on: April 24, 2015, 06:31:22 AM »
I'll show you mine if you show me yours?   ;D

... and its BalUn... no m... as in Balance/Unbalanced

Sorry, that's all I have on that... actually wondering if I'll need a balun for my G5RV and FT-857...

YES,usually a FOUR TO ONE BALUN...I hope you have a tuner because a G5RV is a 20 meter antenna that can be tuned to work other bands.The 4 to 1 balun allows a wider tuning range for your manual or automatic antenna tuner (mis named because it does not "TUNE" the antenna ,but it matches the antenna and feedline to 50 ohms to match to the radio impedance.)
« Last Edit: April 24, 2015, 06:38:10 AM by Carl »

Offline Smurf Hunter

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Re: Antenna help
« Reply #8 on: April 24, 2015, 12:12:32 PM »
Second question, is it possible to make your own balum or coils?

I'm a newer ham, so take my advice for what you paid for it.

I would consider building your own balun more of an academic or craft project.  You could learn a lot, but after you are done the time and money you spend won't net you very much compared to buying one for ~$30.   On the other hand, building your own antennas have fantastic return on your investment.

While I haven't seen one for sale, I stumbled across a PDF manual for the MJF 4:1 balun in "kit" form.  I have no idea if those were sold at a much lower price, but that seems like an interesting middle ground if you want to learn, but still want good odds for success.

Offline cpf240

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Re: Antenna help
« Reply #9 on: April 24, 2015, 08:10:53 PM »
YES,usually a FOUR TO ONE BALUN...I hope you have a tuner because a G5RV is a 20 meter antenna that can be tuned to work other bands.The 4 to 1 balun allows a wider tuning range for your manual or automatic antenna tuner (mis named because it does not "TUNE" the antenna ,but it matches the antenna and feedline to 50 ohms to match to the radio impedance.)

Thanks Carl. I have an LDG YT-100. What commercial BalUn would you recommend?

Offline Carl

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Re: Antenna help
« Reply #10 on: April 24, 2015, 11:02:07 PM »
Thanks Carl. I have an LDG YT-100. What commercial BalUn would you recommend?

I like and use the MFJ 913,it is what Smurf Hunter also uses and I have used for over 15 years with success.

http://www.randl.com/shop/catalog/product_info.php?cPath=1970&products_id=37656


Offline Ken325

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Re: Antenna help
« Reply #11 on: April 25, 2015, 12:43:56 AM »
I am new to Ham Radio and I am still studying for the technician test. I plan to take it in May.  I have started to research radios and antennas.  I plan on using the Dual band 2m 70cm Slim Jim Antenna from 2way electronix.  http://www.2wayelectronix.com/Dual-band-2m-70cm-Slim-Jim-Antenna-dual-slim.htm  another manufacturer of slim Jim antennas (KB9VBR) stated that a station ground was needed.  I am planning on putting the antenna in my attic.  I live in a 2 story town home with an HOA that prohibits external antennas.  I have a big attic and it is equivalent to 3 stories high above the 2nd story.  I plan on hanging the antenna with zip ties or paracord.  As I understand things, the antenna needs to be away from other objects and conductors.  I have asphalt shingles and no radiant barrier.  How do you do a station ground in an attic?  Is it needed?  Does anyone know if a choke balun is needed for this antenna? I watched a you tube video where it showed that it comes with a ferrite thing on the cable.  Isn't that a choke balun? 

My next question.  I live about 1.7 miles (9700 feet) from the exterior fence of a large airport. Does anyone know if this will limit my ability to set up a radio station? 

Do you think I need lightning protection if the antenna is enclosed in the attic?  Will putting an antenna in the attic increase the odds of lightning striking my home?  Do you think Rf interference will mess up my wifi, alarm system, and cordless phones?  I plan on locating my "shack" in my office on the second floor.  The office is full of TVs, computers, wifi printer, and other electronics.  I am hoping the high quality coax and distance to the antenna will help with this. 

I sounds like I will need a SWR meter.  I am assuming the antenna will arrive pre-tuned but I will probably buy a meter.  Any recommendations?  I am thinking of getting a small portable one http://www.amazon.com/gp/product/B00GNVJ8IU/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A3H7GPL9U124TQfor now and an antenna analyzer if I get more into the hobby.

Other information.  I currently have a Baofeng UV5R.  I have already ordered the slim Jim antenna (not arrived yet), 30 feet of LMR400 cable, and an adapter for the Baofeng.  I plan on installing the antenna and using it with the adapter till I pass the test.  Just listening for now.  I also use the Baofeng to listen to the police.  I plan on getting a Kenwood TM-D710G when I pass the test.  That seems like a advanced radio for a beginner but I am very interested in using digital modes.  It seems like digital is the way to go for a prepper.  The D710 seems like it is ready to go with digital modes and the less expensive TM71A would need a $200-$300 dollar upgrade to do this.  Am I wrong?

I think that is enough questions for now.  Any help would be appreciated.




Offline Carl

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Re: Antenna help
« Reply #12 on: April 25, 2015, 07:31:07 AM »
I am new to Ham Radio and I am still studying for the technician test. I plan to take it in May.  I have started to research radios and antennas.  I plan on using the Dual band 2m 70cm Slim Jim Antenna from 2way electronix.  http://www.2wayelectronix.com/Dual-band-2m-70cm-Slim-Jim-Antenna-dual-slim.htm 
This is a good choice as it is not exposed to the elements...The "J" pole/slim jim is a design used for ZEPELINS and no ground is required
another manufacturer of slim Jim antennas (KB9VBR) stated that a station ground was needed.

This is most likely a different design antenna

I am planning on putting the antenna in my attic.  I live in a 2 story town home with an HOA that prohibits external antennas.  I have a big attic and it is equivalent to 3 stories high above the 2nd story.  I plan on hanging the antenna with zip ties or paracord.  As I understand things, the antenna needs to be away from other objects and conductors.  I have asphalt shingles and no radiant barrier.  How do you do a station ground in an attic?  Is it needed?  Does anyone know if a choke balun is needed for this antenna? I watched a you tube video where it showed that it comes with a ferrite thing on the cable.  Isn't that a choke balun? 

Mount the antenna away from large (over 6") metal objects avoiding plumbing and electrical wire etc by a 30" margin.
The ferrite bead does help keep from RF flowing down your coax and into your station area , BUT I suggest  a common mode choke ...made with 6 loops of your feedline about 5 diameter doughnut shape and taped in that shape. The antenna you chose will work fine without earth ground and the length of coax running to the radio serves as RF ground.

My next question.  I live about 1.7 miles (9700 feet) from the exterior fence of a large airport. Does anyone know if this will limit my ability to set up a radio station? 

NO,the only restriction I am aware of is that of antenna height in the glidepath and then it is 20 feet above the existing structure (your home),personal note: I live less than one mile off the end of a military base runway and have a 40 foot tall tower

Do you think I need lightning protection if the antenna is enclosed in the attic?  Will putting an antenna in the attic increase the odds of lightning striking my home?  Do you think Rf interference will mess up my wifi, alarm system, and cordless phones?  I plan on locating my "shack" in my office on the second floor.  The office is full of TVs, computers, wifi printer, and other electronics.  I am hoping the high quality coax and distance to the antenna will help with this. 

Lightening protection <I would say is totally unnecessary as lightening has traveled a mile or more and seeks the closest path to earth(trees,tall buildings,top wire on power pole)..While your antenna will give you good access to others ,it will not attract lightening to your home ...Most noise from current day PCs is from monitor and TV sweep signals so do not worry I just would not put an external hard drive on top of a power supply for your station ,there is little chance of RE problems in my experience

I sounds like I will need a SWR meter.  I am assuming the antenna will arrive pre-tuned but I will probably buy a meter.  Any recommendations?  I am thinking of getting a small portable one http://www.amazon.com/gp/product/B00GNVJ8IU/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A3H7GPL9U124TQfor now and an antenna analyzer if I get more into the hobby.

The meter is a good addition to any station and lets you know about your power out and gives a clue as to feed line and antenna are working correctly (you want to avoid SWR of 2 to 1 and over as your radio doesn't like that mismatch and unless you have a need to experiment with home made antennas the ANALYZER will not give good return of investment and often becomes a dust collector (though fews Hams will admit this ) yourr money is better saved or spent elsewhere

Other information.  I currently have a Baofeng UV5R.  I have already ordered the slim Jim antenna (not arrived yet), 30 feet of LMR400 cable, and an adapter for the Baofeng.  I plan on installing the antenna and using it with the adapter till I pass the test.  Just listening for now.  I also use the Baofeng to listen to the police.  I plan on getting a Kenwood TM-D710G when I pass the test.  That seems like a advanced radio for a beginner but I am very interested in using digital modes.  It seems like digital is the way to go for a prepper.  The D710 seems like it is ready to go with digital modes and the less expensive TM71A would need a $200-$300 dollar upgrade to do this.  Am I wrong?

You are correct on DIGITAL being the future of Ham radio...How does one ground a handy radio??? And now the UV5R will do a great job ,I am glad you recognize the upgrade potential you have and planned for it with the antenna and feed line (I would not worry about the common mode choke but would add two of three of the snap on ferrite beads if interference is noted on any of your electronics when you transmit...I also suggest you look in to HF radio for long range hobby communications and YES an antenna can do great in an attic as SMURF HUNTER will hopefully tell you of his setup we completed not many weeks ago (I am a good supervisor of such things)

I think that is enough questions for now.  Any help would be appreciated.

Offline armymars

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Re: Antenna help
« Reply #13 on: April 25, 2015, 11:23:41 AM »
I'll try to answer a couple of questions.
  1st. You can make your own balun. Jerry Sevick,  W2FMI " Transmission line Transformers " is the book on the subject. I have both his first and second Editions. Jerry use to work for Ma Bell in their research labs. If you need a transformer like a balun or Unun. you'll find it in his book.
 
  2nd, An antenna in the attic will not increase the likely hood of a lighting strike. The antenna in the attic is protected from the wind so electrons are not building up  on it. Also an antenna has a habit of dispersing over a large area the ion cloud that needs to build up. Of course this does not included verticals where all the electrons go to the tip. Polly Phase did a lot of research for the Army on this an you can get some good info off their web site. 

Offline Smurf Hunter

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Re: Antenna help
« Reply #14 on: April 25, 2015, 11:37:03 AM »
In my attic I have two coax feedlines.  One to a VHF(UHF) Jpole the other to HF wire dipoles I setup for 3 bands.   

You've probably figured out the single best way to improve VHF is to add elevation.  I have found I get excellent range from my "copper cactus".
Here's what it looked like outdoors for reference. 



I just used some string to prop it upright against a stud.  If you got with a roll up style you could use a nail or staple and probably be fine too.
I think a variety of slimjim, or "bigstick" would all be comparable.  For an in attic install the durability and weather proofing is not a concern, so you can freely experiment with cheaper materials in some cases. I used hose clamps to connect the shunt to each verticle part of the "J".  That made tuning a breeze.

Here's my attic setup.  It's difficult to show what's going on from any one photo, but from the 4:1 balun Carl mention, I've got 3 pairs of wires.  I cut to length 10/20/40 meters. 



Because my attic length was just under 40 feet, that worked on to run the 20 meter in a straight line, but for 40 meters I had to get creative.  Carl reminded me that wires aren't smart enough to understand how they are oriented.  As long as you don't fold them back on themselves, get too close to other wires or metal objects (heater ducts, house wired, etc.) it should work.


Offline Carl

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Re: Antenna help
« Reply #15 on: April 25, 2015, 12:57:26 PM »
And between VHF and HF Smurf Hunter has great comms capability.

Be warned that Ham can be infectious:My simple station





The good part is you get to buy and add one piece at a time (two at a time ,if you hide one from the wife) and collect the
whole set!


Offline JustinBoots

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Re: Antenna help
« Reply #16 on: April 25, 2015, 08:05:19 PM »
Ok mad scientists. I have figured the balun out, am computing wire lengths.  Now as I figure wire lengths do the loops for attach,net to the balun and the end insulators count towards the entire needed length of the wire?  I am trying to double check myself and not waste wire.  I only bought 500'.  73s

Offline Smurf Hunter

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Re: Antenna help
« Reply #17 on: April 25, 2015, 08:59:56 PM »
Ok mad scientists. I have figured the balun out, am computing wire lengths.  Now as I figure wire lengths do the loops for attach,net to the balun and the end insulators count towards the entire needed length of the wire?  I am trying to double check myself and not waste wire.  I only bought 500'.  73s

No. If you had a 20 foot wire and folded it onto itself length wise at the mid point, the RF would treat it as a 10 foot wire.

So that's an excellent reason to always cut 6"+ longer than you think you need.  Honestly I add closer to a foot on each end and just wrap it through the end insulator and over itself.  If I need to shorten or lengthen I'm setup.

I stole this image from google and added the annotations in color.  You can disregard the lack of a balun - I just wanted a quick diagram of the insulators with wire wrapped back on itself.

Offline JustinBoots

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Re: Antenna help
« Reply #18 on: April 25, 2015, 09:15:36 PM »
Thank you very much! That makes everything much clearer

Offline Carl

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Re: Antenna help
« Reply #19 on: April 25, 2015, 09:29:40 PM »
Ok mad scientists. I have figured the balun out, am computing wire lengths.  Now as I figure wire lengths do the loops for attach,net to the balun and the end insulators count towards the entire needed length of the wire?  I am trying to double check myself and not waste wire.  I only bought 500'.  73s

What band or bands are of primary interest to you??
Make it easy on yourself: Typical dipole/inverted "V" is called HALFWAVE on this page as a quarter wave on each 'leg'

http://www.chem.hawaii.edu/uham/antennas.html

Good illustration SMURF HUNTER ..

Offline cpf240

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Re: Antenna help
« Reply #20 on: April 25, 2015, 10:04:24 PM »
I like and use the MFJ 913,it is what Smurf Hunter also uses and I have used for over 15 years with success.

http://www.randl.com/shop/catalog/product_info.php?cPath=1970&products_id=37656

Thanks Carl!

Offline Ken325

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Re: Antenna help
« Reply #21 on: April 26, 2015, 01:37:39 PM »
Lots of good information.  Thanks for all the help.

Offline Carl

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Re: Antenna help
« Reply #22 on: April 26, 2015, 01:39:20 PM »
Lots of good information.  Thanks for all the help.

All questions are welcome,there are several here capable of answering most Ham/antenna questions..

Offline Carl

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Re: Antenna help
« Reply #23 on: September 29, 2015, 08:44:18 AM »
My ION CLOUD is not as big as it once was,but I use a ground rod and insulated antenna wire so it is hardly noticeable.

Offline Smurf Hunter

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Re: Antenna help
« Reply #24 on: September 29, 2015, 10:11:43 AM »
In the past week I've had to talk 3 people out of expensive, low loss feedline for HF antennas.

I'm tired of arguing, and instead leave them with this online calculator to witness for themselves.

http://www.qsl.net/co8tw/Coax_Calculator.htm

Offline Carl

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Re: Antenna help
« Reply #25 on: September 29, 2015, 01:44:38 PM »
In the past week I've had to talk 3 people out of expensive, low loss feedline for HF antennas.

I'm tired of arguing, and instead leave them with this online calculator to witness for themselves.

http://www.qsl.net/co8tw/Coax_Calculator.htm

Feedline will eat away at your ION CLOUD if you choose poorly.I have coax that has been in use over 25 years...
you get good service when you buy good coax.

Offline Smurf Hunter

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Re: Antenna help
« Reply #26 on: September 29, 2015, 02:24:24 PM »
Feedline will eat away at your ION CLOUD if you choose poorly.I have coax that has been in use over 25 years...
you get good service when you buy good coax.

Here's some ION CLOUD for you

https://www.youtube.com/watch?v=CuRyNJDxBtc

Offline Carl

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Re: Antenna help
« Reply #27 on: September 29, 2015, 03:08:12 PM »
Here's some ION CLOUD for you

https://www.youtube.com/watch?v=CuRyNJDxBtc

That's how my antenna looks when I use high power....

Offline Alan Georges

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Re: Antenna help
« Reply #28 on: September 29, 2015, 04:11:44 PM »
That's how my antenna looks when I use high power....
Here's some high power, some ions, some fire...
https://www.youtube.com/watch?v=LWJPA4WdXXA

Wonder what his SWR is?

Offline Carl

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Re: Antenna help
« Reply #29 on: September 29, 2015, 05:30:46 PM »
Here's some high power, some ions, some fire...
https://www.youtube.com/watch?v=LWJPA4WdXXA

Wonder what his SWR is?

About 6 feet....