Author Topic: Antenna Experts - Advice Needed  (Read 5958 times)

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XJP5

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Antenna Experts - Advice Needed
« on: December 19, 2012, 09:29:35 PM »
I've been looking over HF antenna options to run here at my house. There are two dipole antennas under consideration, but the one I need the expertise on right now is the G5RV in the link below.

G5RV Antenna

Specs:
All Band Performance 80m-6m
102 feet long
The ladder line drop is 31'

I'm limited as to how I can hang this antenna. My lot is 111ft. in length by 53ft. wide and I live adjacent to a common park / greenbelt area. The greenbelt is on the West side (same side as the bedroom shown). After careful evaluation I've determined there is no way I can suspend this 102ft. long antenna in a straight line anywhere on my lot, and running it to a tree on the greenbelt is out of the question. The landscapers will tear it down if they see it. That bedroom is where my shack will be located, on the 2nd floor.

My fascia board (above the soffit) is made of wood and runs 360* around the house, approx. 17ft above ground. I was thinking of running the G5RV around the house, as shown in red below. My questions are as follows:

1. - Will this "U" shaped configuration and proximity to the house destroy my signal propagation?

2. - The antenna will be approx. 17ft. above the ground, but the antenna's ladder (feed line) is 31ft. long. What should I do with the excess and how will that affect my signal?

3. - Should I use RG-213 from the shack to the antenna or something else (RG-8x, etc.) I'm sure there is less loss on RG-213.

4. - I'm planning to use an manual antenna tuner with this configuration. Any brand / model recommendations? The MFJ-949E and MFJ-948 are two possibilities I'm considering. I like the LDG auto tuners, but they're expensive.

Thanks in advance for all your suggestions & advice. Let me know if you have additional questions - XJP5



« Last Edit: December 19, 2012, 10:09:29 PM by XJP5 »

Tempstar

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Re: Antenna Experts - Advice Needed
« Reply #1 on: December 22, 2012, 07:14:04 AM »
Running any of the legs parallel to each other will raise the SWR. I had great success with both a full size and a mini G5RV running as an inverted V. I mounted an antenna pole at the end of the house where the roof was the highest and got 37'  of elevation at the center. I had to make 12" wooden dowel stand offs for the ladder line to keep away from the metal pole.
 Another option may be to go vertical. I have a Chameleon antenna for field ops that works great and tunes everything. I bought it for ALE but now use it for everything. The correct combination for no tune set-ups is the Hybrid base, V1L whip, and MIL whip. The MIL replaces the top whip section of the V1L.

www.chameleonantenna.com

 I have pal that bought a 43' telescoping fiberglass pole with a wire inside and an SO-239 on it. It does really well for the $100 he paid for it.
 You may also want to consider a G5RV mini. They do well, but you need a 10:1 tuner to get 80 meters, as well as around 30' of height.
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XJP5

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Re: Antenna Experts - Advice Needed
« Reply #2 on: December 22, 2012, 09:29:59 AM »
Running any of the legs parallel to each other will raise the SWR. I had great success with both a full size and a mini G5RV running as an inverted V. I mounted an antenna pole at the end of the house where the roof was the highest and got 37'  of elevation at the center. I had to make 12" wooden dowel stand offs for the ladder line to keep away from the metal pole.
 Another option may be to go vertical. I have a Chameleon antenna for field ops that works great and tunes everything. I bought it for ALE but now use it for everything. The correct combination for no tune set-ups is the Hybrid base, V1L whip, and MIL whip. The MIL replaces the top whip section of the V1L.

www.chameleonantenna.com

 I have pal that bought a 43' telescoping fiberglass pole with a wire inside and an SO-239 on it. It does really well for the $100 he paid for it.  You may also want to consider a G5RV mini. They do well, but you need a 10:1 tuner to get 80 meters, as well as around 30' of height.

From a cost perspective, I'll give the G5RV Jr. a go first and see how that works. If it doesn't work well, I may have to look into going with a vertical like the Chameleon, where I can put it up after dark, talk for a while, then take it down before morning with some type of fold-down base mount. That will be a PITA for sure, but I have few choices. The G5RV Jr. has a 51' length and 15.5' ladder height, but I can only use it from 40m - 6m.

I suspected that wrapping the dipole around the roof line in a U shape was going to change the propagation characteristics of the antenna, but just wasn't sure how. I will look further into that Chameleon, but whatever I end up with, it has to be low visibility. Because of my being adjacent to the common areas, the house is very visible, and with all the people walking by, I wouldn't put it past some of them to call the HOA.

Thanks for your input Tempstar  :)
« Last Edit: December 22, 2012, 09:55:14 AM by XJP5 »

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Re: Antenna Experts - Advice Needed
« Reply #3 on: December 22, 2012, 09:33:16 PM »
I missed the coax question: 213 is an excellent choice. The Chameleon setup will rub you $400 plus, but you save on not having to have a tuner. Mine gets up to 2.1:1 swr on the upper side of 40, but the radio handles it (IC-7000). Also I missed on the ladder line too. If it isn't straight you get some crazy SWR too. It needs to be 90 degrees to the dipole portion.
 A 40' flagpole is allowed by a lot of HOAs. A fiberglass one with a random wire works pretty well.
73
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XJP5

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Re: Antenna Experts - Advice Needed
« Reply #4 on: December 23, 2012, 01:57:48 AM »
I missed the coax question: 213 is an excellent choice. The Chameleon setup will rub you $400 plus, but you save on not having to have a tuner. Mine gets up to 2.1:1 swr on the upper side of 40, but the radio handles it (IC-7000). Also I missed on the ladder line too. If it isn't straight you get some crazy SWR too. It needs to be 90 degrees to the dipole portion.
 A 40' flagpole is allowed by a lot of HOAs. A fiberglass one with a random wire works pretty well.
73

Good to know, because I'm leaning towards purchasing an IC-7000 in Feb. I'm still looking at some other units as well, but leaning heavily towards the Icom. I'd prefer a base unit but hate to spend that much, and might look at what's on the used market locally before I buy, just to see if there are any good rigs for sale, but I'm pretty picky and want to get something that was well-cared for, so that might limit my options.

Thanks for all your helpful info Tempstar. I do appreciate it!

BTW - I'd love to install one of the Zero-Five flagpole antennas out front as a way to stick it to the HOA. They nit-picked me once in 15 years for a 3" weed, while some of the renters across the street park on the front lawn. We were like ... "You've got to be kidding me!"  >:(
« Last Edit: December 23, 2012, 02:51:44 AM by XJP5 »

idial1911

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Re: Antenna Experts - Advice Needed
« Reply #5 on: February 28, 2013, 09:46:10 PM »
Before you buy an ic-7000 ping me.. I might sell you mine used.. Works great, just considering of switching my gear around. Might even sell my k3.
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XJP5

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Re: Antenna Experts - Advice Needed
« Reply #6 on: March 01, 2013, 05:58:01 AM »
Before you buy an ic-7000 ping me.. I might sell you mine used.. Works great, just considering of switching my gear around. Might even sell my k3.

Thanks 1911 - I ended up purchasing a Kenwood TS-480HX (200 watt model) last weekend. I'm sure you won't have any trouble selling either of those radios. If I hear of anyone looking, I'll let you know.
« Last Edit: March 01, 2013, 03:33:46 PM by XJP5 »

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Re: Antenna Experts - Advice Needed
« Reply #7 on: March 01, 2013, 01:08:44 PM »
Just a NOTE, on coax.... The losses in coax rise with Frequency,,,, at HF, for runs less that 100 Ft, if your power level is less than 150 watts, it makes very little ACTUAL noticeable difference, in what Type of coax you use. (RG-58, RG-8, RG213, or Beldon 9913) You need MORE that RG-58 if you plan on running a KW, but up to 150 Watts, it is just fine....  I got a heck of a deal on Beldon 9913 a few years back and bought 3000 ft... Use that for everything up to 200 Mhz then go to Heliax from there up...Just Say'en....
Bruce in alaska AL7AQ

Lamewolf

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Re: Antenna Experts - Advice Needed
« Reply #8 on: October 22, 2015, 09:36:53 AM »
Just a NOTE, on coax.... The losses in coax rise with Frequency,,,, at HF, for runs less that 100 Ft, if your power level is less than 150 watts, it makes very little ACTUAL noticeable difference, in what Type of coax you use. (RG-58, RG-8, RG213, or Beldon 9913) You need MORE that RG-58 if you plan on running a KW, but up to 150 Watts, it is just fine....  I got a heck of a deal on Beldon 9913 a few years back and bought 3000 ft... Use that for everything up to 200 Mhz then go to Heliax from there up...Just Say'en....

The loss on coax also rises "GREATLY" as swr increases !  If you are using coax for multiband use, try to keep it 25' or shorter if possible to help reduce losses.  The loss figures for coax are stated in a matched condition, not one with a very high swr !

If I were going to run a wire near the soffit of the house, I would make it a loop that goes all the way around the house and then feed it with as short a coax as possible - just put the feedpoint as near the shack as possible.  Also, use insulated wire for the loop that is the same color as the soffit to help hide it.

spacecase0

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Re: Antenna Experts - Advice Needed
« Reply #9 on: October 22, 2015, 07:37:07 PM »
remote tuner also solves the coax issue

Tempstar

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Re: Antenna Experts - Advice Needed
« Reply #10 on: October 22, 2015, 08:29:31 PM »
Right on Space. The whole tuner game is to make the radio happy, antenna system be damned. Tuning the coax as well helps put more watts out the end.
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