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Author Topic: My New Antenna Situation.  (Read 17371 times)

gil

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Re: My New Antenna Situation.
« Reply #30 on: July 30, 2016, 03:05:06 PM »
Indeed, seemed strange to me.. No explanation was provided...
Gil

cockpitbob

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Re: My New Antenna Situation.
« Reply #31 on: July 30, 2016, 06:23:51 PM »
Great! The EARCHI guy told me yhe maximum length of wire was 60ft, but I think he was just quoting their documentation. One great wire length is 71ft, then 84ft, like the W3EDP which has a 17ft counterpoise, directly into the tuner..

Gil

Don't know why they would limit it to 60' as there are several lengths recommended for use with a 9:1 unun.  Take a look at the chart here: http://www.thedxshop.com/media/wysiwyg/Wire_Lengths_for_9-1_ununs_1.pdf
Nice chart!  It's impressive, almost hard to believe, the low SWRs across all Ham bands they achieve.  I wish they put more specific counterpoise information in it.  My first guess is it's not measured data but calculated from EZNEC.  Still, it has me considering this kind of antenna instead of an EFHW which is confined to only the bands it is resonant on.

gil

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Re: My New Antenna Situation.
« Reply #32 on: July 30, 2016, 07:06:02 PM »
Quote
It's impressive, almost hard to believe, the low SWRs across all Ham bands they achieve.

I would be very surprised if it turned out to be true.

Gil.

Lamewolf

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Re: My New Antenna Situation.
« Reply #33 on: August 01, 2016, 07:12:15 AM »
Quote
It's impressive, almost hard to believe, the low SWRs across all Ham bands they achieve.

I would be very surprised if it turned out to be true.

Gil.

I've experimented with type of antenna on several occasions and found it not to be totally true.  But if you play with the length of the wire you can fins a length that will get you close enough on most bands that an internal auto tuner will handle it on all bands.  The only rig I have with an internal tuner is my Icom 703, but I have found several combinations that gets me multiband coverage with just one or two lengths of wire.  The first successful combo was with a 4:1 unun and a 23' wire for 10 thru 40 meter coverage  and a 50' wire for 10 thru 80 meter coverage.  That was several years back and the info can be found here: http://www.angelfire.com/electronic2/qrp/unun.html

kc8aon

KK0G

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Re: My New Antenna Situation.
« Reply #34 on: August 01, 2016, 08:32:02 AM »
Quote
It's impressive, almost hard to believe, the low SWRs across all Ham bands they achieve.

I would be very surprised if it turned out to be true.

Gil.


I wouldn't be the least bit surprised........ remember, a dummy load also has a low SWR across all ham bands.
"Those who would give up essential liberty to purchase temporary safety, deserve neither liberty nor safety" - Benjamin Franklin

KK0G

Lamewolf

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Re: My New Antenna Situation.
« Reply #35 on: August 01, 2016, 12:13:15 PM »
Quote
It's impressive, almost hard to believe, the low SWRs across all Ham bands they achieve.

I would be very surprised if it turned out to be true.

Gil.


I wouldn't be the least bit surprised........ remember, a dummy load also has a low SWR across all ham bands.

I saw a ham once that thought he had no swr on all bands on his G5RV, I told him that was impossible and he said that the swr meter in his tuner shows no swr anywhere and he just kept the tuner in bypass all the time.  I went over to check it out and sure enough, the swr meter didn't move !  Pulled the top off the old MFJ-989 tuner and there was no bridge circuit in it - just the meter and someone had removed the bridge circuit and soldered the connections straight through.  He had bought it cheap at a hamfest and I don't think he really understood how they worked.  He ordered a new MFJ 300 watt tuner and I bought the 989 and built a new bridge circuit to put in it.  The tuner worked great, but I later traded it for an Icom AH-4 auto tuner.

kc8aon

gil

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Re: My New Antenna Situation.
« Reply #36 on: September 07, 2016, 02:05:22 PM »
My 135ft Windom with dual core Guanella BALUN is up! Now I can use 80m, albeit only up to 3.8mHz. No need for a tuner on 80/40/20/10m.

Gil

RadioRay

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Re: My New Antenna Situation.
« Reply #37 on: September 07, 2016, 03:30:07 PM »
Oh , that's great, Gil!  It will be good to be able to get on the air whenever you feel like it, and with an antenna that is also very effective on the lower bands, maybe you can do a little NVIS conversational CW across the channel with the U.K. and up into Northern Europe where there is better chance of non-contest COMMUNICATION, rather than "599 TU" nonsense.

De RadioRay ...-  .-
« Last Edit: September 07, 2016, 03:31:40 PM by RadioRay »
"When we cannot do the good we would, we must be ready to do the good we can."  ~ Matthew Henry

gil

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Re: My New Antenna Situation.
« Reply #38 on: September 07, 2016, 04:55:48 PM »
Indeed, actually my first contact with the antenna was with the UK on 80m!

Gil

Lamewolf

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Re: My New Antenna Situation.
« Reply #39 on: September 07, 2016, 05:01:38 PM »
I really like my off center fed, it works super on 80, 40, 20, 17, 12, 10, and 6 meters and I have even used it on 15, 30, and 60 meters via the tuner.  It will even work on 2 meters without a tuner !  My homebrew guanella balun is wound on 2 FT240-61 cores and then I have 24 ferrite mix 43 cores on the feedline right below the balun to help choke of any CMC.  I like working DX on 40 meters the most with it and even worked Australia many times with it on 40 - about 10000 miles !

gil

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Re: My New Antenna Situation.
« Reply #40 on: January 13, 2017, 06:47:55 AM »
My Windom antenna broke!  :(

We had a wind storm last night and the thin wire from SotaBeams broke. I am surprised it lasted that long, not being made for permanent installations. The wire is pretty fragile. I need to make a new one, this time using thicker wire from The Wireman, probably #532 or #511. I also need to make a new dual Guanella BALUN, this time with 31 material ferrites, not 61 as I did. 61 is for the higher HF bands while 31 works great on 80m. I usually don't use bands above 20m and mostly stick to 80 and 40; no need to use 43 material either.

This time I won't use a support wire and will use proper insulators. I should look into supporting the BALUN however to use thicker coax than RG-174.

One interesting issue I had was using an RF choke on the coax. The BALUN was fed with 10m of RG-174 which was just long enough to make it through a window frame. From there I would either plug in another 5m or 10m of coax. Using 5m (total 15m) was fine on 40 upwards but not on 80m. I had to use 10m or even 20m (total 20 or 30m) of extra coax to get a low SWR on 80. When using my 10m RG-174 coax cable with ferrite beads on one end, the cable would only work with the ferrites at the radio end, not in the middle of the feedline. That told me I obviously had common mode currents on the coax outer shield. Changing the size of the Windom might solve the problem. I need to do some research on that. The dual-core Guanella was supposed to do a good job of insulating the antenna from the feedline, but it isn't a choke BALUN. I need to rethink my installation and try to avoid common mode currents and the use of a tuner. I could dispense with a tuner but had to play with coax lengths, not ideal.

This time I will build a stronger antenna which i can take with me when I move and won't break in high winds. My concern is the weight... Ah, decisions...

Gil.

gil

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Re: My New Antenna Situation.
« Reply #41 on: January 15, 2017, 01:12:29 PM »
Back to the drawing board...

This time I ordered 136ft of #511 wire from The Wireman. It's 14 AWG antenna wire with 7 strands of copper-clad steel, 349 lbs break strength. For the dual Guanella 4:1 BALUN I have FT114D-31 ferrites coming from an Ebay seller. These are the cheapest 31 material ferrites I could find. Also on the way are ceramic insulators for the ends and center of the new Windom.

I think I will go either with an 80/20% feed-point, 27ft (8.23m) from one end, or the classic 33% 44.5ft (13.5m). The antenna total length should end up being 135ft.

Good reading: http://www.buxcomm.com/windom.htm
BALUN: http://www.kn9b.us/guanella-balun

Stay tuned for photos and a possible video!

Gil.
« Last Edit: January 15, 2017, 02:09:34 PM by gil »

gil

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Re: My New Antenna Situation.
« Reply #42 on: February 08, 2017, 03:51:41 PM »




Radio Preppers

Re: My New Antenna Situation.
« Reply #42 on: February 08, 2017, 03:51:41 PM »