A Plug for the ZS6BKW

K6GBW

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Joined
May 29, 2016
Messages
93
Location
Montebello, CA
I've been running and fed antennas for some time with mediocre results. I later started using a Buschcomm SWC-100 antenna that uses resistors to make it have a low SWR on all bands. Very handy! But it's also dead and eats power so you don't get out too well. Based on some things that PRCGuy wrote I decided to make a ZS6BKW antenna that is a variation on the G5RV theme. I made mine using 93 feet of wire on top and a matching section of 36.5 feet of 300 ohm window line. This was followed with 24 feet of LMR400 to the tuner. Amazingly, this thing only need a touch of tuner (the rigs internal tuner works) on 40 meters. 20 meters needs nothing at all. It tunes all bands 80-10 with a simple external tuner. As for performance, well I can't tell any difference on 40-20 from a regular dipole. On 80 I'm sure its not getting out at well as a dipole but it does work well enough to be heard.

For a cheap and easy antenna that's short enough to use in just about anyone's yard I can't recommend this highly enough!
 

prcguy

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Jun 30, 2006
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11,532
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So Cal - Richardson, TX - Tewksbury, MA
I ran one for many years and was very happy with it. You do need a good 1:1 choke balun at the balanced line/coax junction, otherwise it has a reasonable match on many bands and with a tuner it works surprisingly well on 80m. Its a very good upgrade from a G5RV, which was designed for 20m and has a lousy match on all other bands.

I've been running and fed antennas for some time with mediocre results. I later started using a Buschcomm SWC-100 antenna that uses resistors to make it have a low SWR on all bands. Very handy! But it's also dead and eats power so you don't get out too well. Based on some things that PRCGuy wrote I decided to make a ZS6BKW antenna that is a variation on the G5RV theme. I made mine using 93 feet of wire on top and a matching section of 36.5 feet of 300 ohm window line. This was followed with 24 feet of LMR400 to the tuner. Amazingly, this thing only need a touch of tuner (the rigs internal tuner works) on 40 meters. 20 meters needs nothing at all. It tunes all bands 80-10 with a simple external tuner. As for performance, well I can't tell any difference on 40-20 from a regular dipole. On 80 I'm sure its not getting out at well as a dipole but it does work well enough to be heard.

For a cheap and easy antenna that's short enough to use in just about anyone's yard I can't recommend this highly enough!
 

K6GBW

Member
Joined
May 29, 2016
Messages
93
Location
Montebello, CA
Roger that. I'm using a Palomar Engineers 1:1 tuner balun between the LMR400 and the window line. Just wish I'd tried this thing sooner!
 

K6GBW

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Joined
May 29, 2016
Messages
93
Location
Montebello, CA
PRC, if I want to convert this to an all band(ish) doublet later then all I have to do is extend the twin lead all the way back to the tuner...right?

B
 

prcguy

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Jun 30, 2006
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So Cal - Richardson, TX - Tewksbury, MA
Is this for transmitting or receiving? If you have a tuner with balanced output it should tune just about anywhere using twin lead (450 ohm ladder line) for the entire feedline run and the performance should be about the same on all bands where the stock antenna has a good match and it should work better on bands like 80m where the VSWR is getting up there like 6:1 or 8:1. If you have something like 100ft of RG-58 now, the coax loss could be approaching 6dB on 80m and going all twin lead will fix most of that.

For SW receive I don't think it matters much as reception is governed by signal to noise ratio and several dB of feedline loss due to the coax operating into a high VSWR will reduce signal and noise the same amount. With an antenna that size there should be plenty of signal across the entire SW bands even with high VSWR.

PRC, if I want to convert this to an all band(ish) doublet later then all I have to do is extend the twin lead all the way back to the tuner...right?

B
 

K6GBW

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May 29, 2016
Messages
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Location
Montebello, CA
Transmitting for sure. I have exactly 24' of LMR400 going to it now, but in the future I'm considering lengthening the 300 ohm twin lead all the way back through the wall to the tuner. I'm may splurge for a balanced line, tuner but not sure yet. I just hooked up an MFJ-939 tuner to this thing and it's tuning everything 80-10 just fine. It even tuned 15 meters which I didn't expect. Do you think I have much loss in 24 feet of coax? I only ever run 100 watts so every watt counts.
 

prcguy

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So Cal - Richardson, TX - Tewksbury, MA
That will be very low loss even at 20:1, I wouldn't worry about it. 450 ohm ladder line is better than 300 ohm. I have spools of it if you need some.

Transmitting for sure. I have exactly 24' of LMR400 going to it now, but in the future I'm considering lengthening the 300 ohm twin lead all the way back through the wall to the tuner. I'm may splurge for a balanced line, tuner but not sure yet. I just hooked up an MFJ-939 tuner to this thing and it's tuning everything 80-10 just fine. It even tuned 15 meters which I didn't expect. Do you think I have much loss in 24 feet of coax? I only ever run 100 watts so every watt counts.
 

K6GBW

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Joined
May 29, 2016
Messages
93
Location
Montebello, CA
I went with 300 ohm to make kit less "ugly" according to the XYL. Overall, I'm pretty happy with it. I seem to get out better than I can hear, but that's likely due to the local noise from the neighborhood. The FTDX10d helps a lot with that. Between the DNR and the RF gain I can get most of it out.
 
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