tom:
I have limited experience with the G5RV, but I'll offer what I have observed 
and experienced.
A few weekends ago, we went for an anual ham picnic south of here.
One of the guys there set up a G5RV, one of the original ones built by the 
holder of the callsign G5RV from the UK.  It was old, but he strung it up 
about 10 feet off the ground, and layed the latter line down and hooked up a 
piece of coax directly to the latter line.
He worked 40 meters out to 800 miles without any kind of difficulty using 
100 watts.  Conditions weren't anything special, barely average if anything.
It also performed on 80 as well as could be expected with 100 watts and 10 
feet off the ground.
My point here is that from my fairly limited experience, I think the G5RV 
can be deployed in very limited situations and will perform fairly well.
It appears to be a very forgiving antenna.  Obviously not the best antenna 
you could possibly throw up, but a great performer and able to get you on 
most bands with a regular auto tuner.
My group just built a G5RV style antenna from information gleened from the 
net.  30.6 feet of 450 ohm latter line, hooked to two pieces of wire 51 FT 
long, and fed directly with 50 ohm coax.
Using an LDG z100 pro (I think perhaps z11?), it tuned up on all ham bands 
from 80 through 10 and worked reasonably well.
We had ours at 30FT at the center, and down to 20Ft and 15FT on the ends. 
I'm not all that sure it worked any better than the guy next to us using the 
original G5RV 10 feet off the ground.
Of course, having that 102 feet of linear space is going to be the difficult 
bit.
But, with an end fed zep, your still goign to need at least 66 feet of 
linear space if you want to work 40M and up.
Not to mention the 33 feet of latter line which should be in free space for 
the best results.

73
Colin, V A6BKx
----- Original Message ----- 
From: "Tom Behler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, July 01, 2012 8:23 PM
Subject: Re: End Fed Zep Antenna


>        Mike:
>
> I actually have a 102-foot G5RV, just sitting here doing nothing, but my
> concerns in using it are as follows:
>
> 1.  I don't have 102 feet of space to work with, and
>
> 2.  I don't think I could get it high enough to work well, especially on 
> 40
> meters.
>
> If you have other suggestions for easy-to-deploy wire antennas, feel free 
> to
> send them my way.
>
> I'm looking for something to cover 40 through 10, and 80 through 10 if at
> all possible, although I realize that is a very tall order.
>
> 73 from Tom Behler: KB8TYJ
>
> ----- Original Message ----- 
> From: "Mike Duke, K5XU" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Sunday, July 01, 2012 10:16 PM
> Subject: Re: End Fed Zep Antenna
>
>
>> Tom,
>>
>> I ran one on 80 meters for several years.
>>
>> They work, but the internal automatic tuners are not likely to be able
>> to handle them.
>> For those who do not know what this antenna is, it is a half wave
>> length of wire at the lowest frequency you wish to work. As the name
>> implies, it is fed at one end by connecting one side of a piece of
>> open wire line or more likely now days, 450 ohm window line to the end
>> of the half wave length of wire. The other wire in the window line is
>> left un-terminated at the antenna end, but connected to the ground
>> terminal, or to the other side of the balun of the antenna tuner. This
>> un-used conductor basically works much like a counterpoise, and thus
>> becomes more or less the second half of the antenna.
>>
>> The advantages of the end fed Zep are that it will tune on several
>> bands above the design frequency. Also because it is end fed, it is
>> often much easier to keep all or most of it hidden from the antenna
>> police.
>>
>> One disadvantage is that it tends to be a little less efficient than a
>> center fed, although it certainly works well enough if you can get it
>> tuned.
>>
>> The biggest disadvantage, however, is that matching the end fed zep is
>> very tricky.
>>
>> The matching problem occurs because the antenna is fed at the end of a
>> half wave. This means the impedance is extremely high. Also, because
>> it is fed at a high rf voltage point, rather than at the high current
>> point in the center, not all tuners will handle the high voltage, even
>> at the 100 watt power level.
>>
>> The one I ran was cut for 80 meters. It would tune fine on 40, 20, and
>> parts of 10 meters, but not well anywhere else.
>>
>> There are some end fed zeps on the market that have a matching network
>> for one specific band, and that match the antenna directly to coax.
>> There is also at least one out there that claims to work on 40, 20,
>> and 10 meters.
>>
>> We were trying to use that multi band model for our GOTA station at
>> field day last weekend. However, when we changed to a G5RV Junior, it
>> blew the end fed right off the planet on both 40 and 20 meters.
>>
>>
>>
>> ----- Original Message ----- 
>> From: "Tom Behler" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Sunday, July 01, 2012 4:18 PM
>> Subject: End Fed Zep Antenna
>>
>>
>> Hi, all.
>>
>> As many of you know, I have been struggling with the Predator
>> screw-driver
>> antenna on my 31-foot Holiday Rambler RV, ever since my N2VZ
>> Turbo-tuner
>> became non-functional back about a year ago.
>>
>> The Turbo-tuner issue is another story for another day, but suffice it
>> to
>> say that, due to the fact that N2VZ won't honor is "Lifetime
>> Warranty", it
>> is now not a viable option for me.
>>
>> Anyway, in the interest of moving on, and pursuing other
>> possibilities, I am
>> wondering if something like an end-fed zep antenna might be an
>> easily-deployable HF antenna for the RV.  There is not much room in
>> our RV
>> spot for a traditional half-wave dipole, or even an antenna like the
>> Alpha
>> Delta DXCC, but I thought an end-fed zep might be fun to try.
>>
>> Does anyone have experience with these?
>>
>> How much wire  would I need to get up and running, say on 40 through
>> 10
>> meters?
>>
>> How easy or dificult would it be to make one?
>>
>> I think I could run the antenna from the RV to a tree on the other end
>> of
>> our RV lot, if that would help.
>>
>> Just exploring options here.
>>
>> With the North American QSO Party CW contest coming up in early
>> August, I'd
>> like to have something up and running from the RV by that time, even
>> if it
>> is temporary.
>>
>> 73 from Tom Behler: KB8TYJ
>>