[TowerTalk] Cushcraft R7000 and MFJ-1796, MFJ-1798 verticles

[Bill Coleman AA4LR]

On 5/3/98 2:21 AM, Dan Baldwin at baldwin@primenet.com wrote:

>I am considering buying the Cushcraft R7000 and MFJ verticle antennas
>(MFJ-1796 and 1798). I like the construction of the Cushcraft R7000
>but I would also like the verticle ground mounted. I am really not sure
>the R7000 can be ground mounted (about 3 feet off the ground).

I own an R7000. Right now, since I don't have a tower and my beam is on 
loan to a fellow ham, it is my primary antenna.

According to Art at Cushcraft, the R7000 was designed to be mounted about 
18 feet off the ground. The minimum height should be about 6-8 feet. Mine 
is at 7.5 feet. Since the counterpoise disk can have relatively high 
voltages present when transmitting, having the antenna high enough to 
keep these out of reach is probably a good idea.

> I
>know the MFJ antennas can but have heard that their verticles are not well
>constructed. I don't have room for ground radials so I am looking for
>a verticle which I don't have to attach ground radials. Does anyone have
>any info. on the subject if so I would sure appreciate it. 

The R7000 is a pretty good antenna. While it won't replace a beam on 20m, 
it performs well on 40m, although the usable bandwidth is rather narrow. 
If your rig has an automatic antenna tuner, you won't notice. I haven't 
tried the 80m option, as I feel it narrows the usable bandwidth on 40m 
too much.

If your limited in the number of antennas you can put up, the R7000 isn't 
a bad choice. If you have supports to erect high doublets (I don't), you 
might just consider putting up a few dipoles or a tuned-feeder doublet.

Although it isn't suppose to work, my R7000 is marginally useful on 160m 
-- must be some quirk in the installation. SWR is high, but my rig pumps 
about 60 watts into it. I have made about 4 contacts on 160m CW with it, 
one as far away as Texas (from Georgia). Probably a tribute to the 
receiving arrays on the other end.



Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@radio.org
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901


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