On Thu, 12 Mar 1998 15:12:58 -0500 MALEXANDER@HEALTHDYNE.com writes:
>Thank you all for the responses regarding Legal Limit Tuners. I
>received some excellent suggestions. Everyone agreed to stay away
>MFJ -- surprise surprise...Some recommended the N4XM unit(dddid you
>th-th-thousand ??). Some recommended the old Heathkit roller inductor
>units. I heard both pros and cons regarding the Nye Viking $800 jobs.
>Lotta shillings...it oughta be superb...
First you have to decide WHY you need a tuner; then the bands you need a
There is very little reason to use a tuner with many coax fed antennas. I
have loaded everything from A to Z brand amps into coax fed antennas with
up to 4:1 VSWR or so. I use the same dipole on 3.5MHz as I do on 3.8MHz.
I simply changed the value of the fixed loading cap in the amp to
On 160M I run phased verticals and switch patterns cardioid or broadside
and also just selected the fixed Load C in the amp. The idea of outdoor
networks, relays, etc does not appeal to me.
My HF Yagis are all old homebrew W2PV-4 designs with fairly narrow 2:1
VSWR points...never used a tuner, never had a problem with an amp.
Remember, a tuner will not make your antenna work any better OR reduce
feedline loss. When I run 100W I often use the built-in tuner but that
is strictly to keep the xcvr protective circuits happy.
The Nye and Drake tuners are only L networks, they have very limited
matching range on the lower bands.
The ATR-15 is a very nice unit and is a slightly improved copy of the big
Dentron. It also suffers from insufficient C on 160 and I would not
advise using on 10/12M.
If you MUST have a tuner, pick up a pair of 400-500pf vacuum variables,
turns counters, a large 12-18 position switch, a large ceramic form from
a fleamarket or a swap newsgroup.....the stuff is out there and at
reasonable prices. Use a length of #8 or #6 bare copper wire or
refrigerator ice maker tubing for the coil. If you are real lucky you can
find a 15 Amp fixed inductor made by Multronics or others. You can
customize as required and the above parts will handle all the power you
want, even RTTY.
At 1500W + I would not recommend a roller inductor for long term
reliability..unless you get a 15A + edgewound or copper tubing
type....then the stray L &C will limit the upper frequency limit.
GL Carl KM1H
>I didn't hear anything about the Drake MN-4 or the Ameritron ATR-15
>unit. Does anyone out there have any success / horror stories about
>It may help -- and I should have said this in the first place -- I
>operate 100w up to full continuous power from 160 thru 10 meters. I
>seeketh DX wheresoever it lurketh.
>73 and gd dx, gentlemen --
>Mitch P. Alexander KG9DB/4
>FAQ on WWW: http://www.contesting.com/ampfaq.html
>Administrative requests: amps-REQUEST@contesting.com
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]
FAQ on WWW: http://www.contesting.com/ampfaq.html
Administrative requests: amps-REQUEST@contesting.com