Advanced Electronic Applications IsoLoop LC-2 Operating Manual
Advanced Electronic Applications IsoLoop LC-2 is a compact, high-performance HF antenna that is ideal for hams with limited space or those who want to take their station on the road. The IsoLoop is a tuned loop antenna that covers the 10-30 MHz bands and features a stepping-motor-driven tuning capacitor that allows for precise frequency selection. The antenna is easy to set up and operate, and it provides excellent performance on all bands. The IsoLoop is also very versatile and can be used for a variety of applications, including DXing, contesting, and general purpose operating.
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IsoLoopTM 10-30 HF Antenna
LC-2 Loop Controller
Operating Manual
Advanced Electronic Applications, Inc.
LC-2 Loop Controller
Operating Manual
Advanced Electronic Applications, Inc.
CONTENTS
Helpful Hints
1
Features
4
Theory of Operation
5
Specifications
5
Unpacking Instructions
5
Mounting the Isoloop
6
Hook-up
9
For Your Health and Safety
10
LC-2 Calibration
11
Operation
12
Troubleshooting and Service
13
Packing List
.„
•
14
LC-2 Schematic Diagram
LC-2 Parts Pictorial
16
Warranty
17
•
•
•
Helpful Hints
1
Features
4
Theory of Operation
5
Specifications
5
Unpacking Instructions
5
Mounting the Isoloop
6
Hook-up
9
For Your Health and Safety
10
LC-2 Calibration
11
Operation
12
Troubleshooting and Service
13
Packing List
.„
•
14
LC-2 Schematic Diagram
LC-2 Parts Pictorial
16
Warranty
17
•
•
•
HELPFUL HINTS
• 1. HELPFUL HINTS
The following was sent in by John Pollock, KA7MCX, regarding some of his
experiences with the IsoLoop 14-30 antenna. You may want to read this section
now, as it might provide you with some insight as you set up and operate the an-
tenna for the first time. We also recommend re-reading this section after you com-
plete the installation and have operated the IsoLoop a few times, as some of the
terms and ideas used will be more familiar at that time.
Why was I one of the first to buy the original IsoLoop? Many times
the first few days thereafter I seriously pondered that question. The
durn thing wasn't working, the instructions were less than clear, and
I was hearing lots of "told you so's" from friends. I was on the verge
of returning my IsoLoop for something more conventional, but
decided instead to call the folks at AEA who had had the gall to put
this weird product on the market.
A phone call to AEA's Customer Service made a
big
difference.
From then on, the more I used my 'Loop, the better it seemed to play.
Some of the mistakes I had been making were due to my inability to
understand the instructions, others were due to plain old operator
incompetence. All were, in retrospect, dumb! But as most of them
could still apply to the new (and greatly improved) 10-30 IsoLoop, I'll
list a few hard learned experiences that just may help someone else.
Coax. After I assembled my original 'Loop, I climbed to the roof
and connected it to an unused piece of RG-8. Results were disap-pointing: finally bought some new, lighter coax and things suddenly
got much better. Heavy coax does not appear to be essential andfresh coax is well worth the small investment.
Tuners. I first used my 'Loop with a Kenwood TS-440S. As this
rig has the optional internal automatic tuner, it was in this position
when I connected the coax. Not knowing whether to fist tune the'Loop or the 440, I tried both methods — with horrible results. After
one of the phone calls, I set the AT-TUNE switch to OFF, and the
difference was dramatic! And it certainly made things more simple
when I later used the 'Loop with a TS-680S - meant I didn't have the
cost and bother of an external tuner.
Frequency Modulation. I have a few of the ten meter repeaters
programmed into memory channels, as it can be interesting to hear
FM signals from the other side of the country, or even across the
Pacific. The first time I tried to use the 'Loop on the of these, it
wouldn't tune - until I switched the mode from FM to USB. Once
tuned, I switched back to FM and worked repeaters on severalfrequencies. Moral: tune in SSB, CW or AM modes, not FM. [White
noise will not "peak" in FM mode!]
QSO's. It seemed natural to tune across the bands until
I
heard
an interesting QSO in progress, then to tune the 'Loop on the received
signal(s). I soon learned that this was a tough way to do it because
•
•
• 1. HELPFUL HINTS
The following was sent in by John Pollock, KA7MCX, regarding some of his
experiences with the IsoLoop 14-30 antenna. You may want to read this section
now, as it might provide you with some insight as you set up and operate the an-
tenna for the first time. We also recommend re-reading this section after you com-
plete the installation and have operated the IsoLoop a few times, as some of the
terms and ideas used will be more familiar at that time.
Why was I one of the first to buy the original IsoLoop? Many times
the first few days thereafter I seriously pondered that question. The
durn thing wasn't working, the instructions were less than clear, and
I was hearing lots of "told you so's" from friends. I was on the verge
of returning my IsoLoop for something more conventional, but
decided instead to call the folks at AEA who had had the gall to put
this weird product on the market.
A phone call to AEA's Customer Service made a
big
difference.
From then on, the more I used my 'Loop, the better it seemed to play.
Some of the mistakes I had been making were due to my inability to
understand the instructions, others were due to plain old operator
incompetence. All were, in retrospect, dumb! But as most of them
could still apply to the new (and greatly improved) 10-30 IsoLoop, I'll
list a few hard learned experiences that just may help someone else.
Coax. After I assembled my original 'Loop, I climbed to the roof
and connected it to an unused piece of RG-8. Results were disap-pointing: finally bought some new, lighter coax and things suddenly
got much better. Heavy coax does not appear to be essential andfresh coax is well worth the small investment.
Tuners. I first used my 'Loop with a Kenwood TS-440S. As this
rig has the optional internal automatic tuner, it was in this position
when I connected the coax. Not knowing whether to fist tune the'Loop or the 440, I tried both methods — with horrible results. After
one of the phone calls, I set the AT-TUNE switch to OFF, and the
difference was dramatic! And it certainly made things more simple
when I later used the 'Loop with a TS-680S - meant I didn't have the
cost and bother of an external tuner.
Frequency Modulation. I have a few of the ten meter repeaters
programmed into memory channels, as it can be interesting to hear
FM signals from the other side of the country, or even across the
Pacific. The first time I tried to use the 'Loop on the of these, it
wouldn't tune - until I switched the mode from FM to USB. Once
tuned, I switched back to FM and worked repeaters on severalfrequencies. Moral: tune in SSB, CW or AM modes, not FM. [White
noise will not "peak" in FM mode!]
QSO's. It seemed natural to tune across the bands until
I
heard
an interesting QSO in progress, then to tune the 'Loop on the received
signal(s). I soon learned that this was a tough way to do it because
•
•
HELPFUL HINTS
SSB signals cause the "S" meter to bounce so much that it is almost
impossible to identify the "hot spot" while tuning across it. Much
better to find a nearby frequency and tune on the "white noise"; even
better to find an RTIY signal or a heterodyne where the "S" meter
will have little or no fluctuations. [Also, turn the AGC switch to "FAST"
position to you can see the fast peak on the "S" meter while tuning.]
Audio. The IsoLoop is something the engineers call a "high Q"
design. I now understand that means it is very efficient, but only
within a very narrow frequency range. The motor driven capacitor
lets you move that one spot over several bands; learning to find that
"hot spot" quickly is the key to really enjoying a 'Loop. My technique
when changing bands is to first turn up the transceiver's audio much
higher than normal, then run the motor switch at full speed in one
direction. The higher the gain, the easier it is to hear that very quick
burst of noise the first time the 'Loop tunes through it. Then change
to the slowest speed and run the motor in the opposite direction,
while carefully watching the "S" meter. Now turn the gain down to a
comfortable level. Tweak the motor a click or two at the slowest speed
as you tune up or down a band. It should not be necessary to adjust
the audio level if you pay attention to that "S" meter.
Direction. Soon after learning how to use it, I used the 'Loop in
the CQWW; I wondered if it might be possible to work DXCC during
the contest weekend. (Turned out it was - 116 countries in less than
24 hours operating time!) Each time I changed bands, I would
carefully note which direction the motor switch was working as I
would "hunt & pounce" up a given band. When I later returned to
the previous band, I would tweak the switch the same direction as I
tuned up that band. Sometimes it would work, sometimes it
wouldn't. Finally figured out that each time that giant capacitor
inside the 'Loop makes one complete revolution, it tunes through any
given frequency twice; once in each direction.
[This is important to understand. If you hold down one direction button
on the LC-2, the IsoLoop's tuned or resonant frequency will go up to
the end of the range and then back down, or vice versa. It will not go
up to 30 MHz and then start over again at 10 MHz.]
I soon learned to listed carefully the first time I moved the VFO after
tuning the 'Loop - to nudge the motor just a bit in each direction
until I was sure "which way was up".
Bandwidth. During that contest, I learned that on ten meters I
could often move as much as forty to fifty kHz before retuning the
IsoLoop. When ten [the 10 meter band; 28 to 29.7 MHz] shut for the
night and I moved to twenty [the 20 meter band; 14.0 to 14.35 MHz], I
was not doing as well. Eventually I figured out that the lower the
frequency, the narrower the "hot spot" and the more frequently it
was necessary to retune. I now tend to tune every 30-40 kHz on ten
meters but every 10 kHz when on twenty meters. I also discovered
the fun to be had on the twelve and seventeen meter bands - I tune
the 'Loop near the center of either the CW or SSB portion. and seldom
find it necessary to retune as I listen across these narrow bands. And
2
SSB signals cause the "S" meter to bounce so much that it is almost
impossible to identify the "hot spot" while tuning across it. Much
better to find a nearby frequency and tune on the "white noise"; even
better to find an RTIY signal or a heterodyne where the "S" meter
will have little or no fluctuations. [Also, turn the AGC switch to "FAST"
position to you can see the fast peak on the "S" meter while tuning.]
Audio. The IsoLoop is something the engineers call a "high Q"
design. I now understand that means it is very efficient, but only
within a very narrow frequency range. The motor driven capacitor
lets you move that one spot over several bands; learning to find that
"hot spot" quickly is the key to really enjoying a 'Loop. My technique
when changing bands is to first turn up the transceiver's audio much
higher than normal, then run the motor switch at full speed in one
direction. The higher the gain, the easier it is to hear that very quick
burst of noise the first time the 'Loop tunes through it. Then change
to the slowest speed and run the motor in the opposite direction,
while carefully watching the "S" meter. Now turn the gain down to a
comfortable level. Tweak the motor a click or two at the slowest speed
as you tune up or down a band. It should not be necessary to adjust
the audio level if you pay attention to that "S" meter.
Direction. Soon after learning how to use it, I used the 'Loop in
the CQWW; I wondered if it might be possible to work DXCC during
the contest weekend. (Turned out it was - 116 countries in less than
24 hours operating time!) Each time I changed bands, I would
carefully note which direction the motor switch was working as I
would "hunt & pounce" up a given band. When I later returned to
the previous band, I would tweak the switch the same direction as I
tuned up that band. Sometimes it would work, sometimes it
wouldn't. Finally figured out that each time that giant capacitor
inside the 'Loop makes one complete revolution, it tunes through any
given frequency twice; once in each direction.
[This is important to understand. If you hold down one direction button
on the LC-2, the IsoLoop's tuned or resonant frequency will go up to
the end of the range and then back down, or vice versa. It will not go
up to 30 MHz and then start over again at 10 MHz.]
I soon learned to listed carefully the first time I moved the VFO after
tuning the 'Loop - to nudge the motor just a bit in each direction
until I was sure "which way was up".
Bandwidth. During that contest, I learned that on ten meters I
could often move as much as forty to fifty kHz before retuning the
IsoLoop. When ten [the 10 meter band; 28 to 29.7 MHz] shut for the
night and I moved to twenty [the 20 meter band; 14.0 to 14.35 MHz], I
was not doing as well. Eventually I figured out that the lower the
frequency, the narrower the "hot spot" and the more frequently it
was necessary to retune. I now tend to tune every 30-40 kHz on ten
meters but every 10 kHz when on twenty meters. I also discovered
the fun to be had on the twelve and seventeen meter bands - I tune
the 'Loop near the center of either the CW or SSB portion. and seldom
find it necessary to retune as I listen across these narrow bands. And
2
5
6
7
8
9
10
11
12
13
14
15
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17
18
19
20
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Key Features
- Frequency control
- Visual tuning indicators
- Audio level indicator
- Compact size
- Easy to use
- Intuitive controls
- Frequency indicator
Related manuals
Frequently Answers and Questions
How do I calibrate the frequency indicator on the LC-2?
Follow the steps in section 9: LC-2 Calibration.
What is the proper way to adjust the antenna's tuning?
Use a combination of audio noise levels and SWR readings to achieve optimal tuning. Start by tuning with the SPEED control and arrow keys, then fine-tune using the SWR meter on your transceiver.
Can I use an antenna tuner with the IsoLoop?
No, do not use an antenna tuner with the IsoLoop. Turn off any built-in or automatic tuners on your transceiver as well.
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