MFJ-1020C Indoor Active Antenna

[eraweeb]

Does anyone out there have any experience using an MFJ-1020C Indoor Active Antenna? I would really appreciate any comments or opinions that you have regarding this unit.

I plan to use it with an Icom IC-R20 receiver. Thank you in advance!

 

[E-Man]

Yes unfortunately I do. I purchased the unit because of the favorable review from Passport To World Band Radio. I used it as a tuned pre-selector with an external antenna (which Passport reported worked very well) Well it did not work for me, it was a time consuming chore trying to tune it spot on with no listening improvement. The signal meter showed an increased signal, but there was no difference in audio quality from the peaked meter or bypassing the unit.

I now kinda wonder about Passport, or I guess it could be one of those your mileage may vary kind of things.

My recommendation would be if you try one, make sure the place you order it from has a decent return policy.

 

[Turbo68]

I used the MFJ-1024 Outdoor Active Antenna with no success at all and picked up more signals with a piece of wire than the MFJ.

Regards Lino.

 

[dougw65]

I've found active antennas to be real finicky and less reliable than plain ol wire, an alligator clip to a window etc. For your icom, you may want to give the miracle whip a try. google "miracle whip antenna" I use one with my yaesu vx6 and it works well. A little more $$ than the mfj active but less headaches for sure.

 

[trap5858]

Doug above me here has the right idea. I tried an amplified external antenna on the R-20 and got poor results. Amplified noise but no better audio. I purchased a miracle duck antenna and had something very close to amazing results. They are a bit pricey but much easier to use than an amplified antenna.

I also had good results using a long wire and alligator clip.

 

[lanbergld]

I had an MFJ-1020C once. It works great as a tuner. But as a super-duper indoor antenna, well that's another story:

The MFJ-1020C didn't do anything for me as an indoor antenna, in & of itself, UNTIL I purchased a slinky antenna (Ebay) and clipped THAT to the MFJ's telescopic. At that point the entire world opened up on my Yaesu. It was a good combination, until I realized that I was better off without the noise. So its been nothing but slinky antennas & longwires since...no 'active' add-ons such the MFJ-1020C. But like I said, its an excellent antenna tuner, if you need one of those.

Larry Lanberg

 

[ka3jjz]

Dougw has the right idea. Buying active antennas for radios like the R20 is like trying to kill a flea with an elephant gun. There's just too much raw signal that is being put into a front end that simply isn't designed to handle it.

In fact a tuned short wire or whip (like the Miracle or Performance antennas) are much more likely to perform far and away better. Even a simple tuner with a short wire is likely to perform lots better than an active antenna.

The other mistake most make - even using a good desktop with an amplified antenna - is that they tend to shove the gain all the way up, thinking more gain is better. Sorry, but that's an assumption that's completely wrong. Noise levels vary from band to band, and some desktops are quieter (less internal noise, better shielding) than others. It takes a good deal of practice and listening - something far too few of us do these days - to learn to 'ride' the gain control correctly. You need only as much gain to receive a signal cleanly - and no more than that. Remember even with the gain set to, say 1/2 way, you are still adding some noise from the antenna along with the noise already in the receiver, and/or noise heard in the band itself.

I recommend actives only as a last resort, and folks should always be cautious about buying and using them. There is usually a better solution somewhere, but actives are rarely it. One exception seems to be the North Country kit that's in our wiki. It does seem to work quite well for many; I've yet to see anyone that had something bad to say about it. In addition, I seem to recall that they recommend substituting some components for a lower gain floor for use with portables - you can't say that about the MFJ products, unfortunately.

73 Mike

 

[eraweeb]

Thanks for all the good information!

I'm becoming more interested in that Performance Antenna, especially after reading all the reviews at eham.net

 

[comsec1]

indoor antenna = noise

the best thing you can do is to move your receiving antenna as far away as you can from anything that generates noise. I have about 200' of lmr400 going to my Hf antennas without any noticible loss in signal. its the noise generated by local electronics that kills reception on the HF bands.

 

[ka3jjz]

True enough comsec, but for a R20 handheld (which is where this thread began), that's still way too much overkill. With the right antenna, a good desktop (or even a reasonably recent ham transceiver which nowadays has a general coverage HF receiver built in) would work quite well. 73 Mike

 

[majoco]

You can't make somethin' out of nothin'! No matter how much amplification you have, if there's no signal, you can't manufacture it! All you'll get is noise.

Passport has a wonderful habit of giving great reports to their advertisers.

 

[nanZor]

A good combo for the R20

Wow - has it been 7 years already?

The MFJ 1020C makes a good combination for the Icom R20. I have also tested it with my Kenwood TH-F6 handheld, along with other communications receivers like an Icom R71a, Yeasu FT-840 etc.

Like mentioned before, the same rules about antennas apply: inside the depths of the house, not so good. At the windowsill even better. Better still is outside!

While the comm receivers needed no attenuation, I run them with their own internal preamps off, and the MFJ at max gain. With the Icom R20 or the Kenwood F6, both are running at max gain with NO internal attenuation. Tuning with the handhelds can be tiresome, especially if you are tuning at .01 khz step rate for fine tuning. Still, a lot of fun.

However, on bands lower than about 10 mhz, the R20 and F6 benefit from rolling the gain of the MFJ back just a *smidge*. So the MFJ on it's own is not an overload box.

If I had to compare the MFJ 1020C to something else, it seems to perform about as well as a GOOD mobile setup, or at least as well as a GOOD installation of Hustler mobile whips (for you amateurs out there...)

I run with my own small whip instead of the supplied one. I used an SO-239 to BNC adapter, and a Diamond RH-789 telescopic whip with an angle knuckle. I didn't want to turn this into a different antenna, but stick with the small amplified whip concept. With longer antennas, you might as well build something else.

On occasion I'll run it outside instead of from the windowsill, and that means the loss of convenient band retuning. However, If I'm sitting on a band for the most part, I can pre-tune the unit, disconnect it, and run it outside with my 25-foot long coax feedline. Either that, or crank up the audio and tweak the MFJ that way.

Note that like the Apex 700DTA active antenna, tuning is touchy, and on the MFJ, the bandspread is a general guide - you could be 2 mhz or more away on the dial. To make it easier with the R20 or F6, run the MFJ at max gain, tune for peak, and then back the gain down just a hair.

Running it outdoors on the deck places the unit farther away from noisemakers. And, since I'm not running long antenna elements or radials with it, the small footprint allows me to find spots that are in noise-nulls much easier. While it doesn't seem to rely a lot on the common mode, I do run with an RF choke like an MFJ-919 or airwound choke like the RadioWavz ISO-X just prior to the rigs for good measure. However I had no problem running straight from the MFJ to either the R20 or F6 directly either with just a 1 foot jumper.

Does it replace a good outdoor antenna? No. But instead of heavily attenuating the R20 or F6 with my main antennas, all it took was backing the gain down a *tiny* bit with the MFJ optimizing it for the handheld radios.

So in the end, surprisingly good reception, but it won't open a dead band, or compete with a 120-foot flat-top up at 80 feet. But it does work, and isn't as bad as most people assume as long as they aren't doing something dumb like trying to make it work in the bathtub or on top of wall-wart. (I run mine from an internal 9v battery btw....)

 

[parnass]

Here is an old review I wrote about the MFJ 1020, not
the newer 1020A, 1020B, or 1020C (which may perform identically).
I used the 1020 in the early 1980s when I could not erect an outdoor
antenna.

After writing the article, the low quality variable capacitor in my
1020 "broke."

If I recall, its thin metal plates were sandwiched between
sheets of plastic dialectric. The rotor became difficult to turn.

MFJ 1020 Active (Indoor) Antenna

Bob Parnass, AJ9S

The MFJ 1020 Active Antenna consists of a telescoping
antenna and a preselector-type circuit inside the now
familiar beige and wood grain cabinet. The frequency
coverage of approximately 200 KHz to 30 MHz is divided
into 5 bands.

A small, external power supply is required, but not
provided.

The 1020 lists for $80 new, but I purchased it at a
hamfest for $20, and performed one minor repair
(replaced a fiber washer at the base of the telescoping
antenna). I use this unit with an ICOM R-70 general
coverage receiver. Overall, the MFJ 1020 works better
than expected, although still not as good as an outdoor
antenna.

The Bad News

Phono jacks are used rather than the SO-239 type.

The inclusion of an LED indicator lamp in the 1020
really precludes the prolonged use of any internal bat-
tery.

One problem with my particular unit is that, despite
the dial markings, coverage ends at about 28.5 MHz
(rather than 30.0 MHz). There is no simple trimmer
capacitor that can be adjusted as a remedy. One of
these days (yawn), I'll have to trim an inductor.

Active antennas are more prone to electrical interfer-
ence. A photoelectric night light in an adjacent room
causes a high QRN level, due to the SCR in the dimming
circuit, and must be disabled during listening periods.
Emissions from the horizontal oscillators of TV sets in
the building also cause problems.

Use of a narrow band (tuneable, in this case) antenna
makes "instant QSY" impossible. One cannot make full
use of the broadband capabilities of the new generation
of general coverage receivers. This is a shame, espe-
cially if one has a receiver such as the ICOM R-71 or
the Kenwood R2000 which contain several memories.

The Good News

The MFJ 1020 works! The bypass switch on the front
panel allows quick in/out comparisons.

The 1020 has a jack on the rear for another antenna.
(This jack is always connected to the telescoping
antenna.) I use a 30 foot piece of wire connected to
this jack, and dressed internally around a window
frame. In this setup, the 1020 is used essentially as
a super preselector, and it permits me to hear many
more stations than using the telescoping antenna pro-
vided.

Using the 1020 and some wire indoors allows one a fair
level of SWL'ing.

Closing Comments

If you are in a condo/apartment situation, I recommend
buying an MFJ 1020 at a hamfest or a sale. Like many
MFJ products, it looks good on the outside, but you may
feel guilty if you've paid the $80 list price after
looking at the simplicity inside.

 

[nanZor]

Hi Bob! Great review and I think we're on the same page.

Here is an old review I wrote about the MFJ 1020, not the newer 1020A, 1020B, or 1020C (which may perform identically).

I'm using the late model 1020C since I wanted to compare it against my recent arrival of an Apex 700dta active. According to MFJ, they've made improvements over the 1020 ...

After writing the article, the low quality variable capacitor in my 1020 "broke."

Still the same, although mine seems to work fine. Although it has only been two day's worth. We'll see if it suffers the same fate. Note that the Apex uses what appears to be a varactor tune with a pot.

Phono jacks are used rather than the SO-239 type.

S0-239's now.

The inclusion of an LED indicator lamp in the 1020 really precludes the prolonged use of any internal battery.

Yeah, my first mod will be to either crush the led, or replace it. I use rechargeable Imedion 8.4v low-self-discharge types, with a Maha 9v charger ... So not too big of a deal. Compared to Apex, at least you can use an external dc wiring setup with the MFJ and not have to open the unit for replacement if you like. The Apex is twice the build quality for sure though...

One problem with my particular unit is that, despite the dial markings, coverage ends at about 28.5 MHz (rather than 30.0 MHz).

It now goes up to 40 mhz, but the bandspread indications are a general guideline - one can be many mhz off the dial when the peak occurs. I was trying to chase down some 6 meter openings, but it slipped away before I got a chance to see if the MFJ would even work half-heartedly up there...

Active antennas are more prone to electrical interference.

I think that is more due to physical proximity, and / or common mode / noisy safety grounds actually. I run this baby off dc and not off the wall for sure. I wouldn't say that active antennas that are engineered well are prone to interference beyond that which ANY indoor antenna would suffer. Those which rely on the coax braid as an antenna may have much worse time.

Use of a narrow band (tuneable, in this case) antenna makes "instant QSY" impossible. One cannot make full use of the broadband capabilities of the new generation of general coverage receivers.

I've seen some broadband ones like the PA0RDT mini-whip etc, but don't know how well they hold up under extreme broadband exposure. The homebrew SDR antenna that the Univ of Trente seems to be doing ok:

http://www.websdr.org/

I use a 30 foot piece of wire connected to this jack, and dressed internally around a window frame. In this setup, the 1020 is used essentially as a super preselector, and it permits me to hear many more stations than using the telescoping antenna provided.

I prefer the short amplified whip concept - if I'm going to run 30 feet of wire around the room, I'll be using a passive tuner instead of putting an inexpensive preamp inline. Perhaps you may want to reevaluate with a more modern active whip than the original 1020.

On a side note - both the Apex 700dta and the MFJ 1020c are well behaved with the Icom R20 and Kenwood F6. Although the Apex doesn't have a gain control, with the F6 on 7mhz, I needed to just pull it down a smidgen - and I just off-tuned the Apex every so slightly and that works.