N9EWO Reviews : Ameco TPA / MFJ-1020B Antennas

Plastic Cabinet and Knobs

Flyweight plastic case with pretty spartan innards. Front panel is made of metal (aluminum). Just molded feet in the sets cabinet. Owner can easily add stick on "hardware store" feet in short order. Otherwise it will still slide around like a "greasy dead fish" in use. Be sure the cabinet is totally free of dirt and oil before attaching any adhesive type feet (and then allow 24 hours for the adhesive to set before moving it around).

Nice big metal knobs with set screws (first test sample). This along with simple clear front panel markings with the bands, I found this was the easiest and most pleasant box to use of any active antenna-preselector we have ever tested. However with the second sample (later production) a switch was made to the use of smaller plastic knobs (still uses set screws). While ergonomics are still OK this way, substituting larger knobs will help bring back the stellar ease of use.

Appearance also changed a bit over the years. Originally it was in a black plastic cabinet that in time was changed to a Gray color (made in Taiwan). It's lone power LED went from RED to GREEN color. NOTE : A reader has indicated to us that later production runs went back to black color cabinet to late 2019 when it was discontinued. I'm unable to verify this information.

2 bottom (and long) large machine screws are used with brass inserts hold the cabinet together, no self tapping screws are used. As they indicate in the manual do not over tighten these as it will warp the top and bottom pieces. But if the screws are too loose the front panel will shift around a bit if the whip in not attached. It is a bit daunting to reassemble the case as the front and rear panels fight each other channeling back into their respective groves. But is not any real drawback (just take your time).

TIPS (for later PC Board Production Samples Only) :

- With PC board samples this front panel being loose will aid in screwing in the top telescopic antenna. However this is really of little moment as most will not make use the whip anyway.

(However IF you are lucky enough to have a extremely low noise household environment, THEN you may have great results with the included whip antenna. But these days that is becoming more and more of a rare oddity.)

- We hunted down a proper size screw (and length) that inserted into the whip socket in order to raise the PC Board up proper level when the Whip is not used (which will be for most owners). This makes a huge improvement in stability of the front panel and with the collapsed whip (not being installed) will reduce close radio room interference with external outdoor antenna use.

Power and DOA's

Operation is via a internally mounted 9 volt battery (that is held in place by a nice metal clip) or via a external 9 VDC AC wall adapter. Best to use a regulated type NON SWITCHING type power supply to rule out any self inflicted hum/noise. We used a old linear and REGULATED RadioShack 273-1662A wall wart (set at 9 volts, + tip polarity) and worked good with no hum or buzzes. DO NOT power it using 12 or 13.8 volts (you will be sorry, best to NOT use any unregulated AC Adapters), Uses a rear mounted standard coaxial type DC jack (accepts a 2.1 mm ID x 5.5 OD size plug, long shaft type recommended). Ameco sell (or sold) a matching unregulated AC Adapter for the TPA marked as the P-9T (not tested).

From reading internet observations and comments elsewhere, quality control on the TPA appears to have been a "crap shoot" over its long run in the marketplace. Samples being "Dead on Arrival" are more common then it should be. As it usually goes if any sample operated properly out of the box new, and if it continued to be stable say after a week or so of use (aside from any owner self inflicted happenings like ESD or RF damage), it was a good one !

Decent Performer for This Class of Device (but don't expect miracles)

The Ameco TPA uses 2 semiconductors (as noted in both test samples) : one - 40673 MOSFET and followed by one - MPS6507 RF transistor. Unlike other Ameco products the owners manual contains no schematic digram.

Has high gain at a tad over 20 db and longest whip (32 inches) that easily beats out the MFJ-1020B/C (see B review below). Not that the whip is all that useful (it really isn't at any length), but is OK for moderate strength MW / SW broadcast stations. As far as I could tell gain was pretty even across it’s range too (this also includes the Medium Wave band which the TPA covers). As it goes with all of these devices, the lower you go in frequency the higher the "Q". In other words you will need to tune more often the lower in frequency you go.

We say "Low Noise" as when compared to other models, but ALL of these devices have some added noise floor and is only made worse with ANY local interference. With it's whip or connected longer indoor antenna (say under 30 feet) gave no overload issues. Use with a better long external outdoor antenna it can severely overload. In some cases with stronger signals oscillation can also occur (as covered in the manual) Of course just deceasing the "Gain" control tames both of these issues.

Outdoor Antenna as Usual for Good Performance / Now Discontinued (hunt on the used market)

Not everyone is able to have a larger loop or any other antenna outdoors (Apartments / Condos / HOA's etc). One can always carefully "sneak" an extremely thin short insulated wire out a window (at least say at least / over 30 feet / 10 meters or longer) and connect it to the TPA (center pin on the RCA external antenna jack). When you get down to it, for this device to work properly in this day and age it really needs to have some sort of a OUTDOOR antenna as high as you can get it and away from structures / noises and fed with RG-58 coaxial cable (even if again only say a short 30 foot short wire).

The owner must have reasonable expectations with a SW antenna product like this. As normal local "indoor or outdoor" noise / interference will greatly affect these devices. As it ALWAYS goes with mother nature (storms) one MUST be sure and disconnect ANY outdoor antennas from ALL receivers and / or pre-amplifiers like the TPA when not being used. This is just common sense stuff of course.

Overall we found the Ameco TPA a decent performer after using many of these tuned preamp boxes over the years (as far as these limited one piece INDOOR preselector - whip active antenna boxes go).

Sadly after being on the market for a number of decades it was discontinued in late 2019.

Dave N9EWO
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ver 3.8

Internal photos of the Ameco TPA (later production with PC Board)..

Decent performer, however the PC Board is disconcertingly supported by just the control / switch wires.
(N9EWO Photo)