N9EWO Reviews :
- Ameco TPA
Tunable Preamp - Active Antennas
Tunable Preamp / Active Antenna
The "Made in USA" Ameco TPA Tunable Preamp /
Active Antenna (gray plastic cabinet).
Review : Ameco TPA Tunable Preamp / Active Antenna
Has had a number of changes in production (internal and external).
For it's class, has been the best combination "Tunable Preamp" -
one piece INDOOR active "whip" antenna
performer we have ever used.
Sadly discontinued, so it's used market only now. (N9EWO
Two samples were tested for this report.
(approx. 2002 and 2010 manufacture)
Country of Manufacture: USA
Frequency Coverage : 220 kHz to 30 MHz in 5 Bands
Approx. Serial Number of Test Samples : No Serial Numbers on product
PC Board Marking (second 2010 sample) : Ameco AP-1 / C-1-HB Rev B-HC
Outdoor Antenna's Used for Testing : Comet H-422 dipole (total length
34 feet long), RF Systems MLB-Long Wire (55 feet long).
- 20 db + high gain.
- Low Noise (as far as these
low cost preamp devices go).
- Generally free of spurious signals with 9 volt battery or proper REGULATED power supply (see text)
- Coverage also includes Medium
Wave (MW) and a good part of the Long
Wave (LW) Band.
- Above average 32 inch whip antenna that is easily detachable.
- Most pleasant unit to tune to
Easy to read "metal" front panel.
Large Metal knobs with set screws (first
test sample only, see con).
Standard AC Adapter Jack (DC
coaxial 2.1 mm ID x 5.5 mm OD).
Power "Preamp" ON LED (Red on early sample,
Green on later sample).
PC Board used with later production (see text).
- Cabinet held together using 2 machine screws with brass metal inserts (no self tapping screws).
Low current consumption (battery miser).
Limited Dynamic Range. Can easily overload with any long external
- Ultra light plastic cabinet
shielding (Color : Black First Sample / Gray Second Sample).
- Uses two “RCA” phono
jacks-plugs for external antenna and receiver connections.
- No rubber feet so
slides around hopelessly in use with it's very light cabinet weight
(easy fix, see text).
Uses low cost plastic variable
Second test sample used smaller plastic knobs for not as nice
Ameco P-9T AC Adapter is not included. (optional, see text).
Earlier production used strange Internal "Point to
Point" Construction with no PC Board (looks like a radio made in the
- Highly variable quality control
years on the market ("Dead on Arrival" samples were common).
- No Schematic Diagram provided
in it's 4 page owners manual.
General / Construction and "NO PC Board" Used with Earlier Production
3 knobs (TUNE - BAND - GAIN) and 2 slide switches (PREAMP IN OUT / POWER) with a Power ON LED round out the front panel. All controls operate smoothly, however the quality of the plastic
variable capacitor ("Tune" knob) is like what is found in a ultra-cheap
AM pocket radio. Frequency Coverage is from 220 kHz to 30 MHz in 5 Bands.
With the first test sample
(2002) construction is completely
todays standards. No PC Board was used and the parts are hap
mounted between the gain control / band selector switch / variable
capacitor and the 2 slide switches. Good news
is with later production (second 2010 test sample), a PC Board was used
and much improved (see photo). The zinger here is the board is ONLY
held in place by just the extra heavy gauge wires on the 2 switches,
thin wires on the band rotary switch and gain control, plus the
telescopic antenna socket/threads if used. There are holes for L
brackets on the PC Board (see photo below), but were never used.
Wiring from the two rear RCA
jacks to the front panel are made with general hookup wire (no shielded
wire is used at all, see internal photo below). Those jacks use a most desirable 2 screw
mounting, so less prone of becoming loose. However more recent production went to a less desirable "single hole" mounted RCA jacks with a
single mounting nut. Of course this should have been SO-239 connectors for a high
frequency SW antenna device.As
it goes with all these devices, the required coax cables to the host
receiver and antenna are not included. Highly suggested to use the less
bulky (and as flexible as you can get) RG-58 coax cable with no
adapters used on
the TPA end. This will help greatly with it's very lightweight
plastic cabinet (more below on this).
Plastic Cabinet and Knobs
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"
short order. Otherwise it will still slide around like a "greasy dead
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
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
plastic cabinet that in time was changed to a Gray color (made
in Taiwan). It's lone
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
. 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
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
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
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.
© N9EWO, all rights reserved
photos of the Ameco TPA (later production with PC Board)..
performer, however the PC Board is disconcertingly supported by just the control / switch
MFJ-1020B Tunable Preamp / Active Antenna
Review : MFJ-1020B Tunable Preamp / Active Antenna
MFJ-1020B Tunable Preamp / Active Antenna.
No real horsepower at only <10db gain as an active antenna using
with it's own whip.
Best used with longer outdoor antenna's as a active-preselector device.
(IMPORTANT NOTE : We tested the older discontinued "B"
version of this
Country of Manufacture: USA
Frequency Coverage : 300 kHz to 30 MHz in 5 Bands
Approx. Serial Number of Test Sample: No Serial Number on product.
Outdoor Antenna's Used for
Testing : Comet H-422 dipole (total length 34 feet long), RF Systems
MLB-Long Wire (55 feet long).
- Very Good Dynamic Range.
- Low Noise.
- Coverage includes the MW band.
- Choice of SO-239 or RCA
Phono antenna/radio connections
- AC Adapter Jack (see con).
- Red "Power On" LED indicator
- Skimpy very low gain 10 db
gain (or less) when compared to other
models (see text).
- All 3
knob’s are small, stiff and hard to adjust.
- Tuning capacitor hard to peak.
- Confusing "Band" makings
on front panel.
- Quality control lacking (test
sample had crooked front panel and
other construction gremlins).
- AC Adapter is not included
(extra cost option).
- Short 21 inch included whip
antenna doesn't help it's dismal use as a standalone active antenna.
discontinued MFJ -1020B model
uses 2 semiconductors (as noted in the test sample) : one -
3N211 MOSFET (schematic indicates 40673) and one - 2N5179.
IMPORTANT NOTE : Current MFJ-1020C
(not tested) version uses different 2 semiconductors as listed in the
owners manual : one - J310 FET, one -
2SC2498. Unknown if the performance is similar to the older B version
as tested here ?
you desire a small amount of gain (10 db if you are lucky) say
connecting up to a large OUTDOOR antenna, this could be a good
it’s a nice quiet box of electronics and has decent dynamic range (as it goes with ALL of these boxes the included 21 inch antenna is near useless except for very STRONG signals).
However, if you do find a used 1020B, better plan on
replacing the 3 knobs on the front with larger ones. They are just way
also the tuning control is really stiff, The worst of any active
ever used in fact. Larger
knob’s (with set screws) should help this (not tested) ? To make
ergonomics even worse, the A-B-C-D-E band marking's
on the front make the user go ,”duh.....what
band I'm I on again?.....” every time you use
it ! So make a little 3 x 5 card might help here or use a label maker
to improve the band markings (on the Band knob) ?
Nice touch is that MFJ gives YOU the
choice on what
connectors to use. Either RCA phono OR SO-239’s.
Good for a Pre selector
device when being used with a external
outdoor antenna. However for use even with a shorter say 30 foot indoor wire antenna as a
standalone "indoor" active
antenna....we say look elsewhere.
© N9EWO, all rights reserved
Links For Additional Information
(all subject to change without notice)
eham Ameco TPA Reviews
Ameco Manufactures Web Page (Milestone Technologies)
Universal Radio's "Ameco TPA" Web Page
Gerchmez's MFJ-1020B Review (from 2000)
MFJ-1020C Reviews (sorted by date)