As you will be aware there has been a lot of talk recently about the UK launch of the Superstar 3900EU. Below you can read a full technical report about the radio as provided by Superstar UK:
(Click images to enlarge)
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Superstar
3900 EU - Complete Technical Analysis
"This is
a very stable and very well built radio. Congratulations to Ranger on this
radio. I can't fault it."
Superstar UK asked Steve Gibbs of Gisco UK to take a
Superstar 3900 EU and give us his analysis. Steve Gibbs is one of the UK's most
well known radio engineers in the UK. Steve has serviced and aligned tens of
thousands of radios over the last 30+ years and is highly respected in this
sector.
Whilst
Superstar UK have great faith in the Superstar 3900, Superstar UK wanted to have
it independently and impartially analysed. So we asked Steve Gibbs to take a
look at a factory-sealed Superstar 3900 EU. Steve is well known for telling it
how it is with a no-nonsense approach. Here's Steve's analysis of the
Ranger-built Superstar 3900 EU.
Steve's
first comments were on initially opening the box were presentation. Steve was
particularly impressed that Ranger had taken the time to place a protective film
over the black power-coated back casing.
After
unwrapping the radio, Steve commented on the outer build quality. Unlike some
earlier 3900s he'd seen in the past, which had felt a little flimsy; this one
felt like a quality bit of kit. Steve initially tested the knobs on the front
commenting on how precise they felt with absolutely no wobble or excess play
"very nice" he said. Steve added that the front knob shafts are rock solid, with
no reduction in spring pressure when the volume control on/off switch is
used.
Then Steve moved on to the channel select commenting that its
"probably the most used switch on a radio such as this". He commented that it
felt very precise and well put together, and that some cheaper products' channel
select can feel flimsy, this one felt solid - you can feel a definite clunk when
a channel is changed ensuring a solid connection.
From left to
right is Volume Control (inner) & Squelch (outer), Mic Gain (inner) & RF
Gain (outer), SWR Calibrate, Dimmer (or band select in export mode), mode
select, Clarifier Course control (outer knob) Clarifier Fine control (inner
knob).
Aesthetics aside, Steve's passion is for the electronics! So
Steve naturally moved on to open the unit. Steve's first comment was on the
tidiness of the board, and wiring. All engineers like a tidy board, as it makes
for easy servicing.
From a service point of view, some radios such as
this have the speaker cable soldered to the main board which means the first
thing you have to do unsolder the speaker cables. Not with this radio, the
speaker connector is conveniently connected using a simple PCB plug and
socket.
Speaker and
bottom casing out of the way Steve again commented on the channel change
mechanism from inside, commenting that it looks very good quality and unlike
cheaper channel changes he doesn't envisage any issues to develop with this
one.
Moving on, Steve
removed the top case to take a look at the solder work. Here's a look at the
solder side of the PCB. Steve comments included very tidy; no scorch marks and
very neat.
Fig. 1: Superstar 3900 Right Side of the Board - Voltage
Regulator, Mic Preamps etc.
Fig. 2: Superstar 3900 Left Side of the Board - Output
stages, VCO & Crystals etc.
Now that Steve
was satisfied with the solder work, he moved on to inspect the component
quality. Starting from the output stage he worked his way along the
board.
It's important to note that the Superstar 3900 Steve had on his
bench was a randomly selected radio from the first batch sent from Ranger. Steve
did not adjust or realign the radio. This is Steve's analysis directly out of
the box.
Fig. 3: Superstar 3900 Output Stage View
The output stage
of the Superstar 3900 is made up of a single IRF520. Straight out of the box on
FM the radio did 4.0W on FM/AM and ~ 12W SSB.
Steve added that this radio
would be capable of up to around 50W by using an uprated mosfet. As can be seen
on the top-left side of fig 5.1.
Fig. 5.1:
IRF520 Mosfet & Gate Voltage Circuitry Close Up
Next up is the
front middle section. Steve's first comment is that sometimes manufacturers try
to make micro cost savings by using the cheapest components resulting in a
component mismatch. Ranger, here, have used all the same brand and type
capacitors. This is great for build quality, but also for easy service. Thumbs
up to Ranger here!
Along the left
hand side, from left to right here we have TX adjust, RX adjust, NB/ANL adjust.
The two pots in the middle are for SSB, then there are three smaller pots below
which is the location of the FM discriminator. Steve's comments are that all adjustment pots are
exactly where you'd expect them to be and meet or exceed expected component
quality.
Fig. 6.1: Front
Middle Section - Radio Adjustment
Superstar 3900
is a PLL controlled radio with two 4008 binary adders. Here you can see a close
up of the VCO.
Fig. 6.2: VCO
& Phase Locked Loop
Looking closer,
we can see the reference crystal, and offset crystal, alongside their adjustment
pots. Directly beneath the crystal to the right of Fig. 9 we can see the export
jumper (more about that later). Again Steve comments that these pots are of
expected quality.
Fig. 9: Reference
Crystal & Offset Crystal
Looking at Fig. 10, we
can see that Superstar 3900 is fitted with a ferrite coil. This is essential
when using a radio in a vehicle as it helps to dampen the engine noise and
reduce it coming through the radio.
There's also a diode across the power
terminals. This will ensure that if you power the radio with incorrect polarity,
that the fuse in the power will be blown before the radio suffers any damage.
This is a really good reason to ensure that the correct power cable is used with
the correct current rating of fuse.
Fig. 10: - Input
Voltage Regulator etc.
Steve was then
keen to get the radio powered up and on to his fully calibrated set of
instruments. Again, it's important to point out that Steve was asked not
to align this radio and not to adjust it, in any way. Superstar UK wanted an out
the box analysis that accurately reflects the radio a buyer should expect to
receive.
The following
analysis was done immediately out of the box whilst the radio was cold. Steve
was asked to give Superstar UK a screen-shot of the instruments as they changed,
noting the length of time the radio had been switched on, and monitor the radio
as the it warmed up.
Steve
continually monitored and used radio for 90 minutes whilst attached to his
calibrated set of instruments. To Steve's surprise the radio was smack on
frequency immediately on switch on, and nothing changed as the radio warmed up.
Here's the screen-shots Steve gave - here's the moment of truth.
The first thing
Steve wanted to measure is the FM reference frequency. This should show
16.4900MHz - and it does.
Fig. 12: FM
Reference Frequency Analysis - 16.4900MHz
Next, the USB
reference frequency, spot on at 16.4925MHz
Fig. 13: USB
Reference Frequency Analysis - 16.4925MHz
Next, the LSB
reference frequency analysis, again spot on at 16.4875MHz
Fig 14: LSB Reference
Frequency Analysis - 16.4875MHz
Next, the LSB offset
frequency analysis, spot on at 10.6975MHz
Fig. 15: LSB Offset
Frequency Analysis - 10.6975MHz
Finally, the USB offset
frequency analysis, spot on at 10.6925MHz
Fig. 16: USB Offset
Frequency Analysis - 10.6925MHz
The transmit.
And the result? Right out of the box on FM is 27.185001MHz and smack on
4.0W.
Fig. 18:
Transmit Test
Receive Test.
The receive parameter standard set in the manual supplied says 1.0uV at 20dB.
Steve does his test at 0.821uV and 21dB, which exceeds the manufacturer's
recommendations. Here's the result. Smack on at 27.18500MHz.
Fig. 17: Receive Test
- 27.18500MHz
Steve had the Superstar
3900 EU on his fully calibrated instruments for over 90 minutes, re-analysing
all of the above with virtually no change. Steve added, "This is a very stable
and very well built radio. Congratulations to Ranger on this radio. I can't
fault it.".
So there we have it. A
glowing analysis from one of the industry's most well respected and trusted
radio engineers. Steve pulls no punches and tells it how it is.
The most observant will
have noticed that the Superstar 3900 EU is the same Superstar 3900 which has
been for sale in the EU marketplace for some time now. When it was agreed that
the Superstar 3900 was to be brought into the UK, a decision was taken to call
it Superstar 3900 EU to differentiate it from any previous model of Superstar
3900. Superstar 3900 EU is locked to mid-block CEPT EU channels at 4.0W making
it legal for sale in all EU countries. It was important that this 3900 was not
confused with any previous versions that might have been 10m amateur
radios.
The Superstar 3900 [EU]
is ROHS compliant and CE approved. The ROHS/CE certificate is available to
anyone by simply emailing sales@wearesuperstar.co.uk
Superstar
3900 has been manufactured by many factories in China over the last two decades.
There have been many versions which may have been of a reduced quality and have
suffered from "frequency drifting". It was important to Superstar UK that this
version of the Superstar 3900 was easy to differentiate from those older
models.
There has been much speculation that this version of the
Superstar 3900 may suffer from the same frequency drifting issue as
previously Chinese manufactured versions. Superstar UK contacted Ranger about
this issue. Ranger were confused as they had never had this queried on their
product before. They responded with "[There is] no drifting frequency problem for
our product.".
Superstar UK are very excited to bring the Superstar 3900
back into the UK market place. And with Gisco's analysis, buyers can be
confident in their purchase. As we can see from the analysis by Steve, the
current Superstar 3900 is stable and a beautiful, rock solid AM/FM/SSB
radio.
Superstar
3900EU is available at most major UK CB/ham radio retailers from Monday 12th
September 2016.
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This report was kindly sent for publication on the blog from Superstar UK and has been published in full. From a personal point of view I'd like to thank all those involved and say 'top marks' to Superstar for taking the time to publish this report. Afterall, when was the last time you seen a report like this from other radio manufacturers????
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