Category Archives: How To

The Tecsun PL-990/PL-990x as an MP3 Player, Bluetooth Receiver, and PC Speaker

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Many thanks to SWLing Post contributor, Bob Colegrove, who shares the following guest post:

The Tecsun PL-990/PL-990x as an MP3 Player, Bluetooth Receiver, and PC Speaker

By Bob Colegrove

Source: PL-990x Operation Manual

Sometimes after a medium wave or shortwave DX session I just like to kick back and listen to good music.  Perhaps this is an age-related malady.  I recently did a scan of the FM band and came up with 60 listenable stations in my area.  By listenable, I only mean they can be received clearly.  In practice, I only listen to a couple stations.  Although, my tastes in music are quite varied, apparently, they do not coincide very well with local FM broadcast station formats.  No matter, I can still indulge myself listening to diverse favored artists.

The Tecsun PL-990/990x offers a ready solution having both an MP3 player and Bluetooth connectivity.  Actually, there are several compatible audio formats available on the player, but for simplicity I will merely refer to them as MP3.  I really didn’t buy this radio purposely for these additional features.  I bought it as a follow-on to the PL-880, which I still like very much for all its well-known features as a multiband radio.

I spent some time on the Internet reading all the reviews and watching many YouTube videos.  Among useful things, I learned how to take the radio out of its box.  The aggregate of all this information was thorough coverage of all the salient features of the 990 – all except the treatment of the MP3 player and Bluetooth connectivity.  These generally appeared at the end of each review in a by-the-way fashion with little detail.

I bought a PL-990x with expectations that it would be a good radio performer, and that has proven to be the case.  During its setup and checkout, I realized the potential for its MP3 and Bluetooth capabilities.  A few years ago, I digitized all our vinyl recordings and cassette tapes, so I had many hours of material readily available for inclusion on a micro-SD card, which can be inserted on the bottom of the cabinet.

Source: PL-990x Operation Manual

The radio, MP3 player, and Bluetooth modes are available by toggling a single switch.

Source: PL-990x Operation Manual

As an MP3 Player

Unfortunately, the display does not have a multi-segment set of characters for text.  This is the way random RDS information is displayed on radios such as the XHDATA D-808 and Eton Elite Executive.  So, selecting albums and tracks on the 990 is limited to numeric representation, which doesn’t provide much of a clue identifying the musical selection.  The user must either remember where favorite files are stored by number or keep some sort of number-title log.

Files are stored on a micro-SD card having up to 128 GB in capacity.  That’s a lot of content.  The radio comes with a 16-GB card, which will probably be large enough for many users.  There are some details to consider when setting up the card.  This information is lacking in the manual, but I have tried to fill in the blanks below.

Some rules:

1. There is no purpose in trying to alphabetize or otherwise edit album or track titles to locate them in a specific sequence.  The 990 doesn’t understand this.

2. Generally, albums and tracks will be assigned numbers by the 990 in the order in which they are saved to the SD card by the computer.

3. Albums equal folders.  Tracks equal (MP3) files within each folder.  You can mix and match the content in albums and tracks any way you want to.  It does not have to conform to the publisher’s album content.

Source: PL-990x Operation Manual

4. An album/folder can contain both its own tracks/files and nested folders containing other albums.  A nested album/folder will be numbered in sequence after the containing folder.  Any previously saved album/folders will be renumbered higher in sequence.

Rule 4 offers some flexibility.  You can come back later and prioritize any album/folder by simply nesting it with another album/folder.

The table below is an example of five different musical genres compiled into separate albums.  On the computer, the polka album was transferred to the SD card first, then classic country.  At that point, the polka album was A01 and country A02 on the 990 display.  Later, Dixieland and waltz albums were added to the tracks in the polka folder.  They then became A02 and A03 respectively, and the country album advanced to A04.  Finally, the chorus album was added in the root directory and became A05.

  • The 990 recognizes the SD card quickly after it is inserted into its slot.
  • The number of tracks and albums (files and folders) is only limited by the SD-card format, which for all practical purposes, won’t be a limitation.  By way of example, I used the default exFAT format and loaded an album with 657 tracks; I don’t recommend that many.
  • A single track can be repeated by long-pressing the PLAY/PAUSE button.
  • The tracks in an album will be repeated continuously.
  • There does not appear to be a way to shuffle tracks.

I did encounter some difficulty with micro-SD card compatibility, which was independent of brand.  A couple micro-SD cards were prepared on a computer using an adapter card and a micro-SD card reader and operated correctly in the computer, but the content was not recognized by the 990.  I suspect this might be due to the early manufacture of the cards, but I’m not sure.

The 990 manual picks up the explanation from there describing operation of the control keys.  I found it most convenient just to scroll through the albums with the FINE TUNING knob and through the tracks with the main TUNING knob.  The number pad buttons will also work for direct album or track selection.  Their application depends on the last tuning knob turned.

Bluetooth

Bluetooth is a hidden feature of the 990.  Activation is partially covered on the hidden feature sheet.

  1. With the radio off, press and hold the PLAY/MP3 button.  If OFF (for Bluetooth) appears in the display, press and hold the button again until ON appears in the display.
  2. Turn on the radio.
  3. Toggle the PLAY/MP3 button until “BT” appears in the display.  The display will have a horizontal, animated dashed line for a few seconds, then it will change to an animated rectangle indicating that the Bluetooth feature is on.
  4. Follow the procedure for your tablet, computer or phone to pair the device with the 990.  “Tecsun PL-990” should appear on the device as a choice for pairing.  The 990 only pairs with one device at a time.  If you have trouble, ensure that the 990 has not inadvertently paired with another device.

Bluetooth, of course, opens Internet streaming from a phone, tablet or computer.  These ‘remotes’ have the convenience of full text capability and offer easier selection of content.  I paired my PL-990x with a Kindle tablet; it has a range of at least 25 feet.  The same micro-SD card could in theory be transferred from the radio to the tablet and function the same way.  A smart phone would add cellular connectivity.

Control:

Three of the four player control buttons above the display are active in Bluetooth.  The stop button has no effect.  As with the MP3 player, the main TUNING and FINE TUNING knobs will also advance or reverse the track selection.  Interestingly, this works with audio player apps as well as services such as YouTube, where it advances or reverses videos on the tablet, computer or phone.  In addition to the RADIO/MP3 button, pressing any of the band buttons will immediately exit Bluetooth and tune to the selected radio band.

Source: PL-990x Operation Manual

In MP3 or Bluetooth mode, there is no noise from a USB wall wart.  It might be a good time to charge the battery.

As a Computer Speaker

Finally, there is what the 990 manual calls the computer speaker mode.  Sounds inconsequential.  Why would anyone want to use a monaural radio on a computer that’s likely outfitted with stereo speakers?  Actually, it’s more than that.  By plugging your 990 into a USB port on your computer you have the normal charging feature, but you will also have complete USB connectivity with your PC.

Turn on the 990.  You may have to press RADIO/MP3 button until “PC” appears in the PL-990 display.

  • You will not be able to use the radio.
  • The content of the micro-SD card in the 990 should appear as a USB drive in the computer’s file directory.  You can transfer files on or off the 990, but the process will be very slow.  Transfers from the computer to the 990-installed SD card follow the same rules listed above for the MP3 player.
  • The computer will provide the MP3 play function through its own app.  You can select files from either the 990 SD card or those on the PC and play them through the 990 speaker.
  • You can switch speakers between the 990 or those on the computer by selecting the speaker icon on the computer task bar, then selecting the available speakers.

  • The pause/play button on the player controls will work, but the reverse, stop, and advance buttons will not.

Final Thoughts

Some disappointment was registered in the reviews that the 990 does not have a recorder.  Yes, this would have been nice.  One thing it does have is a line out jack which has adjustable gain.  This makes my outboard recorder much happier than when it is used with some other radios.

Since we are talking about audio, I have noted that some reviewers still prefer the sound of the PL-880.  To my ears, the 990 sounds every bit as good.  Remember, these are mid-size portable radios.

The inclusion of MP3 player and Bluetooth capabilities on the 990 adds very useful functionality to this radio.  After nearly four years of consumer availability, I must wonder why they haven’t received more attention.

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Kostas improves the contrast on his FRG-7 digital display

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Many thanks to SWLing Post contributor, Kostas (SV3ORA), for sharing the following guest post which originally appeared on his radio website:

FRG-7 digital display contrast improvement

by Kostas (SV3ORA)

The FRG-7 digital by Marcel Jacobs PA8MA, is a very well thought modification KIT for the Yaesu FRG-7 receiver. It really adds to it one of the things it misses (and it misses a lot) to become a more “serious” receiver in the modern era, the digital frequency readout and S-meter. If you are like me and enjoy classic radio gear, but you do not want to compromise much the every-day usability, I recommend you this KIT. I have to say here that, the first thing you would want to do if you use the receiver for SSB, is to perform my SSB-related mods as well.

When I installed this KIT on my FRG-7 The first thing I did not like about it, was the very bright display which blasts your eyes with light especially at night on a low-lit shack. Not only that, but your eye will condinuously focus on the bright display and you loose the magic of the rest of the radio controls and displays. I wanted the digital display to be one of the parts of the radio and not the major thing that my eyes will look all the time. Marcel was smart enough to include 2 brightness levels in software. The low brightness setting does not actually change the backlight of the display, it just changes the graphics in more dim colors. As a result in either setting, the backlight color is very bright and this decreases contrast a lot. The background of the numbers in the display has a blue-ish color and not true black. Not only that, but the edges of the display, are visible too. I have solved all of these problems with a simple modification to the KIT.

The picture above, shows the display after my modification. The picture is taken on a dim-lit shack using my phone, with no further image processing. What you see in this picture, is exactly what it looks in reality, after my modification. Notice how the background of the display, remains pure black and the numbers and graphics of the display do not blind you anymore and are of the same brightness as the rest of the original backlit graphics of the radio. This allows your eye to wander around to the rest of the nice radio backlit things, without focusing all the time on a bright display. This is very relaxing to the eye and the brain as you scan for stations. You actually only look at the digital display when you want more accuracy. Compare this nice display contrast with the one presented on Marcel’s manual and you will notice the difference.

The modification is really simple and it does not need a schematic. It is just a 22k potentiometer, connected as a variable resistor like shown in the picture. I just cut the second cable (from the left), of the ribbon and then soldered the variable resistor there. That’s it. Depended on the light conditions in which you operate the receiver and on your personal preference, you can set the brighness from full to very dim. In the software setting, set the brightness to maximum. Then use this variable resistor to decrease it to your desired level.

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Frans Receives Amsat QO-100 Es’hail2 stationary satellite

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Many thanks to SWLing Post contributor, Frans Goddijn, who shares the following guest post:

Es’hail-2 Geostationary Satellite – credit Es’hailSat (via Amsat-UK.org)

Receiving sounds from the Amsat QO-100 Es’hail2 stationary satellite

by Frans Goddijin

Over the last 1-2 years several radio enthusiasts have mentioned the Amsat QO-100 Es’hail2 stationary satellite but so far I had no clue where to begin receiving signals from it. There seems to be no shop selling a complete kit so one has to source and assemble the parts.

Here’s a video (below) about how I did it.

Tije de Jong helped by building me a custom stand for the satellite dish, Hans Holsink (see https://www.youtube.com/watch?v=ZDBIMjCUKtY and www.hybridpretender.nl) gave me some tips over the mail as did William Lagerberg, a fellow radio enthusiast who has built a small forest of antennas around his home.

In preparation, I looked for pages and videos of other setups but often what I found was way too technical for me, or focused on one or two aspects while skipping over everything else.

So I gathered material from different sources, gleaned information from several websites and videos.

But above all I had the help of Tije, Hans and William who enabled me to get there.

One shortcut that I thought I was taking in the beginning was using an app to get the dish lined up but as it turned out the app seemed to think the satellite was playing hide and seek, sometimes in plain sight across the street and then slowly disappearing around the corner. 😉

Also, I used LiDAR measurement in the app to establish what size and type dish I had bought (a cheap no-brand thing in a store where immigrants buy satellite dishes to watch homeland TV) but later on Tije pointed out to me that the dish on the app screen looked nothing like mine which explained why the orientation tool of the app had me pointing the dish ever higher.

Once I used the information on https://eshail.batc.org.uk/point/ I got going and lining up the dish was easy.

Video:

[I also] made a second video this time highlighting the simple details of the setup so others can easily copy the approach:

Best regards,

Frans

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Guest Post: Bob’s conundrum with the Radio Data System (RDS)

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Many thanks to SWLing Post contributor, Bob Colegrove, who shares the following guest post:

A Conundrum with the Radio Data System (RDS),
or Why I Set the Clock Manually

By Bob Colegrove

There’s an old story about a man who owned two watches.  One watch ran but lost a minute every hour.  The other watch didn’t work at all.  He always wore the watch that didn’t work, because as he said, “At least it will have the correct time twice a day.”

First off, a couple of caveats.  This is not a definitive description of the Radio Data System (RDS).  I leave that to much more knowledgeable sources.  One detailed description is at https://en.wikipedia.org/wiki/Radio_Data_System.  Second, my experience described here is confined to the Eton Elite Executive and the XHDATA/SIHUADON D-808.  Other radios may operate differently.

I have surrounded myself with several multiband travel radios over the past year and enjoy them very much – each for different reasons.  Besides listening, I like to push buttons to see what happens.  The manuals?  At best they occasionally provide a clue.  I read them, eventually filling in the blanks on my own.

XHDATA/SIHUADON D-808

Basic RDS

What is RDS? RDS is a system which enables an FM station to transmit various fields of information such as date, time, call letters, frequency, and program information in text form.  The call letters are useful, but if you have a digital radio, you already know the frequency.  The name of the song and artist are particularly helpful if the DJ won’t tell you.  As for the date and time, well, I’ll get to that.

RDS is an international standard and Radio Broadcast Data System (RBDS) is the official name used for the U.S. version.  So why don’t we in the States just call it RBDS?  Probably because our radios aren’t made here.

Eton Elite Executive

The XHDATA and Eton allow the user to display four of the several fields comprising the RDS standard.  They each step through the same sequence, indicating a similar or possibly the same demodulator chip.

PS and RT seem to be freeform fields with stations providing whatever information they want to share.  Often the call letters and frequency are contained here, along with program content.  Clock Time (CT) is not displayed per se, but is used to set the radio time, and is included as part of the DATA field.  DATA is important; it has four elements, which should provide the listener with an indication of the call, day, date, and time being received by the radio.  The international RDS standard omits the call letters.

The RDS information transmitted by any given station may not contain all the fields identified above, including the time.  For example, stepping through the fields you may encounter “NO PTY,” “NO PS,” “NO RT,” or “NO DATA.” Consequently, you may tune in to a station broadcasting RDS and wait a long time for the radio clock to synchronize, which it never does.  The display of any content in the DATA field is probably the best clue whether CT is being transmitted.

It is interesting that the Eton is programmed for the US RBDS system, whereas the XDATA follows the international RDS system.  For the international system on the D-808:

  • “DATE” replaces “DATA” in the display.
  • The call letters are omitted from the DATE field.
  • The terms in the PTY field differ; for example, WRBS, 95.1 MHz, the PTY element displays “SOCIAL” instead of “RELIGIOUS MUSIC.”

International PTY RDS term on the XHDATA

US PTY RBDS term on the Eton

The Conundrum

The mischief all began when I got my XHDATA D-808 and tried to program the clock to automatically update using the RDS information off FM stations.  Minutes seem to display correctly, but try as I might, I couldn’t get the hours to register properly.  Then I bought an Eton Elite Executive.  It also has the RDS feature, so I tried again.  It appeared to work OK for a day or so.  Then the hour indication started to misbehave.  In addition to the clock, the Eton allows programming of time zones and day of the week.  I determined that the erroneous indication did not appear to be related to GMT, EST, 12-hour or 24-hour format settings.  In theory, if you try to set your radio to GMT or some other time zone, the RDS time from a local station should override it.

When I tested the radios side-by-side, the DATA field was fraught with problems on both radios.  Several local RDS stations containing CT were monitored.  The whip antenna was extended a tad, as the information may not reliably register with some otherwise clear audio signals.

  • When tuned to the same station, there were occasional inconsistencies between the two radios, presumably receiving the same exact information from the station.

 

  • Sometimes the hour would not advance on the XHDATA after minutes transitioned from 59 to 00.
  • Curiously, both radios might exhibit the correct date and time during the day, then at 1900 EST, several stations on both radios prematurely advance to the next day and date, and the hour would display incorrectly, completely unrelated to local hour.  Minutes may or may not be correct.  1900 EST happens to be 0000 GMT.  Are some station clocks running on GMT?

RDS content obviously requires some attention at the station.  In the end, they are responsible for the information going out.  In fairness, with all that goes on in a studio and limited staffing, RDS content may not be a priority.  As an example:

  • Call letters in the DATA field for local WMZQ read KZQK, which is not assigned.

Conclusions

There are two main factors which may impinge on the accuracy of a radio clock when set automatically by the RDS:

  • Accuracy depends on the station transmitting it correctly.
    • With RDS set to the AUTO mode, there is a good chance that the clock will be updated repeatedly as the radio is tuned among various stations – not necessarily to the correct time.
      • For the Eton, the clock would reset each time when changing stations between WTOP (correct time) and WPRS (incorrect time).
      • For the XHDATA, the clock would reset each time when changing stations between WTOP (correct minutes) and WPRS (incorrect minutes).  In both cases, the displayed hour remained 00.
    • There is still the unexplained premature update of day and date by some stations observed on both radios.
  • Correct time depends on the radio’s RDS demodulator to interpret the incoming data.

Trivial?  Perhaps, but you may want to reconsider and program the clock manually, particularly if you depend on the alarm function of the radio to get to work on time.

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D.I.C.A.: Giuseppe’s latest homebrew portable antenna

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Many thanks to SWLing Post contributor, Giuseppe Morlè, who shares the following antenna project:

Dear Thomas and SWLing Post Friends ,

I’m Giuseppe Morlè, iz0gzw, from Central Italy, Formia on the Tyrrhenian Sea…
Some time ago I had drawn this minimal HF antenna on paper…

I took advantage of the New Year’s Eve rain to be able to build it with the usual leftover scraps…

The system consists of a 35 cm tube with two separate windings of telephone cable on it, 2.5 m on each side, green and white…in the center I connected the 4 ends to X…

The green lead with the white and the white with the green to the variable capacitor and the other two leads to the RG58 cable that goes to the receiver.

I started the test and noticed that the agreement was possible from 7 to 21 MHz…

I then placed a long ferrite inside the tube…

I noticed a strengthening of the signal and consequently of the noise picked up and the chord dropped to 3.2 MHz.

Tests inside my shack showed decent reception on all ranges…in the evening on the balcony on 80 m. I could perfectly listen to a QSO between Italian stations.

Everything is still in the experimental phase and I think I will try this minimal system also in QRP transmission.

In this first video I explain how this minimal antenna is made:

The second video concerns a 20 meter test by car. The antenna is placed on the dashboard of the car inside:

In the third video, I explain how it works without the ferrite and with the ferrite inside the tube:

In this video you can see the test on 40 m. outdoors on the roof of the house:

The tests are carried out at home in order to understand what can be achieved in an environment that is difficult to receive.

I will do more outdoor tests and I think this small minimal antenna will receive better. I will keep you informed.

Thank you all for your attention and I wish you all a new year full of satisfaction.

’73 de Giuseppe iz0gzw.

Fascinating, Giuseppe! I love all of these brilliant little antennas you design out of your “junk” drawer! We look forward to hearing more about this antenna and any modifications you make to it!

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Martin builds a simple ferrite rod to inductively couple radios to his external mediumwave antenna

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Many thanks to SWLing Post contributor, Martin Tobisch, who shares the following guest post and videos from his home in Malta:

New AM Signal Coupler

Many AM medium wave listeners are looking for solutions to improve the reception performance of their radios.

After many attempts, which I don’t want to entertain anyone with, a coupler was created that feeds the external antenna directly into the ferrite antenna. I use my 66 foot long wire antenna on 50 ohm RG-58 cable, but other antennas will have similar success.

The clips available on YouTube speak for themselves:

 

Experiments with smaller ferrites and antenna rods met with no success. It is important that the coupler still works even at a distance from the ferrite antenna and without precise alignment.

With tube radios it easily bridges the distance from the housing to the ferrite rod Antenna
The finished coupler consists of 6 NiZn ferrite cores, which are connected with glue to form a rod. 8 turns of wire are wound over this and soldered to an RG-58 cable. Some electrical isolation tape and ready. So far I’ve just put it in a box. Of course there are finer solutions and it should be protected against shock. Ferrite cores are notoriously brittle.

Here is a link to the ferrites used (purchased at AliExpress).

Advantages: Advantages to what? Nothing comparable exists.

So there are advantages to feeding via an antenna socket. The signal coupler is also good for radios without an antenna socket. But in case of using an antenna socket, common mode wave interference picked up in the house goes unlimited into the radio. Due to the magnetic coupling to the ferrite antenna, common mode waves are completely suppressed. They do not create a magnetic field in the coupler.

No changes are necessary in the radio

The biggest advantage is, that you can listen to distant stations loud and clear, which previously only produced a quiet scratching noise.

I very much welcome reports of experiences.

[email protected]

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Guest Post: Switching a Remote Antenna, Low Noise Amplifier, and an Antenna and Audio Between Two Radios

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Many thanks to SWLing Post contributor, Bill Hemphill, who shares the following guest post:

Remote Antenna Switching Remote Low Noise Amplifier Switching and Switching an Antenna and Audio Between Two Radios

by Bill Hemphill, WD9EQD

Remote Antenna Switching

I have two YouLoop Antennas.  I had been placing them at right angles to each other.  I would then put one of them on the AirSpy software defined radio.  But manually switching from one antenna to the other was a real pain.  If only there were a way to electrically switch between the two antennas.

It would be nice to place the antennas remotely from the radio (and computers) and then have some sort of remote switch that would select an antenna and then a single feed line to the radio.  It was research time.

The YouLoop and the Airspy both use SMA connectors.  An SMA switch would be required.  A little research and I came across the following small board that can switch between two SMA antennas:

From Amazon Description:  50 Ohms RF Switch Module, 3-5V Remote Wireless RF Switch Single Pole Double Throw Board Input Output Impedance for DIY Electric Doors (HMC349)

This board is perfect for RECEIVE only projects.  Apply 5V to the board and then 5V to the VCC (control pin) to switch from RF1 to RF2.

Now that I had the SMA switch module, a way to actually do the switch remotely was required.  Maybe WI-Fi or Bluetooth module would do the trick.  I found a nice Wi-Fi module on Amazon that looked like it would do the trick:

Amazon Description:  DIYmalls SV Safe Low Voltage WiFi Wireless Switch Module DC 5V-24V Phone APP Remote Control Smart Home for Amazon Alexa Google Assistant

But do I really want to use a phone app to switch antennas.  Further investigation discovered a really neat module that uses a Car Fob type control:

Amazon Description:  RODOT Mini Relay Wireless Switch, 433Mhz Remote Control Relay Switch, DC 6V 12V 24V 1CH Channel Relay Wireless Secure RF Transmitter and Receiver kit, Momentary Toggle Latched Mode

BIngo!!  I could just press a button and switch antennas.  But a problem quickly arose.  I hadn’t fully read the description of the RODOT switch:

The blue output wire is ALWAYS Vcc (input voltage)! The device only switches the ground.

So the RODOT switches the ground but the HMC349 uses positive voltage to switch.  OOPS.  Next step was to place a latching relay to take the on/off ground and convert it to on/off positive.  Again, another nice board was found:

Amazon Description:  HiLetgo 2pcs 5V One Channel Relay Module Relay Switch with OPTO Isolation High Low Level Trigger

The nice thing about the Relay Module is that it can be latched either High or Low, so the RODOT switching ground can be used to latch the relay and then provide a positive voltage to the HMC349 antenna switch.

All modules are powered by 5V.  There are other modules available that use higher voltages.  But I wanted to be able to use a 5V power source for everything.

I learned a quick lesson on the first layout I did. I had directly connected the antenna cables to the HMC349 module.  A quick accidental side yank on one of the antenna cables and the SMA connector tore off the board.  A replacement board and some quick wiring and I had a workable antenna switch that with the press of the car fob button, either antenna could be selected.

I found a nice small plastic box that allowed for the HMC349 module to be suspended between SMA bulkhead connectors.  By using bulkhead connectors, there is no strain placed on the HMC349 connectors. The relay module was attached to the box lid.  The modules are mounted using brass standoffs.  The finished box is about 3”x4”x 2” high.  Either battery or a 5V wall module can be used to power it.

Overall, I’m quite pleased with the results.  I find that sometimes switching antennas (and their orientation) can make a big improvement in the signals.  Other times, there’s very little difference.

Remote Low Noise Amplifier along with Antenna Switching

Now that the antennas can be switched, it would be nice if a Low Noise Amplifier could be switched in and out of the circuit.  Something like the Lana HF Barebones LNA made by NooElec:

For testing purposes, I first did a quick layout of just using one antenna with the ability to switch the LNA in and out.  Note:  I took a gamble on hooking the antenna cables directly to the HMC349 modules.  Luckily, the SMA connects didn’t tear off the boards.

Two HMC349 modules are used.  The first module selects the bypass or the LNA.  Likewise, the second module also selects either the bypass or LNA.  Note that the second module is turned upside down so that the switches match up when activated.  Two modules were used so that the LNA is totally switched out of the circuit. Continue reading →

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