11 September 2017

Looking for clean SS HF PA w/QSK - part 5 (Elecraft)

Hi all,

"Everything goes very well with the FCC approval and there will be the KPA1500 linear amplifier official announcement soon on Elecraft list and Elecraft pages as informed Wayne, N6KR few weeks ago....

Short time after I noticed the note that FCC approval arrived and KPA1500 is ready for orders! Official announcement then appeared on the Elecraft pages as same as on the Elecraft mailing list quickly.

So new 1,5kW Solid State HF-6m PA w/QSK was born in Elecraft and it comes to be available worldwide. soon

As you know my preview parts talked about:
ACOM 1200S
LINEAR Amp Gemini HF-1K

Azden AZR-1000

The Elecraft KPA1500 is 1500 watt PEP output, MF, HF and 6 Meter linear amplifier. It utilizes the latest LDMOS transistor technology to provide a robust desktop amplifier in a compact cabinet, with an included companion power supply that can be located off your desktop.

The Elecraft KPA1500 was designed with the serious operator in mind. Its no-nonsense front panel shows all important parameters at a glance, with a high-contrast 32-character LCD and fast, bright LED bar graphs. Band switching is instantaneous, via control inputs or RF sensing. Protection and monitoring circuitry is extensive and foolproof, letting you focus on the job at hand — breaking pileups and overcoming the most difficult operating conditions. And it wouldn’t be an Elecraft amp without robust PIN-diode T/R switching. Like the KPA500, the KPA1500 offers fast QSK without a noisy relay!

So it looks like there is "thanks god" second 1kW+ SSPA with silent, fast and well working QSK system on the market...

The amplifier’s rugged internal ATU can handle full power with load SWR up to 3:1, while a wider matching range is allowed at lower power levels, including up to 10:1 in standby mode.

Compare to their preview products initially this KPA1500 will be available in Factory-built form only.

According to Elecraft announcement an introductory pricing is $5,995 U.S. This includes the 1500-watt linear amp. internal tuner and separate switching power supply.

Compare it to other amplifiers on the market and you will notice that it is not so bad.

The most important KPA1500 features:

- 1500W RF output
- Very compact design
- Fast, silent PIN diode T/R switching system
- Built-in Antenna Tuner with dual antenna jacks
- Compatible with nearly any transceiver
- 160-6 meters

Freq. (MHz)Pin (W)Pout (W)Gain (dB)

New KPA1500 solid-state amplifier won’t take over your entire desktop: it’s just 4,5 x 13,5 x 11,5” (HWD; 11,5 x 34 x 29 cm). The lightweight companion power supply can be placed on the floor or in any other convenient location...

According to the user guide the duty cycle at 1500W out is 10mins key down / 5mins standby.

Interesting functions:

- Automatic Band Switching mode
- Manual Band Switching mode
- Coordinated K3 and KPA1500 Band Switching mode
- Remote PC control using RJ-45 or USB
- Power meter internal calibration procedure (PWR ADJ)
- Internal automatic band selection w/master-priority to protect KPA1500
- Icom, Yaesu and BCD codes available to incorporating w/other radios

Thanks to Martin, OK1RR and OKDXF you can find more details here(CZ) or as follows:
KPA1500 User Manual.pdf
KPA1500 Pics outside.pdf
KPA1500 Pics inside.pdf
KPA1500 EMC test protocol.pdf
KPA1500 EMC test pics.pdf
KPA1500 Spectrum purity.pdf

If you remember the LinearAmp Gemini HF-1K
implemented the fully solid state QSK switching. No relays. Diode switched system turned of hard by a 300V rail.

So there is another competitor on the market with robust PIN-diode T/R switching and even more power up to 1,5kW.

KPA1500 Shipments are planned to start Mid to Late October against the backlog.

KPA1500 Flyer.pdf
KPA1500 FAQ.pdf

Ordering info

73 - Petr, OK1RP
"auf die Dauer hilft nur Power" (Erich, HB9FIH)

08 September 2017

Looking for clean SS HF PA w/QSK - part 4 (Azden)

Hi all,

next part of my investigation on the market in order to find highly reliable, output clean, compact, solid state HF-6m bands PA with 100% working, smooth QSK at around 1-1.2kW heavy-duty output and standard radio interface is here...

As you know my preview parts talked about:
ACOM 1200S
LINEAR Amp Gemini HF-1K

After the Japan Ham Fair I realized that two new SS amps by AZDEN are coming to the market. As I read somewhere already the AZR-550FZ looks a lot like a Tokyo Hy Power clone and the second bigger brother the AZR-1000 looks a little like an all black SPE Expert 1K...

What can we find at that moment (as Azden has nothing on their pages in Ham radio Products section yet) is as follows:

Azuru/Azden Corporation is a booth of HamFair 2017 at the company’s booth, HF (1.8 to 28 MHz band) + 50 MHz band linear amplifier “AZR – 550 FZ (maximum output 550 W)” and “AZR – 1000 (maximum output 1,000 W)” using MOS FET We released two models. Both are small and lightweight by adopting switching power supply.

● AZR-550FZ is a compact and lightweight HF band linear amplifier. By adopting the switching power supply, the total mass is only 9.2kg, it is very convenient to carry.

● MOS FET (4x MRF 150 in parallel) adopted. Maximum output is 550 W. It has the characteristics of broadband amplifier, only band filters switching are adjusted.

● Supply voltage range from AC 100V to 240V without switchover, wide range of operations can be performed not only in Japan, but also overseas DX-peditions.

● Drain current (ID), drain voltage (VD), output power (PF), reflected power (PR) can be measured with a multimeter, and the operating status of each part can be easily confirmed.

● Protection circuit is carried for each part protection. Over input, SWR excessive, abnormal overheating, drain overvoltage, overcurrent.

● Size: 232 W × 142 H × 392 D mm, Weight 9.2 kg

According to the company, this linear amplifier is domestically manufactured and the auto antenna tuner is not installed. It is a reprint version of HL – 550 FX that was released from Tokyo Hy Power. It is scheduled to be released within the year.

● AZR-1000 is a compact HF band linear amplifier. By adopting a highly efficient switching power supply circuit using SiC, it has become compact and lightweight.

● Use MOS FET (8x VRF 151 in push-pull). Maximum output is 1,000 W (SSB/CW) It adopts low distortion broadband amplifier, it can obtain 1,000 W typical power.

● Supply voltage range from AC 100V to 240V without switchover, wide range of operations can be performed not only in Japan, but also overseas DX-peditions.

● Operation status can be easily controlled by LCD display.

● Protection circuit is carried for each part protection. Over input, SWR excessive, abnormal overheating, drain overvoltage, overcurrent.

● Size: 370 W × 200 H × 300 D mm, Weight 15 kg

The display of the AZR – 1000 is a touch type and the size is 7 inches. This is for the operation of the built-in auto antenna tuner.

According to the company, this product is equipped with an auto antenna tuner of type that measures the impedance of the antenna and takes matching. In addition to the SSB/CW, RTTY etc. can also get output of 1,000 W, they says. The display is a touch type, and it is possible to connect to each company transceiver of the type that outputs band data. The product is domestically manufactured, the release is scheduled for 2018.

The AZR-1000 has six antennas switch implemented. Each antenna can be assigned to each frequency. That means, if you preset antenna and the frequency into the AZR-1000 and when transmitting, the AZR-1000 recognizes the TX frequency and switches antenna as preset. That is not all. The AZR-1000 will adopt silent switching mechanism. Some conventional ATUs alter relay sound noise. The AZR-1000 will reduce the noise sound drastically. The show model is only for displaying. "Concept of the AZR-1000 has been finished. Now we make samples and test." A staff said at Tokyo HamFair...

There is nothing about the T/R switching circuitry but it sounds promising. On the other hands remember all of the horrible T/R switching circuits in Japanese radios for past years so we should be very careful and wait for more detailed information and field tests of the QSK feature!

The AZR-550FZ should be offered at 285,000Yen ($2600).
The release date for AZR-1000 will be 2019. Price might be less than $7000.

Azden at Hamlife.co.jp

Do not hesitate to email me in case of translation help needs...

73 - Petr, OK1RP
"auf die Dauer hilft nur Power" (Erich, HB9FIH)

04 July 2017

SOP - The Sea of Peace hunting started...

Hi all,

The Sea of Peace hunting started. If you want to get also your beautiful SOP pennon awarded first time by the amateur radio organization of the former GDR in 1958... then you should turn on your radio!

SEA OF PEACE is the certificate steeped in tradition of the DARC district Mecklenburg-West Pomerania.

This certificate in form of a beautiful silk pennon will be awarded for QSOs with the Baltic neighbouring states and regions in July. Annual stickers can be acquired for repeated fulfillment of the rules during the subsequent years.

Beyond coming SOP-owners will receive special recognitions after 5-and 10-times achievements of the pennon and stickers. This popular certificate was awarded by the amateur radio organization of the former GDR in 1958 and has been continuing by the DARC district Mecklenburg-West Pomerania since 1991.

In 2008 it was celebrated 50 years of SOP with a special call signs and a jubilee pennon.

The SOP pennon is pentagonal and multicolored; 22 cm wide and 33 cm long. The sticker about 7 cm wide and 10 cm long.


73 - Petr, OK1RP

07 February 2017

Elecraft KPA500 - LPF T/R Switch Rework Rev. E

Hi all,
if your KPA500 has LPF board rev. D9 or earlier with surface mount board then you will probably need to make LPF T/R Switch Rework Rev.E modification, Elecraft parts kit: E850607.

The modification can be done as prevent action in order to avoid the loosing the full power accompanied by burning smell or it can be the solution for your already ruined amplifier.

Caution!  This mentioned E850607 parts kit is needed for the Rev. D9 board that is populated with surface mount components! If you have an EARLIER board (A or B) that has the non-surface mounted yellow capacitors it is not for you... Because Elecraft could no longer procure components for the A or B boards, they went with a surface mount board in later KPA500 units. It is this surface mount board that needs its parts changed and not the earlier A and B boards.

As I cured several of the KPA500 amps for friends around me using this modification and I still getting emails regarding this kind of rework, manual, parts needed etc. I decided to post short article over here in order to help to others.

The typical KPA500 misbehavior sounds like it is arcing inside and smells the classic something is burning smell. The SWR LED's are dancing upwards as it arcs. If you have connected the KAT500 tuner then it has the SWR around 1.3:1... and power is lost. Try to read first then decide...

If you want and you have SMD tools as same as ESD protection tools then you can try to make this mods first and test if it was the root-cause of your problem. If not then you can send to Elecraft service.

It is not complicated just a bit tight on the board and there is not so much space around the parts to remove the old one.

Step 0. Remove the PA/LPF module from your KPA500 amplifier unit. It is not so complicated just maybe a bit tricky. I can recommend to follow the Elecraft KPA500 Kit Assembly Instruction manual (which is downloadable on the Elecraft web pages in Manuals section) but in reverse direction.

See and follow the Pages 28 - 21 in this manual including the pictures of the module in the cabinet. KPA500 Assembly Instruction

Step 1. Check if it is applicable for your KPA500.

Your Low Pass Filter board the Elecraft part number E850406 is old Rev.D9 or earlier.

Step 2. Remove the parts and replace with new one.

KPA500 LPF module Rev.D

1. Remove R9 and replace with new 6.8Ohms/1.5W size 2512 resistor

Elecraft part - E500567
Digikey part - RPC2512JT6R80CT-ND

2. Remove R24 and replace with new one 1kOhm size 0805 resistor

Elecraft part - E500230
Digikey part - 311-1.00KCRCT-ND
3. Remove Q5 and replace with new BU931T transistor

Elecraft part - E580068
Digikey part - 497-2797-5-ND

4. Remove R5 resistor (no replacement)

5. Check R3 and verify that in this position of R3 is soldered Zener diode. Many people asked me how to determine that it is diode instead of resistor. If it is diode the band on the component is visible and this band will point to Q4 when installed.

Elecraft part - E560074
Digikey part - CD1005-Z7V5-ND

6. Check C43 and verify by C-meter that in this position C43 is soldered 82pF. It is in 12m band LPF part. If you are not sure or you can not measure it to double check then replace it with new capacitor 82pF value.

Elecraft part - E530494
Digikey part - 490-11627-1-ND

7. Check C44 and verify by C-meter that in this position C44 is soldered 68pF. It is in 12m band LPF part. If you are not sure or you can not measure it to double check then replace it with new capacitor 68pF value.

Elecraft part - E530489
Digikey part - 1206GA680JAT1A-ND

Digikey part - GRM31A7U3D680JW31D-ND
Mouser part - 81-GRM31A7U3D680JW1D

8. You should mark your modified board with Rev.D10 label in order to identify it later if needed.

KPA500 LPF module Rev.B

All work must be done very carefully. Do not overheat the PCB and check that you are not damaging the nearest parts with your hot soldering tip while you are removing the desired parts.

I made this modification on KPA500 for several friends already and in all cases their amplifiers worked well after that.

The datasheet for Darlington BU931T is here.

Drop me an email if you need the complete manual for the KPA500 LPF T/R Switch Rework Rev.E modification in pdf format. The parts can be purchased from Digikey or other suppliers. If you would like to buy the parts in kit directly from Elecraft then the ordering number is E850607.

Caution 2! If you are not moderately experienced with SMD or if you have not the SMD tools like soldering machine, hot-air machine, fine tweezers or if your hands and eyes are no longer reliable... or you do not know what is the SMD then I am recommending to ask someone close to you with these capabilities to help. In the opposite case I am strongly recommending to contact Elecraft service directly.

Hope it helps.

Document revision (rev.10-19) dated 1-Oct-2019

73 - Petr, OK1RP

03 February 2017

The TinyKeyer - building, tips and tricks


if you are looking for small, powerful, fully featured and PC driven keyer instead of your old, outdated machine without PC interface then you must try the TinyKeyer designed by Martin, OK1RR based on open source K3NG code.

Here is my assembly guide including some tricks and tips for builders. It is not for real beginners but it is not complicated and it can be built by moderately skilled builders during few hours. So we can call it "one evening project" let say...

The TinyKeyer kit by Martin, OK1RR (PCB Rev.8.0)
the (possibly) World's Smallest Fully-Featured CW Keyer with Computer Support

This keyer, based on Arduino design, employs the famous K3NG code. It can be used with any Windows/Linux/Mac logging or contesting software with Winkeyer USB (K1EL) support. The credit & big kudos goes to Anthony Good (Goody), K3NG, who did the tremendous work.

It is a very small unit (outer dimensions 45 x 45 x 18.6 mm, appx. 1.8 x 1.8 x 0.73 in) which does not have any fancy options (a zillion of buttons, psychedelic flashing LED lights or cockatoo colored displays). It is intended for regular CW work and contesting with computer support, most of functions should be adjusted and operated via the computer. For standalone work an acoustic menu in command mode is used. Otherwise, only speed control knob and a mini LED indicating the command mode is on the front panel, nothing more. See here.

This is what you will get if you have the TinyKeyer full kit. You can have also just keyer motherboard itself and then you can buy the Arduino Nano by yourself on eBay or somewhere else. Just be sure that you are ordering the Arduino Nano Rev.3! In case that you have just motherboard PCB with parts you will get also the Aluminium case as it is showed on the picture above.

PCB is manufactured professionally with printed mask and it is easy to solder on it.

If you are not sure with the components value then check them by DMM. Do not worry if you have not as same equipment as I have from Agilent.

Prepare the ESD mat working tool to protect your ESD sensitive parts like FETs as same as Arduino Nano Rev.3 board!

If you are not familiar with tweezers or your fingers are no longer reliable then the Sticky pen will help a lot.
Follow the instructions on Martin's web here and start with bottom PCB side... resistors then capacitors etc.

If you are not skilled so much with SMD... the key is to not put so much of iron on the pads!

You should finishing this bottom side with FET switching transistors.

Bottom side assembly finished. I am recommending to work slowly, be precise and do the clean job.

Continue with the top side of the PCB accordingly. As it is described in the assembly instructions you will put in place the electrolytic capacitor and then go to encoder installation.

The Faston blade before modification

Martin, OK1RR saying "it is a bit tricky". For the first time maybe it looks like, but believe me it is not so difficult.

The Faston after first modification - cutting

Tip 1. Check the height of the Faston blade towards the top of encoder in the PCB before soldering both of them! Cut it a bit higher then the top side of encoder is and then refine it slightly using flat file. The maximum height of the Faston blade in PCB after soldering is defined by top flat of the encoder in order to fit into the Aluminium case finally.

I prefer to drilling the standard circle hole (2-2.1mm diameter worked for me) instead of refining the oval shape.

Neatening is not necessary but I prefer it (12-15mm diameter is ok and make just single rev manually. Do NOT use the power drill for neatening of this hole!

The Faston blade after all modifications ready to assembly to PCB together with encoder.

Tip 2. Try if it will fit into the Aluminium case again before the soldering both of these parts (Faston + encoder) into the PCB! If the problem is with encoder push it carefully into the PCB)

Follow the instructions to assembly the encoder...

Just modify the top and bottom pins according to the pictures above to fit into the PCB smoothly.

Trick 1. Keep the encoder as left as possible while soldering it onto the PCB. You will avoid the later collision with front panel right-top screw!

Solder it precisely and clean on the PCB. Do not use excessive amount of the iron but be sure it is properly soldered.

Finish the soldering of the top pins of the encoder into the Faston blade hole. Do not overheat the encoder! Be quick and precise. Excessive heat can damage the encoder so count 1-2-3-4 then stop and take it cool-down. After that you can repeat if it is needed.

Bend the pins according to the picture to be able to solder the short piece of wire bridge to Faston blade.

The encoder is soldered on the PCB finally.

Tip 4. Be sure that the encoder is straight and encoder's axis is perpendicularly mounted to PCB otherwise the knob will not be in parallel with your front panel during boxing! 

Check if it really fit into the case smoothly... Then continue with top side mounted parts following the assembly instructions.

I am using the assembly lab microscope in order to help to my eyes and be as precise as possible. 

To be sure that jacks will fit to case and rear panel keep them in line with Aluminium case edge.

Tip 5. Be sure that both jacks are straight and their axis is perpendicular otherwise the nuts will not be in parallel with your rear panel during boxing!

Tip 6. The Arduino Nano board must sit down on the header directly otherwise You can have problem to fit into the Aluminium case!

The TinyKeyer assembly is finished and ready to be boxed now.

Checking if all is fit smoothly and panels can be drilled and refined accordingly.

Painting job done as I do not like to have refined hole for USB in different color from the box itself.

Boxing is finished and all looks good. The last job is put in place tiny legs and let's go to test it...

Job done. The another TinyKeyer is born and can be tested together with PC and the radio in the field.

Regarding the programming the Arduino (if you have not pre-programmed in the kit) follow the instructions on the Martin's web here.

Caution! As described in the beginning this assembly guide is valid for TinyKeyer PCB motherboard Rev.8.0! Nevertheless the newer PCBs Rev. 11.2 available are just slightly different (LED position etc.) the most of this guide as same as tips and tricks will work for both.

I hope it will help to some builders in order to put another TinyKeyer alive.

73 - Petr, OK1RP