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Fujitsu 251-9735-010 6GHz amplifier fixed

July 7, 2014, 10:14 am
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I was given a Fujitsu 251-9735-010 6cm 5W amplifier by WA5VJB about 12 years ago for my Transverter but never got round to trying it out, this weekend was an opportunity. I borrowed a 5760MHz California Microwave brick which gives 16dBm at 5760.000MHz from W5LUA to save needing to retune my DB6NT 5616MHz LO. This needed a -19V supply, provided from my 57A 28V PA supply (yes overkill!) According to Kent's notes the PA needed 4A at 12V and 200mA at -12V for the bias for which two other additional PSUS were found (a variable one and the 13.8V rig supply). Applying the -ve bias the power supply immediately current limited, but the resistance to ground from the bias supply lead was 12kohms. Time to take the lid off. LOTS of screws later the lid was off. The -ve bias supply feeds a 7905 regulator. As a quick test (to avoid more screws) the regulator was cut out and the -5V applied to the regulator output pin. With the 12V supplied 5W was seen. The control board was removed and a new regulator fitted. It still produced 5W. 
The opportunity was taken to measure some voltages and currents. Full output was produced until the positive supply dropped below 12.00V. Full output was produced until the negative bias dropped below -6V, The measured currents were 12V at 3.9A and -12V at 50mA. It was noted that the detected output was a negative voltage. Not good for Microchip PICs! The detector diode was reversed and resistors adjusted so that the detected output was +10V at full output. 
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432MHz Solidstate Amplifier Completed

July 18, 2014, 9:16 am
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Over 3 years ago I bought a W6PQL 500MHz amplifier module  with the matching LPF/Directional coupler. Before I moved out of the McKinney house I quickly mountedthe modules on a heatsink inside an aliminium chassis to protect it in storage. Over the last few weeks I have finished the metal bashing thanks to WA5YWC and built a PIC controller and LCD display.  The biggest issue was testing it as I no longer had a 432MHz transmitter in the USA. W5LUA kindly offered to let me use the facilities in his shack which included drive source, Power meter and dummy load.
The first thing we learnt was that the RF got everywhere inside the chassis. Initially there was no screening around the PIC board which caused measurement issues. After a trip to the local hobby store for some .015" ali sheet and the donation of many 1nF bolt in feedthroughs by W5LUA that issue went away. It was necessary to put a screening can over the directional coupler (w6pql only suggests it for his 1kW amplifier) as the calibration of the bargraph meter changed dramatically when the cover was put on the box
 
When completed the amplifier gave 420W for 6W drive when running 17A at 48.0V. Looking at the W6PQL figures I could hit the amplifier harder to get the full 500W but this way I have a safety margin. All harmonics were over 65dB down on the fundamental power.
 
 
 
 
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KX3-2M KX3 144MHz Internal Transverter

August 9, 2014, 5:39 am
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The KX3-2m module is lower left
I ordered this during Dayton and it arrived this week after 3 months. It took about 20 minutes to fit into the KX3. Measurements showed 2.5W output off 13.8V and the w5hn beacon was audible on a whip attached to the SMA antenna connector, so sensitivity seems ok.

I originally also ordered a 4m transverter module, but after seeing warnings about the limited number of times the two RF cables interconnecting the modules to the KX3 could be plugged/unplugged, I gave up on the idea and reverted to the external DEMI Transverter
 
 
Closeup of KX3-2m module
 
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August 50MHz UKAC

August 26, 2014, 3:09 pm
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As GW5NF was having trouble with his TS2000 FMing on 2m and 6m(as reported by TF3ML/P!)  Meg offered to loan him her Elecraft K3 while it was in for repair.   Looking at the calendar a 6m UKAC was impending so we decided to take it and install it that day and see how it worked under the GW0FRE call. It took just a few minutes to install the K3 along with the matching KPA500 and interface it to his computer. We had a listen on 6m and heard a few signals so tried calling them Worked were IK5ACO(JN52),  ISOCDR(JN40) and ISOBSR/P (JM49) Next we hooked up the Microwave modules 70MHz transverter for a listen and heard CS5BALG/B (IM67) and CT1HZE (IM57) calling CQ on SSB who came back first call with our 7W! After a meal break,  6m produced EA5GLN (IM98)and EA7/G4GCP (IM76) then it was time for the contest.
Deciding to live dangerously we installed the N1MM software 20 minutes before the contest began!  The contest started with stations in Scandinavia. The best was OH2TP(KP20) at 1920km, but it was nice to work SM4IVE other than via the moon. Conditions then died. The contest ended with a burst of Italian stations giving the best DX,  IW8PQU (JM88) at 2078km. 60 stations were worked. The complete spread geographically is as follows: 
 
 
 
 
Looking at the UK stations worked it is noticeable the lack of Northern Stations, due to the large mountain less than a mile north of the QTH blocking takeoff that way:-
 
 
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Telford Rally Weekend

August 31, 2014, 2:20 pm
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This weekend was the annual Telford Radio Rally that is held at the The Enginuity museum at the Ironbridge Gorge. This area also has a lot of interesting museums so it was decided to make a weekend of it. We drove up Saturday morning, following the Tom Tom route that was an alternate to the motorways which visited lots of back roads and no towns! First we went to the Coalport China museum, then the Tar tunnel and finally the Jackfield Tile museum before retiring.
Sunday morning we followed the very noticeable Fluorescent road signs to the rally and parked in the adjacent AGA works (of stove fame)  to the Enginuity complex.
 
 
 
There were a selection of stands outside in the courtyard and more in an inside hall. I bought a 12v 7AH SLAB to power the KX3, guy rope, an EF183 (for my PW 6AF11 RX) and an 8W 6cm amplifier (from the G3OHM club stand). I did resist the British Tube tester for 250 pounds! I spoke with Gordon, G8PNN who I had not seen since staying overnight at his place on the way back from the GB2YS/GB2ZR expedition in Aug 1986...he still remembered the car I had!
 
After the rally we walked uphill to the Darby House museum which were also very interesting. On the way back to the car we noticed the date the Rally building was built, you never see such age at USA hamfests! 
 
 
When we got back to the Rally carpark we were the last car there:-
 
 
 
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144MHz Portable Backpacking Activity

September 7, 2014, 1:22 pm
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Having worked a few stations early on in the 144MHz September contest from the house on the dual band collinear,  I wondered how much louder they would be from the top of the hill. As the contest continued until 3pm clock time on Sunday and there was a backpackers contest 1200 to 1600 there should be a few signals to work.  I packed up the FT817, the KX3 with the internal 2M module, a 7AH battery and the whip off my FT817 (the only 2m portable antenna I have) in my rucksack and headed up the hill.

A few signals were heard on the east coast so these were used to compare the receivers of the FT817 and the KX3. The KX3 won by a mile, so the FT817, despite its slightly higher power was packed away. I discovered I had left the KX3 lead for the battery so it had to be used all the time on the internal cells.

The biggest challenge was how to hold the KX3 in one hand, use the microphone in the other AND put entries in the log, something I will need to work on

To avoid confusion with G4FRE used from home I used G0FRE/P, which did confuse one stations lookup database! A total of 22 stations were worked the best DX being F6KCZ/P at 324km. One ON and two PA were heard but too weak to work.
 

 
After the contest finished I walked along to the Malvern Hills Hotel for an Ice cream from the stall opposite

I need to consider investing in a small, transportable beam like an HB9CV for such outings. I already have one for 4m and 6m in the loft but I only have a dual band collinear for 144/432
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50MHz RF survey of the Malvern Hills

September 13, 2014, 1:20 pm
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After operation from Black Hill last weekend I decided to see how it compared with the other hills in the Malvern Hill Range. On Summer Saturdays there is a Bus from Worcester to Ledbury that stops at British Camp which avoids the need of doing a round trip along the hills) to get to a car parked at British Camp. The bus stops next weekend so this was the weekend to try it. It was also good exercise being about 8km walk in total and rising to 1400'

As there was no contest this weekend comparison would have to be by looking at 6m and 2m beacons. Again using the KX3, but this time with the 6m extension on the whip antenna. The following is a summary of the 6m results

Black Hill GB3BUX 529 , GB3BAA 539, GB3MCB 549, GB3RAL 529
Pinnacle Hill GB3BUX 549 , GB3BAA 549, GB3MCB 559, GB3RAL 539
Jubilee Hill GB3BUX 519 , GB3BAA 539, GB3RAL 529
Worcester Beacon GB3BUX 519 , GB3BAA 539, GB3RAL 519
North Hill. GB3BUX 549 , GB3BAA 539, GB3RAL 519

GB3VHF on 2m  being to the East of all of the hills did not vary in signal strength. GB3BAA and GB3RAL similarly  are to the East and were little affected by location. I was a little surprised that RAL was consistently weaker than BAA. GB3MCB is South West and on any hill North of Pinnacle hill is blocked by the other hills hence its no show.
 
Pinnacle Hill looking South from Perseverance hill
 
Worcester Beacon looking North from Perseverance hill
 
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Arduino Uno and GPRS shield

September 14, 2014, 7:07 pm
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While looking at the design of the OZ7IGY beacon I noted they were using a GPRS shield  to remotely manage the beacon via cellular http://rudius.net/oz2m/ngnb/management.htm. I could see all sorts of applications for the system. I looked at the module they were using and decided it was too expensive to play with and looked for cheaper alternatives.  I came across the EEGTECH WGW-06633 which was only $33 but did have audio in and out so I ordered one.
 
A few weeks ago I came to the conclusion that there was no point in doing RSGB 50MHz and above contests without having access to ON4KST. After consulting with G4BVY I bought a Huawei E5330 cellular to WIFI converter and got the cheapest cellular plan I could find from giffgaff which would give me 250MB of data and 200 minutes of phone for 7.50 a month. They also supplied the sim. O2 were the carrier, which was unfortunate as they have awful coverage around here, but it was worth a try.

The internet revealed a very useful tutorial at http://www.seeedstudio.com/wiki/GPRS_Shield_V1.0 This has examples for making voice calls, sending sms, receiving sms and reading html files all of which worked fine.
 
The ultimate test that I achieved was to have my shack PC monitor 10m wsjt JT65B signals and upload the decodes to my web site. The arduino and shield recovered these spots from the website and sent an sms  of them to my phone. I can see some useful variations of these scheme being deployed on a long term basis  
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Interfacing the Elecraft K3 to an Acer V5 Laptop

September 17, 2014, 11:30 am
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Having upgraded my Acer Aspire one to an Acer V5 laptop which has a faster processor and larger screen, I was surprised to see it had a single connector for Audio Input/output and was therefore incompatible with all the Interface cables I had made for the K3/IC706/FT817. As a quick fix I plugged in my USB soundcard which did have separate audio in and out  while I made some cables
 
I had a suspicion the TRRS connector on the Acer was wired like the one on the Nexus 7 as I discovered when building the PSK Interface . I searched the Acer manual but that was unhelpful. I called Acer helpline but even their Tier 2 technical support had not a clue, so I assumed it was the same
 
I found a mono 3.5mm lead for the K3 Line In connection, a stereo 3.5mm lead for the Line Out and a TRRS plug.  I wired up the connector to feed audio into the K3 and that worked fine. Feeding audio out of the K3 into the computer was a failure. It was unsuccessful and it was impossible to disable the Laptops Internal Microphone.  Measuring the open circuit voltage on the Mic Pin showed 2.8V, obviously intended for an Electret Microphone. When the K3 was attached this voltage dropped to 0.8V, the Line input obviously had a DC path. Searching the internet I found a few articles on using a resistor of a few hundred ohms on the mic input to control Play, forward and stop of a media player on a Nexus 7. I wondered if a load resistor must be used to emulate the current drawn by an Electret Microphone to disable the Internal Microphone. Electrets are typically 1600 ohm, so I put a resistor across the mic input and used a 10uF capacitor to stop the K3 DC loading the port. The final circuit is as follows:-
 
 
 
This worked fine, but now it needed Tidying up. By using an 0805 size resistor and an 0805 size ceramic capacitor the components could be fitted inside the plug shells.
 
NOTE: No PTT signal was needed via the interface as the K3 was controlled by CAT signals
 
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Interfacing multiple 9 pin RS232 connectors to the Acer V5 Laptop

September 23, 2014, 10:29 am
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Having got the Audio interfacing to the V5 sorted it was time to look at the serial data. The V5 has no RS232 connectors and only 2 USB ports.  Normally I have one serial connection to the radio (9 pin), one to the GPS (9 pin for timing) but now I needed an extra one for the winkey usb (true USB) having recently discovered mine in a drawer. I could have used  a USB hub but past experience has found them unreliable in RF environments. Searching my goodies box I found my Edgeport /4 USB serial converter  (bought off Ebayusa for $10) that I used to use on my old Win XP contest computer. This box has one USB connector and four 9 pin serial sockets.  I could connect the Radio and the GPS to the Edgeport box and the Winkey USB directly to the computer, leaving 2 spare com ports.
 
Configuration software and drivers were available for Windows 7. Comports can be allocated as desired,  I used COM3, COM4, COM5 and COM6. WINKEY USB has COM2
 
 
 
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RSGB National Hamfest 2014

September 27, 2014, 1:32 pm
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In my early days of Amateur radio I used to visit THE national radio Rally at the Granby Halls in Leicester in November. This finished many years ago and it has now morphed into the RSGB National Hamfest that is hold at the Newark & Notts Showground in October. Viewers of the BBC Programme "Bargain hunt" will have seen it many times as it often has antique fairs used in the series.
It is held over two days, Friday and Saturday so I decided to go on the Friday. It is a 120 mile trip from Malvern which took 2.5 hours, arriving 15 minutes before the official opening time of the indoor exhibits but the flea market was fully in motion, and it was sunny. I made a few  purchases from the Fleamarket. A Wouxun KG-UVD1P 144/70MHz FM Transceiver , (now I can speak to WA5VJB when he comes to England) a 13.5V 22A PSU which cost £1 and a bag of fifty 10uF 25V tanatulum Capacitors for 50pence . Most Interesting was meeting G4AEH who was assisting a seller and catching up on old times, mentioned in my blog entry "blast from the past" 
I then went indoors. There were RSGB stalls and the RSGB bookshop, so I used my £5 off voucher to buy the EI5GQ "Building a Transceiver" book (which was technically interesting but included some "non sentences"!).  I had a "long" lunch with G4HUP and caught up with G3XTT, G4BAO, G7OCD, G4KUX, G4FSG and G3CWI.  I picked up the pre-ordered 4+4 ele 6/4m antenna from Innovantennas and just about fitted it into the Car. There were a few interesting items, if one looked close enough. One was a Telford Communications TC10 receiver that was used as a 28-30MHz tunable IF for 2m/4m with the matching G8AEV converters and a Hughes 1077TWT which had a beaten up PSU . Both were resisted, I did however buy a "drive on" base for my portable mast and a couple of pieces of ex-military RG213 for the new antenna. The rally ended at 4pm, sharp. The return took almost 3 hours due to the dense Friday afternoon traffic. Overall an Interesting day out
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Power Cabling in the car for portable operation

November 7, 2014, 1:29 pm
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I have been looking at providing 12V power for portable operation. Until now I have been running the K3 and transverter by using Jump leads from the Car Battery. This has caused intermittent contact issues and large Voltage drops in the past, so a better solution was needed.
In my connector collection I discovered some 120A red and black power pole connectors. I put these on the end of a pair of Halford jump leads after removing the crocodile clips.






A pair of connectors was attached to the battery using "switch leads" with 8mm eyelets from ebay. For the other end of the cable I made a breakout box. I got a large plastic box from Maplin and mounted a pair of 120A connectors on one end and five regular powerpole power connector pairs on the other end.



The connections between the connectors at both ends were made through a 30A thermal switch

To allow connection to a car without the prewired connector I attached the crocodile clips to a pair of connectors to allow connection to the battery by this method





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Regulated 13.8V mobile Power supply

November 7, 2014, 2:36 pm
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Having minimized the cable voltage drop in the car portable wiring system I noticed I was only getting 60W out of the K3  unless the engine was running when I got the full 100W.  This was due to the drop in the supply voltage from 13.8V to 12V. What was needed was a box that maintained a constant 13.8V irrespective of the volts being supplied by the car.

I vaguely remembered that N2CEI had battery conditioning modules in his rover setup.
The large box at the rear of the trailer contained 2 car batteries and 2 voltage condition which maintained 13.8V. So I asked him who made them. He pointed me to his supplier TG Electronics http://stores.tgelectronics.org/ . They did the The New N8XJK Boost Regulator:-
Voltage: Input: 9 to 15 Volts DC.
Output voltage: up to 15 Volts DC at 30A.
Dimensions: 7" wide x 3.5" deep x 2.25" high 
 I also found MFJ did a similar unit "MFJ-4416B Battery Voltage Booster 12V" for $160, however having had reliability issues with MFJ equipment I decided to go with the TG Electronics unit. I ordered the optional 30A thermal trip to save having to replace fuses. It took a week to arrive.



The unit has a UHF socket which can be used to RF trigger the unit and place it in circuit when in transmit mode. Note this only works on HF/6m. 
Performance was most impressive. When providing 20A at 13.8V from an 11.1V Input there was only 5mV RMS ripple on the output and the K3 produced 100W. I also had a listen on the KX3 while on transmit and no noise could be heard from 160m through 6m.
Another neat feature is that I could set the unit to put itself into bypass mode and sound an alarm when the input voltage dropped to 11.0V.  

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Time to buy a Generator

November 9, 2014, 5:15 am
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Having now put the power provision requirements in order inside the car, there are occasions when more power is required and a generator is needed. I started looking at what was available at around the 1kW level. In the USA I had a Honda EX1000 1kW for 15 years which worked well and provided ample power, but looking at the UK prices a cheaper solution was needed! I noticed while researching that nowdays there were "generators" and "inverter generators" which were new to me so I sought the advice of the local "portable operation with a generator" owner, Roger G4BVY. After much discussion I decided that the main advantage of the inverter generator is that the volts and frequency are not so controlled by the motor speed and are therefore better for "delicate electronic equipment" and they are lighter.

With this in mind I started looking online at the "normal" Clarke G1200 generator and an Inverter Clarke IG1000. The most noticeable difference was the weight, The G1200 was 25kg the IG1000 was 15kg. It was time to physically look at them. Roger had recently received a postcard with VAT free Granger purchases at the local machinemart in Worcester; time for us to visit.  There was indeed a noticeable difference in weight, the IG1000 could be easily moved with one hand, the G1200 took effort. The IG1000 was well enclosed; ideal for wet Welsh mountains. The decision was made to buy the IG1000, even though it was slightly dearer,  during the voucher validity window the following Sunday. I was at this point cautioned by others about the amount of RF noise the Inverter can produce, but I went ahead.  The shop was visited and the boxed generator easily fitted in the back of the Jazz with the back seats up.


The following day a visit was made to the Rogers to christen the generator. Following the instructions, (most noticeably waiting 5 minutes for the new oil and petrol to get everywhere it should),  the generator started. With no load it produced 230V. At this point the calibrated dummy load was found  (a 600/1200W switchable fan heater). Applying the load caused the motor to "think" briefly but the voltage only dropped 1V. We  decided it was time to look at the waveform so an oscilloscope was extracted from the shack. There was NO difference in waveform between 0W and 600W. It wasn't a pure sine wave but it was very stable

Next test was RF noise The Elecraft KX3 was moved all around the generator (which had been given an antenna...the mains extension lead) but no noise could be found through 6m.
The following day, while setting up for the 2m UKAC I ran my 2m setup from the generator. Elecraft K3 + 500W I0JXX LDMOS module based PA ran off a 48V switcher power supply, It produced the usual 400W without tripping the generator. The AC voltage still only dropped 1V.
I am most impressed with its performance.
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Exercising my 2300MHz NOV

November 22, 2014, 11:44 am
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After seeing the announcement that the 2300MHz NOV were finally available I decided it was time to get one. After reporting some disparities between the RSGB website and the application form (eg the website said "main address only"; the form allowed a list of portable locations) I managed to get an NOV. The issues have been corrected


 For EME operation from the USA one needed to cover 2300, 2304 and 2320MHz so a Transverter for 2300MHz was already available as written up at http://g4fre.com/13cm_xv.htm My PA using the driver stage from the Spectrian Amplifier produced 10W, I didn't have enough drive to get the full 30W.


On Thursday evening I tried a sked with G4BAO at 170km. I used my only  13cm antenna, a 25 element (the one with the horn feed) taped to a cardboard box pointing out of the bedroom window.



It was suggested to try ISCAT-A digital mode.




213800   1 -12 23.2  -65   0 *  G4FRE G4BAO                   12 10 10  4.5
213900   1 -11  2.0  -65   0 *  G4FRE G4BAO                   12 10 10  2.2
214000   3  -9 16.5  -65   0 *  G4FRE G4BAO                   12 10 10  4.5
214100   1 -10  2.0  -65   0 *  G4FRE G4BAO                   12 10 10  2.2
214200   4 -10 12.0  -65   0 *  G4FRE G4BAO R-15 R-15         22 10 10  8.9
214300   3 -10  3.1  -65   0 *  G4FRE G4BAO R-15 R-15         22  9 10  4.5
214500   6 -10 19.8  -65   0 *  RRRR RRRR G4BAO               16  3 10 17.8




It took a while to complete the QSO, aircraft reflections were non existant but we completed for my first trop QSO on 2300.2MHz. A quick try was made with G4DDK at 246km but no two way QSO


On Friday morning I tried again with G4DDK. His signals were weaker by some 5dB than the previous evening but were there most of the time. It took a long time to get a signal report exchange on ISCAT-A. 


105100   1 -15  6.5 -118   0 *  G4FRE G4DDK                   12 10 10  8.9
105200   3  -9  3.1 -118   0 *  G4FRE G4DDK                   12 10 10  4.5
105300   3 -11  5.4 -108   0 *  G4FRE G4DDK                   12 10 10  8.9
105400   2 -13 12.0 -108   0 *  G4FRE G4DDK                   12 10 10  8.9
105500   1 -12 21.0 -129   0 *  G4FRE G4DDK                   12 10 10  4.5
105600   2 -12 10.9 -129   0 *  G4FRE G4DDK                   12 10 10  8.9
105700   2 -14 19.8 -129   0 *  G4FRE G4DDK                   12 10 10 17.8
105800   4 -10 23.2 -129   0 *  G4FRE G4DDK                   12  9 10  8.9
105900   1 -11 14.3 -140   0 *  G4FRE G4DDK                   12 10 10  4.5
110000   2 -13  9.8 -140   0 *  G4FRE G4DDK -17               16 10 10  8.9
110100   2 -13  5.4 -140   0 *  G4FRE G4DDK -17               16  5 10  8.9




Signals were not "bursty" as would be produced by aircraft, so we switched to JT65c, which is good for weak, continuous signals. The QSO completed quickly:-




110400  8  -10 -1.7 -137  6 *      G4FRE G4DDK JO02          1  10
110600  5   -9 -1.7 -143  7 #      G4FRE G4DDK JO02    OOO   1  10
110800  7  -16 -1.7 -143 11 *      R-17                      1   0
111000 10  -23      -142  2   RRR ?                               
111200 10  -22      -145  4   73  ? 


The lesson learnt is that the digital mode used needs to be carefully chosen based on the received signal characteristics
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Seperate Receive and transmit paths for the K144XV Transverter

December 4, 2014, 11:41 am
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When using the Internal K144XV  2m transverter in my Elecraft K3, it has a single BNC connector on the back panel for receive and transmit signals. Having obtained an HA8ET 2m mast head preamp I needed to separate the two signal paths to avoid putting RF up the back of the preamp.

Elecraft in the past have said it is possible to connect a separate RX antenna to transverter but nothing has ever been documented! The only clues have been the comment  in the K144XV manual about not removing links P2 and P3 inside the transverter. Time to investigate! I took the cover off the K3 and the K144XV transverter and found that if the link between pins 1 and 2 of P3 was removed the receiver went deaf.  Pin 3 was ground.  I connected a coax cable with centre conductor to pin 2 and the braid to pin 3 the GB3VHF beacon could be heard on my collinear. The radio still produced the normal 9W out of the BNC connector on the back panel.
I did not want to solder to the header so I found a 3 pin female header (previously used for arduino shields) and soldered a piece of RG174 with a BNC socket on the other end, which hung out of the back of the lid panel. I did look at tidying up the cabling by using the AUX RX BNC connector but this would mean taking the K3 apart and removing the sub receiver every time I wanted to change between internal and external 2m antenna switching.
For reference P2 link allows the Receive IF output to be diverted from going to the KXV3A module. P8 link enables the dc voltage on transmit on the centre pin of the Transmit port. 
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LED lighting Interference...solved, thanks to G4BVY

December 15, 2014, 11:49 am
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A couple of years ago I was convinced that swapping out the apartment lamp lighting for LED lights would save money so I bought a load of GU10 6W LEDS from Homebase and Installed them. Disaster! When any lights were turned on the noise floor on 10m and above shot up by a considerable amount. Classic FM disappeared on 100MHz. Classic FM on DAB disappeared.


Recently this situation has resulted to running some Tuesday night UKAC events by the light of a (non LED) bedside lamp, with all other lights off!


I was told LED lights had got better in the intervening years, interferencewise, so I bought some more  LED samples from Tesco, B&Q and recent samples from Homebase to see if they had. The Tesco ones were the best of the collection, but still produced a noise floor increase.




It was at this point that Roger G4BVY posted to the MHRAC reflector that he had bought some Phillips 4.5W LED in twin packs for 9.99 from Wickes from which he could detect no interference and they were quite bright. Off to Wickes in Worcester to buy a couple. Installed them in the stairs lights listened on 144MHz turned the lights on...Nothing!  The noise floor did not increase at all!


I was intrigued how much the noise floor increased on 2m for each type, so I needed a calibrated receiver. The easiest option was to use the SDRIQ in continuum mode with my Nacton transverter for 144MHz. The increase in noise floor could be easily seen in dB. The results were Interesting:-


Homebase  6W (2012)             24dB
TCP 5W (Homebase)              26dB
TCP 4W  (B&Q)                     18dB
Tesco 5W                                 8dB
Phillips 4.5W                           0dB


The Phillips was by far the best. Interestingly Homebase don't actually sell their own brand any more, they only sell TCP so I got one of their 5W ones. haven't improved their version, It was returned as "unfit for purpose"! I was so impressed by the Phillips I went back to Wickes to get replacements for all the other Homebase lights.  Before fitting the new ones I decided to see how the Homebase LED interference varied with frequency. This time I used the SDRIQ with external Nacton transverters for 6, 4 and 2m. The noise floor increase was as follows:-

7MHz                0dB
14MHz              5dB
28MHz              7dB
50MHz              16dB
70MHz               18dB
144MHz             24dB


As a check, I also measured the results using my ANAN-10 as the receiver. The results were within +-1dB


The remainder of the Phillips LED were fitted. For the record the twin packs have the UPC 8718291789994. I looked on all the frequencies I had (even 136kHz) but couldn't find a noise floor increase. Good news all around; lower noise, decreased power consumption and Meg says that, unlike the previous LEDS the increased brightness will even support her sewing! Thanks Roger.



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Seperate Receive and transmit paths for the Elecraft K3 Internal K144XV Transverter Update

January 21, 2015, 11:12 am
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Remote Controlling the K3 using remotehams software and 2 PC

January 22, 2015, 2:28 pm
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When they were first launched I bought a pair of RRC-1258mkIIs remoterig boxes to control my K3 across the Atlantic. They were quite large and needed lots of cables amd 12V. Recently the need to control the K3 resurfaced. Having seen and used the remotehams system at the 2014 Hamcom to control the KG6YPI remote in California from Dallas I decided it was worth investigation

The system requires a windows computer at the K3 end running the server software. At the other end a windows computer is needed running the client software. The computer can either display a radio front panel or drive a K3/0.

The client can also be used to connect to one of the radios around the world listed/registered with remoterigs 



Note in the list of rigs above the variety of rigs available. The software supports other rigs than elecraft. I used the KG6YPI (the software writer)  remote again to get familiar with the client software.


Next I installed the server software. For this I used an Acer V5 laptop. Audio connections to the K3 were made using the LIN IN/OUT on the back of the K3 using the method of my writeup along with a serial connection to the K3 serial port. The audio and rig settings under <options> on the server were adjusted appriately adjusted.  The 4 ports mentioned in the server documentation were opened and the server launched. Even though I allowed Upnp on my router the server software never found/used it.

Using my Dell laptop, I launched the client software and saw my server on the list at remotehams.com. This list saves the current internet details of the server, data between server and client is not sent through this location. Doubleclicking my server Launched the radio front panel. Using the <skins>  tab I choose the k3 skin which gave me an authentic looking K3 front panel:-



The received audio came out of the Dell laptop.The rig could be tuned band changed and, as I had given myself transmit priveleges I could also transmit.

Three discoveries I made early on:-
1. Under >publishing> on the server if "visible on remotehams.com" is unclicked the server will not appear on the list of available servers on everyones list. If you have a fixed ip this information can be entered under <file> <new connection> allowing a connection to be made more easily.
2. The volume control is at the top of the screen for the client. If the volume on the client K3 front panel is used the volume of the remote K3 is increased which may be a surprise to anyone nearby. For this reason the main and sub volume sliders are prevented from being displayed on the client
3. By default the power on/off button is shown on the client.  The K3 can be turned off by this button but without extra hardware it cannot be turned back on. For this reason in the server settings the"power" button is prevented from being displayed on the client



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K3 remotehams software with N1MM

January 23, 2015, 5:10 am
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Now being able to control the K3 remotely, I next wanted to integrate It into the N1MM contest software. To do this I would need a virtual com port setup on the client PC that would allow the serial data to be seen from the remote K3. Fortunately the remotehams client software under "options" has  "Elecraft K3 emulation" To install the drivers for this,  one needs to tick the install virtual port when installing the client software, then when that has successfully installed, under "options""Elecraft K3 emulation" I chose com2 as the port to create under the "create virtual port" tab.. Note the data rate is fixed at 38400bd.


After this was done I chose "com2" "k3" 38400" under "config""config ports....""hardware" in the N1mm software and the remote K3 acted exactly as if it was local


Note this same technique can be used in any software requiring to see the K3 on a serial port. Fldigi, WSPR v2.12 and logger32 have all been successfully tried
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