Friday, February 27, 2015

Anglian 4m Transverter

Having had success with the 2m Anglian I decided it was time to finish its cousin the 4m Anglian Transverter . I also put the tinplate box module  in a cabinet along with the 7W power module mounted on a heatsink on the back panel, using the same metal box from makerbase.co.uk A metal plate would be needed for the inside of the box to mount the modules on, I found one off ebay that could be supplied cut to size



The transverter was setup so that 0.5mW from the K3 on 10m produced 5W on 70MHz, which is the ideal drive level for my amplifier

Thursday, February 26, 2015

Anglian 2m Transverter

A while ago I populated the pcb for my G4DDK 144MHz Anglian transverter. I finally got round to putting it in the tinplate box and tuned it up. All was well, so I decided to put it in a cabinet along with the 8W power module mounted on a heatsink on the back panel. I found a couple of cheap Metal boxes off makerbase.co.uk A metal plate would be needed for the inside of the box to mount the modules on, I found one off ebay that could be cut to size

To add heat transfer, I wanted to mount the power module directly on the heatsink rather than mount it on the back panel then on the heatsink. To do this i would need to make a rectangular hole in the back panel. Discussing this at the Malvern Radio Club, it was recommended I used a nibbling tool. I found one on the internet for 9.00 shipped. It is a brilliant tool; I can see a lot of use in its future!



As there is no conductivity between the metal parts of the case due to the paint a lot of time was spent removing paint to allow good electrical contact between metal surfaces. I also add a piece of ali angle between the back panel and the cahssis plate.

The transverter was setup so that 0.5mW from the K3 on 10m produced 5W on 144MHz, which is the ideal drive level for my amplifier

The 144MHz connetors were spaced to allow an external coaxial relay to be attached with a pair of BNC to BNC male adapters. This allows use with a sngle antenna feeder. Normally when using a masthead preamp the two connectors are used, eliminating the prospect of transmitting up the back end of the preamp


Friday, January 23, 2015

K3 remotehams software with N1MM

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

Thursday, January 22, 2015

Remote Controlling the K3 using remotehams software

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



Monday, December 15, 2014

LED lighting Interference...solved, thanks to G4BVY

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 effect of turning on the Homebase lamp on the 2m noise floor

The overall 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.



Thursday, December 4, 2014

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

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.


I have written up the "Seperate  Receive and transmit paths for the Elecraft K3  Internal K144XV Transverter" modifications with pictures at http://g4fre.com/kx144_split.htm


Saturday, November 22, 2014

Exercising my 2300MHz NOV

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