Monday, 30 January 2012

Dipole centres, trap formers. Free.

Hi got a number of these after building the workshop... every unit had 4 of these but didn't use them on most so got about 50 of these. Rather than going into the bin... they are some sort of ABS type plastic and didn't seem to suffer in a microwave.

If you have a dipole or windom antenna and need a centre, perhaps with a ferrite rod balun etc then these might suit.

The inside diameter is about 25mm or 1 inch with about 5 1/2" or 140mm inside length and the top screws on.

There are small holes in the cap (one) and the non screw end which means any water ingress would have an escape... you could fill those if needed though.

Free to any that want one, first come first served...but you'll need to send me a self addressed jiffy bag. Note the postage must be a LARGE packet stamp not a first class one.

Wednesday, 25 January 2012

2SCxxxx replacements

I have seen a few posts on lists about possible 2SCxxxx replacements and chinese fakes and as some know I build a lot and I have used these before I have been asked to test a few supplier options one being the ebay trader most know. I'll put these into a simple TX (the Junk Box Special) and an AB linear and test CW and SSB on bands between 0.5MHz to 30MHz which is where the original 2SCxxxx were used without problems. The results will then be put up here.

I might even go as a far as the push pull 2sc2166 linear designs.

Tuesday, 24 January 2012

AFS Contest CW 2012

I got talked into entering the AFS Contest CW 2012 by the Camb Hams group

Contest :AFS Contest CW

Submitted :Tue Jan 24 21:44 2012

Deadline :Tue Jan 24 2012

Section :ALL

Callsign :M1KTA

Group :Camb-Hams

QSOs :80 and one dupe.

DXCCs :3

I made 80 qso on cw and 3 DXCC during the 4 hour contest, hardly a thrilling rate but added my bit to the group.

Was FT897 @ 20W (So not qrp, I tried but at 5W but in a session just prior to contest was confirmed would have had a hard time so increased output to 20w and contacts were possible) to a G5RV centra at 18ft AGL ends about 6ft AGL.

Bringing up the rear making 79 qso after 1 dupe 1/2 the count of most and 1/3-1/4 rate of the 'leaders' if I heard some the serials been given out correctly, however, 'cut numbers' confused me a little initially. I recorded the contest (just my audio in/out) and might be worth checking I got the serials right before submitting.

Bob (G3PJT) was not kidding about needing sharp elbows, an hour in and you just got stomped on and my 500Hz filter did not seem narrow enough I think I might invest in a 300Hz filter for the FT897 or homebrew something. I heard from another with a IC-7000 the DSP was working overtime to keep everything outside the passband out of their ears, but the AGC was suffering - at times despite basically no audio, the S-meter was showing S9+20.

My exchange was often M1KTA 599 my serial PSE CFM their serial TU, so I programmed that into wintest, seemed to be a few exchange variants in use.

I think many were more or less on the standard Win-Test set, removing the ++ and -- speed change operators, and sure some stripped down a couple of spaces between RST and serial number. -Speed demons!

So normally, in run mode it should have been:

Listen for caller
[Optional, but frequently used: G1AB?]
G1ABC 599001
Listen for his serial number
Listen for next caller before CQ again

And in S&P:
Find station (there were loads!)
Listen for M1KTA 599 123 or similar
Should have sent
But often sent
599 my serial PSE CFM their serial 
Listen for TU

Also had the usual other macros to send repeats of the serial number, "NR?", their call, our call and so on, but the ones above were the normal set. I think it is possible to run wintest to do a lot of this automatically but being a bit dim to set it up correctly.

No doubt not confirming I heard their number correctly will lose a few QSOs in adjudication,  in combination with CWGet's attempt, I had two values to choose from. If both were the same, we were happy; if differed, I asked for a repeat!

I gave up trying to cq as I was too slow for those that responded even about 3.580. I have to say, most stations were very patient in the face of my mistakes, and many would quickly increase their letter spacing if I didn't get their call the first time. No doubt a few (reasonably enough) got impatient and wandered off before I worked them, but that's fine.

I predict I'll come last :-).

My full log is:

CREATED-BY: Win-Test 4.7.0
CLUB: camb-hams
CLUB: Camb Hams
NAME: Dominic Baines
ADDRESS: 34 Bury Road
ADDRESS: Stapleford
ADDRESS: Cambridge CB22 5BP
SOAPBOX: My 1st time and you need sharp elbows after an hour or so as the 
SOAPBOX: frequencies get a bit packed.
QSO:  3525 CW 2012-01-08 1403 M1KTA         599 0001   G4ODB         599 001   
QSO:  3525 CW 2012-01-08 1405 M1KTA         599 0002   M0TCL         599 001   
QSO:  3525 CW 2012-01-08 1407 M1KTA         599 0003   G3WOV         599 001   
QSO:  3525 CW 2012-01-08 1414 M1KTA         599 0004   G0LZL         599 018   
QSO:  3525 CW 2012-01-08 1415 M1KTA         599 0005   G0TPH         599 022   
QSO:  3525 CW 2012-01-08 1417 M1KTA         599 0006   G3SJX         599 024   
QSO:  3525 CW 2012-01-08 1422 M1KTA         599 0007   G3LIK         599 027   
QSO:  3525 CW 2012-01-08 1424 M1KTA         599 0008   G4CKH         599 033   
QSO:  3525 CW 2012-01-08 1426 M1KTA         599 0009   G4ARI         599 039   
QSO:  3525 CW 2012-01-08 1432 M1KTA         599 0010   G3OPY         599 051   
QSO:  3525 CW 2012-01-08 1435 M1KTA         599 0011   G3LVP         599 038   
QSO:  3525 CW 2012-01-08 1439 M1KTA         599 0012   G3LDI         599 053   
QSO:  3525 CW 2012-01-08 1447 M1KTA         599 0013   G3LUW         599 034   
QSO:  3525 CW 2012-01-08 1451 M1KTA         599 0014   G4DQP         599 026   
QSO:  3525 CW 2012-01-08 1453 M1KTA         599 0015   M1BXF         599 032   
QSO:  3525 CW 2012-01-08 1455 M1KTA         599 0016   G4WUG         599 058   
QSO:  3525 CW 2012-01-08 1456 M1KTA         599 0017   G0TPH         599 068   
QSO:  3525 CW 2012-01-08 1458 M1KTA         599 0018   G3RTE         599 082   
QSO:  3525 CW 2012-01-08 1500 M1KTA         599 0019   G0LHZ         599 055   
QSO:  3525 CW 2012-01-08 1501 M1KTA         599 0020   G3XVR         599 077   
QSO:  3525 CW 2012-01-08 1502 M1KTA         599 0021   G0DVJ         599 083   
QSO:  3525 CW 2012-01-08 1504 M1KTA         599 0022   G3UFY         599 078   
QSO:  3525 CW 2012-01-08 1506 M1KTA         599 0023   G0MTN         599 104   
QSO:  3525 CW 2012-01-08 1507 M1KTA         599 0024   G3ZVW         599 084   
QSO:  3525 CW 2012-01-08 1509 M1KTA         599 0025   G0AAA         599 106   
QSO:  3525 CW 2012-01-08 1511 M1KTA         599 0026   G4BCA         599 096   
QSO:  3525 CW 2012-01-08 1514 M1KTA         599 0027   G4BJM         599 126   
QSO:  3525 CW 2012-01-08 1516 M1KTA         599 0028   GW3SQX        599 104   
QSO:  3525 CW 2012-01-08 1517 M1KTA         599 0029   G3TBK         599 132   
QSO:  3525 CW 2012-01-08 1519 M1KTA         599 0030   G3ZGC/A       599 115   
QSO:  3525 CW 2012-01-08 1520 M1KTA         599 0031   G4PIQ         599 129   
QSO:  3525 CW 2012-01-08 1521 M1KTA         599 0032   G3RXP         599 121   
QSO:  3525 CW 2012-01-08 1523 M1KTA         599 0033   GM3WOJ        599 120   
QSO:  3525 CW 2012-01-08 1524 M1KTA         599 0034   G3LZQ         599 110   
QSO:  3525 CW 2012-01-08 1526 M1KTA         599 0035   G4BUO         599 121   
QSO:  3525 CW 2012-01-08 1527 M1KTA         599 0036   G3PND         599 078   
QSO:  3525 CW 2012-01-08 1529 M1KTA         599 0037   G7VJR         599 104   
QSO:  3525 CW 2012-01-08 1532 M1KTA         599 0038   M0PTO/P       599 028   
QSO:  3525 CW 2012-01-08 1536 M1KTA         599 0039   G3JRM         599 078   
QSO:  3525 CW 2012-01-08 1537 M1KTA         599 0040   G0BBL         599 074
QSO:  3525 CW 2012-01-08 1540 M1KTA         599 0041   G3SVL         599 100   
QSO:  3525 CW 2012-01-08 1543 M1KTA         599 0042   G4FSU         599 112   
QSO:  3525 CW 2012-01-08 1544 M1KTA         599 0043   G4BYG         599 128   
QSO:  3525 CW 2012-01-08 1546 M1KTA         599 0044   G3SWC         599 124   
QSO:  3525 CW 2012-01-08 1548 M1KTA         599 0045   G3DTZ         599 097   
QSO:  3525 CW 2012-01-08 1551 M1KTA         599 0046   GM4FAM        599 128   
QSO:  3525 CW 2012-01-08 1552 M1KTA         599 0047   G3RVM         599 163   
QSO:  3525 CW 2012-01-08 1554 M1KTA         599 0048   G3VYI         599 146   
QSO:  3525 CW 2012-01-08 1559 M1KTA         599 0049   G4SGX         599 059   
QSO:  3525 CW 2012-01-08 1601 M1KTA         599 0050   GW0GEI        599 138   
QSO:  3525 CW 2012-01-08 1603 M1KTA         599 0051   G4AFS         599 136   
QSO:  3525 CW 2012-01-08 1605 M1KTA         599 0052   M0DHO         599 155   
QSO:  3525 CW 2012-01-08 1607 M1KTA         599 0053   G4CWH         599 140   
QSO:  3525 CW 2012-01-08 1608 M1KTA         599 0054   GM4SID        599 124   
QSO:  3525 CW 2012-01-08 1610 M1KTA         599 0055   G4DJX         599 185   
QSO:  3525 CW 2012-01-08 1612 M1KTA         599 0056   G3UJE         599 175   
QSO:  3525 CW 2012-01-08 1614 M1KTA         599 0057   G3BJ          599 188   
QSO:  3525 CW 2012-01-08 1616 M1KTA         599 0058   G0CKV         599 143   
QSO:  3525 CW 2012-01-08 1619 M1KTA         599 0059   M0UNN         599 166   
QSO:  3525 CW 2012-01-08 1620 M1KTA         599 0060   G3NKC         599 180   
QSO:  3525 CW 2012-01-08 1624 M1KTA         599 0061   G3VDB         599 152   
QSO:  3525 CW 2012-01-08 1626 M1KTA         599 0062   GM4AFF        599 162   
QSO:  3525 CW 2012-01-08 1630 M1KTA         599 0063   G6MC          599 193   
QSO:  3525 CW 2012-01-08 1633 M1KTA         599 0064   MM0ROV        599 097   
QSO:  3525 CW 2012-01-08 1635 M1KTA         599 0065   GM4ZUK        599 150   
QSO:  3525 CW 2012-01-08 1640 M1KTA         599 0066   G4TSH         599 193   
QSO:  3525 CW 2012-01-08 1644 M1KTA         599 0067   G3TJE         599 148   
QSO:  3525 CW 2012-01-08 1647 M1KTA         599 0068   G3YLA         599 122   
QSO:  3525 CW 2012-01-08 1648 M1KTA         599 0069   G3TXF         599 214   
QSO:  3525 CW 2012-01-08 1655 M1KTA         599 0070   G3RKF         599 113   
QSO:  3525 CW 2012-01-08 1657 M1KTA         599 0071   G3KLH         599 189   
QSO:  3525 CW 2012-01-08 1700 M1KTA         599 0072   G3KNU         599 138   
QSO:  3525 CW 2012-01-08 1707 M1KTA         599 0073   G3RWL         599 178   
QSO:  3525 CW 2012-01-08 1715 M1KTA         599 0074   G3PJT         599 196   
QSO:  3525 CW 2012-01-08 1718 M1KTA         599 0075   GM0WED        599 165   
QSO:  3525 CW 2012-01-08 1722 M1KTA         599 0076   G4ZUL         599 160   
QSO:  3525 CW 2012-01-08 1725 M1KTA         599 0077   G7TWC         599 123   
QSO:  3525 CW 2012-01-08 1728 M1KTA         599 0078   G3ZBU         599 116   
QSO:  3525 CW 2012-01-08 1731 M1KTA         599 0079   G3PYE         599 168   
QSO:  3525 CW 2012-01-08 1734 M1KTA         599 0080   G4KZD         599 154   

Tuesday, 17 January 2012

Great new Manhatten/SOTA blog

You have to take a look at this blog. The images and constructions are simply great.

The comment I had from Colin was..." I have just started to do a blog ... I've never done a blog before, so I'll just have to see how it goes."

Well Colin doing very well so far. 72 Dom M1KTA

Friday, 6 January 2012

N2PK VNA Build

I made a start on a N2PK VNA last night. I had a spare PCB and parts from a group buy back in 2005.

Just a couple dozen of the discrete C fitted so far.

I have a new PC motherboard arriving tomorrow for a quad CPU I have and the motherboard has a native LPT port and COM port and I will build the system just for the test bench as I will also run a digital oscilloscope and other various com and lpt based test kit with it.

I also have the newer N2PK V5 PCB arriving soon which has a second detector and can plug into a USB port. I'll build up both versions side by side and probably compare them... then apart from the other builds I really must advance some more on the PIC-A-STAR's.

Now where did I put all those SMA connectors?....

Tuesday, 3 January 2012

Change rockmite (not 20m) 30m PA

Original unmolested.

Going to have a bit of fun with a rockmite kit I have unfinished.

I think it is 20m but might be for 30m I have the SCAF filter boards with it too.

I'm going to play about with the pa and see what is possible.

Then time to play with what a PP3 battery can do with a rockmite.

I'll update this post or create a new one with the results.

It was a 30m kit... Q6 (PA) was already soldered in but I'll chop it out, add some turned sockets (and something for bias if using a FET) and try some PA fun and games. In the meantime I also added a VXO mod (Xtal freq 10.116), I'll include schematic details later but pictures here...

 Note I added shrink wrap to the multiturn resistor connections.
 Yes I really have glued two pads to the top of the AF chip :-)

I bought a whole box of random pots and multiturn pots at GQRP Rishworth 2011 and this is a 20k 10 turn Bourns pot.
The VXO mod is from KE2SP. The details are on the rockmite yahoo group but here they are as well.

These two images are the board before and after modification.

The MV1662 varicap... don't discard it they are like hens teeth. The 5V1 zener you should save and use again another time. The pads on the AF sound chip do not have to be round I have used two 5mm pads but small square off cuts of pcb also work.
The 220K resistor, you can just add a 120K in series with the 100K that is already there.

Sunday, 1 January 2012

DC-DC converter

After a visit from Johnny SM7UCZ and some exchanges and after santa brought some components (IC,FET and Zeners) I am going to build one of his DC-DC converters for /P valve trips.

My version of the PCB is here

Note I have used TO220 with mounting holes but I'll not etch them or drill them and will solder the tab to the boards.

His original (in Swedish is here)

I will use plastic D cell holders and a 30VA transformer I bought from Farnell and I have a big 470uF 450V electrolytic already.

The meters I will use are from John G8BTU

Sussex Valve Tester

Just before xmas the parts and the specially wound transformer arrived along with a PCB that needed to be drilled so just finished drilling the PCB.

Dad suggested I need to make a metal brake/bender so that I can work with sheet aluminium (and steel) so ill make up a case for the valve tester.

Johnny (SM7UCZ) also suggested a double triode tester as well.

DL4YHF Counter

I bought a couple kits from Sunil a while ago and I have just made up the three kits. is the originating site you need to view.

I'll be using one as a bench frequency counter and combined function generator (XR2206) as I bought a couple XR2206 IC from ebay over xmas.

Another I'll use with an LTC1799 IC which is a simple signal generator. To which I will add attenuation on the output. It will product almost 5V p-t-p square wave.

[another photo]

The last will go into a Norcal40A kit.

500KHz transverter

Back on this again and just finished it.

I went with a 7MHz LO and SBL-1 mixer very similar to G3XBM layout but I made a PCB for it.

Elecraft T1 for £10 a 2N3906 and 1/4W 3K3

I picked up a T1 that someone built at a rally a while back but was stated to be not working cost me £10. If really was dead I could use the L match network.
I didn't find a troubleshooting guide to figure out what the problem is but his is what I did...
All the values, and components 'appeared' to be in the right place etc Resistance checks on page 15 and 22 of the manual seem fine…
Apply power (with PIC removed) and the regulators appear to be applying the correct voltages etc..
The section reads:
Use your DMM to make the following resistance checks. If the board fails any of the following checks,
carefully check the position and orientation of all parts and inspect the board with a magnifier for solder
bridges or missed solder joints.
Resistance across capacitor C19: between 137 K-ohms and 148 K-ohms. Press S2 and confirm reading
drops to between 117 K-ohms and 135 K-ohms.
Resistance between D3 anode (end without the band) and the “ –“ pad near D7 (ground) where the
black wire is attached: > 100 K-ohms (may show open or infinite on some DMMs). Press S1 and confirm
the reading drops to between 117 K-ohms and 130 K-ohms. If the resistance is higher, try reversing your
DMM leads.
Set your DMM to diode test. Connect the negative probe to either end of resistor R9. Touch the
positive probe to the following pins on J5 and verify that the diode tester shows approximately 1.6 volts
forward drop across each LED. J5 is the connector at the opposite end of the control board from R9. Pin 1
is the round pin at the end near S2. Each LED may also light up when the test voltage is applied (not all
diode testers supply sufficient current to produce light):
__ Pin 1: Red LED ___ Pin 2: Yellow LED __ Pin 5: Green LED
The LED do not light up. And the diode tests fail.
Humm ... scratched head a bit and had a chat with Elecraft and this extra info helped and I include it here in case anyone else have a problem:

Also for starters I had removed the switch bord from the uPC and relay board underneath for the first set of tests.

Make sure the red lead from the battery goes to the + connection near the unbanded end of the 1N5817 diode at D3. The smaller round positive connector on the 9V battery goes to the battery terminal for this red wire. (That was fine)

The black lead from the battery goes to the - connections between the yellow and red LEDs. (That was fine too)

J4 is the connector on the left side of the T1 control board.

J5 is the connector on the right side of the T1 control board.

Verify the MCU has no bent pins and is fully pressed all the way down in its IC socket. (OK)

Do you see 6V on pin 1 of the U1 processor when the PWR button is tapped? (use the thumbscrew or BNC jack for ground) (Yes)

You can test this at J4 pin 3, which is the pin just above and between the green and yellow LED, and it is the 3rd pin when counting beginning with the round pin 1 of J4. U1 pin 1 and J4 pin 3 are directly connected together. Remember that J4 is on the left side of the control board.

Also, J5 pin 3 should show 9V to ground  when the unit is off and S1 has not been pressed. Remember, J5 is on the right side of the control board as you would normally face the unit. (OK)

When PWR button S1 is pressed and HELD down, J5 pin 3 should be 0VDC. (OK)

If the MCU comes ON and is working, when the S1 button is released, after a few seconds - J5 pin 3 will rise back to 9V . This is when the MCU times out and returns to "sleep mode", and releases the /HOLD_ON line at U1 pin 5. (I will test later... and it was fine, after I fixed some things but it did not work as it should initially)

This change in voltage at J5 pin 3 and U1 pin 1 and the 6V appearing at U1 pin 1 must occur, or something is wrong with the power up circuit of D3, R7, C20, Q1, R14, S1, D4, C19, U2, D4. Check all of those parts and their soldering very closely. Both U2 (78L06) and Q1 (2N3906) should be installed with their flat side facing up.  (Problem #1 Q1 was inserted backwards so chopped it out and replaced it with a new component the right way around this time)

Be sure U2 and Q1 are not swapped with each other. Be sure R7 is 120K and R14 is 3.3K.
(Problem #2 1K resistor in place, replaced with 1/4W 3.3K)
Verify all of the parts are in the correct locations, and are not damaged or unsolder-ed. (OK on parts spent some time going over the underneath solder connections)

Be sure D3 and D4 are not installed in reverse. D3's banded end goes toward R14, and D4's banded end goes toward switch S2. (Both OK)

MCU U1 must be installed with the notched end closest to the J3 remote 1/8" phone jack, or to the left as you face the main board. (Problem # 3 the uPC socket and uP were in reverse, so I flipped the uPC and T1 worked fine)

You can use an ohmmeter to check for any shorts between the connector pins and ground with the battery removed, and between any pins of the parts and a nearby connection that is not at ground. Note some connections are intentionally grounded. Use the schematic as a reference for these tests. You can find an accidental short circuit or solder bridge this way.

Examine both sides of both PCBs very closely using a bright light and a magnifier. Look for missed solder connections, shorts or solder bridges or splashes, etc. Remove any excess solder and clean up any poor connections as needed, using Soder Wik and a Q-Tip moistened with acetone or alcohol to clean the PCB. (The board was cleaned up a bit)

Do you ever see any LEDs light up when the PWR button is tapped (yellow LED),  or if it is held down for more than 1 second (green LED)? (Operating as should now)

Did you verify the LEDs are not installed backwards? You can check them for correct orientation by using the diode test function on most DMMs. (Diodes fine)

First remove the 9V battery.

Then place the positive test probe on the anode connections for each LED at pins 1, 2, or 5 of the J5 connector, and the negative lead on the common cathode connection at either end of R9. 

J5 is the connector on the right hand side of the tuner as you would normally face the top and front of the PCB (near R21). Pin 1 is the round pin near the battery compartment. R9 is near the left top edge of the T1 control board.

Each of the LEDs should light enough to be seen in a dimly lit room as you move the positive probe to J5 pin 1, 2, or 5 and hold the negative probe on R9.