Wednesday, May 16, 2018

SWR Bridge

For performing measurements on antennas with a spectrum analyzer an swr bridge is a very nice instrument to calculate the SWR of antenna systems.

CNC craftmenship by Theo PA0KN who made a perfect fit enclosure. Decal is laser engraved.

SWR bridge was bought on ebay and fits very good in the enclosure designed and made by PA0KN

Friday, February 23, 2018

10 meter (CB) transceiver.

Many CB transceivers are sold on the market as a 10 meter ham transceiver.
Of course this is done to “fool” the law and give CB operators the chance to buy an all mode transceiver with a large frequency span and more power than legal equipment.
These transceivers are very easy to modify to cover 11 and 10 meter as well.
For amateur use the models without fixed channels are quit usefull, although the lowest tuning frequency is limited to 100 hz.
I was able to buy a very nice Alan 9001 for 50 euro. You can also consider a Uniden / President Lincoln or Anytone models.
Qrv for a budget? Get a used CB radio!
Alan 9001 10-11 meter transceiver 26500 - 30 mhz allmode 25 watts.

Sunday, December 24, 2017

Season's Greetings

Wish you all a merry Christmas and a happy 2018.

MCHF finalized in 2017.

At the last days of 2017 i had to update my blog since there where no single posts this year..
The main focus was to finish my MCHF sdr transceiver. Theo PA0KN did a tremendous job; the complete enclosure was made by Theo incl knobs etc.

PA unit is cooled by temperature controlled fan, and the finals are embedded in the case's heatsink.

MCHF owned by Theo - PA0KN with cw keyer, all home made. (knobs to be completed)

In Nov this year, we participated at the AMRATO 2017 Dutch exhibition. Many hams came to visited us with a lots of compliments of the high quality of Theo his CNC work.

My MCHF, the microphone is a Baofeng type.

Theo PA0KN (L) and myself at the AMRATO 2017. At the desk MCHF transceivers, MCHF automatic antenna tuner, and other projects.

Sunday, August 7, 2016

Kenwood TS-940sat bulb and battery replacement

The TS-940Sat was Kenwoods former "flagship" from the eighties.
Early versions of this hf transceiver got some issues with bad solder joints and bad connectors.
Also the pll has a notorious status.
This unit has a high serial number and lacks all this issues.
Due to her age the battery from the sub display has to be replaced. Easy to check when the sub display is malfunction.
To replace this battery just remove both covers and loose both srews from frontpannel so it can be bend forwards. Behind the subdisplay one can see the battery.  A CR2032 battery is perfect as replacement.
New battery soldered on sub display board.
Note: to avoid damage on connectors, do not remove this board.

New bulbs for the S meter and a working sub display.

Sunday, July 3, 2016

Icom IC-730 repaired ( counterfeit 2SC1945 drivers)

Some years ago i aquired an Icom IC-730 from an estate.
This transceiver came with original manual, serv. manual and invoice included.
It had 2 major issues; no rf power and on-off switch was not working.
An evening measuring on the final boards with Theo PA0KN concluded defective driver stage.
Other challenge is to find a spare on-off button.
I ordered 2 new 2SC1945 and a 2SC1971 at a French Ebay seller, this to be sure i would receive no fake parts.....
For several reasons the transceiver was put on the shelf and ten months later the new parts where put in the final stage of the IC-730.
Unfortunately still no rf power....strange because all transistors measured okay...
We removed the new 1945 transistors and test them with a component they where fake! Counterfeits with another pin layout. Also the 2SC1971 was fake...
Ofcourse i contacted ebay seller BIANCAS66. He told me that i was the only customer who encountered problems and that his parts where real... Sure! I asked him to solve this issue but he refused. So stay away from this French cheater!!!
I was able to buy some new 2SC1945 here in the Netherlands for a fair price. These where real and after putting them in, the IC-730 came to live with 100 watts of power.

The only thing to do was to replace the power button.
A couple of months ago i found one on a dutch selling site for a very low price.
Paid and got it the other day. Looked and worked okay, time to replace the broken one.

It's a lot of work to get access to this knob. But when you remove the frontpannel and loose the screws off the frame you can remove the mode switch and unmount the power switch. Take the new switch, fix it with the 2 screws and mount all back in reverse order.

After 2 years a complete and 100% working IC-730.
Note that frontpannel and knobs are not placed yet.