This is not the latest build information for this converter
If you are wanting the latest build information, please go to:
http://www.earf.co.uk/3cm_conv1.html

What is it?

The converter is a single box module, intended to be used with a modern satellite LNB, for receiving narrow band 10 GHz amateur band signals on an HF receiver. It converts 10 368 - 10 369 MHz down to 18 - 19 MHz. The kit does not include the LNB, which may be mounted seperately  (on a dish, say), or on the converter housing itself. A mounting saddle is provided that is suitable for LNBs with a 40mm collar.

For an explanation of how the converter works (ie, manages to cancel out the LNBs internal LO drift) have a look at the Scatterpoint article reproduced here.

The cost!

For the moment, the cost is £35, which reflects the component cost only!. It is achieved by using several reclaimed parts that would otherwise put the price up to the £50 mark. If an LNB is also required, it can be bought on ebay for less than £10 (alternatively, contact me and I will supply one with a 40mm collar for £10). Included in the price is a build/alignment day, at the new National Trust centre at Anglesey Abbey. This will be run on Sat 18th April between 10.30 and 17.00. Kits will be handed out as soon as available, so that anyone who wants build the boards up can do, and those who want to wait for the build day session can do so. In this way, we can (hopefully) reduce any bottle-necks for tools/test equipment use on the day. If you wish to leave construction till the build/alignment day, please bring a soldering iron with you.

Build information is linked here

Prior to construction, familiarise yourself with the circuit for that particular board, and try to relate it to the layout. During construction, start with the surface mount components, paying particular attention to place the tantalum capacitors in the correct polarity - see the layout drawing and confirm on the board (there is a '+' symbol etched in copper at the 'bar' end of the capacitor), as below:

There are only 25 sets of pcbs, and it will be first come, first served, so if you are interested, and your name isn't on the list opposite, please email to the address below, and I will add you to it. I'm afraid all the current stock of boards have now been allocated                                              The majority of components are surface mount, but large lead spaced items have been chosen where it was thought that it might be a problem for anyone new to this type of component.  One of the reasons for holding a build/alignment day was to provide assistance to people who might lack confidence with smd components. We will have at least one stereo microscope available - it is suprising how much easier this makes construction (and each kit includes a pair of tweezers!!). To give an idea of what to expect, here is a component side photo of the most complicated board of the three that are used:	Serial No	Destination	Notes
	1	test	TR4 = RF2312
	2	test	TR4 = RF2312
	3	Kevin G3AAF	Guinea pig  (test of paper-work!)
	4	Allan M0CBG
	5	Martin G8OFA
	6	Peter M0DCV
	7	Andrew M0BXT
	8	Peter G8KJP
	9	Mike G8VCN
	10	test	TR4 = BGA6489  Scratched pcb
	11	David G6KWA
	12	David 2E0BPX
	13	Mike M0BLP
	14	Dave G4HUP
	15	Sam G4DDK
	16	John M0ELS
	17	Dave G8JKV
	18	Sean M1ECY
	19	Dave G3VZE
	20	Dave G4FRE
	21	Alan G3NYK
	22	Graham G4FSG
	23	Finningley
	24	Finningley
	25	Finningley

Thomson 13553	Cambridge AE88	Lidl IP-401	MTI AP8-XT2EBL	Thomson Quad	Supermax DX-700

Integral LNB	This is quite a tidy self-contained configuration, useful for general band monitoring - it's interesting what can be heard with this (remember that the LNB feed horn itself has over 10 dBd gain. I often use this in the car in combination with my IC-706). With the 'external reference' option components fitted (not part of the stadard kit), it can be used with a 10 MHz rubidium or GPS locked standard to enable frequency measurements to be made on incoming signals (a 2ppm transceiver, such as the IC-706 will have an accuracy at 18 MHz of +-36 Hz, so quite accurate measurements are possible).
Remote use	When required to be used with an external dish mounted LNB, the converter will require waterproofing. For a chimney mounted dish, it may be possible to locate the converter in the false roof - this will also reduce the temperature fluctuations that the unit will experience, and will minimise oscillator drift accordingly. If the converter is mounted outside, it should be placed within a second enclosure, since it isn't waterproofed. The maximum length of interconnecting cable for the probe feed is dependant on the actual LNB in use and the type of cable used. If RG223 is employed (this is a quarter-inch double screened flexible coax, which can use SMA connectors that are readily available), this will usually be about 4 metres. However, by using the thomson 13553 LNB, it should be possible to run a 6 - 7m run successfully. The cable type and length linking the LNB IF output to the converter is much less criticle, since this is operating at a much lower frequency (618 MHz). It obviously makes sense to put a system together at ground level first to ensure that there will be enough probe power at the LNB. As long as the noise level at the receiver increases 10 dB when the probe is brought close to the LNB, then all will be well. The actual location of the coupling probe depends on how much signal is available after being attenuated by the interconnection cable. If a long cable run has been used, it may be necessary to put it very close to the LNB horn input, but if the run is short, it may be adequate to simply push the probe through the back of the dish. Again, try all of this at ground level first! Part of the Scatterpoint article relates to probe placement It feels as though the Thomson LNB would support 6 - 8 m of thi cable, which would be enough to run all the way from the chimney to the shack in my bungalow, which would be excellent. I will try this when I can obtain some more cable, and will also measure the loss per metre at 10.350 GHz at the same time.
Extended use (requires mod)	If a much longer run than that shown above is required, it is always possible to take the x23 multiplier pcb out of the converter box and mount it in its own housing near the dish. The feed coax will then be carrying a 450 MHz signal rather than the 10.35 GHz one, and the attenuation will be much less. This should allow a 25m run or more to be employed.