Down Conversion Receiver Project

Group-buy March 2011

Depending on how many builders are interested, a new group-buy is anticipated to provide the PCB's, the crystals and possibly the tinned metal boxes. Pricing will depend on volume and with similar quantities as before a similar pricing is expected. Exact pricing needs to be looked into when I have more information available. If you are interested in building the signal path published so far, please let me know exactly what you are interested in:

  • Only QT Crystals.
  • Only the Frontend.
  • Only the Backend.
  • Both the Frontend and the Backend.
  • The above with or without the tinned metal boxes.

Once the quantity is established I can set the price and get the group-buy started for those interested.

With regard to the Euro-Card sized tinned metal boxes I have made the following decision: Only the power connector and the I2C connector holes on the right side will be machined. This makes all Euro-Card sized boxes identical, except for the Switcher Board and of course the BPF Box. This simplifies the logistics for me considerably. It means you will have to drill the holes for signal connectors in the bottom side yourself. This simplification helps to reduce my distribution effort, which leaves me with more time to finish the receiver!

Please note that the two DDS oscillators, the 1GHz Reference Clock and the Controller + Software are still work in progress and those final PCB's will be part of a future group-buy as soon as they have been finalized.

My email address is:

Best regards,
Martein, PA3AKE


The prices have been set given the current group-buy quantity.

  • QT-Quartz
  • The price of the crystals is the same as the price established in the 1st group-buy, August 2008. The price per crystal is 9.65€ resulting in about 135€ for a 14 crystal frontend set, 58€ for a 6 crystal backend set and 193€ for a complete receiver set. Factory lead-time is between 6-8 weeks and production has started 14-April-2011, so we may expect the crystals ready end of May, beginning June. This is if quantity does not change. It already looks like I have to order more crystals as still new requests are coming in!

  • Frontend PCB-set
  • The price of the frontend PCB set is 65€. There have been no changes since the first version of August 2008 with this panel and the manufacturer has not changed pricing, so similar pricing as before is done, given the quantities. Factory lead-time is approximately 3 weeks.

  • Backend PCB-set
  • The price of the Backend PCB set is 55€. This price, given total surface area, is somewhat higher than for the Frontend PCB-set. The reasons are twofold. First this is the first run and this comes with additional startup cost. Second the panel is smaller than the Frontend panel, which makes it somewhat less price effective. Factory lead-time is approximately 3 weeks.

  • Metal boxes
  • The price of the BPF-box is 34€. Quantities are similar as before and the manufacturer has not increased its price, so the same price as with group-buy October 2008 is possible.

    The price of the PSU-box is 17.50€. The connector holes are all machined, but the many ventilation holes I used in my prototype are not. This keeps the cost down. They are not really necessary and can be drilled easily anyway, using the connector PCB with the holes as a drilling template.

    The price of the generic Eurocard-box is 7.00€. This price is considerably lower than the previous times due to the much larger quantity and the simplification not to have the signal connector holes machined. The power and I2C connector holes are machined.

    Factory lead-time for the metal boxes is approximately 2 weeks.

  • Shipment
  • The price of shipment depends on weight and destination. A complete Frontend (boards, boxes, crystals) weighs around 1.6Kg The estimated weight of a complete Backend (boards, boxes, crystals) is approximately 1.4Kg.

    Shipment prices for most European countries are: 14.30€ up to 2Kg, 20.80€ up to 5Kg, 26.30€ up to 10Kg. For most countries in eastern Europe pricing is: 19.80€ up to 2Kg, 26.30€ up to 5Kg, 32.30€ up to 10Kg. The rest of the world or "DX" is priced as follows: 25.60€ up to 2Kg, 35.60€ up to 5Kg, 59.60€ up to 10Kg.

    Within the European Union Track & Trace is available. A signature is required at delivery. The package is insured up to 500€. In all cases 1.50€ package material is needed.

  • Payment
  • I prefer payment through PayPal because of simplicity and safety. However PayPal is not a non-profit organization and I will have to charge you the fee that they charge me! Within the EU the PayPal fee is 3.4%, outside the EU it is 3.9%

    Payment through electronic bank transaction is also possible. I will supply my IBAN and BIC when needed. All transfer cost should be made by you. Within Europe sometimes there are no costs involved anymore!

    Last options are cash money through registered post or when picked up at my home.

Lodestone coil formers group-buy

Richard Patten is currently organizing a group-buy for coil formers from Lodestone Pacific. A maximum of 8 L45-6 formers are needed on the Selectivity Board if all 4 crystal filters slots are used. Please contact Richard if you need L45-6's. I have arranged with Richard that when desired I can ship the coil formers to your destination. This is very cost effective as long as the formers are not causing the parcel to arrive in the next weight range! Payment for the L45's must go to Richard.

INRAD Crystal Filters group-buy

Trey, N5KO, from INRAD has made an offer for 9MHz INRAD filters at a reduced price of $104, if minimum quantities can be met. This is a useful price reduction from the normal $130 single quantity price. I am prepared to arrange this for anyone interested as part of the group-buy. This price is excluding VAT and import tax. The following filters can be ordered: #2308 (1800Hz SSB), #2309 (2100Hz SSB), #2310 (2400Hz SSB), #2304 (500Hz CW). A 250Hz CW filter at 9MHz is not yet available, however this is looked at. If a sample becomes available to me in time it can be part of this offer also.

KVG Crystal Filters group-buy

The Selectivity Board is also compatible with 9MHz crystal filters from KVG. The KVG filters can also be supplied at reduced price if minimum quantity is met: XF-9B (2400Hz SSB) 120€, XF-9NB (500Hz CW) 135€, XF-9P (250Hz CW) 130€. These prices are without 19% VAT. At single quantity these filters are normally listed at 175€, 195€ and 190€ respectively. I am prepared to arrange this for anyone interested as part of the group-buy. Lead-time is approximately 8 weeks.

Buyers List Status

The following table reflects the current status of the buyers list:

PA3AKE Group Buy List (08/10/2011)
Name Call sign Frontend Backend #QT xtal #Eurocard
Pawel Stobinski SQ9NRY 1 1 6 4 08/08/2011
Ned Joldersma WB8NBV 1 1 6 4 16/06/2011
Dan Rae AC6AO 1 1 6 4 08/08/2011
Paolo Odone I1ODP 3 3 10 12 26/08/2011
Wald Sznajder 3Z6AEF 1 1 6 4 18/08/2011
Luca Fusari IK2LRN 1 1 6 4 18/08/2011
Michael Cook G7RIA 1 1 6 4 16/06/2011
Gerard Perrier F6EGX 1 1 14 1 08/08/2011
Mike Mertel K7IR 1 1 6 4 16/06/2011
Daniele Bortoluzzi IZ3LEO 6 5 3 1 20 5 01/09/2011
Wilhelm Kinowsky DG8CAA 1 1 6 4 08/08/2011
Jarmo Blomster OH8KVA 1 1 6 4 18/08/2011
Dudley Atkinson NO5L 14 08/06/2011
Hans de Bok PA1HDB 1 1 1 6 5 06/07/2010
Nick Feakes KJ4SBO 1 1 1 1 20 5 05/07/2011
Karel Naessens ON4FI 1 1 6 5 18/08/2011
Jim Pake VE6ACY 1 1 1 1 20 5 16/06/2011
Bill Carver W7AAZ 1 1 20 4 16/06/2011
David Cummings AB3LM 1 1 1 1 20 5 08/08/2011
Alan King VK6AAK 1 1 6 5 18/08/2011
Peter Montnemery SM7CMY 1 3 2 2 20 6 20/08/2011
Richard Patten 1 1 1 1 20 5 08/08/2011
Henry Pasternack 1 1 20 08/08/2011
Adolf Schendl OE5DS 1 1 1 1 20 5 16/06/2011
Richard Pedowski HB9TQU 1 1 2 2 26 9 18/08/2011
Ron Kuijper PE8E 1 1 6 4 08/08/2011
Juan de Oρate M0WWA 1 1 4 16/06/2011
David Smith WW1O 3 3 18 12 08/08/2011
Hans Summers G0UPL 14 08/06/2011
Andrzej Gwara SP5INC 1 1 1 1 20 5 16/06/2011
Dan Mills 2E0CHE 1 1 1 1 20 5 09/09/2011
Gιrard Grandjean F6HZO 1 1 1 1 20 5 08/08/2011
Christian Kalberkamp DK8DV 1 1 6 18/08/2011
Lars Pettersson SM6RPZ 1 1 6 4 08/08/2011
Robin Davies G7VKQ 1 1 1 1 20 5 26/08/2011
Andrea Montefusco IW0HDV 1 1 1 1 20 5 26/08/2011
Lasse Moell SM5GLC 1 1 6 4 16/06/2011
Jim Gailer G3RTD 1 1 1 14 6 18/06/2011
Aung Moe MM0MRM 1 1 6 4 16/06/2011
Volker Banfield 1 2 05/07/2011
David Morrison KF5JNR 1 1 1 1 34 5 08/08/2011
David Craft WB2RNC 20 08/06/2011
Les Tocko VA7OM 1 1 1 1 20 5 18/08/2011
Sergio Cartoceti IK4AUY 1 1 1 6 5 16/06/2011
Herbert Raudszus DL4YEQ 1 1 28 5 20/06/2011
Rainer Deutsch DL1AUZ 1 1 1 20 18/08/2011
Olaf Koch DL7HA 1 2 1 1 20 7 08/08/2011
Paul Reeves G8GJA 1 1 14 3 16/06/2011
Miroslav Ivan OM3LZ 1 1 6 4 01/09/2011
Johannes Trabert DK5II 1 1 1 1 20 5 18/08/2011
Fabrizio Sabatini I5UKN 1 1 01/09/2011
Georg Hieber DK4SE 1 1 1 1 20 5 05/10/2011
Paul van Dam PA7UL 1 6 05/10/2011
Maco Bauer PA7UL 1 1 6 4 08/10/2011
Egon Goršeg S51HO 14 08/10/2011


  • 22/03/2011, I have added the table with group-buy data. The following explains the numerical columns of the table:

    • Frontend PCB-set. This consists of the BPF Motherboard + 5x T94-3 + 4xT80-4 + 1x T50-5 + 1xNotch + 1x I2Control + 1x Attenuator daughter boards. It also includes the Frontend Board.

    • Frontend BPF-box. This consists of the big tinned metal box for the BPF's. It includes the machined holes for all the connectors.

    • Backend PCB-set. This consists of the following boards: Selectivity Board, Variable Gain Board, Detector Board, Audio Board, Switcher Board including the small board for mounting the terminal blocks and Rectifier Board.

    • PSU-box. This consists of the tinned metal box for the Switcher Board. It includes the machined holes for the connectors.

    • QT Xtal. This consists of the total ordered number of QT crystals. 14 are needed for the Frontend, 6 are needed for the Backend.

    • Eurocard-box. This consists of the total ordered number of Eurocard sized tinned metal boxes with 30mm height. It includes the machined holes for the power and I2C connector. The holes for the other connector are not machined. All subsystems except BPF-box and Switcher Board use this standard box. So 1 is needed for the Frontend. 4 are needed for the Backend.

    Please note that Board-sets must be ordered as a whole. The reason is that they are made from panels to be cost effective and partial panels are of little use to me. Boxes and QT crystals however can be ordered individually.

    Please carefully check if your order is correct! It is sometimes not exactly clear from the emails if for instance crystals are needed or not. In general the QT crystals are highly recommended. It is not very likely to reproduce the frontends IMD performance with low cost crystals made for clock oscillators. Special surface treatment is needed for quartz to be used in very linear filters.

  • 21/04/2011, the group-buy has been open for one month now and a sufficiently large group has formed to be cost effective with crystals, boards and boxes! The prices have been set given the current content of the list. The QT crystals have already been ordered as lead-time is longest and production is started. An email has been sent to everyone on the list to request a confirmation of participation with the group-buy.

  • 05/05/2011, all confirmations are in. There is sufficient quantity for the crystal filters of INRAD and KVG also! Orders wil be placed in the next few days. In case of KVG it means a payment in advance. More details later.

  • 11/05/2011, still more orders are coming in, but I have now decided to stop taking new orders! I have increased the amount of crystals that are produced by QT to the current needs and will reserve a few spares of all items in case more late comers are coming! Also the crystal filters are closed now. I will not take new requests for crystal filters and there are no spares.

  • 13/05/2011, the INRAD filters have been ordered. Expected date of shipment to me is early July.

  • 19/05/2011, the KVG filters have been ordered. Expected date of shipment to me is mid July. A request for payment in advance is send out to all KVG buyers. Many have responded quickly. Also the boardsets and metal boxes have been ordered. The longest lead time now is KVG. I expect to be able to ship first to people that did not order any filters, probably mid June.

  • 08/06/2011, a shipment of metal boxes has arrived. Also the PCB-sets have arrived, so I am ready to ship the first parcels. 3 have been shipped today with crystals only. I will ship to those that did not order crystal filters in the next 10 days if payment has been received.

  • 16/06/2011, 12 parcels have been shipped today! 35 still to go.

  • 18/06/2011, 1 parcel has been shipped today.

  • 05/07/2011, 2 more parcels have been shipped today.

  • 08/08/2011, both INRAD and KVG flters have arrived last week and today 13 parcels have been shipped to those that don't have enlisted for Lodestone coilformers through me. Waiting is now for the coil formers that have been shipped to me last week to arrive before I can begin shipping the remaining parcels.

  • 18/08/2011, Lodestone coil formers from Richard have arrived last weekend and 10 more parcels have been shipped today. Only 7 more to go now, for which delayed shipment was requested.

  • 26/08/2011, 4 more parcels have been shipped. Only 3 remaining delayed on request due to holidays.

  • 01/09/2011, 3 more parcels have been shipped.

  • 09/09/2011, 1 more parcel has been shipped.

  • 08/10/2011, this groupbuy has come to an end. I am fully sold out. Many thanks everyone for good cooperation!

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