Monday, December 27, 2010

Getting ready for the 4m band

If all goes according to plans/wishes, Dutch radio amateur will soon be allowed to use the 4m band between 70.0Mhz and 70.5Mhz. Trying to avoid the mistake of being surprised and hence not properly prepared for 600m, I started considering options for 4m.

First thing was looking for available surplus/commercial equipment. Unfortunately, in this range, all available surplus rigs are providing FM only. Best candidate so far, the VRC8000; actually, I plan to pick up one, before they are all gone. Advantage of this rig, it will also cover 6m.

I guess, a lot of operation will make use of CW and USB. Since no commercial rig seems available, a transverter could be the best shot here.
There are two CMOS oscillators available which would be suitable for the job converting/transverting to the 30m band: 60MHz (regular mixing) and 30MHz (subharmonic mixing).
Another two CMOS oscillators would enable us to convert the 4m band to the 6m band: 20MHz (regular mixing) and 10MHz (subharmonic mixing).

For being prepared, I will to pick a VRC8000 asap, and also consider to build a subharmonic transverter for the 6m band.


  1. Hi Joachim,

    Seen this one?

    73 de Ron & best wishes for 2011

  2. Hi Ron!

    Good one! Jan PA9QV (OZ9QV) told me before that 70MHz is available up there in DK. Did not know about the kit though.

    Meanwhile, I went to North Holland and picked up a VCR8000 ;-)

    73 en beste wensen voor 2011!


  3. OK Joachim,
    Alles gute,
    also spotted this one:

    Also available from the shelf: AKD4001

    I have never heard of VCR8000. Do you have more details? I am interested as well.
    Alvast dank Joachim
    73 Ron

  4. Hi Ron!

    My mistake, you could not have heard about a "VCR8000", because it does not exist... typoe on my side! It should read VRC8000 (shame on me! I will correct my posting)
    Check it out:

    The radio covers 30-88MHz, by 25kHz channels. Additionally, the channel can be shifted by +/- 5/10kHz., providing a 5kHz spaced coverage.

    73! Joachim

  5. Thanks!
    That's a real army-radio !
    Have a good weekend

  6. Artikeltje voor de lokale om gemaakt:

  7. Ron,

    nice collection of information! I guess that fellow ham w/o knowledge of the Dutch language can profit from the links!

    Cheers and have a good start in 2011!

  8. Zit aan een transverter te denken voor 50 MHz (+20 MHz uit x-tal). Wat zou je als mixer gebruiken voor het zendsignaal en wat voor filter na de mixer ?
    73 Ron

  9. Hi Ron,
    I thought about the same actually. (English, since others may be interested in this too). Have not started building anything yet. I picked up CMOS oscillators for 20MHz and 10MHz. Will use crystal filter to form a sine, as I did in my subharmonic receiver.

    Speaking of sub-harmonic, this would be one solution:
    (check out "21-7) Bilateral mixers").

    For regular mixing (i.e. 20MHz local oscillator), I would probably go for an IE-500 diode ring mixer at least for RX, TX would not be critical, for simplicity I would may opt for a single diode mixer.

    73, Joachim

  10. Tnx Joachim, very good info !
    Yesterday I started with the receiver part of the transverter according to
    20 MHz x-tal oscillator already works. Now busy with the antenna-switching circuit.
    In the end the transverter will be used with the FT450 which has the 6m band included.
    73 Ron