Tuesday, March 19, 2019

Transverters for 40 MHz

One of the obvious problems with the new 8-metre (40 MHz) band is the lack of equipment. Some amateur radio transceivers could be modified but there is a risk doing this as the output filters in the PA stages might be way off.

Transverters-Store is a company in Ukraine and they make a number of transverters that allow a 28 MHz radio to covers various bands from 40 MHz to 432 MHz.

The 40 MHz version converts 40-42 MHz down to 28 to 30 MHz. The PCB is shown below.

Technical specifications
RF range  -  40 ... 42 MHz
IF range  -  28 ... 30 MHz
IF input power  -  1 ... 50 mW (0.05 W max.) or 0 ... 17 dBm
Output power  -  10 ... 15 W
Noise figure  -  typ. 1.0 dB
Supply voltage  -  +13.8 V DC (+12 ... 14 V DC)
Current consumption  -  typ. 2 A (TX)

With an unmodified 10-metre transceiver covering 28.0 to 29.7 MHz, this gives a transmit coverage of 40.0 to 41.7 MHz.

Note that this doesn't overlap with anyone using one of the Italian 43 MHz CB radios which cover  43.3 MHz to 43.5875 MHz  OR 42.3 MHz to 45.0875 MHz with the export version.

This transverter would seem to be ideally suited to a small transceiver like the Yaesu FT817 and there is also an attenuator board for sale.

Technical specifications
Attenuation Level - 30 dB (10 W IN - 0.015 W OUT adjustable almost to ZERO)
RF Input Power - 5 ... 10 W (15 W Maximum)
HF Bypass Power - 100 W
PTT control - Contact closure to ground or RF SENSE PTT SWITCH
RF Sense Minimal Input Level - 0.5 W
Supply voltage - +13.8 VDC (+12 ... 14 VDC)
Dimensions (mm) - 39 x 67

There is also the option of purchasing it as a kit with enclosure and associated parts.

Or the finished assembled transverter can also be bought.

For more information, go to http://transverters-store.com

1 comment:

Bo, OZ2M said...

I imagine that there are a lot of unused 50 MHz transverters lying around. So why not make some use of your decommissioned 6 m transverter, if your radio cannot listen (transmit) on 40 MHz?

Here is an idea:
- use 18 MHz as IF because then the 22 MHz LO can remain intact and you don't need a new crystal
- add 25% (50/40) to the value of all the RF relevant Cs and Ls should do the job in most cases. Many tuned Ls can probably be reused or if there is space between the windings give it a gentle squeeze.