Re: [softrock40] 40m/30m/20m RXTX Ensemble board
- Brent, AB1LF, has completed initial test on a 40m/30m/20m RXTX Ensemble example I recently built and sent to him.
Brent finds that with 40m output set to about 30dBm that the second harmonic is at about -9dBm. For 30m and 20m the second harmonic is typically around -27dBm. Thus for 40m operation, to be FCC compliant, an external LP filter will be needed so that the 2nd harmonic of 40m is down 43dB or better from the one watt 40m output level.
Highter harmonics of each of the three bands are typically down more than 50dB form the one watt output level.
Early this week I will modify the RXTX Ensemble schematic to include the 40m/30m/20m case and add the external 40m LP filter information. The RXTX Ensemble kits to be shipped soon will include the components such that five band group options are covered: 160m, 80m/40m, 40m/30m/20m, 30m/20m/17m, 15m/12m/10m.
Thanks very much Brent for testing the 40m/30m/20m option.
Tony Parks kb9yig@... http://www.kb9yig.com
On Sat, 2010-07-03 at 01:21 +0000, kb9yig wrote:
Good Evening All,
I am thinking about building up a 40m/30m/20m version of the RXTX Ensemble board over this holiday weekend to evaluate the performance of the RXTX Ensemble for that band combination.
Like several of the other multi-band RXTX Ensemble transceivers this unit will also have an external LP filter to make sure the second harmonic of 40m is sufficiently attenuated to meet FCC requirement.
I am wanting to find someone who has access to the necessary test equipment to properly evaluate RX the TX operation of the unit.
If you have interest in doing the evaluation, please send me an e-mail directly to kb9yig@... . The built unit will be your compensation for doing the testing.
Thanks and 73,