Hi, my opinion is that if you use an RTL you will see no difference. If so, most important is to adjust the gain of it in order to archive max SNR and maximum dynamic range. If you mix it to a lower ham band I think using a BPF you gain 3 dB of the noise of the opposite sideband, that has no signals in our case. You lose some dBs of the filter but you have gain at the SNR.
Posts by SV1BDS
-
-
Hi,
IC735 is aligned, it was about 100 Hz off ...
Searching for FreeDV and KG-STV QSO now.
-
Hi,
A simple ground isolated PC interface , ready now for digital modes ...
-
Hi, I have involved in earthquaqe prediction research for transfering data among others topics. Is it inside the scope of this satellite to transfer such research data once a day at night ?
-
DD0KP I try to install the software and the drivers but still errors... TNX Heiner !
-
DD0KP Yes Atmel TINY45
-
-
Hi, I bought a red USB 2*relay PCB for SDR-Console with green connectors but the WIN7 can not detect the driver.
Any ideas ?
-
2N2222 is also TUN ; -)
-
PA3FYM Is for the TUN C & E opposite placed ?
-
PA3FYM Now it is a pleasure to do QSO !!! All the devices are in final place.I transmit exactly at the receiving frequency and I can monitor also with RTLSDR. The shack table now is free from all the boxes !!! Also the quality of transmition is better now. Its time for our third QSO ...
-
Hi, the transverter from 28 to 739/430 is put in to a box. One eBay SMA female chassis connector was defective (the center pin was missing !!!).
-
Hi, updated block diagram.
-
Hi,
The driver from ADF4350 for 2 * SBL1 (one for Rx and one for Tx) is finally build. It is a SBB5089 (20 dB 4 GHz !!! 20 dBm) and a splitter, driving two 4 dB attenuators before the 2*SBL1. The MAV11 that I plan to use did not give enough gain (only 12 dB) as the ADF4350 was giving 0 dBm maximum at 402 & 711 MHz and the signal produced after the MAV11 and division was less than +7dBm required by SBL1. Now aftrer the attenuators is about +10dBm which gives better performance to SBL1.
The first QSO with the 28 MHz If and IC735 is done with Alex SV8QG. Extracting from the ADF4350 the TCXO and driving it with GPSDO 25 MHz out, I can finally transmit at the same frequency I receive. I have S 1-1.5 noise level and the beacons are S 6-6.5.
-
Hi the expected ADF4350 arrived but not working. It was going at nearby frequencies and when I touch some components the lock led was light for a while and then stop. Also the frequency was going at higher frequencies when I touch the +5V and some pins. The conclusion was that the phase comparator was not driving the VCO. This it was and a jumper cable replaces the cut PCB.So it is repaired and 28 MHz Tx&Rx can go on !!!
-
Hi, a harmonics frequency generator with a fundamental frequency of 125 MHz which generates f up to 10 GHz is build driving a SBB5089 MMIC with 2.2 pF from a 4 pin oscillator.
-
Hi, if you disconnect the antenna ALL the output power will go this termination load. Else in normal operation only the reflected power.
-
Hi Remco, for 402(430-28) and 711(739-28). It read a pin and when changed by PTT it resend data.
-
Hi, I use an other frequency generator that has very low harmonics , it produces 25 MHz but LNB did not work as the produced signal was square after the division...
Also for RX/TX at 28 project I try a ADF4350 but it does not lock. I try also the same settings as done before with no luck. It seems that is defected.
-
PA3FYM I try with a /16 divider which did not work maybe due the harmonics of the square wave which created. I have to build one more low pass filter to test.