Hi Frank,
This overview contains a description and internal picture of the Megasat Multifeed. But it sadly is a DRO model..........
http://www.pabr.org/radio/lnblineup/lnblineup.en.html
73 de Cor
Hi Frank,
This overview contains a description and internal picture of the Megasat Multifeed. But it sadly is a DRO model..........
http://www.pabr.org/radio/lnblineup/lnblineup.en.html
73 de Cor
PA0P Cor do you have this already??
Heiner,
Yes, do have for several years a few MMDS downconverters,, including this one model. They are easy to convert by changing the Xtal and tuning the filters.
Did use them for AO40 and regular 13cm reception.
Perhaps this is costwise a better alternative? Delivered from the UK.
IF frequency 122 MHz so ideal for the SDR. Antenna can be replaced by a N connector if wished so.
https://www.ebay.com/itm/MMDS-…Swqu9Uz7bU&frcectupt=true
73 de Cor
someone was having a better result with the 1 watt board:
Hi Richard,
I have removed all shunt caps and things got a wee bit better. I then added 1p at the device in and out and now have about 9 dB gain at 2.4 GHz at 400mW.
I may leave it this way for the moment but i think i will be taking a knife to the wider part of the lines on the input and output.
Geoff GI0GDP
So keep on trying!! Cor
For the Spectrian driver board owners in this thread pointing to low output level, please note this rather simple mod to achieve over 30W at 2.4GHz.
It comes from a message by VK4OE (remember the Aussies do use 2.4 as their normalcommunications band). Here a copy of the message:
Hello Colin and other readers.
I feel that I can't assist your problem any more than the help you've already received. But I wanted to add that I do have one of these amplifiers working perfectly well at 2403 MHz, the centre of amateur activity here in VK.
However, I did go through the whole amplifier chain trying to find locations for solderable tabs ("snow flaking"), hoping to make it work better at this further-out-of-band frequency. The interesting thing is that I did find one sensitive/responsive point and it was between the final device and the output port, where the microstrip track takes a left hand turn - see attached 'image.
At 2403 MHz, 10 mW input delivered 31 Watts output following this small addition.
It was also interesting that there seems to be a layer of some plastic material everywhere which has to be melted away before the solder will 'take' - it makes the resulting soldered joint less than good looking!
I wish you well with rising to your challenge!
--Doug Friend, VK4OE.
Success!!
73 de Cor
Hi Kurt,
You are running behind the market. Pick your choice from already available solutions:
F6BVA - 20W with MW7IC2725N, DIY project
SG Lab - 20W with PA2400, readily built
Rene PE1CMO - 20W with BLM2425, readily built
Further options are: the 30W Spectrian driver board readily built with small mod to do, the Andrew MRF21045 modules with15-20W (with mod to do) and several other UMTS boards.
For sure there will be more designs applicable.
73 de Cor
I've done a look in the datasheet, think i have to modify the value of the input and output C's.
chances for success are low, I did run just by accident into the following article about the same problem:
https://groups.io/g/UKMicrowaves/message/47995.
maybe you can use the board with another type of MMIC for better results.
Roberto,
The module is a class A configuration with low IMD, no worries for SSB though.
interesting PA 3 WATT I am preparing I wanted to know from Cor PA0P if possible have the schematic I wanted to do it and how much power should the module insert?
73 de iw5bsf Roberto
Hi Roberto,
Schematic is very simple. As per datasheet do not drive more than 5 mW at the input (50 ohm), put 12 to 28 Volts on pins 2 and 3 depending on the output you want and output is at pin 4 (50 Ohm).
See the photograph for the decoupling of the powerlines. Take several values of capacitors, I did 22pf, 5000pf and 100nf. Any series inductor from the junkbox will do.
Take attention to get a good ground connection, remember it is 2.4GHz...
Hi, do you have a part numer or seller?
The only one i found, dont ship to Germany.
If I do check at eBAY.com there are currently 11 suppliers, no delivery restrictions.
you can choose from new or used. My supplier was from HongKong.
PA0P nice design..but in the datasheet from Freescale there is no pin description..
See on page 4 Package Dimensions.................
Only 4 pins, 1 input, 2 and 3 VCC and 4 output
You cannot miss
Hello,
Sorry to read about your bad experience.
If you are looking for a low power PA maybe this can be an alternative, in case that you are willing to solder a little bit.
The board is made very easy, however a solid ground between the module and board is required. I did use 35u copper foil under both.
Gain of the module is 30dB with an output of over 3 Watt at 2.4GHz.
And the cost is ridiculously low : 9 Dollar on eBay !!
I added a 6dB attenuator at the input to avoid oversteering. My use is as a driver for a (Andrews) MRF21050 module.
73 de Cor
For the daring "snowflakers" here is a nice 50 Watt output PA board on offer:
https://www.ebay.com/itm/Board…e7e80d:g:IY8AAOSw15ZbxotX
All hybrid couplers function still well at 2.4G. Includes output coupler to measure VSWR.
73 de Cor
Please do study this excellent article by G4BAO which will help understanding the effect of "flaking". Learning to read the Smith Chart is essential.
http://www.bravoao.co.uk/g4bao/Files/EME2012.pdf
Cor
Hello Arne,
Plse check this article which gives you a more detailed description.
http://www.vklogger.com/forum/…703ca8f1859714ba81e706fff
Succes!
73 de Cor
Hi Remco,
Still work in progress, 3 items from China went missing and I need absolutely better weather to climb my roof (considering my age).
But it is fun to watch all the approaches in the meantime.
73 de Cor
Hi Frank,
It is a japanese IC-375 with max 10 Watt output, hi.....
So it's working well.
73 de Cor
Dave,
Have to apologize for not reading first the datasheet, considered it as a 'normal' TCXO. However looking at the unit-price (5 times that of my OCXO!!) there had to be a difference.
After studying the sheet I see a drift of 2ppb per degree C, which still gives a drift of the 9750 MHz LO frequency of 195 Hz/degree.
Taking into account long term stability, jitter and phase noise my preference stays with the SC-cut OCXO .
Here is my system set-up:
Dave,
0.08 ppm equals a drift of more than 800 Hertz per degree Celsius....
So not OK for CW and digital modes and trivial for SSB.
To me it is important to know my frequency and by using one central OCXO reference in my shack, I can have my receive and transmit frequency exactly synchronised. No separate tuning/RIT necessary.
The LNB LO signal is simply fed thru the coaxline, less work than the TCXO modification I guess.
But it is everyone's own choice how to do it. That is clearly visible on this forum!
73 de Cor