The company HobbyPC sell a band pass filter for 2M, 1.25M or 70cm for 20$ each that can handle 20W … I have some and they are more than adequate … I use a low pass filter after my VHF amp because it outputs 100W with roughly 10mW drive (single block amp with bias control for SSB)
Do you guys have any updates on your amped up limesdr? I’m very interested in hearing how it worked out. I’d like to make an HF rig using a limesdr.
I have had several projects going & haven’t gotten back to it. BUT, I picked up an FT-857D chassis, with a blown driver. The PA deck is fine. Once I figure out the signaling into it, I will slap it all together. It just has a TX input & RX output, along with LPFs, BPFs, Diplexers & the such. Perfect.
I have ordered two of the Power Amplifier Kits and heatsinks and waiting for their arrival.
Do you have the assembly instructions? I cannot find them online and the link given goes
off to some other place.
I am in the process of putting parts together for my radio. LimeSDR + BeagleBoard X15.
This is how looks 2m band today in KN05AD (its is contest time, not sure which one):
SDR device is LimeSDR-Mini but for now only RX. In my frontend RX preamplifier is with PGA103+ with additional helical BPF. For TX my plan is to build 30W PA kit (https://www.minikits.com.au/electronic-kits/rf-amplifiers/rf-high-power/RA-VHF-Amplifier) which will complete setup for 2m. Overall very cheap 2m SDR.
I purchased my amplifier reassembled with the heatsink - so I don’t have any assembly instructions but the seller has to (according to what they have on EBay).
73 de Marty, KN0CK
I’m setting up my Lime for HF. I am trying to work out a box for it all. It will include a Mini ITX motherboard, filter board, switching board and small amp.
The amp has 2 - 3 watts output. Should that be moved far away from the Limesdr ? I was thinking of having the Amp right under the Lime (to save space) but worried about high levels of RF getting into the receiver and potentially overloading it ?
Hi, I also have one of these. Did you try it? Did it work? What TX gain settings did you use?
I finally got my amateur radio call sign (R2AUK). Although I have Yaesu FT-891 I thought it should be fun to make a few QSO with LimeSDR. One thing I don’t quite understand though - can I somehow use the same antenna for both TX and RX with LimeSDR? Considering that SWR of my antenna is far from 1:1 just transmitting 45W through the amplifier doesn’t sound like a good idea. And even if I use two antennas, one for RX and another for TX they will be quite close to each other and the effect could be the same.
The assembly and tuning instruction can be found here https://www.algissalys.com/tech-notes/projects-45w-ssb-am-linear-cw-fm-power-amplifier-hf However please note that your version of the PCB may differ a little bit.
Also Vladimir Karpelyanskiy (R2AJI) recorded two videos of assembly of this amplifier:
The language is Russian. If something is not clear in the videos I will be happy to translate.
If you would like half duplex on the same frequency’s you could use a antenna switch (rx/tx) on a GPIO.
For full duplex u’ll need a duplexer/diplexer which only works on different frequency 's.