Don’t waste your $$$$ on that battery. I had one. At best it was about 5600 mah under realistic 5-watt radio loads. It appears to have a built-in balancing charger, but in fact it does not. After about a dozen uses, minestarted to swell. So I cut it open and found out it did not have the balancing circuit, and one cell was way out of balance.
If you buy it with the idea it will only gove you about 1/2 the rated energy, and you think of using it a dozen or so times, then tossing it, you will not be disappointed. But if you are looking for something to be a solid performer, there are better choices. I use Nosram V-Tec, Turnigy and Sky Li-Po, all have done me well.
Not much Homebrew on here, So I thought I would add mine. It is based on a design by Ashhar Farhan, called the Minima, the signal path uses all 2N3904’s with the exception of one 2N3906, Local Oscillator is a Si570. Working on just 40M at the moment until I write some more software for the Arduino controller. My radio is significantly different from Ashhar’s regarding the front end / PA with a number of soft changes as well. Currently puts out around 45W. Consumes less then 250mA on Rx. I may be publishing it as a kit soon, with a professional PCB and case, at the moment it’s in prototype “dead bug” style. Excuse the messy bench !
It’s Activated five summits so far and hope to be out with it this weekend, sounds great on receive and it’s been reliable. Its tremendous fun to build something out of stocked parts that works so well !
My rig:
Ft-817 ND + Buddistick antenna, radial, lighter connector and lipo battery. 3/8 antenna mirror mount bracket for my mountain stick. Buddipole bag, Weight: 2,580 kg.
I know I stopped replying frequently, but I’m definitely still watching this thread. Thanks, everyone, for sharing. I love seeing the homebrew setups, and I also admit I’m a little partial to the FT-817 rigs as well, as it was my first HF rig and still occasionally serves duty on a summit. The KX3s and Mountain Top’ers all make me drool too. Such awesome rigs.
FT-817ND, I’ve always used digital modes and started with HP iPAQ hw6915 smartphone
with pocketdigi that can do RTTY PSK etc.
Recently I’ve upgraded to 12" laptop and Yaesu SCU-17 for JT65 and so far I’ve tested the setup in my car.
Also I’m switching from 80m-6m doublet to a simple vertical and a linked dipole but haven’t yet finished trimming them.
My portable HF rig consists of a Yaesu FT-857D, running through an LDG Z-11 Pro II antenna tuner to a Yaesu ATAS-25 vertical antenna. Power comes from a Bioenno BLF-1206A LiFePO4 12V 6 Ah battery.
For VHF/UHF I usually use my Yaesu VX-6R, with a homebrew portable 2m vertical antenna that I built from the book Portable Antenna Classics from the ARRL.
Two more homebrew rigs, left is a scratch-built ‘TCF’ 40m SSB superhet rig, 5 watts. Right is an MST-400 (kit) by OzQrp, similar, both on VK3/VC-027 Mt Little Joe, 1.5 hours north east of Melbourne.
Below, the MST400 on The Hump VK3/VE-019 at Mt Buffalo, 4 hours north of Melbourne in winter.
I don’t blog any of my project work, although I still do a lot of electronics away from work. I don’t have enough time at the present. The Minima is well written up in numerous places.
Its OK, the KISS mixer has too much conversion loss, so I substituted it for a Minicircuits diode ring mixer. It amused me how well a load of 2N390x could make quite a fair radio transceiver for SOTA. Its stuck on 40m at the moment, I may convert it to 60m and head back out with it one day.
My conclusion of the project is that its a bit half-baked compared to Ashhar’s previous designs. Front end filtering is also a bit too optimistic. I run my own version of the Arduino software that incorporates some more features. But it has the basis of a very good transceiver.
I agree that BitX, uBitx and Minima are intriguing designs, with the Bitx Farhan has found the balance between simplicity and acceptable function. Note that the mixer was lossy, I like a ‘gainy’ receiver and have found myself adding gain stages in several QRP class circuits. I have a uBitx on the shack table but lack the time to get it going. 2n390x’s give remarkable perofrmance in the Bitx – one RF stage, into a lossy hand made DBM, one IF gain stage, a lossy xtal filter, another post filter gain stage, a lossy product detector, an audio preamp and an LM386. And hams all over the world seem generally happy with it.
Its always better to keep the gain to absolute minimum before the final stages of the receiver, that way you preserve as much of the dynamic range available.
I do like these small radios. They deliver an enormous sense of satisfaction and surprising reliability for what they are. All brought about because of the need in India to have a inexpensive transceiver for the ham bands.
I used this homebrew 20M rig on a successful SOTA activation yesterday. 5W output, and the impetus for this project was my desire for an analog CW speed control. The rest of the setup consisted of a pair of earbuds, a 1300mAH 11.1V battery and a set of PicoPaddles.
The antenna is a tuned 20M EFHW with an SWR of 1.2:1 across the low end of 20M- no tuner needed. It connects to the rig with a 6-foot (2m) length of RG-174- BNCs at both ends.
My equipment:
3om30 3b: 3 band home made CW TRX - 7, 10, 14 MHz
Ext. home made DDS VFO
Fuchs ant 20 m, 15 m, 10 m
LiPo battery 3.7 V / 5 Ah
DC/DC converter to 12 V
RF field meter
