Blockquote You definitely don’t NEED it - but clearly you want it!
Unfortunately, I agree… I love my MTR and not planning to sell it, but what I like really much about the SW3b is its tolerance to 13.8 V within its limits. This will make a perfect companion to place in my car. I am thinking of having one in the car all the time. It would suit into a glove compartment and will be always at hand with a simple setup (antenna, a 10m mast, perhaps spare batteries, but maybe relying on a small 12v battery. And always easy to carry if I pass by a mountain.
(yes, I know, I am making a list why I NEED it, not want it.
Blockquote NEED is the word I use when discussing new purchases with my wife.
I like it!
So far I used the phrase “it is just for testing, I will sell it after it’s done”
The problem is the testing time is indefinite…
I’m very pleased with my SW-3B-QRP. Runs for a long time on 3x18650 lithium cells (supply voltage is displayed on screen). Rx and cw filter are plenty good enough. It also seems well put together and robust. Still looks new after a few activations and one pre-lockdown wild camping trip.
In qso I don’t say RIG HR IS SW-3B-QRP as it’s quite a mouthful on the key, so I just use the manufacturers name, Venus.
Thanks for sharing. I didn’t know Practical Wireless. For those interested, it offers a free 14-days trial with access to the July issue. I’ve just availed of this via the iPhone app.
I am playing around with the rig, and I noticed something which I am not sure whether it is a defect or normal behaviour.
I use the rig with a doublet antenna, and I am tuning it with an Elecraft T1. When I tune on 10MHz and 14MHz, everything seems ok, it tunes, and then I can operate.
When I try to do the same for 7MHz, the power drops to zero, but before that at first it starts to TX and drops within half a second. When I am persistent in attempts and finally tuned SWR 1:1 (with those small hits at the paddle, just chunks of pwr before the rig stops transmitting, doing it over and over again until fine-tuned), then the TX starts to work FB at 7MHz, too.
I am not sure what the problem may be - is the SWR too high at 7MHz at my doublet and does the rig have any protection to cease TX when detecting too much going back reflected? But then, why are 10 and 14 MHz fine, and the symptom is observed only at 7 MHz?
Has anyone come across this issue? Thanks for your thoughts on this.
The arms are about 17m long (each), the 450 ohm ladder feeder is about 10m, but not extended fully straight, rather curled and not vertical due to the conditions of my balcony (the anchor point is about 1,5m higher than my rig.
Of course, I do. To be precise, the antenna works fine with an Elecraft KX3 and its internal tuner, it has absolutely no issues to tune at 7MHz with oter tigs in the configuarion with the Elecraft T1 (I played with all MTRs - 3b, 4b, 5b). So I am not sure whether the problem lies in the antenna.
Below is a video showing the issue. I speak Polish as I shared this with Polish friends, but below is what I am doing in the video. 7MHz problem - SW3b - YouTube
00:00 - 00:25 10MHz tuned with “dots”
00:30 then I switch to emulating straight key to tune 7MHz (just to avoid “dots” for long time)
00:35 switch to 7MHz
00:37 switch T1 into tuning mode
00:40 - 00:46 tuning in chunks of signal which is being cut off each time SWR is high
this time it got quickly to 7MHz tune-in, but it takes a while at times, esp. if I do not switch to simulation of straight key, but either way I always get sending signal cut off in a fraction of a second
the problem is nonexistent on the two other bands in case of SW3b and does not exist on any band in the same setup with another TRX (MTR3b, 5b, etc), also smooth at 7MHz - it is just my SW4b doing this at 40m.
It seems also to make occassional errors (as in minute 01:40) in sending from time to time - sometimes it adds sometimes it misses a reaction (03:40). I do not have it with any other trx.
about the keyer problem. I just tried it on my own (for one minute) but couldn’t get any errors. How often does it happen with your rig? Once every xxx minutes? And, do you have a dummy load? Does it happen with dummy load too?
There might be another good test: Transmit your cw outside the band limits, e.g. at 6999 KHz. SW-3B will not output any power outside the band limits, but you will get the CW side tone. Is it erroneous too?
Hi, Axel (and Richard) - thanks for your inputs - I will give it a try - I am going out on Thursday - so I will take a resonant antenna (trapped EF 40-30-20) and check. For the keyer - I will keep on testing, too.
I had some keyer problems with my IC703. It is a known problem with a known solution. See Mods.dk for the original fix in the instance of the IC703.
The cause is RF on the shield of the key line which in the original radio setup is not :“earthed” to the radio’s case or to the “ground” of the main PCB. Instead, the connections to the (giant sized 1/4") key socket are all carried in unshielded wire across to a connection point on the PCB, from where they connect to the CPU. needless to say, with RF present on the “earth” connecton of the key, taking it all that way across the radio PCB and then connecting the lines to the CPU occasionally locked things up. Computer chips are full of diodes and semiconductor junctions that can rectify RF and produce stray DC voltages in places you don’t want to know about and can’t see anyway.
The standard solution in the case of the IC703 is to connect a short bit of wire from the ground side of the key socket to the nearby PCB. A bit of paint is rubbed off the PCB first, then the exposed copper is tinned, then the wire soldered. That completely stops the keyer problems.
I did try various common mode chokes and some of those methods did reduce the effect. one was simply rolling up a metre of the feedline coax near the rig so as to choke off some of the RF. That was often enough. But fixing the socket earth was even more effective.
There maybe something in that story for the SW3B too.
