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ATS-4b Transceiver Kits again avaliable


#1

A new Batch of ATS-4b Transceiver Kits are avaliable. The best SOTA Rig I ever operated! The best Kit I ever built. Be quick with orders! See KD1JV.com Steve’s homepage.
GL Guido, HB9BQB


#2

In reply to HB9BQB:

It looks good - if it had a mic socket I would definately be interested!

73

Brian G8ADD


#3

In reply to HB9BQB:

Correct link: http://kd1jv.qrpradio.com/


#4

In reply to G8ADD:

Me too hihi :wink:

73 de Franz ON9CBQ


#5

In reply to ON9CBQ:
The ATS-4 has a KEYER Socket - What else!
73
Guido


#6

In reply to HB9BQB:

I think most people know what works best for lightweight HF portable operation. And the rest will have to make do with microphones, bigger batteries and heavier gear.

Kjell’s PP3 challenge is presumably open to SSB entrants - who will be the first? I wonder if anyone could make even 10 SSB contacts on the HF bands with a PP3?

73

Richard
G3CWI


#7

In reply to G3CWI:

I think most people know what works best for lightweight HF portable
operation.

Indeed. I’ll consider something like an ATS-4B if I ever manage to get my brain, ears and fingers to work with morse…

73, Rick M0LEP


#8

In reply to G3CWI:

In reply to HB9BQB:

I think most people know what works best for lightweight HF portable
operation. And the rest will have to make do with microphones, bigger
batteries and heavier gear.

Oh, its not “making do”, its accepting the greater challenge!

Apropos, does anybody remember the reports of the first transistorised TX getting contacts on 160 metres, somewhere about 1960? As I remember it, the TX was using a home-made point-contact transistor. Now there IS a challenge!

73

Brian G8ADD


#9

In reply to G8ADD:

Oh, its not “making do”, its accepting the greater
challenge!

Brian

Good to hear that you are up for a challenge! Shall I post a PP3 to your address on QRZ? :wink:

73

Richard
G3CWI


#10

In reply to G3CWI:

Good to hear that you are up for a challenge! Shall I post a PP3 to
your address on QRZ? :wink:

Not yet! I have seriously looked at the “half-way house” of a QRPp DSB rig but wonder if I could avoid the power penalty of DSB and keep the component count low by building a phasing-type exciter…winter dreams!

73

Brian G8ADD


#11

In reply to G8ADD:

If you must insist on a microphone, the Epiphyte design is a well respected simple transceiver design:

http://www.norcalqrp.org/files/Epiphyte3Mnl.pdf

ISTR you talking about the MKRS80 a while back.

…or is this all really just a dream after all?

73

Richard
G3CWI


#12

In reply to G8ADD:

Brian, I was thinking of ways you can play this QRPp game with a voice signal and not be at a disadvantage to brass bashers.

Morse gets it’s advantage over voice in that the information rate is slower than speech and so the bandwidth needed is lower to send the signal. Shannon showed that for a given signal to noise ratio you can improve the error rate by slowing the data rate. The advantage is enhanced because of the low bandwith our power spectral density is greater. (i.e. 100mw spread over 200Hz for CW vs. 100mw over 2.4kHz for voice). So we have more watts/Hz and a lower data rate so we can recover the message at much worse signal to noise ratios than voice. All this is well known.

Now what you need is some way of fitting your voice into 200Hz. So what you could use is the opposite of high speed meteor scatter CW. I’m sure you recall that you would transmit the CW at say 200wpm for 2.5mins whilst the other station used a modified tape recorder and heterodyning up converter. The tape recorder ran 10x faster on record and the upconverter converted the incoming audio at 1kHz to 10kHz. When you played the tape back at the correct speed, the audio was 10x slower so you could hear Morse at 20wpm. Of course the frequency was 10x lower but as you had shifted it up 10x before recording you ended up with 10x slower audio at the right frequency. All analog solution to speeding up and slowing down the audio rate without changing the tone!

You need to run this in reverse. i.e. record your normal frequency speech 10x faster on the tape. Then playback 10x slower into the transmitter. That way your audio will fit in a similar bandwidth as a Morse signal and you’ll get a simimlar PSD giving you a similar error rate to Morse for a given signal to noise ratio. At the receiver you record the audio at normal speed but playback at 10x speed and thus your audio is resolvable by ear.

Of course it will take 10x as long to send the message so you need to keep the overs short, but you’ll have recovered the advantage Morse has. The downside is the complexity of the system and the fact you are transmitting 10x longer so you wont get as many QSO/battery as the Morse guys. So they’ll still out perform you.

Or you could learn Morse!

:slight_smile:

Andy, MM0FMF
(Inventing solutions to problems that don’t exist!)


#13

In reply to MM0FMF:

Slow voice mode - genius! It could more easily be done using digital recorder chips these days. Lugging an X-1000R up a hill would be hard work.

73

Richard
G3CWI


#14

In reply to G3CWI:

I’d forgotten about the MKRS80 - there were a couple of things I didn’t like about it, and in any case I was thinking of one of the higher bands. I’ll take a long look at the epiphyte (nice name!) I was actually thinking in terms of 100 - 200 mW, as I have found little difficulty in getting contacts at 500 mW on the 817 on a good day, even so that would knock heck out of a PP3! The challenge for me lies in the actual construction as my eyes are not as good as they used to be, but I am looking for a big magnifier - it would be nice if it didn’t magnify the bit and my shakes…

I’d have to be quick as I only seem to work up any enthusiasm for construction in the bleak midwinter and I used part of this season building a tidier version of my little QRP Z-match, modified to include Top Band.

73

Brian G8ADD

PS Andy, I learned Morse in 1962 and never forgot it (not quite true, I forgot things like full stop, slash etc!) but knowing it and using it are two different things!


#15

In reply to G3CWI:

I did think about a DSP solution rather than using tape but the only way I could think of getting the current consumption low enough would be to sample the voice with the DSP running fast and then massively slow the DSP clockrate down so the consumption dropped. But then the downconversion would not be realtime so it would take even longer to send/receive.

Andy
MM0FMF