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Tuesday, 27 August 2013

So the radios good, what about the new Ham cat?


Been fiddling at home a bit recently, changed a few things around and played mostly with JT9. Yesterday morning I was calling CQ on 20M when VK1DW called me - he's in Holder, Australia - that's just over 10,500 miles away - thanks Dean! I was running 20W into the homebrew Windom I made here:

Its during moments like that when I remember what inspired me into Ham radio in the first place; it never fails to send a tingle down my spine. Simply amazing.

Here's a pic of the shack as-is today:

and here a close up from the weekend of the TS-990 in RTTY mode interfaced to the contest logging program Writelog:

Here's Florrie the new ham cat, she is definitely getting the hang of being my second shack assistant:

And chief ham cat, second in command the Geddy cat has found yet another new place to take it easy (you can see the paws):

Fun, egh?

Saturday, 24 August 2013

TS-990; Hows the filtering?


Since my TS-990 came home with me I've been spending some time understanding the filters and their configuration. You basically have, in each mode, three sets of filters that you can pre-configure. The configuration comprises the roofing filter, IF and AF filter shape. On top of this you can also then configure the IF width.

In FSK mode, I've set mine so that the filters are:

In addition to this I have configure the selections so that the IF bandwidth is 1500Hz when FIL-A is selected, 500Hz for FIL-B and 250Hz for FIL-C. This alone is allowing me to reject very close and swamping signals from a crowded RTTY band. Additionally this radio has an Audio Peak Filter for FSK or RTTY mode which will also include a null or notch between the mark and space tones. Here's a decode window without the APF:

And here with:

So I tune round the band with a wider filter selection, perhaps starting with A and then moving to B. Once I find an individual signal I then switch to filter C and include the APF if there is another signal intertwined with the one I am interested in.

Here's a quick video to try and illustrate this in action:

The video isn't very good quality, but you get the idea.

Here's the new ham cat who has taken to sleeping inside a cupboard:

Fun, egh?

Sunday, 11 August 2013

New Radio, New Interface


After some serious contemplation, I have traded in my FT-DX-5000 plus my FT-DX-3000 and brought home a Kenwood TS-990. This is the much larger cousin of the TS-590 that I owned some time ago. I was very impress with the 590, and initial impressions of the 990 are astonishing!

So, above you can see the new beast installed on the LHS of the radio shelf, I've managed to move the FT-847 down into view so operations and monitoring of 4M will be much easier now.

I've decided that the TS-990 will be used for all things HF except the odd play in SSB with the FT-1000; that radio will remain with the Yaesu desk-mic connected, the two headsets I have here (one from Heil and one from eBay) have been re-wired to work with the Kenwood (same connector but different wiring - yes , I know, really).

I've modified (or read completely re-made) the digital mode interface for the radios to simplify the switching. The 990 will do all things AFSK plus FSK RTTY and will also switch the linear PTT, with the FT-847 only needing to be able to do computer based CW and AFSK modes (like WSPR). I've opted to use separate soundcards for the two radios so there will be no need to switch any of the audio lines. Effectively I have built two interfaces into one box:

This time I have used opto-isolators so there is now 100% isolation between the radios and the computers. There are 5 opto-isolators in all, on the TS-990 control there is the PTT, FSK line and the CW switch; on the FT-847 I am switching just PTT and the CW line with the PC. The rear panel is a bit of a muddle:

So, here we have a com port connection for each radio, a radio data interface connector (the radio 1 connector is 6 pins as I will take both Main and Sub VFO audio feeds for SO2V), then there is a line in and out for each of the two soundcards and a CW key jack socket for each radio.

The front panel is much neater as there is just a TX and RX audio level control for both radios plus a TX light each. As you will see - I am in need of some suitable knobs!

The radio room is now completely ditched as a result of the arrival of the new radio and the associated plumbing plus the construction project debris, but it's time to get this radio on the air!

Fun, egh?

Saturday, 10 August 2013

So who is Caroline? Ah, Carolina Windom!


In my never ending fashion of fiddling with antennas, I have just replaced my 40M dipole with an off-centre fed dipole. This should be equally as resonant on 40M but also give me an alternative antenna for the other HF bands. Really I can only expect a close to resonance on 40, 20, 15 and 10 - the antenna will be a major compromise on the WARC bands (30, 17, 12).

So, having had a rummage in the ARRL antenna handbook and also a quick search using Google, I came up with this basic design (0 points of originality claimed here):

So, what's it like? Well initially I can see that I certainly have an antenna connected to the radio - so it is not just a dummy load. Here's what the antenna analyser makes of the antenna:





As expected on the WARC bands it's not so hot, 30M:

It looks remarkably OK on 17M:

And ditto on 12M:

So, a complete compromise antenna that's just 66 feet long. Looks like it might work though.

Here's the two ham cats meeting for the first time:

What do you recon? Interesting, egh? 

Thursday, 8 August 2013

Introducing the new....

Ham Cat:


much more to follow on both topics.

Must dash, fun though egh?