Hi Mal
I do indeed have a decca unit with 3 onboard 5501s and 2 spare 5501s and a home brewed 5501 test rig. I bought it all in Dec. 2009
from the SK sale of the late great G3AQC along with a Decca vario/coil, a 60V PSU (heavier than jupiter!!) and several W&G rx and tx units, but due to work and later illness issues with me and the XYL they have lain fallow for a few years.
Now we're all healthy again , at some point I'm going to commission it with the PSU.
If you have details on how best to feed my IC706 into it then I'd be very grateful. I don't have a TS590, though I know they are a good
box. I do have a 570S but that won't play down at LF/MF.
The 706mk2G and even the aged and venerable IC735 will play down at LF and MF, though the IC735 is less happy and has a tendency to burn
its LPF and/or PA. (I've done both!! Geoff at Castle likes me!)
The 706mk2g is very well behaved @ 472khz and while only generating around 33% of it's nominal max rating, that's still the thick end
of 30W @ MF.
At 137 it is very QRPP and only gives out a few milliwatts at best. The TX only really comes alive at about 250khz+
At 137 though, there's enough to act as a low power exciter for a Hafler or a Decca. The haflers only need 10dBm in to get 250W+ out.
The haflers are rated at 500W @ 50khz and -3dB down at 150 to 500 khz but that's still 250W
Last year, I treated myself to a ELAD FDM Duo and that will happily squirt out 0dBm at anything from 10hz up to 60mhz via the transverter
output. A cheapo 1w broadband amp off ebay spins this up to 1w and then that can be fed into the Hafler or Decca to get some QRO. I'm thinking of using the ELAD as an exciter for the dreamers band. Last time I was on 8.9khz, I was using an old audio
sig gen, but my antenna system was nothing but a "worm warmer". I think now with some daisy chained coils and a better earth I might just be able to make the hop to G3XIZ, 2 miles away or I may try Roger's earth electrode system too.
If you can email the schematics for interfacing the 5501s that would be great
[email protected]
With best regards
Jim
Dr. Jim Cowburn
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Do u have Decca 5501 units if so they work well on MF
I can supply details to resonate on MF and interface to ts590 or ic706
Hi all
John sent me over this sketch of how best to interface my 706 to a Hafler audio amp as well as some schematics from their excellent website on the subject
http://www.w1vd.com/page21.html
http://www.w1tag.com/pix/Hafler_Amp.jpg
http://www.w1vd.com/Haflertransformers.html
I have a 3000, though John informs me that these don't play nice on 472.
I've got the coax and the -77 material cores and caps so it's time to get building.
I'm on the lookout for a 9505 but most on Ebay are outside my budget and also US spec and need 110V, though I could always get a converter.
If the weather stays dry, then I'm hoping to crack on with this, this week and get G7NKS to be a bit more QRO and hopefully crack the T/A and 2000km barriers
on WSPR 472.
That'll be the broadband gone then! Stefan helpfully sent me over some ideas to look for how to proof the router against interference, but it may well just
be a cheapo BT Homehub 4 and it’s internal aerials.
Enjoy the darker months guys and hope to see you all on MF and LF
With best regards
Jim
Dr. Jim Cowburn G7NKS IO92ub
<Halfer interfacing with 706 courtesy John in US.pdf>
