[Milsurplus] 500 Kc XMTR

[Bill Cromwell]

Hi,

I will have to build something to transmit on either of the new bands 
but I do have (and use) command receivers - R-23 and BC-453. I also have 
(and use) a RAK-7 that hears all the way down to 15 kc. I have seen 
where some hams have used audio power amplifiers (Marantz stereos etc) 
in their LF (not MF) lashups. I have doubts and there is a lot more to a 
station than the final amp.

I have been able to hear 'low power' transmitters without too much 
strain out to around 1250 miles or so. I don't expect any 'regular' QSOs 
nearly that far from my small lot. But let's see what happens. First of 
all, 30 days must lapse before the key goes down. And the TX is not even 
built yet.

73,

Bill  KU8H



On 09/16/2017 08:26 AM, Mike Morrow wrote:
>
>> Looking for something I can use on the new 630 Meter Band.
>> Tnx, Dick, W1KSZ
>
> The T-47 (USN) or T-47A/ART-13 (USAAF) is a good candidate, using the optional LF/MF oscillator:
>
> O-16/ART-13   200 to 1500 kHz in six   bands (USN)
> O-17/ART-13A  200 to  600 kHz in three bands (USAAF)
>
> But that alone will NOT put the transmitter on LF/MF, because it has NO LF/MF PA tank circuit.  That is in an external unit:
>
> CU-25/ART-13   200 to  600 kHz (USN)
> CU-26/ART-13   500 to 1500 kHz (USN)
> CU-32/ART-13A  200 to  600 kHz (USAAF)
>
> The best of these is the CU-32, but it is as large as the T-47A!
>
> Don't forget the DY-12/ART-13 or DY-17A/ART-13A dynamotor.
>
> The CU-32 and O-17/ART-13A are shown on the complete AN/ART-13A system schematic that Mike Hanz corrected and improved legibility from the defective copy found in original AN/ART-13A manuals:
>
>  http://aafradio.org/docs/ART-13A_schematic.png
>
> The receiver that the USAAF used was the AN/ARR-11 (a.k.a. the BC-348-Q or -R), which has a 200 to 500 kHz band.  Together, the AN/ARR-11 and the AN/ART-13A made the AN/ARC-8.
>
> The USN used the ARB or R-23*/ARC-5 with their T-47.  The R-23*, BC-453-B, or ARA/nt-46129 190 to 550 kHz "command set" receivers should do a pretty good job.  Fifty years ago I kept a BC-453 on my favorite band of all time...the old 410 to 535 kHz MF Morse maritime band and it worked very well.
>
> It'll be interesting, this new OLD band.  I just wonder how long it will take for hams to realize that 472 kHz is not even close to being LF...which runs 30 to 300 kHz.  Even a recent ARRL e-mail newsletter made that error.  But the other new band at 136 kHz...now that's right in the middle of the real LF band.  There's not much military surplus transmitting gear for that frequency.
>
> Mike / KK5F
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-- 
bark less - wag more