[ARC5] Using SCR-274N

[Geoff]

> On Thu, 2013-03-28 at 08:32 -0700, Bob Macklin wrote:
>> How do you use them?
>>
>> This stuff was intended for short range communication  (not DX) and not
>> under crowed ham band conditions.
>>
>> They were really made for voice operation, not CW.
>>
>> Bob Macklin
>> K5MYJ
>> Seattle, Wa.
>> "Real Radios Glow In The Dark"
>
>
> Hi Bob,
>
> There have already been some comments about how the radios are used. I
> only use the MF and HF command receivers (no "ARC-5" transmitters). I'm
> not particularly fussy whether they were ordered by the Army or the Navy
> but I do have an acquired bias in favor of Navy and I prefer them
> dressed in black.
>
> My R-23 and BC-453 radios aren't too short on the range. I have picked
> up an NDB transmitter at 1025 miles and one of the hams with an
> experimental license for 600 meters with a very few watts (about 3) ERP
> at almost 1200 miles. Of course my antenna won't really fit a B-17! At
> 140 feet I might find a way to wind it around here and there and force
> it to fit. I have received 40 meter CW from the west coast in here
> without too much trouble (great lakes neighborhood) using a plain
> command receiver. Not DXCC. Not short range either.
>
> It's the 21st century. Older scaf filters and later digital processing
> (without modding the radios) does a lot to sort things out after the
> radio grabs the signals from the ether and presents them at the output
> terminal. We also have that grey filter between our ears that can deal
> with a lot.
>
> The 80 and 40 meter radios have a wider IF but the modern filters really
> make a difference. There are a lot of add on tricks that I will be
> trying but all of them are applied from outside the radios. A couple of
> them - like a Q-multiplier, need access to the internal wiring but still
> no butchery.
>
> Finally, we don't have to be chasing DX wallpaper every time we turn the
> radio on. At least..some of us don't.
>
> 73,
>
> Bill  KU8H


A pair of surplus crystals and a few other small parts would help narrow the 
bandpass on the wide open sets. It could all be done with a couple of tacked 
in solder lug strips and easy to reverse. I havent looked at what is 
actually available but it wouldnt hurt to look.

Slight regeneration of an IF stage would also narrow it a bit without that 
extreme hollow sound. No parts required maybe, just a gimmick feedback cap 
grid to plate.

A BC-454/455 that has already been bandspreaded could become a very nice CW 
radio with minimal work. I believe Ken also mentioned that the 454 IF 
transformers look possible to seperate the coils a bit.

Carl