[ARC5] TRF - RAK "Q-5er"

[Geoff]

The Navy thought they were a bit lighter
http://www.hnsa.org/doc/ecat/cat-0908.htm

http://www.hnsa.org/doc/ecat/cat-0912.htm



----- Original Message ----- 
From: "Kenneth G. Gordon" <kgordon2006 at frontier.com>
To: "Geoff" <geoffrey at jeremy.mv.com>
Cc: <Arc5 at mailman.qth.net>; "Alan Morriss" <mohawk at clara.co.uk>
Sent: Friday, July 06, 2012 3:33 PM
Subject: Re: [ARC5] TRF - RAK "Q-5er"


> On 6 Jul 2012 at 14:39, Geoff wrote:
>
>> While a TRF may require 3 RF amps a TRF-regen does not unless there is a 
>> lot
>> of circuit loss. The added front end selectivty of either 1930's design 
>> is
>> minimal.
>
> RAK has enough selectivity at RF to exhibit single-signal (one side of 
> zero-beat) throughout
> its tuning range. RAL, of course, isn't as good as that, but it is 
> completely adquate.
>
>> The RAK/RAL use tubes designed in 1933 which are actually 6,3V versions 
>> of
>> the ones designed in 1931.
>
> And which were followed by octal versions: i.e.,the characteristics of the 
> 6SK7 (or 6K7) is
> almost identical to the 6D6. National used the 6SK7 in their RBL which is 
> a close copy of the
> RAK.
>
>> Even so the CW sensivity of the RAL is easily .5uV thru 14MHz for a 10dB 
>> SNR
>> (NOT MDS) when the input is well matched to the signal generator.
>
> Thank you for that info. I never did measure mine, and always wished I 
> had. I wonder what
> MDS would be?
>
>> With an adaptor and a 6SG7 in place of the first 6D6 it would likely do 
>> well
>> on 15M or even go with a 7 pin miniature such as the 6BZ6 or 6GM6,
>
> Very interesting! I had not thought of that.
>
>> The RAL covers up to 23MHz.
>
> Well, the reason I originally traded my BC-348 for an RAL-7 was so that I 
> could work 15
> meters...which I did with it regularly.
>
>> The RAK/RAL also have an excellent audio limiter which works excellent 
>> for
>> storm static as well as a sort of audio AVC. The selectable audio filters
>> also do a good job on CW QRM.
>
> Yes.
>
>> OTOH the tuning and lack of calibration is far from user friendly so its 
>> not
>> a band scanner.
>
> As far as I was concerned, that was the only place the RAL could have been 
> improved. I
> even bought an Eddystone 898 once to correct that, but could never figure 
> out how to mount
> it, so I didn't. I really didn't spend very much time on it though.
>
>> Both are around 70# plus
>
> Closer to 80#; 79 lbs in the case of the RAL, 81 lbs for the RAK.
>
>> another 40# for the remote PS
>
> Closer to 65#, I think.
>
>> but a HB one is very
>> simple as long as its well filtered. I use an original on the RAK and a 
>> SS
>> all regulated DC version on the RAL where it is usually used on 30M.
>
> I use a much smaller SS supply with my TRFs too. Takes up less room and 
> gives off less
> heat.
>
> I had thought, once, of using an RAK as a "Q-5er" for any of my 
> single-conversion receivers,
> but thought better of it later. Having a second-IF twice as big and 5 
> times as heavy as the
> main receiver seemed kinda weird...even for me. ;-)
>
> Besides, the BC-453 was quite adequate in that service.
>
> Ken W7EKB
>
>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1424 / Virus Database: 2437/5112 - Release Date: 07/05/12
>