[ARC5] ARC-2 on Ebay

[Doran Platt]

If this is a repeat post, my apology...
A communications receiver, loose coupled via an insulated loop to the ARC-2 IF amp tube area, and then tuned from 1000 to 1500 kHz, will give any ARC-2 a second chance.  Mine sits on 3885 so not much tracking tuning to do. 
I quote from my article:
Reading the manual AN 16-30ARC2-126, one finds the block diagram of the receiver chain as well as a chart showing the mixing frequency bands, Fig. 3.  The tunable IF range of the ARC-2 is 1-1.5 MHz.  The master PTO provides a range of 1-1.5 MHz multiplied in 4 bands to a range of 3-7.541 MHz.  In that the IF frequency varies between 1 and 1.5 MHz, a scale formula is necessary for each band. The resultant frequencies for each band are indicated in Figure 3.  The band scale divide factors are Band A=2, Band B=3, Band C=4, and Band D=6.  It can be seen that, for example, 80 meters, the scale factor is 3.  Assume an operating frequency on Band B of 3885 kHz. Divide the frequency by 3, the resulting in an IF frequency of 1295 kHz.  By using the old Q-5er technology, one can indirectly or directly couple (2pf) to Pin 4 of V-113, the 4th IF amplifier (see Fig 5) and apply the signal to, as in my case, an ARC-5/R-24 b.c. band receiver, or any decent general coverage receiver capable of tuning 1-1.5 MHz.

Jeep K3HVG

>     On 09/14/2020 7:28 AM Hubert Miller <kargo_cult at msn.com> wrote:
> 
> 
> 
>     Dave, or anyone really, what did you do trying to improve selectivity? I see the ARC-2A has IF coupling caps of 12 pF and i wonder how low u can go on these. For my money the regenerative IF idea is out; i hate the way this performs.
>     I have puzzled over the design, 3 RFs w/ 2 tuned LC and 4 IF  w/ 5 tuned LC. But i see that all 3 RF are AVC'd and no IFs are AVCd. So i'm guessing Collins wanted super AVC control ahead of mixer, like to prevent blocking. I would have used 1 RF and an AVC amp. I note also that the gov't spec cares most about *minimum* -6 dB BW spec and let the -60 dB fall where it may, who cares. Note the -60 spec is for freq off center, not the modern way spec of *bandwidth*, so it's actually worse than it looks. Sorry.
>     I admit i haven't actually looked at mine for some ages now. Is the dial resolution to 1 kHz ? Is there backlash to make this actually less wonderful ?
>     The CW setup is a little bit of hassle, looks like. You and outstation have to be offset. As long as that's understood, okay. I think there was a ham rig that had similar CW way, that was the Dentron Station One, which never actually hit the market.
>     -Hue Miller
> 
> 
>     Sent from my Verizon, Samsung Galaxy smartphone
>     ______________________________________________________________
>     ARC5 mailing list
>     Home: http://mailman.qth.net/mailman/listinfo/arc5
>     Help: http://mailman.qth.net/mmfaq.htm
>     Post: mailto:ARC5 at mailman.qth.net
> 
>     This list hosted by: http://www.qsl.net
>     Please help support this email list: https://www.qsl.net/donate.html
> 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20200914/aaf2211a/attachment.html>