[ARC5] First Post and Questions

Mon Jul 3 17:55:37 EDT 2017

Thanks for the feedback, Neil.

I noticed that there are two relays, one up near the antenna output
connection that moves a contact from the rotary inductor to the antenna
output when the relay is energized.  The second relay I saw is located at
the bottom of the transmitter and looks like it switches plate supply
voltage to the oscillators (VFO/1626 and the magic eye tube tuning
indicator tube) and the cathodes of the 1625s to DC plate voltage supply
negative. (I need to get out a schematic and follow those)

I was under the assumption that the rig could be keyed by connecting the DC
negative side/connection of the relays to the negative supply of the 24
volts DC via a code key.

In your opinion, Neil, what is the best way (within reason) to key the
transmitter (already altered as mine is) for best keying characteristics
and minimal/zero key clicks?

I am open to ideas.

73 de AK4JA

On Mon, Jul 3, 2017 at 5:31 PM, AKLDGUY . <neilb0627 at gmail.com> wrote:

> Hi Bobby
>
> Congratulations and welcome on joining the list. You stated that you "plan
> on using conventional keying (keying relay built in the BC-457 A)".
>
> There is NO keying relay in the BC-457 A or in any of the ARC-5
> transmitters. The relay connected to the antenna post (if still fitted) and
> the relay mounted on the sidewall next to one of the 1625 sockets are
> SELECTOR relays. They become operated when the pilot selects that
> transmitter. They stay permanently operated even while receiving. The
> bottom relay prepares a path for the VFO B+ and the cathodes of the 1625's.
> The keying and Push To Talk is performed by a relay in the modulator which
> switches the +550 volts from the dynamotor to ALL transmitters in the rack.
> Only the one with the selector relays operated will function.
>
> This is a very common misunderstanding. The bottom selector relay is
> actually fast enough to follow keying and many hams have successfully keyed
> the transmitters by using it, but the RC constants in the 1625 screens and
> VFO B+ do not then come into play and the result lacks proper shaping of
> the keyed waveform.
>
> 73 de Neil ZL1ANM
>
>
> On Tue, Jul 4, 2017 at 6:58 AM, Bobby Drummond <alphak4ja at gmail.com>
> wrote:
>
>> Hello to all.  Name here is Bobby Drummond and the call is AK4JA.  I've
>> been licensed as a Amateur Radio operator for 35 years and just heard about
>> and signed up for this list.
>>
>> My passion is homebrewing (radios that is) and CW.  I'm not averse to
>> restoring old gear as well and hence we arrive at the real reason I am now
>> a member of this mailing list:  I bought a BC-457 A transmitter at the
>> Dayton Hamvention this year.
>>
>> Have you seen the recent commercial where two women are talking about a
>> sofa just acquired and the owner says, "I had to have it!"  (then two
>> burglars are looking at the same sofa later while burglarizing the same
>> house and one of the two says the same thing:  "I had to have it."  Guess
>> what I thought when I saw the BC-457 A on a table in the Hamvention Flea
>> Market area in Xenia?   Yep, the exact same thing.
>>
>> The plan:   restore the BC-457 A using every trick in the book to make it
>> work reliably and be as stable as possible.  The reason being that I want
>> to put it on 60 meters (CW, of course - see first sentence in second
>> paragraph above)   The BC-457 A "tops out" from the factory at 5.3 MHz
>> according to what I have read and I want to put in on frequencies from
>> 5.332 to 5.405 MHz.  I'm thinking that some minor adjustments to the
>> oscillator tuning should do the trick.  Adjustments that would be easy to
>> "undo" if I want to put the radio back in "just like it left the factory"
>> condition. I would also like to put it on the air regularly in a net if
>> that is possible, too.
>>
>> Any suggestions, hints, caveats, or advice related to doing said tasks
>> would be greatly appreciated.
>>
>> Here are some questions that come to mind:
>>
>>    1) Has anyone on the list already done what I am thinking about? (I'm
>> especially referring to putting a "Command Set" on 60 meters)
>>
>>    2) Is there a net for ARC5 or equivalent radios that I can listen to
>> now?  If so, how can I get details about the net?
>>
>>    3) what is the best cleaner to remove oxidation from the roller
>> inductor?
>>
>>
>> My plans are to power the BC-457 A with a power supply that I will build,
>> using the best voltage regulators available and with a large enough
>> transformer to be rated at least double the power requirements of the
>> BC-457 A. I will power the filaments with a tightly regulated 24 Volt DC
>> supply and plan on using conventional keying (keying relay built in the
>> BC-457 A)
>>
>> So, that's it for my first post.  Any help would be greatly appreciated.
>> With the long and storied history of these rigs, built and operated by our
>> Greatest Generation, I think it would be an honor and privilege  to restore
>> one and put it to good use on the 60 meter ham band, a band that I really
>> like a lot.
>>
>>
>> 73 de AK4JA
>>
>>
>>
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