[Milsurplus] Milsurplus Digest, Vol 223, Issue 25
Mack McCormick
w4ax.mack at gmail.com
Wed Nov 9 05:58:12 EST 2022
Thank you to everyone for your kind suggestions. After doing some extensive
testing with my spectrum analyzer and o'scope I've determined the T-21
transmitter is stable. The issue is the tuned circuit I'm transmitting into
is changing impedance and pulling the oscillator off frequency. I have a
design change to make today and will report the results here after further
testing.
Thank you again to everyone!
73,
Mack
W4AX
https://www.qrz.com/db/w4ax
On Tue, Nov 8, 2022 at 12:16 PM <milsurplus-request at mailman.qth.net> wrote:
> Send Milsurplus mailing list submissions to
> milsurplus at mailman.qth.net
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://mailman.qth.net/mailman/listinfo/milsurplus
> or, via email, send a message with subject or body 'help' to
> milsurplus-request at mailman.qth.net
>
> You can reach the person managing the list at
> milsurplus-owner at mailman.qth.net
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Milsurplus digest..."
> Today's Topics:
>
> 1. Advice Please: Frequency stabilizing a 80M ARC-5 transmitter
> (Mack McCormick)
> 2. Re: Lawrenceville GA hamfest photos (Joe Connor)
> 3. Re: Advice Please: Frequency stabilizing a 80M ARC-5
> transmitter (Mark Foltarz)
>
>
>
> ---------- Forwarded message ----------
> From: Mack McCormick <w4ax.mack at gmail.com>
> To: milsurplus at mailman.qth.net
> Cc:
> Bcc:
> Date: Tue, 8 Nov 2022 10:41:25 -0500
> Subject: [Milsurplus] Advice Please: Frequency stabilizing a 80M ARC-5
> transmitter
> I have an ARC-5 transmitter that I am using as a VFO for the BC-375 to
> prevent FMing from the BC-375 MOPA oscillator/PA.
>
> The ARC-5 exciter is working great except for frequency stability. The
> peak carrier frequency starts about 1 kc low and after about 1 minute is
> about 1 kc high. Not really a big deal except it drives the SDR folks crazy
> when I'm on an AM net.
>
> The 1626 oscillator is exceptionally well regulated using a FET in the
> external power supply. It is rock solid.
>
> *Do you have other ideas on how I might further improve frequency
> stability? *I built a crystal oscillator but it does not have enough
> drive using a 12A6 vacuum tube to drive the 1625's above about 5 watts. I'm
> still troubleshooting this circuit.
>
> I need about 20 watts out of the 1625s.
>
> 73,
>
> Mack
> W4AX
> https://www.qrz.com/db/w4ax
>
>
>
> ---------- Forwarded message ----------
> From: Joe Connor <joeconnor53 at yahoo.com>
> To: "milsurplus at mailman.qth.net" <milsurplus at mailman.qth.net>, Hubert
> Miller <kargo_cult at msn.com>
> Cc:
> Bcc:
> Date: Tue, 8 Nov 2022 16:50:49 +0000 (UTC)
> Subject: Re: [Milsurplus] Lawrenceville GA hamfest photos
> A belated thank you for the hamfest photos, Nick. As always, they're a
> blast to scroll through. I say this as I continue cleaning the drool off my
> keyboard!
>
> Joe Connor
>
> On Sunday, November 6, 2022 at 01:58:40 PM EST, Hubert Miller <
> kargo_cult at msn.com> wrote:
>
>
> Yes, really great photos, it's the real thing, a fully qualified hamfair.
> I see plenty of items that at one time, would have really tempted me. A
> Drake TR-7, R-392, BC-683, even a GE table radio X-371, 2 photos. I saw one
> recently on Ebay sold for
> around $500. I had for years wanted one but...i looked at Ebay closeups of
> the semicircular tuning scale and realized that the bands toward the center
> of the scale, closer to the axis, have sparer room for markings. Hence the
> low band on the X-371, the MW broadcast band, has really miserable
> frequency markings. Oh, good, i wised up and can delete that thing from my
> "list". Sliderule dials rule!
> Hue Miller
>
>
> Sent from my Verizon, Samsung Galaxy smartphone
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
>
> ---------- Forwarded message ----------
> From: Mark Foltarz <Foltarz at rocketmail.com>
> To: "milsurplus at mailman.qth.net" <milsurplus at mailman.qth.net>, Mack
> McCormick <w4ax.mack at gmail.com>
> Cc:
> Bcc:
> Date: Tue, 8 Nov 2022 17:15:52 +0000 (UTC)
> Subject: Re: [Milsurplus] Advice Please: Frequency stabilizing a 80M
> ARC-5 transmitter
> Tell the SDR folks where they can go.
> Of course having a freq counter to show you where you're at is probably
> the cheapest and easiest.
> Otherwise, you may try something like the following :
> http://www.hanssummers.com/images/stories/library/afc.pdf
>
> 73
> de WA4AM
> Mark
>
> On Tuesday, November 8, 2022 at 10:41:48 AM EST, Mack McCormick <
> w4ax.mack at gmail.com> wrote:
>
>
> I have an ARC-5 transmitter that I am using as a VFO for the BC-375 to
> prevent FMing from the BC-375 MOPA oscillator/PA.
>
> The ARC-5 exciter is working great except for frequency stability. The
> peak carrier frequency starts about 1 kc low and after about 1 minute is
> about 1 kc high. Not really a big deal except it drives the SDR folks crazy
> when I'm on an AM net.
>
> The 1626 oscillator is exceptionally well regulated using a FET in the
> external power supply. It is rock solid.
>
> *Do you have other ideas on how I might further improve frequency
> stability? *I built a crystal oscillator but it does not have enough
> drive using a 12A6 vacuum tube to drive the 1625's above about 5 watts. I'm
> still troubleshooting this circuit.
>
> I need about 20 watts out of the 1625s.
>
> 73,
>
> Mack
> W4AX
> https://www.qrz.com/db/w4ax
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/milsurplus/attachments/20221109/f430f46d/attachment.html>
More information about the Milsurplus
mailing list