[R-390] test equipment question

Sun Feb 15 17:54:03 EST 2009

Yup..I used the URM25 and it did do the job.  But is wasn't real easy 
because of it's accuracy.  Had to use a frequency counter to make sure it 
was on frequency and wasn't drifting.

I currently use the HP-410c....love it....and the 505 is a great analog 
meter.

My biggest gripe was the signal generator.  I moved up to the 8640B because 
it had digital display but don't let that fool you.  It's a boatanchor too. 
Probably was current issue in the early 70s if I had to guess so it's nearly 
30 years old..  It's not a synthesized modern marvel.

I set the range switch....dial up the needed frequency on the display and 
push the lock button which does a PLL type function to hold it exactly on 
the frequency desired...if it drifts out of lock range the display flashes. 
Release the lock, reset the frequency and relock.  Works much easier and 
presents a 50 ohm load.  I work on modern gear as well so it was needed for 
that too.

What you have is all one really needs to do the work on the R-390 series and 
I don't think anybody is trying to sell you on something else.  But if you 
ever decide to upgrade you know what's out there to go to...

I also have an HP 606A which I like using as well...  It's a necessity on 
the 50KC IF's....

Cecil
----- Original Message ----- 
From: "rbethman" <rbethman at comcast.net>
To: <r-390 at mailman.qth.net>
Cc: "Patrick" <brookbank at triad.rr.com>; "Cecil Acuff" 
<chacuff at cableone.net>; "Tisha Hayes" <tisha.hayes at gmail.com>
Sent: Sunday, February 15, 2009 2:00 PM
Subject: Re: [R-390] test equipment question

>I guess I'm STILL in the dark ages!  from 2 to 34 Mc doesn't cover the IF.
>
> I do NOT require an HP-8640B just to replace either the URM-25 NOR the 
> GR-1001A.
>
> The B&K Frequency counter does fin, have an HP-410B (or C - don't remember 
> at THIS moment), ant a TS-505D/U.
>
> Old Tek scope that I can use to ensure the 455Kc IF isn't over done and 
> distorted.
>
> I have difficulties understanding the NECESSITY for all this NEW test 
> equipment for this OLD '50s radio.
>
> Cecil, tell me you NEVER used this old gear to setup an R-390 or R-390A!
>
> Just another opinion of an old goat!
>
> Bob - N0DGN
>
> Patrick wrote:
>> To me, the best Frequency Generator that I have is a 0-464/SRC 
>> Synthesizer Electrical Frequency. works from 2 to 34 MCS, is solid a a 
>> rock and plenty of adjustable power to use with a small antenna. A little 
>> big a heavy (rack mountable) but very reliable. The other one is an old 
>> tube one, a Hampden HBT 477 that has a Xtal socket, perfet for testing 
>> crystals. Anyhow, only the opinion of and old FA%&.
>>
>>     ----- Original Message -----
>>     *From:* Cecil Acuff <mailto:chacuff at cableone.net>
>>     *To:* Tisha Hayes <mailto:tisha.hayes at gmail.com> ;
>>     r-390 at mailman.qth.net <mailto:r-390 at mailman.qth.net>
>>     *Sent:* Friday, February 13, 2009 1:22 PM
>>     *Subject:* Re: [R-390] test equipment question
>>
>>     Actually a good HP-8640B can be had on ebay for fairly
>>     cheap....don't go to Fair Radio though...not the place to buy test
>>     gear....except maybe scopes. The 8640B is an analog sig gen but has a 
>> lock feature that will
>>     lock it down to the dialed up freq so no problems with drift.  I
>>     would imagine a working example could be had for less than $400.
>>      I didn't like the URM-25 either and got rid of it quickly....  The
>>     HP-606A and a freq counter was a better solution and then I added
>>     the 8640...
>>      Cecil...
>>
>>         ----- Original Message -----
>>         *From:* Tisha Hayes <mailto:tisha.hayes at gmail.com>
>>         *To:* r-390 at mailman.qth.net <mailto:r-390 at mailman.qth.net>
>>         *Sent:* Friday, February 13, 2009 11:55 AM
>>         *Subject:* Re: [R-390] test equipment question
>>
>>         I know that this is broaching on heresy to mention this;
>>
>>         I found the URM-25D to be less than helpful when compared to a
>>         good signal generator. It is drifty, the impedance matching
>>         module is a joke and it is hard to get repeatable results when
>>         trying to chase the performance dragon.
>>
>>         But; if you use a good frequency reference (like the 100 KHz
>>         calibrator and that is not waay off and WWV) you can get
>>         darned close to being on frequency.
>>
>>         If you dare to dabble with the compensation screws on the PTO
>>         to correct linearity you need a much better frequency counter
>>         and signal generator. Of course, gettting used HP/Agilent
>>         equipment will cost you more than any one radio would ever
>>         sell for. You can find a really decent HP 400 series VTVM or a
>>         Boonton that would do an excellent job on measuring RF levels
>>         for a song-and-a-dance.
>>
>>         The original maintenance manuals were written around the
>>         inherent limitations of the test equipment available at the
>>         time (URM-25's). While I try to keep the filaments glowing and
>>         avoid transistor/IC based radios in my setup I do use more
>>         modern test equipment.
>>
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>
> -- 
> Bob - NØDGN
>
> 