[Heath] Question

Sun Apr 24 23:20:48 EDT 2011

Hello all,

I have to say that I have never had any problems with my SB-650 being connected to (or removed from) my SB-401/SB-303 combo after proper alignment of the all the Tx/Rx circuitry on the 401/303 pair.  The SB-650 does not go flaky on 10 or 15 meters nor does it cause the 401/303 to go wacky.

Bear in mind that when using a properly connected SB-650, if you don’t read that right frequencies on the 10 and 15 meter bands (when connected to a SB-401/SB-303 pair, for example) it is quite probable that the SB-303 oscillators (especially the problematic HFO on the SB-303, as Glen mentioned) have to be tweaked/aligned.  The SB-650 may be “correctly” seeing the situation; i.e. that there is a problem – the HFO dropping out periodically -- which manifests itself as an improper count/display.  But that ‘problem’ is not necessarily being caused because an SB-650 is being used with an SB-303.

And remember, there should be an isolating resistor branching off from each oscillator’s (HFO, LMO and BFO’s) main output connector on the back of the SB-303 to three spare SB-303 outputs; and from those ports you connect the other cables that go to the SB-650.  Maybe some people are using a “T” directly from the SB-303 to the transmitter and the SB-650 – that won’t work.  [The manual indicates you must use spare connectors on the SB-303 isolated (to some extent) by resistors.]

Having said that, it is true that the SB-303 has a ‘problem’ with the HFO output.  The SB-303 should have had an emitter follower (or source follower) added to drive the cable after terminating the internal oscillator correctly.  But if the SB-650 is showing a haywire reading, that is likely that it is a problem that will remain with the SB-401/SB-303 pair even when the SB-650 is removed.  When aligning the SB-401/303 pair together (to operated as a pair)-- but without connecting the SB-650 -- I have found that the SB-303’s HFO always takes a lot of work on the higher bands (to get it stable).  Adding or removing the SB-650 doesn’t seem to be the problem, or add to it.

Now forgetting about the transmitter for a moment, the other thing is this:  If you are using an SB-303 as just a standalone receiver, it makes no sense to connect the HFO, LMO and BFO directly to the SB-650 either (as you might be tempted to do) because the SB-303 must have a 50 ohm dummy load plugged in to the LMO port to operate as a receiver only in the absence of a transmitter to load that output.   You need to plug in the dummy load to the LMO port, and branch off prior to that (through resistors) to pare ports, and then to the SB-650.

Any way you slice it, you can’t connect an SB-650 to an SB-303 without going through those isolating resistors. But when the 401/303 are aligned and peaked properly, adding an SB-650 properly doesn’t seem to affect anything negatively.

Anyway – that’s what I have found.

--- Rob VE3JQL.

From: heath-bounces at puck.nether.net [mailto:heath-bounces at puck.nether.net] On Behalf Of Dave Edwards
Sent: April-24-11 12:15 PM
To: Glen Zook
Cc: heath at puck.nether.net; w9bzn1 at gmail.com
Subject: Re: [Heath] Question

Thanks Glen!  I have a few of each of those model numbers, but never used the 650 with the 303 on transceive.

...Dave

Sent from my iPad

On Apr 24, 2011, at 11:52 AM, Glen Zook <gzook at yahoo.com> wrote:

The tube-type equipment seems to have more output from, especially, the heterodyne oscillator.  I have an SB-650, along with an SB-303 and SB-401 in right now for a client.  When the SB-303 is hooked to the SB-401 the SB-650 does not read correctly on the 10-meter band and is flaky on 15-meters.  However, when hooked to an SB-301 along with the SB-401 it reads fine on all bands.

Now when used with one of the transceivers, since there is not an additional load on the heterodyne oscillator from the transmitter, it works fine.

Glen, K9STH

Website: http://k9sth.com

--- On Sat, 4/23/11, Dave Edwards <kd2e at comcast.net> wrote:

From: Dave Edwards <kd2e at comcast.net>
Subject: Re: [Heath] Question
To: "Glen Zook" <gzook at yahoo.com>, heath at puck.nether.net, w9bzn1 at gmail.com
Date: Saturday, April 23, 2011, 9:22 PM

Just curious....Why does the SB-650 work better with ...for example, an SB301 than the solid state SB-303?

Does it have to do with tapping in to the oscillators without pulling them off?

....Dave

----- Original Message ----- 

From: Glen Zook 

To: heath at puck.nether.net ; w9bzn1 at gmail.com 

Sent: Saturday, April 23, 2011 12:07 PM

Subject: Re: [Heath] Question

Try AADE for a readout.

The SB-650 actually works better with the tube-type equipment than the SB-303.

Glen, K9STH

Website: http://k9sth.com

--- On Thu, 4/21/11, william moody <w9bzn1 at gmail.com> wrote:

From: william moody <w9bzn1 at gmail.com>
Subject: [Heath] Question
To: heath at puck.nether.net
Date: Thursday, April 21, 2011, 9:24 PM

I have a question for you gentlemen, I have purchased a hr1680 and hx1681 and would like to have a digital readout. Is there a such an device available for this setup made by heath or someone other than heath that I might turn to.....
 I am aware of the sb 650 but I thought it was just for the 303...
 Thanks Guys
     Bill

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