[Boatanchors] Hammarlund Pro 310 Rcvr on eBay

[David Knepper]

I own a PRO-310 with original speaker.  To those who have never owned this 
receiver, your comments are banal,

If you did own one, you would know that the greatest shortcoming of this 
receiver is the type of drive belt that is used on the bandspread - its 
composition is like leather - it may be in fact!  This belt with age slips 
making the receiver almost worthless from that standpoint.

Yes, I would agree that it is just a nice receiver to put on the shelf and 
admire not use.


David Knepper, W3CRA/W3ST
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----- Original Message ----- 
From: "Robert Nickels" <ranickel at comcast.net>
To: <boatanchors at mailman.qth.net>
Sent: Thursday, December 29, 2011 7:57 PM
Subject: Re: [Boatanchors] Hammarlund Pro 310 Rcvr on eBay


> On 12/29/2011 4:53 PM, Richard Knoppow wrote:
>> I am under the
>> impression that the Pro-310 is single conversion on the two
>> lowest bands using a 50khz IF. If so it would have pretty
>> bad image response in this range despite the -50db spec.
>> Does anyone know if this is indeed the case.
>
> You are correct Richard.  The PRO-310 is double conversion above 2.2 mc,
> single conversion below that.  A separate 1.75 mc oscillator is enabled
> for the lower two bands to convert directly to the 52 kc IF.
>
> Like the SX-88, the PRO-310 was obviously designed with a certain set of
> customers in mind (I doubt even back then the bean counters allowed
> phrases like "cost is not a factor" to be used!)     I don't know how
> disappointed the companies were with sales figures, as they knew the
> market well and perhaps saw these receivers more as a "statement" about
> the level of design and performance they were capable of, similar to
> some high-end automobiles.      In 1955, single sideband was still just
> a novelty so there's no surprise it did not play a greater role in
> defining the feature set, but clearly things like mechanical stability
> and bandspread repeatability were considered important.    Having
> completely rebuilt the double gearbox of the SX-88, I can say that the
> mechanical complexity of the PRO-310 is vastly greater, and also the
> weakest point in the design.    I know the drive cord system in mine
> needs attention, fortunately there is a very detailed Electric Radio
> article that shows how it's done.   You can get some idea of the
> mechanical construction at W8ZRs website:
> http://www.w8zr.net/vintage/receivers/pro310.htm
>
> Back in the day, the performance differences would have been more
> apparent, perhaps.  I can't imagine Hammarlund ever made any money on
> them,  so maybe low sales were a blessing in disguise.  Maybe there were
> PR benefits from using the PRO-310 as a showcase for their
> capabilities.   But today it's just another interesting boatanchor radio
> with a combination of good and bad points,  although it certainly is 
> unique.
>
> I have a little 12 page booklet that was published by Hammarlund called
> "The PRO-310 Story".   It's advertizing fluff, but also provides insight
> into what the company was thinking:  "The PRO 310 the the culmination of
> a carefully planned intensive engineering development program of more
> than two years duration, based upon studies and investigations prompted
> by our customers".
>
> "This superb receiver is by no means an accident - it is certainly not
> the result of a pressured effort to get a piece of merchandise out onto
> the market by a specified date with the usual number of compromises
> which must result from "Engineering by Crisis".
>
> Signed by Lloyd A.Hammarlund, President
>
> 73, Bob W9RAN
>
>
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