[Hammarlund] HQ140X questions

Wed Dec 13 14:45:50 EST 2023

Regarding Hammarlund receiver serial numbers. The only way I am aware of is to see the date code on the Crystal, the filter electrolytic can (if original) or,
a stamp on the inside of the front panel.

I have owned several of the HQ-150 series, the serial numbers on them were: B6035, B6440, B6084, 5096, B6597. One HQ-140-X 3988. I wasn't curious enough back in those days to either check or write down Crystal or Filter Cap dates. I have no clue why some serial numbers were preceded by a letter (B in these examples).

I'm not aware of any internal Hammarlund memos or records showing that serial numbers had a date code in them.

Having said that, many years ago the noted author, collector and antique radio historian and collector Alan S. Douglas (a SK since 2015) collaborated on an informal
survey of The serial numbers of the Hammarlund SP-600 receivers. We came to the conclusion that the suffix ((model) numbers had no bearing on the serial numbers
which were sequential no matter if it was a JX-14 or JX-26 there are instances of the earlier model numbers having a higher serial number than a JX-26 or JX-39. The separate serial numbers stamped on the separate Military tags (usually on the top L.H. upper corner of the front panel) corresponded to how many that particular military contract number were built. Alan and I agreed that contracts were filled simultaneously, so the model designations were hopelessly scrambled. Alan noted
the serial numbers are apparently "real" since they track very well with the date codes on the electrolytic capacitors, and the bathtub capacitors located along the rear panel of SP-600's.

The highest SP-600 serial number recorded ( I once owned it) was a JX-17 serial number 20137. In Hammarlund's later years at the Mars Hill manufacturing plant
The started used metallic foil labels on both the HQ and SP-600 receivers that had an entirely different series of numbers. As an example a HQ-180A serial number
30038202. Is there some sort of code as to build date? I have no idea.

However I do have a great deal of information regarding the build dates and the model (suffix) numbers along with contract numbers and some differences (if any) on the various models.

That information is available here: https://www.hammarlund.info/sp600.html  You will notice that these were extrapolated from ECN (engineering change notes), so dates are only approximate.

----- Original Message -----
From: Dan Martin <pitfit at comcast.net>
To: <ray2.s at btinternet.com>
Cc: <hammarlund at mailman.qth.net>
Sent: 12/13/2023 12:39:21 PM
Subject: Re: [Hammarlund] HQ140X questions
________________________________________________________________________________

> Yep, this is a mod. A means to enter the path between the output of the mixer, 
> pin 5, and the first IF can, Z1, which has as an internal component, T1. Pin 5 
> has 200-plus VDC on it, by the way.
> 
> Hammarlund serial numbers are a mystery, at least to me. I have both an HQ-140 
> and HQ-150, both identical but for the Q-multiplier in the 150. My 140 has a X-
> XXXX stamped on the back where all characters are numbers. The 150 also has X-
> XXXX stamped on the back but the first character is a letter. Go figure! Both 
> were made in the same mid-late 50’s era and may have even been made 
> concurrently for a short time, at least.
> 
> Both are fine single conversion receivers and among my favorites.
> 
> Dan
> WB4GRA
> 
> Sent from my iPhone
> 
>> On Dec 13, 2023, at 12:45 PM, Ray G3XLG via Hammarlund 
>> <hammarlund at mailman.qth.net> wrote:
>> 
>> ?Just had a look Richard, the centre pin of the strange chassis connector
>> goes via a 56K resistor to pin 5 the anode of V3 the mixer.
>> 
>> A blue wire also on pin 5 goes up through the chassis to T1 between the
>> mixer and the first 1st IF.
>> 
>> I think you are right it's a Ham mod, perhaps to feed a signal generator?
>> 
>> 73
>> 
>> Ray G3XLG
>> 
>> ______________________________________________________________
>> Hammarlund mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/hammarlund
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Hammarlund at mailman.qth.net
>> 
>> List Administrator: Gary Harmon, K5JWK
>> ** For Assistance: gharmon at idworld.net **
>> 
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
> 
> ______________________________________________________________
> Hammarlund mailing list
> Home: http://mailman.qth.net/mailman/listinfo/hammarlund
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Hammarlund at mailman.qth.net
> 
> List Administrator: Gary Harmon, K5JWK
> ** For Assistance: gharmon at idworld.net **
> 
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html