[Heathkit] WTB: Stand alone HF Receiver

Steve Sutfin stephoto at mind.net
Sun Jul 16 20:26:19 EDT 2017 

Yep, those also. My 'Elmer' had an NC-300 which was the biggest radio  
I ever saw (I still have his later Swan 350C). When I looked inside I  
was hooked!
Steve k7dna

On Jul 15, 2017, at 11:42 AM, Ed K. LAST_NAME wrote:

> My .02 FWIW would go with an NC303 or NC300. Got one of each and  
> they're keepers !
>
> Ed K.
>
>> On July 15, 2017 at 12:17 PM Rodger Singley <wq9nsc at live.com> wrote:
>>
>>
>> Steve makes a great point that Hallicrafters has a family of  
>> selectable sideband receivers that do a wonderful job on AM in  
>> addition to CW and SSB. Using selectable sideband on AM allows you  
>> to often enjoy interference free AM when the primary source of QRM  
>> is either only above or below the frequency of operation thus you  
>> choose to demodulate the sideband with the least QRM.
>>
>> The Hallicrafters selectable sideband receivers, starting with the  
>> SX-96, do an excellent job on AM and I prefer the Hallicrafters  
>> method (also used by Heathkit for the RX-1/Mohawk) to the  
>> Hammarlund method of providing selectable sideband. In the setup  
>> used by Hallicrafters upper or lower sideband is chosen by either  
>> high or low side injection in the final mixer so that only the  
>> bandwidth of the 50 Khz. IF section is changed as you use the  
>> various selectivity choices and response on either sideband is  
>> identical. Hammarlund changes both the bandwidth and the frequency  
>> of their 60 Khz. IF as mode and bandwidth are changed which is a  
>> more complex method and it doesn’t produce as clean a result. With  
>> the Hallicrafters setup if you tune an AM signal to zero beat then  
>> you can switch sideband at will without retuning while the  
>> Hammarlund setup generally also requires a tuning touch up.
>>
>> Note that with Hallicrafters (and the Heathkit RX-1) with age  
>> sometimes one or both of the sideband selection conversion  
>> oscillator crystals can drift with age and if they do you need to  
>> account for this in the alignment of the final IF and the BFO in  
>> order to retain the original performance level.
>>
>> People are often confused by the bandwidth of the Halli (and  
>> Heathkit RX-1) selectable sideband receivers when operating AM  
>> because from the marked control it appears too narrow. But these  
>> receivers ALWAYS receive AM as only one sideband so the 5 Khz.  
>> Selectivity choice is equivalent to 10 Khz. selectivity with a  
>> traditional AM receiver. Until you become used to proper tuning of  
>> these receivers it is easy to mistune on AM but the learning curve  
>> is short. To make it easy to ensure proper tuning as you get used  
>> to the receiver characteristics tune in the AM signal in SSB mode  
>> with the pitch control (BFO) set to zero and tune for exact zero  
>> beat. With a properly aligned SX-96 family or RX-1 receiver this  
>> is the exact proper tuning point for correct AM operation and from  
>> here switch to AM mode (BFO off) and select the sideband with the  
>> least interference. Although most SW broadcasting has disappeared  
>> the selectable sideband receiver is more robust against selective  
>> fading than a traditional AM receiver and using it in exalted  
>> carrier mode (tuned to zero beat and run in SSB mode) it does an  
>> excellent job when selective fading becomes an issue. Most of  
>> these receivers have a t notch filter and this can be used when in  
>> exalted carrier mode to notch out the station AM carrier reducing  
>> any heterodyne beat that may occur from slight mistuning/BFO offset.
>>
>> For ham band only coverage I prefer the SX-115 or SX-101 series to  
>> the other Halli selectable sideband units and I wish my SX-88 had  
>> the same electronic sideband selection as the later family members  
>> but it requires a slight tuning adjustment to select the desired  
>> AM sideband in its narrower bandwidth settings. The special very  
>> high Q IF transformers in the SX-88 provide a better bandpass  
>> characteristic than the later family members but I do miss being  
>> able to just flip a switch on AM to remove interference from one  
>> side or the other.
>>
>> The HQ-180 and HQ-170 are also excellent receivers and some prefer  
>> them over the competing Hallicrafters so there is definitely  
>> personal choice involved. The Hammarlund selectivity system does  
>> work quite well and although I am now using the proper matching  
>> GSB-1 sideband adapter with my TMC GPR-90 receiver the Hammarlund  
>> HC-10 I used previously is far more versatile and I prefer its  
>> audio characteristics. The HC-10 is basically the final mixer, 60  
>> Khz. IF, detector, and audio system from a HQ-170/HQ-180 and will  
>> greatly improve the performance on ALL modes for many midrange  
>> vintage receivers with a 455 khz. IF. One of my favorite  
>> Hammarlund setups is a HQ-160 with an external HC-10 because this  
>> provides very nice wide AM audio when conditions permit while the  
>> HC-10 can be brought into play when needed.
>>
>> Rodger WQ9E
>>
>> Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for  
>> Windows 10
>>
>> From: Steve Sutfin<mailto:stephoto at mind.net>
>> Sent: Saturday, July 15, 2017 10:31 AM
>> To: Howie WA3MCK<mailto:wa3mck at gmail.com>
>> Cc: Boatanchor group<mailto:boatanchors at mailman.qth.net>; QRP-L  
>> Mailing List<mailto:qrp-l at mailman.qth.net>; Glowbug  
>> Tetrode<mailto:tetrode at googlegroups.com>;  
>> Heathkit<mailto:heathkit at mailman.qth.net>
>> Subject: Re: [Heathkit] WTB: Stand alone HF Receiver
>>
>> The Hallicrafters SX-115 has always been popular or even the smaller
>> SX-117.
>> 72/73,
>> Steve k7dna
>>
>> On Jul 14, 2017, at 2:49 PM, Howie WA3MCK wrote:
>>
>>
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