[ARC5] Zero Beat Question

Tue Jul 12 12:49:43 EDT 2016

Your old Hammarlund had an I.F. Bandwidth of probably 15 kHz or more. You can't expect the same tonal quality out of your new rig except MAYBE one of the full DSP rigs with variable  bandwidth AND a Hammarlund S-200 or equivalent speaker!

73 - Mac, K2GKK/5 in OKC
HQ-145, IC--7410 

Sent from my iPad

> On Jul 11, 2016, at 22:31, Jim Falls <radio-tuber at att.net> wrote:
> 
> I have a relatively modern Yaecomwood with AM. Weak signal receive stinks without a BFO to assist with exalted detection. 
> 
> Is there a work around? I've heard using a BC-221 or LM close to the same frequency works, but I've never done it. Is this snake-oil?
> 
> Reception improves a bit if I listen in USB/LSB, but not as good as my old Hammarlund. 
> 
> Cheers!
> Jim K6FWT
> 
>> On Jul 11, 2016, at 17:39, Glen Zook via ARC5 <arc5 at mailman.qth.net> wrote:
>> 
>> If you watch the "S" meter, as it gets closer, and closer, to zero beat the needle will start to vibrate and the closer to true zero beat the slower it will vibrate.  When the needle moves, from side to side, taking more than a second, you are within 1 Hz of true zero beat.
>> 
>> 
>>  
>> Glen, K9STH 
>> 
>> Website: http://k9sth.net
>> 
>> 
>> From: D C _Mac_ Macdonald <k2gkk at hotmail.com>
>> To: "WB6KBL Knoppow, Richard" <1oldlens1 at ix.netcom.com>; ARC-5 Mail List <arc5 at mailman.qth.net> 
>> Sent: Monday, July 11, 2016 12:45 PM
>> Subject: Re: [ARC5] Zero Beat Question
>> 
>> Attempting to "true" zero beat with a modern receiver 
>> or transmitter can be frustrating, for sure. 
>>  
>> This new gear has either crystal or digital filtering which 
>> effectively removes low pitched "sounds" below around 200
>> or so Hz.  
>>  
>> However, a receiver/transceiver with passband tuning is 
>> capable of restoring sound down to below 60 Hz.  The audio 
>> circuits in communications gear probably won't go much 
>> below 25 Hz, though. 
>>  
>> As others have noted, as two signals get closer and closer 
>> to equal, you can hear an increasingly slower wah-wah-wah 
>> sound. The slower that sound gets, the closer you are to 
>> true zero beat. 
>>  
>> You can frequently hear this at night on an AM broadcast 
>> radio when two fairly weak distant stations are within just 
>> a very few Hz of each other. 
>>  
>> It's a phenomenon with which we old farts and the primitive 
>> gear which we used "way back then" are more familiar! 
>>  
>> As some others have noted, using skill and stable VFOs, we 
>> could frequently work the SSB folks (using full carrier AM) 
>> and not be discovered until an SSBer tuned off frequency 
>> for some reason or another!  'Twas great fun for sure! 
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