[HBR] (no subject)

n2ey at aol.com n2ey at aol.com
Wed May 31 15:23:13 EDT 2006


Some comments:
 
1) The 3395 Heath filters are pretty good but they require matching (2000 ohms). On 80 meters you will probably have IF feedthrough - 3395 is just too close to 3500.
 
2) Fitting all of that stuff (LMO, dial, filter, matching transformers, preselector, 3 octal tubes, connectors, etc.) onto a 6x8 chassis (including power supply?) with octals is going to be quite a trick. If the idea is simplicity and ease of construction, why not a chassis that's big enough? The AC-1/GB-1 could have been built on a smaller chassis but Ameco had the sense to realize doing so would make it harder to build. 
 
If the goal is a reproducible project, it's better to have a too-big chassis than a too-small one, because of the need to use substitute parts.
 
3) How will the various bands convert to 3395 with a VFO that tunes 5000-5500? The sum is 8395-8895, the difference is 1605-2105. Heath (and the Southgate Type 6) used double conversion with a crystal controlled heterodyne oscillator and 8395-8895 second IF.
 
4) The HW-101 VFO isn't the best, particularly from a junker. The SB LMO is much better. Either way, you have some fussy mechanical work to do, fabricating a dial drive.
 
5) Most junkers won't have the CW filter. I'd rather have an FT-241A CW filter than an SSB filter.
 
6) Cost of project? 
 
7) KJ4KV's idea of reverse-band-imaging (IF in the 5 MHz range, VFO in the BC range) has a lot of merit. But look out for the VFO harmonics! They will take the form of a very loud birdie.
 
73 de Jim, N2EY


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