The AM Forum

I now own an Hammarlund HX 50 xmtr, waiting for it to be shipped. Anyone have experience with this rig? What mods did the HX 50A have compared to the HX 50? Is adding 160 m a huge project?

It is a tube AM CW SSB rig which I believe uses an xtal filter for SSB gen rather than phasing. Is it a decent AM rig?

I bought it mostly just to have a Hammarlund xmtr mate for my HQ 180, but want to make the most of it.

Any tips or info much appreciated.

73,
AF6IM

No experience with the HX-50 in particular, but I've converted a number of slopbucket rigs to hifi AM and it's pretty easy.

You bypass the crystal filter (on BOTH ends!!) with 2 small relays.  Feed audio right to the balanced mudulator, adjust the carrier balance for about 1/4 the rated carrier output, and you're pretty much done.

Many rigs, even if they have an AM mode, still have the crystal filter in circuit which essentially gives you a carrier and 1 crummy sounding sideband.  Bypassing the filter and audio circuits, which are tailored for the 300-3000 hz response necessary to keep artifacts out of the filter, are all necessary for hifi AM.  You gotta be careful though because with no lowpass audio filtering, the rig might pass 100KHz right straight thru, so be sure you have an EQ with good HF cutoff.

The factory issued several service bulletins on this rig. Cleaned the rig up with the HX-50A. Probably not worth the effort for 160 conversion.

Thanks for the info, much appreciated. Any idea where I could get a copy of the HX 50 service bulletins? Looking forward to getting on HF AM.

73,
AF6IM
Mark