[CW] CW headphones

[1oldlens1]

I am a small collector of headphones and something of a historian.  This is the first I've heard that National made them. I wander I'd you (or anyone else) has pix.  A number of companies, radiomarine and Mackay for example, had custom phones made by Trimm. There were other custom makers like William Murdoch.  Trimm made very light weight phones which were very popular. Sent from my GalaxyRichard Knoppow Los AngelesWB6KBL
-------- Original message --------From: DAVID EISENBERGER via CW <cw at mailman.qth.net> Date: 2/12/26  9:49 AM  (GMT-08:00) To: Reflector CW <cw at mailman.qth.net> Subject: Re: [CW] CW headphones I am also a former Coastie Radio op!  Sailed in 1954-1956 on USCGC Humboldt/NEJL and USCGC CastleRock/NBZF 1956-1958. The “Cans” we used were from National Radio in Mass, I know because I had several that the Chief asked me to drive up to Melrose, Mass to have them repaired.  I enjoyed your story very much and found it to be quite interesting! It surely would have helped on 500 KHz!!  73 de K8KEM **** check me out on QRZ Page***David F Eisenberger On Feb 11, 2026, at 16:00, Chris R. NW6V <chrisrut7 at gmail.com> wrote:Hi Jeff.Mechanical acoustic filters work great. Modern radios often contain the electronic equivalent - my K3, for example, has brilliant AF filtering—no way I could have made 80 M DXCC from this noisy city QTH without it. But I LOVE the idea of resonating to a harmonic reed... just LOVE it :-)73 Chris NW6VOn Wed, Feb 11, 2026 at 10:00 AM Radio KH6O <radio.kh6o at gmail.com> wrote:I'm enjoying the CW acoustic speaker discussion on the Topband list but here's an entirely different idea: I was a US Coast Guard radioman back in the 70s when almost all maritime traffic was conducted in Morse. We were issued government headphones that had a metal diaphragm held in place with a magnet. A colleague used a pair of metal cutters to cut out a small rectangular area from the diaphragm and riveted a reed from a harmonica in its place, then reassembled everything. Adjusting the receiver BFO to match the reed's frequency resulted in that reed acting as an incredibly sharp and narrow bandwidth filter. Pretty soon we were all bringing harmonicas to the station and removing our favorite musical frequency reed to do the modification! This really helped clear the pile ups on the HF maritime frequencies during the every-six-hour weather OBS from the ships. (Ham pile ups are nothing compared to what we encountered!)Today's headphones no longer have metal discs so some other method would have to be employed to implement this idea.Station name: US Coast Guard Communication Station Honolulu, callsign NMO.-- 72 / 73 / 3579, Jeff KH6O 
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