Thanks Patrick, Robert, and John
Patrick, the former is pretty much what I've been doing at demos. A fairly large unpowered Radio Shack speaker with a long cord, plugged directly into the D72's output jack. I then point the speaker away from me and stand several feet away and use the D72's internal mike, full duplex
.This has worked well for the audience being able to hear. No feedback problems reported yet. I would like to be able to hear better though, hence the point of my post. ;-) I think I've only made a couple of Q's for this reason.
I'll check out the Amazon link. I think Fry's Electronics may have something similar. (I need a good reason to go to Atlanta anyway <grin>; Ham Radio Outlet is only about 5 miles away from Fry's). I'll look for a Bluetooth speaker like you described too.
John, come to think of it, you did tell me - and sent pics - of the adapter you made using the resistors . (The plug was from a TI calculator, I think.). I'll have to look for that email
Robert, the clip on speaker idea sounds great. Did you use it at the AMSAT Academy demos?
Philip N4HF
On Thu, Jun 20, 2019 at 7:07 PM Patrick STODDARD (WD9EWK/VA7EWK) < amsat-bb@wd9ewk.net> wrote:
Philip,
I often use my TH-D72 for demonstrations, and have gone with a simpler setup than in the past. I use an unpowered external speaker with a long patch cable, and put it a few feet away from me. I also make sure the speaker isn't firing back at me, to avoid audio feedback when I am transmitting. I use this short cable with right-angle plug to go into the TH-D72's 2.5mm speaker jack:
https://www.amazon.com/gp/product/B01KOJAJKW/
I find the TH-D72 has enough audio output to drive an unpowered external speaker to a reasonable audio level. I sometimes plug a splitter into this short cable with adapter plug, if I want to directly record the downlink audio, but usually skip the splitter and put an audio recorder in my pocket - or hold it in the same hand as the TH-D72. Then I make sure to say the call sign of each station I work, so the recorder at least picks that up.
I also have a no-name Bluetooth speaker, which also has a jack for a patch cable on the back side. This is an amplified speaker with a built-in battery (which can also be used to power or charge devices through a USB connection), so there are no extra cables needed when I use this speaker instead of the unpowered speaker I normally use.
If you would like to see pictures of my setup, please let me know. I will e-mail you some pictures directly.
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ Twitter: @WD9EWK or http://twitter.com/WD9EWK
For those of you who have attempted to use just a D72 for a demo - with an
external speaker as well as the headset/mic - this results in a rat's nest of adapters/connectors/wires. I have the adapter sold on eBay, but unfortunately it attenuates the audio signal (for digital voice recorders), instead of amplifying it for an external speaker , which is what I need. (I guess I could use a powered speaker on that output, but that's one more thing to carry - and power-up! :-) )
So I think *two* radios might work better - wiring wise - for demos. If I buy a Baofeng (or similar), I won't use it for the receive part due to the desense problems on some models (looking at the section in 2019's "Getting Started with Amateur Satellites"). I'm considering the Alinco, since it does have 1.2 Ghz, and using the D72 for receive in that set up (but that still doesn't easily solve the wiring/connector mess for an external speaker/headphones for that radio).
Are there other radios which are more "external speaker" friendly which I should consider? I'm open to almost any combination of manufacturers (except for the Baofeng types for receive, as noted above). I'm even open to buying another D72 (but probably hoarding it except for special occasions.)
In short, what are your recommendations for a second, spare, radio for the FM birds?
I'm also curious how others have wired their single HTs - or two HTs - for demos using an external speaker. So if you could explain - with or without pictures - how you accomplish this, I'd appreciate it.
Thanks
Philip N4HF