[Brian Reynolds]

Could the mic have the slightest bit of corrosion on the battery terminals?
Do you live in a humid location, has a battery gone flat and been left in the mic for a while, or do you permanently leave the battery in the mic for extended periods of time?

[Brian Reynolds]

I think you are getting bogged down with complexity, any communications system works on send and received principle, you just need to split them apart.

Telephone hybrids feed a signal ‘in’ instead of the mic and ‘out’ instead of the earpiece.

Mobile phones will work as a send / receive with a split cable.

A computer should work the same just think about a headset used sometimes with Skype, you just need to feed a mix-minus signal into the ‘mic in’ and your return should come out the ‘earphone out’ (you just need to get the signal levels right and block off any rouge DC on the mic input).

[Brian Reynolds]

Cat5 works better at line level over long distances.. Here is a link for some more info.
https://audio-video-supply.markertek.com/broadcasting/Insta-snake
OR you can make your own.

You have probably also found lead gowns used in theatres are great RF stoppers and the radio mic TX need to be placed above shoulder height to get any range at all.
The powered speaker we use in the theatre are (one only) Fostex or Yamaha personal monitors. They are more than enough for most productions. https://www.fostexinternational.com/docs/products/6301_Analogue.shtml or https://au.yamaha.com/en/products/proaudio/speakers/ms101iii/?mode=series

[Brian Reynolds]

A delay shouldn’t be a problem at all… its just getting the correct things going to the correct places.
Sometimes it can take a while to get your head around things.

Just a couple of other tips, if your cameras have SDI out its a great way to send the audio back as well.

CAT5 cable is able to carry 4 channels of analogue audio in either direction. (most hospitals have CAT 5 points all over the place)

[Brian Reynolds]

I have not used skype to do this but the principle is the same…

In LIVE News feeds etc for broadcast a ‘Mix-Minus’ is used, Let me explain…. From the studio a FULL mix is sent to the remote location MINUS what the remote is sending back to the studio….. and visa versa. In news broadcasts remotes often wear ‘in ear’ monitors but speakers can be used at a low- moderate level.
If a PA setup is required at the remote location the ‘presenters’ mic need to be mixed in at that remote location.

I have done many medical setups over the past few years with great success most of them are Q&A from a lecture hall (100+ people) to an active operating theatre.

In the lecture hall we normally have 1/2 podium mics and up to 2 roving radio mics and a lapel radio mic on the host person giving the lecture + other play out machines + the remote feed ALL going to PA via a small desk (Mackie style)
A feed of all the inputs of the desk are sent out via an AUX channel…. the remote incoming feed MUST NOT be sent back to the remote location.

At the remote end we use a small mixer 8 channel (mackie style), the normal mic set up might be 4 radio lapel mics, 1 hand held radio for introductions and a standby cable mic. ALL these mics are mixed to LEFT channel of the mixer with the pan control and this feed is sent to the lecture theatre.
The return audio (from the lecture hall) signal is brought into the mixer and panned to the RIGHT channel and this then goes to a small powered speaker out of the way in the operating theatre.
This set up enables every one in both the lecture hall and operating theatre to talk freely to each other.

[Brian Reynolds]

Is the SD card formatted?
Is the H4n in endurance mode? If it is, are your recording presets suitable for that mode?

[Brian Reynolds]

Did you do a scan for frequencies?

[Brian Reynolds]

https://rycote.com/images/uploads/technical_articles/Lyre_Technical_Notes_and_Graph.pdfhttps://www.rycote.com/products/softie_kit/softie_lyre_mount/

[Brian Reynolds]

Have you used the ‘Scan’ function?….. These days with the amount of RF around you really need to do a scan on every unit every time at every different location.

SCAN should be the most used function after the ‘On / Off” switch.

[Brian Reynolds]

There are other brands of adapters that would work fine like ‘BeachTek’ or ‘Juiced link’
The problem with an unbalanced cable is it might work fine 60% of the time but there will be other times it won’t. And you will never know unless you monitor the output of the camera or when you get to play it back…. And by then it’s often to late.
You maybe happy to accept the risk but as a person that makes a living from location sound I wouldn’t touch an unbalanced extension mic cable with a barge pole.