Bluetooth and ham radio - Page 1
Forum section: electronics / rf-microwave

author: bob91343
author_rank: Super Contributor
timestamp: April 04, 2020, 06:20:52 am
content: Recently I got a bluetooth adapter for my hearing aids. It works with my cellphone but what I want to do is listen to my transceiver (not a modern one already so equipped) on my hearing aids.I think what I need is called a bluetooth transmitter. Something with an audio input (and maybe a charging socket although I don't care if it's battery operated) and that will transmit to my hearing aid bluetooth adapter.What do I need to get, and what are the important parameters? I have heard that some units have a great amount of latency and I don't want that if I am in a QSO. I don't need long range, as I would use it while sitting in the shack.

author: 9aplus
author_rank: Regular Contributor
timestamp: April 04, 2020, 08:16:16 am
content: Other possible way is to use SDR panoramic adapter for your TRX anduse notebook PC bluetooth interface connected to your hearing aid.Some delay must exist, test with SdrGlut SW - latency is sustainable...

author: bob91343
author_rank: Super Contributor
timestamp: April 04, 2020, 07:24:59 pm
content: I don't want to put the transmitter over bluetooth, just the receive audio.What do you mean 'notebook PC bluetooth interface'? That's the device I want. How much latency can I expect? If you can give me links to a suitable unit I would appreciate it.The only connection to the radio would be the audio signal. The device would process that and send it via bluetooth to the hearing aid (after being paired). That way I can probably hear the radio better than I now do.

author: 9aplus
author_rank: Regular Contributor
timestamp: April 04, 2020, 09:29:02 pm
content: Most of modern notebooks have built in bluetooth interface.Go to Setings and Device Manager and find out about yours. (Win10)In case your PC have bluetooth you need to source IF or aux RX signal from yourtransceiver and add SDR receiver like panoramic adapter and sound path to yourhearing aid device over the PC and above mentioned bluetooth interface.1. check for bluetooth on PC2. check about present IF or aux RX outputs on your transceiver3. buy or borrow SDR can be even cheap rtl-sdr V3 usb dongle or something better like SDRPlay4. select SDR software you likeinstall all HW and SWand you can start to explore.... regarding delay, it depends on software and power of your PC butyou can be happy in case you reach less than one-one and half second delay.In regard to that delay, sometimes I am listening weak CW with headphones, left channel direct from receiver,right through SDR chain. In case I miss the letter, sometimes can recognize in second chance over the delayed SDR.Sorry my scope is not with me at the moment to measure exact timing of my system.At the moment my SDR RX system is quite complex, consist of ICOM PCR1000 + Lime SDR all goes through ethernetusing Soapy Remote not USB like usually but in that case I have less noise induced by PC.

author: bob91343
author_rank: Super Contributor
timestamp: April 04, 2020, 10:18:35 pm
content: I don't want to have a computer in this setup. I simply want to connect audio from transceiver to some device that sends signal to bluetooth adapter for my hearing aids.

author: 9aplus
author_rank: Regular Contributor
timestamp: April 05, 2020, 09:08:53 am
content: https://velvetsundown.com/best-bluetooth-transmitter/

author: bob91343
author_rank: Super Contributor
timestamp: April 05, 2020, 05:56:33 pm
content: That looks like an Amazon advertisement. But it does clarify some of my concerns so thanks for the link.I was hoping for something cheaper but maybe that's not to be. Nowhere does it quantify latency, one of my concerns. Also I wonder about the audio interface, the impedance and level needed for normal operation.

author: rcbuck
author_rank: Frequent Contributor
timestamp: April 09, 2020, 05:55:42 pm
content: I bought one of these a couple of months ago.https://www.ebay.com/itm/2-in-1-Bluetooth-5-0-Wireless-Audio-Aux-3-5mm-Adapter-Transmitter-and-Receiver/401042530359?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649I wanted to use it with bluetooth headphones to listen to TV since my hearing is slightly diminished. It works well except there is about 1/4 second latency so the audio isn't in sync with the person's lips. I tried to get used to it but it was too irritating and I gave up on bluetooth. I got one of the little cheap FM transmitters and receivers off of the auction site, about $10 total. That works fine as there is no latency and both units have batteries that recharge through USB.I think for ham usage the bluetooth would work fine with 1/4 second latency unless you are trying to work QSK (break-in) CW mode. For SSB it would be perfectly acceptable.

author: bob91343
author_rank: Super Contributor
timestamp: April 09, 2020, 09:56:56 pm
content: rcbuck that is the most useful response so far. Thanks for that, and I will check it out.Tell me more about the little transmitter and receiver. I have a transmitter something like that, used to send audio to a car stereo on the FM band. So all I need is an appropriate receiver, but still I'd like not to have to remove my hearing aids to use it. Right now I listen via the ham speaker with aids in and it's not as good as I'd like. I thought bluetooth might be the answer but maybe not.I don't need this setup for CW, as I hear well enough even without hearing aids to operate. But for SSB it can be a pain when the other guy is a bit mealy mouthed or there is a high noise level. There is a Japanese YL I have worked several times who has the world's worst articulation; other hams have had trouble undertanding her as well. Plus there is an Italian ham who speaks so poorly that even other Italians can't understand him.

author: rcbuck
author_rank: Frequent Contributor
timestamp: April 10, 2020, 03:28:46 am
content: I had a couple of details slightly incorrect on cost and power. It has been a couple of months since I hooked this up so I didn't remember that the transmitter requires a power supply. The receiver has a rechargeable battery and gives you about 4 hours of usage time. The transmitter requires a 5 volt power supply. I am using a wall wart that has a mini usb connector on it for power. Power has to be fed in on the USB connector. The 3.5 mm connector is for audio line input. I don't remember where I got the power supply but I think it was the battery charger for an old cell phone I had at one time. I'm sure they are readily available on the auction site.I bought this receiver and there are several sellers on the auction site.https://www.ebay.com/itm/Mini-Digital-Portable-Pocket-LCD-AM-FM-Radio-2-Band-Stereo-Receiver-w-Headphone/382435123299?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649I bought this transmitter, again several sellers.https://www.ebay.com/itm/FM-Transmitter-Digital-Module-DSP-PLL-Wireless-Stereo-Microphone-87-108MHz-New/272314811804?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649I live in Phoenix and most of the FM channels are occupied. The good thing about the receiver is it will tune down to 87.0 MHz. I have the transmitter and receiver set to 87.5 MHz which is below the FM band so I don't have to worry about interference from FM stations.

author: bob91343
author_rank: Super Contributor
timestamp: April 10, 2020, 05:06:08 am
content: I ordered a unit from China and when it gets here I will see how useful it is. It uses bluetooth 5.0 which is touted to have short latency.https://www.ebay.com/itm/bluetooth-5-0-Wireless-Receiver-Audio-Adapter-Transmitter-3-5mm-Music-AUX-Car/372725116786?ssPageName=STRK%3AMEBIDX%3AIT&var=641536409707&_trksid=p2057872.m2749.l2649I figure for the price it's worth a gamble. I just have to figure how to set up. I guess put the audio from the rig into it, as well as 5V power, then pair it with my hearing aid device.