Many thanks to SWLing Post contributor Dan Greenall, who writes:
Hi Thomas
Regarding your recent post on June 5: https://swling.com/blog/2025/06/twr-guam-to-end-broadcasting/
KTWR, Trans World Radio has recently announced they will be ending their shortwave broadcasts from Agana, Guam by October 31, 2025. However, unlike some stations that have vanished somewhat abruptly, there are still a few months remaining to log this station before they are gone from the airwaves forever. As well, with the help of various SDR’s located around the globe, this task should not be too difficult. The attached recording was made this past weekend on June 8, 2025, through the use of a Kiwi SDR located in northern Thailand on a frequency of 11965 kHz. At first, there is just background noise, but then, you will hear their transmitter come onto the air and power up for a few seconds. Their interval signal is played a number of times followed by sign on in English at 1100 hours UTC.
Audio Player73
Dan Greenall, Ontario, Canada
The cost of a new HF transmitter is now prohibitive expect for government owned stations. There is currently a 2 year wait and a minimum $2,000,000 price tag. And where will you find the engineers? Im fully aware of the transmitters you mentioned.
KTWR is facing three major realities. First, the cost of living on Guam has gotten prohibitive for a non-profit. Second, they are facing the sad reality that the personnel needed to operate, maintain, and repair high-powered shortwave are dwindling and aging out of the industry. There are no schools or training grounds as in decades past to replace them. Qualified engineers are becoming an extinct species. Third, the number of equipment manufactures has shrunk significantly and certain parts have become extremely expensive or unobtainable. In addition, there is no manufacturer that makes a solid state options in these power levels for shortwave. Sadly, the saga at KTWR is going to become more prevalent in the not too distant future as it already has for other station.
I don’t know that the situation is quite as black as you paint.
There are two manufacturers of high powered high frequency transmitters
https://www.contelec.com/shortwave/ and https://ampegon.com/shortwave-transmitters/ You will note that these models only have one tube. per high power transmitters. Ampegon also makes high powered electronics for scientific and defence industries.
Radio New Zealand Pacific installed a new Ampegon last year. It is the only way to cover large areas where disasters occur often. As they sound with volcanic activity in Tonga satellite signals do not penetrate ash clouds or hurricane rain clouds and undersea fibre optic cables can be cut by volcanic activity. This is also true of Papua New Guinea, which also has rugged terrain with jungle. Now they may also install one.
Oh the receiver side Software Designed Radios which include the high frequency band are virtually the same price to manufacture 2h3n compared to their MF/VHF FM cousins There is more than one manufacturer of SDRs excluding those making mobile phones which are SDR designs.
China has extensive domestic HF broadcasting and will soon include it in new cars for domestic consumption witch will include their own digital radio standard in the VHF band..