chris451rr
Member
I have a cushman ce-24e frequency selective level meter.
It tunes from 0k to 5mhz, and has a level attenuator from -80 to +10, and a meter from +2 to -20dbm. This one has a 3.1khz filter which provides USB LSB and a narrow filter that provides 45hz bandwith. It has balanced or unbalanced input with impedance of 75 to 600 ohms selectable.
I tried small wire loops with it but these were very noisy. I built a 6foot diameter
'shielded loop' out of 75 ohm coax. Its fed with a tv 300 balun (pretty poor at LW).
The feed is 75 ohm coax to the balun. The loop is two coaxes with the centers fed to each side of the balun, with the shields grounded to the coax. The top is where a split is done and the centers and shields are crossed over. Thus it gets rid of all E field noise.
It had to be hung a few feed in the air to pick up two good reference signals, Navy at 25khz FSK and wwvb at 60Khz on off keyed. I have not heard differential GPS at 311khz maybe its shut off now.
A clock app was located that decodes WWVB which is keyed on'off with BCD pattern of time code.
I tune wwvb so its 60khz comes out at 930hz and set the decoder app to that signal, and its decoding the WWVB Time. The name of the app is multipsk by f6cte. He is a real software wizard. The sound card of the pc was fed from the cushman and its decoding wwvb fine. It is much stronger at night, the day absorbtion must be pretty bad at LF.
There are some of these cushmans on Ebay. It has a volume control and speaker, 1/4" jack, A digital counter freq display, a 10/100hz res switch, a lock switch so it can be stabilized, a coarse tune and fine and super fine tune. This is not about the tecsun but I have 3 of them the PL365 PL368, use them so much they are worn out, great little radio but it quits at 153khz and misses the VLF signals available here in central USA. I do not pick up any more NDB signals, nor the military 125khz, nor the loran 100khz any more.
Used to pick up 100khz loran on the Icom HF rigs.
So the cushman which is a microwave link tester works great as a LW VLF receiver, only thing its missing is am mode. To hear the MW stations just zero beat the tuner.
This cushman came from a power company that upgraded the system, but some are for sale on the internet, worth a look! Great way to sample VLF.
It tunes from 0k to 5mhz, and has a level attenuator from -80 to +10, and a meter from +2 to -20dbm. This one has a 3.1khz filter which provides USB LSB and a narrow filter that provides 45hz bandwith. It has balanced or unbalanced input with impedance of 75 to 600 ohms selectable.
I tried small wire loops with it but these were very noisy. I built a 6foot diameter
'shielded loop' out of 75 ohm coax. Its fed with a tv 300 balun (pretty poor at LW).
The feed is 75 ohm coax to the balun. The loop is two coaxes with the centers fed to each side of the balun, with the shields grounded to the coax. The top is where a split is done and the centers and shields are crossed over. Thus it gets rid of all E field noise.
It had to be hung a few feed in the air to pick up two good reference signals, Navy at 25khz FSK and wwvb at 60Khz on off keyed. I have not heard differential GPS at 311khz maybe its shut off now.
A clock app was located that decodes WWVB which is keyed on'off with BCD pattern of time code.
I tune wwvb so its 60khz comes out at 930hz and set the decoder app to that signal, and its decoding the WWVB Time. The name of the app is multipsk by f6cte. He is a real software wizard. The sound card of the pc was fed from the cushman and its decoding wwvb fine. It is much stronger at night, the day absorbtion must be pretty bad at LF.
There are some of these cushmans on Ebay. It has a volume control and speaker, 1/4" jack, A digital counter freq display, a 10/100hz res switch, a lock switch so it can be stabilized, a coarse tune and fine and super fine tune. This is not about the tecsun but I have 3 of them the PL365 PL368, use them so much they are worn out, great little radio but it quits at 153khz and misses the VLF signals available here in central USA. I do not pick up any more NDB signals, nor the military 125khz, nor the loran 100khz any more.
Used to pick up 100khz loran on the Icom HF rigs.
So the cushman which is a microwave link tester works great as a LW VLF receiver, only thing its missing is am mode. To hear the MW stations just zero beat the tuner.
This cushman came from a power company that upgraded the system, but some are for sale on the internet, worth a look! Great way to sample VLF.
