UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - 4 Metre Converter

G6Tanuki · 3rd Dec 2017, 6:02 pm

There's actually quite a bit of activity on 70MHz: see http://www.70mhz.org/

It tends to divide into local/semi-local chat-nets on 70.26/70.45MHz using AM or FM and vertical omnidirectional antennas (where it's good for covering 100 miles or so if the terrain's not limiting) and the hardcore DX-types who run horizontally-polarised multi-element Yagis and use SSB/CW where they can work well into central-Europe when the weather's in their favour.

My only serious foray onto 70MHz used the repurposed front-end of a Dymar "Lynx 2000" lowband radiotelephone, feeding the 10.7MHz +/- 200KHz IF into an AR88. We used to listen on 70.31MHz for the Gdansk high-power FM broadcast transmitter to tell us if there was an 'opening' - that was back in the days when Soviet-controlled countries used something like 70-85MHz for their FM-broadcast band.

3rd Dec 2017, 6:02 pm	#12
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,996	Re: 4 Metre Converter - but which design? There's actually quite a bit of activity on 70MHz: see http://www.70mhz.org/ It tends to divide into local/semi-local chat-nets on 70.26/70.45MHz using AM or FM and vertical omnidirectional antennas (where it's good for covering 100 miles or so if the terrain's not limiting) and the hardcore DX-types who run horizontally-polarised multi-element Yagis and use SSB/CW where they can work well into central-Europe when the weather's in their favour. My only serious foray onto 70MHz used the repurposed front-end of a Dymar "Lynx 2000" lowband radiotelephone, feeding the 10.7MHz +/- 200KHz IF into an AR88. We used to listen on 70.31MHz for the Gdansk high-power FM broadcast transmitter to tell us if there was an 'opening' - that was back in the days when Soviet-controlled countries used something like 70-85MHz for their FM-broadcast band.