71 MHz - Revision history

M0YDH: /* Equipment for 71MHz DATV */ cost of a converter system

2022-09-09T19:24:13Z

Equipment for 71MHz DATV: cost of a converter system

M0YDH: /* Antennas */

2022-08-12T14:07:00Z

Antennas

M0YDH: /* Antennas */ 6m url too

2022-08-12T14:03:53Z

Antennas: 6m url too

M0YDH: /* Antennas */ revised URL

2022-08-12T14:02:06Z

Antennas: revised URL

M0YDH: /* Receiver */ M0YDH upconverter number 2

2022-08-12T13:46:26Z

Receiver: M0YDH upconverter number 2

G8GTZ: /* Receiver */

2020-02-16T17:23:19Z

Receiver

M0YDH: /* Equipment for 71MHz DATV */ filters link to page

2020-01-15T18:11:57Z

Equipment for 71MHz DATV: filters link to page

M0YDH: /* Equipment for 71MHz DATV */

2020-01-13T18:17:41Z

Equipment for 71MHz DATV

M0YDH: /* Receiver */ video of upconverter in action

2019-11-22T13:27:16Z

Receiver: video of upconverter in action

M0YDH at 19:07, 21 September 2019

2019-09-21T19:07:21Z

@@ Line 65: / Line 65: @@
 THis picture shows a later upconverter system built by M0YDH. Clockwise from bottom right:- 12V in and 5V regulated supply // BATC PIC card with program for 400MHz to control the sysnthesiser // ADF4351 synthesiser as LO // EBay 400- 470 MHz low pass filter // SPF5189Z amp // G0MJW upconverter card with -6dB attenuation// pair of G0MJW RF SPDT relay boards / The Normally Closed bypass line in SMA fittings. One switch on the unit front panel when turned on energises the upconverter. The other side of the plain PCB card has a Minitioune v1.5 mounted on it.
-[[File:M0YDH Upconverter.jpg|600px]]
+[[File:M0YDH Upconverter.jpg|600px]] The assembly shown cost about £85 to put together in 2022 [the ADF4351 was bought for £10 secondhand]
 ===Antennas===

@@ Line 70: / Line 70: @@
 Before buying or building a beam here are two low cost designs to get you onto the band
-) [https://sites.google.com/site/gw7aav2/70mhz(4metre)deltaloop A 4m delta loop by Steve GW7AAV]. David M0YDH made one of these some years ago for SOTA and it was a VSWR approaching 1:1 straight away. Old TV coax is used for the matching section. Electrical conduit is used for the boom [not flimsy waste water pipe!]. You could fasten two mini telescopic masts to a plastic bread board with pipe clamps to support the wire triangle. [https://sites.google.com/site/gw7aav2/50mhzdeltaloop There is a 6m version on the site too.] Also a combined pair of these antennas are shoen.
+) [https://sites.google.com/site/gw7aav2/70mhz(4metre)deltaloop A 4m delta loop by Steve GW7AAV]. David M0YDH made one of these some years ago for SOTA and it was a VSWR approaching 1:1 straight away. Old TV coax is used for the matching section. Electrical conduit is used for the boom [not flimsy waste water pipe!]. You could fasten two mini telescopic masts to a plastic bread board with pipe clamps to support the wire triangle. [https://sites.google.com/site/gw7aav2/50mhzdeltaloop There is a 6m version on the site too.] Also a combined pair of these antennas are shown on the 4m page.
 )[http://www.70mhz.org/coaxdipole.htm A centre-fed "co-axial" dipole for 4m by Tony G4CJZ] was built quickly be Noel G8GTZ with acceptable results to get on the band.

@@ Line 70: / Line 70: @@
 Before buying or building a beam here are two low cost designs to get you onto the band
-) [https://sites.google.com/site/gw7aav2/70mhz(4metre)deltaloop A 4m delta loop by Steve GW7AAV]. David M0YDH made one of these some years ago for SOTA and it was a VSWR approaching 1:1 straight away. Old TV coax is used for the matching section. Electrical conduit is used for the boom [not flimsy waste water pipe!]. You could fasten two mini telescopic masts to a plastic bread board with pipe clamps to support the wire triangle. There is a 6m version on the site too.
+) [https://sites.google.com/site/gw7aav2/70mhz(4metre)deltaloop A 4m delta loop by Steve GW7AAV]. David M0YDH made one of these some years ago for SOTA and it was a VSWR approaching 1:1 straight away. Old TV coax is used for the matching section. Electrical conduit is used for the boom [not flimsy waste water pipe!]. You could fasten two mini telescopic masts to a plastic bread board with pipe clamps to support the wire triangle. [https://sites.google.com/site/gw7aav2/50mhzdeltaloop There is a 6m version on the site too.] Also a combined pair of these antennas are shoen.
 )[http://www.70mhz.org/coaxdipole.htm A centre-fed "co-axial" dipole for 4m by Tony G4CJZ] was built quickly be Noel G8GTZ with acceptable results to get on the band.

@@ Line 70: / Line 70: @@
 Before buying or building a beam here are two low cost designs to get you onto the band
-) [https://sites.google.com/site/gw7aav/main-index/antenna-index/antenna-design/4m-delta Delta Loop by Steve GW7AAV]. David M0YDH made one of these some years ago for SOTA and it was a VSWR approaching 1:1 straight away. Old TV coax is used for the matching section. Electrical conduit is used for the boom [not flimsy waste water pipe!]. You could fasten two mini telescopic masts to a plastic bread board with pipe clamps to support the wire triangle. There is a 6m version on the site too.
+) [https://sites.google.com/site/gw7aav2/70mhz(4metre)deltaloop A 4m delta loop by Steve GW7AAV]. David M0YDH made one of these some years ago for SOTA and it was a VSWR approaching 1:1 straight away. Old TV coax is used for the matching section. Electrical conduit is used for the boom [not flimsy waste water pipe!]. You could fasten two mini telescopic masts to a plastic bread board with pipe clamps to support the wire triangle. There is a 6m version on the site too.
 )[http://www.70mhz.org/coaxdipole.htm A centre-fed "co-axial" dipole for 4m by Tony G4CJZ] was built quickly be Noel G8GTZ with acceptable results to get on the band.

← Older revision		Revision as of 13:46, 12 August 2022
Line 62:		Line 62:

	[https://youtu.be/D9r-Zb_YhsU A video of an upconverter in action by David M0YDH is here.]		[https://youtu.be/D9r-Zb_YhsU A video of an upconverter in action by David M0YDH is here.]
		+
		+	THis picture shows a later upconverter system built by M0YDH. Clockwise from bottom right:- 12V in and 5V regulated supply // BATC PIC card with program for 400MHz to control the sysnthesiser // ADF4351 synthesiser as LO // EBay 400- 470 MHz low pass filter // SPF5189Z amp // G0MJW upconverter card with -6dB attenuation// pair of G0MJW RF SPDT relay boards / The Normally Closed bypass line in SMA fittings. One switch on the unit front panel when turned on energises the upconverter. The other side of the plain PCB card has a Minitioune v1.5 mounted on it.
		+
		+	[[File:M0YDH Upconverter.jpg\|600px]]

	===Antennas===		===Antennas===

@@ Line 63: / Line 63: @@
 [https://youtu.be/D9r-Zb_YhsU A video of an upconverter in action by David M0YDH is here.]
-<u>Antennas</u><br />
+===Antennas===
 Before buying or building a beam here are two low cost designs to get you onto the band
@@ Line 70: / Line 70: @@
 )[http://www.70mhz.org/coaxdipole.htm A centre-fed "co-axial" dipole for 4m by Tony G4CJZ] was built quickly be Noel G8GTZ with acceptable results to get on the band.
-<u>Filters</u><br/>
+===Filters===
 These are in the [[70MHz_filters|Filters section of this Wiki]].

@@ Line 11: / Line 11: @@
 ===Transmitter===
+Portsdown 2018, Portsdown 2019 and DATV Express are all capable of DATV transmissions on 71MHz.
 ===Receiver===
 Notes for the G0MJW up-converter from CQ-TV260 are available here.
@@ Line 62: / Line 62: @@
 [https://youtu.be/D9r-Zb_YhsU A video of an upconverter in action by David M0YDH is here.]

← Older revision		Revision as of 13:27, 22 November 2019
Line 60:		Line 60:
	<br />		<br />
	[[File:BPFQ10.jpg\|400px]]		[[File:BPFQ10.jpg\|400px]]
		+
		+	[https://youtu.be/D9r-Zb_YhsU A video of an upconverter in action by David M0YDH is here.]

← Older revision		Revision as of 19:07, 21 September 2019
Line 24:		Line 24:
	In the parts list, there may be a bit of confusion over L11 and L15. L11 is only fitted if you are planning to send volts up the coax to provide the bias for the modamp. L15 is the RF choke for the modamp and should be fitted if the PGA103+ modamp is used. You can of course do without the modamp if you have an external pre-amplifier with sufficient gain. Ideally you would run this board just over 2V over the regulator voltage. Using the recommended 3.3V regulator 5V is marginal but probably fine. The PGA103+ takes up to around 100mA. With a 12V supply the regulator will get hot.		In the parts list, there may be a bit of confusion over L11 and L15. L11 is only fitted if you are planning to send volts up the coax to provide the bias for the modamp. L15 is the RF choke for the modamp and should be fitted if the PGA103+ modamp is used. You can of course do without the modamp if you have an external pre-amplifier with sufficient gain. Ideally you would run this board just over 2V over the regulator voltage. Using the recommended 3.3V regulator 5V is marginal but probably fine. The PGA103+ takes up to around 100mA. With a 12V supply the regulator will get hot.

−	The Mini-Circuits Mixer and MMIC amplifiers are stocked by [https://www.minikits.com.au/components/mini-circuits Mini-kits]although an email to Mini-Circuits sales in Surrey (sales@uk.minicircuits.com) would be a best first approach and avoid paying import duty. Update:- Mini-circuits UK advised that applications for EZ Samples of the PGA103+ and ADE-11X+ are acceptable for home constructors. Register with the Mini-Circuits website. Go to the page for one of these parts then press the EZ sample button on the right, fill out the application, reasons and objectives form, add the second item, do the export declaration and press send.	+	The Mini-Circuits Mixer and MMIC amplifiers are stocked by [https://www.minikits.com.au/components/mini-circuits Mini-kits]although an email to Mini-Circuits sales in Surrey (sales@uk.minicircuits.com) would be a best first approach and avoid paying import duty. Update:- Mini-circuits UK advised that applications for EZ Samples of the PGA103+ and ADE-11X+ are acceptable for home constructors. Register with the Mini-Circuits website. Go to the page for one of these parts then press the EZ sample button on the right, fill out the application, reasons and objectives form, add the second item, do the export declaration and press send. Free of charge components arrive a few days later!