Amateur Radio New Hobby For Winter ?

[PerdioPal]

"A loop is good, but are narrow band and need tuned at the loop," Untuned active loops are available such as the Wellbrook (of uncertain future) or home made Wellgood https://www.george-smart.co.uk/projects/wellgood-loop/ and the RSP series of SDRs (software external to the box, defined by it though) are very good and toe dippable from 1kHz to 1GHz, there is an overload warning and attenuator built in just in case.

[Mike Watterson]

Untuned loops are very poor and also can't be used for tx.

The wellbrrok is poor compared with any decent homemade tuned loop. Any loop needs designed for about 1:4 frequency range max and 1:3 is better..

The RSP series is about the cheapest decent SDR, but because it's not got RF tuning and is 14 bits, it's inferior to a 1970s to 1990s dual conversion superhet for 100 KHz to 30 MHz. A decent sound card can do SDR at VLF better. The RSP are immensely better than even the rarer 10 bit TV sticks (24 or 42 MHz to 1200 MHz and more a cheap spectrum display), but in absolute terms they are a basic budget model, not "very good" by professional standards, or compared to commercial main brand amateur gear.

I'd maybe have considered an RSP1B if I didn't have my FT817ND and only had the FT101ZD MkIII for HF. But I also have a VR500 and a VX5R and replaced the FT101ZD with the FTdx10 (a hybrid SDR with dual SDR, one for 1 MHz width spectrum display and the other 16 bit for Rx/TX, with an FPGA for the SDR.

The best use for the RSP1B on HF would be to drive it from the input (or output of 1st IF if RF on aerial is more than 75 MHz) to the 1st IF on an existing rig and then there is proper RF tuning, switchable pre-amps and attenuators, and coverage above half the sample rate without the doubtful downmixing by aliasing.. A 16 bit sound card with a filter is better for VLF and the coverage about about 75 MHz is relying on bandpass filters and downconversion by aliasing. That is indeed done on phone handsets / mobile modem / data links for 750 MHz to 6 GHz using ADI made ADCs that are clocked at 50 MHz to 200 MHz. I know someone who does the SW for those SDRs (on FPGAs for prototypes or low volume and ASIC for portable devices. ADI is 6 km up the road here and I know two people working there. They do also have PC based tools for development. The better systems are now 16 bit rather than 14 bit and some instead of two ADCs driven I & Q, used an array of psuedo-randomly connected ADCs to sample at 8 times the clock.

[Mike Watterson]

AN HF loop needs tune at the loop if in attic or on roof.
RX can use varicaps via DC on coax (via balun)
TX needs a motorised vacuum cap.
Typically 1 turn at 1m to 3m dia.

To reduce local electrical interference you need a screen earthed at the loop drive point and open circuit at the top. It need greater spacing from the loop as frequency increases as it look like a capacitance in parallel. At MW & LW you can use multiple turns of cat 5 / cat 6 (10 to 20), using each twisted pair as one wire. Thus a 10 turns coil has 40 turns when the wires are in series (x8 inductance) and 10 turns but higher Q when all four shorted twisted pairs are in parallel. Then it needs screened with two pieces of Alu. foil earthed at drive and open at top. You can use screened cat5, but the screen is only earthed at one end and only on LW as it is too much capacitance. The screen could double as an HF unscreened loop and one French LW/MW/SW VHF set had a large drum with two vertical coils at right angles instead of a ferrite rod. A knob on the set rotatated it. The finer more turns coil for LW. A third wire was an open helix around the drum, earthed on LW and MW, and optionally a SW aerial.
https://www.radiomuseum.org/r/schneider_..._1961.html

A Vidor valve portable with the beading is actually a tuned VHF loop. Only one of two UK AM/FM valve portables, the other was the Ever Ready.
https://www.radiomuseum.org/r/vidor_cn436cn_43.html
I forget how the LW & MW aerial works.

[bobhowe]

Hi Mike and PerdioPal thanks for advise kind regards Bob

[bobhowe]

Hi Bob
The first step is to study for the Foundation license go to Essex Ham and do their course it's by far the best.
Don't spend out on a new transceiver, if you are serious then look out for a older radio that covers HF from Yaesu or ICOM. 2 meters FM (145.200-145.550Mhz ) may be fairly busy in your area so again a cheap 2 meter radio is what to look out for this will give a far better feel of the hobby, while the SDR Play receivers are good you don't get the feel of amateur radio transceivers. Do Not be tempted to press the PTT button.
For 2 meters you need a suitable antenna, you could make a Slim Jim or a J pole or buy a Diamond X30 as an entry antenna, put up as high as you can and use 50 ohm coax, no old TV coax as it's lossy and 75 ohm.
For HF a long wire will do in the meantime.
If you need help give me a ring.

PS id not recommend the ELAD if you are serious, you'll get a brand new Xiegu G90 for the same price and it's power output is within the Foundation License conditions. Remember you will need a resonant antenna when you pass and start to transmit, power supplies, SWR meter and many other things, it's a rewarding hobby and you'll gain many friends.
Good luck.

Hi Trevor good to speak on the phone tonight I will send you some pictures of the Yaesu FT-480R when it arrives it needs cosmetic paint work but the vendor has assured me it works 100 % . Looked on the Essex Ham and as you say it is the far of the best . Should I join the RSGB ? thanks Trevor kind regards Bob

[Mike Watterson]

The RSGB is useful to exchange QSL cards. Radcom used to be very good (not had it for years, but kept all the back issues), which is why I joined for a year, but it's expensive outside the UK.

The FT-480 is quite old, but almost no vehicle / portable 2m only rigs now do SSB. DX VHF (which can be remarkable in a high pressure) often is SSB. Repeaters are usually FM, but some newer ones do any mode (inc digital).

A great find if the price was right and far better than any of the 2m only rigs I had. You can make a yagi for 2m SSB (usually horizontal). A watson 300 or similar ready to go vertical is best for FM repeaters, though in theory a 1/4 wave wire vertical in the attic can be easy to make and work well. The wire lengths will be about 90% of 1/4 wave at 145 MHz.

Essex area sounds good for Amateur activity. I've got as far as Belfast, Devon and Nottingham with 20W SSB on 2m on a horizontal 10 element Yagi from my QTH 9 km west of Limerick city centre. A small  amp on the FT817ND, but in the attic near aerial on gable so as to not lose power in the long feed cable.

Aerial array nearly 20 years ago now gone due to failure of TV aerial rotater.
   
Originally only the vertical 10 element was on the pole, and horizontal. The 3rd aerial is 70cm.
You can just see the top of the Watson 300 on a pole on garden wall. It's dead now. Investigation revealed the internal ceramic cap had fractured. I've used the housing to make a 4m band whip, which with the FC40 remote "ATU" works on 14 MHz to 50 MHz for TX. I fitted a remote relay on the FC-40 o/p to select whip or long wire manually.


View from house some years ago
   
The council chopped down a lot of the trees on the edge of the field citing safety. We are just at the edge of the village and that view is across Limerick toward Tipperary, where those hills/mountains are. Keepers Hill is just behind. On a clear day you can see the edge of the Galties to the South East, and the Shannon makes a gap to the North East. Poor VHF to West as the ground and houses rise just behind.

I have plans to put up a S/H rebuilt bigger X yagi intended for circular polarisation only, but with two feeds so a box stuffed with 50 and 75 Ohm lengths and a six way switch can do | — \ and / as well as LH and RH circular.
Vertical or horizontal can switch polarisation on a very long path or a reflection. The | or — can become closer to \ or / on a long tropospheric path.

I'm not as young as I was so waiting for an assistant! I have also a stronger refurbished rotater.

[PerdioPal]

Untuned loops are worse than a tuned one at that frequency, for wideband use they are fine for HF where the atmospheric noise is larger than the antenna noise. They do match an SDR for HF and low VHF work very well.
I would love a 10kHz to 1GHz log periodic, money and space prohibit this ;-) meanwhile I am more than happy with my SDRs and loop antenna, the beat bit is it is visual as well as sound. BTW the RSP line have input filters, just band pass and stop (for the "loud" bands) and do work surprising well for but a sprinkle of very small SMT (surface mount) components.

A proper tuned antenna and radio will (may?) give better performance on one frequency (or nearby). The visual bit of an SDR is still fascinating and quite often I just look at that without audio (stops the missus missing the TV). And they are on the (home) network, I can enjoy from anywhere in the house on a laptop or tablet.

Don't underestimate the new SDRs they are pretty good.

[Mike Watterson]

You'd want several log periodics for 14 MHz to 40 MHz, one for 30 to 150 is large. And then 150 to 400, 400 to 1.2 GHz.
I've seen a big one on a USA embassy roof that looked like part of HF to low VHF.
The Band III only log periodics common here and Band III ended 2012.

10 KHz to 7 or 14 MHz better served by multiple loops.

An untuned HF loop is only good for a coarse wideband spectrum display. I had an HP 141T with 100MHz , 1 GHz and 10 GHz approx plugins. Replaced with a Rigol 9 kHz to 1.5GHz analyser with Tracking Gen (works as sig gen if span = 0). https://www.amazon.de/-/en/dp/B00CLWJA38 You do need to tune an HF loop for actual reception and it's simple.
At zero span you can use the Rigol as an AM or FM radio (has a headphone jack!) at 9kHz to 1.5 GHz. I could have bought the 3.5 GHz version, but it's nearly x2 price and I hardly need more than 450 MHz. Maybe 1.2GHz

Even to get one long wire rather than two working on 1.8 MHz to 30MHz with a match box (ATU) is tricky. Most will not tune (really match) 1/2 wave or integer multiple, though something around the 20m (but not electrically 20m) seems to work even at 50 MHz. I have a flagpole (if anyone asks) at the front gate and a long-wire to back of roof via plastic stand off on the chimney. I did have the remote FC-40 on the roof, but it's moved into the attic this week. However something has gone wrong with the home made vertical for 70MHz (4m) supposedly matched using a nanoVNA. It's working too well on 14 MHz to 50 MHz via FC-40 and about 5:1 on 70 MHz. I connected the VNA with rig on and used remote relay for whip, and the nano-VNA confirms that. So it needs examined. I suspect connection bad at base or connector and that the random coax to it is radiating.

[Mike Watterson]

I seriously considered a 30 MHz to 70 MHz logperiodic, but it would be huge and boom about 4.5m long, minimum
A 50 MHz to 150 MHz (or 440 MHz) log periodic is nearly as big.

Also you can't do a colinear that's 50 + 70, or 70 +145 MHz., yet 28, 50, 145, 435 MHz is possible, though not great.

A 5/8ths CB silverstick (adjusted) with base loading coil can work 1.8 MHz to 50 MHz with a military whip matchbox, but only about 7 MHz to 50 MHz with any Amateur ATU.

I got rid of the two military HF rigs (Racal), one portable 20W with 6' or 8' whip and one 200 W base running only off AC mains, but I have two sets of military aerials still, one is 80 MHz vertical dipole with pole and guys (OK at 70 MHz) and one is a double discone (biconical) using 4x mil whips for top and 4 guys insulated at base for bottom. Work 14MHz to 50 MHz no tuning and will work at 70 MHz 144 MHz with marginal SWR, matching to 3.5 MHz if coax is short.

[Cleggy]

Untuned loops are very poor and also can't be used for tx.

The wellbrrok is poor compared with any decent homemade tuned loop. 

Could you point us in the direction for a published design for a good homemade tuned loop? I've spotted a few in the past, but cannot say I've heard much discussion about them.

I have a Wellgood version of the Wellbrook. On 80m, signal strength was only slightly down compared with the Inverted V I had and the noise level was well down.

C